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    California Apportionment Case Law Outline (January 2025 Edition) 

Editor: Raymond F. Correio, Senior Associate, Pearlman, Brown & Wax,  LLP; Workers’ Compensation Judge (retired); Prior editions dated July  2024; January 2024; July 2023, January 2023, July 2022, January 2022,  July 2021, January 2021, July 2020, January 2020, July 2019, January  2019, January 2017, (110 pages), April 2013 (67 pages), and January 2011  (120 pages) can be found at: https://www.pbw-law.com under the  “Resources” tab. 

© Copyright 2025, All Rights Reserved. 

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TABLE OF CONTENTS 

  1. Fundamental Analytical Principles ………………………………… 3
  2. Age, Gender, and Genetics ………………………………….……….12 
  3. Risk Factors (Causation of Injury versus Causation of Permanent Disability)…………………..…………………………….30
  4. The AMA Guides: Disability versus Impairment….………………..41
  5. Petitions to Reopen/Vargas…………………..………………………46
  6. Benson…………………..………………………..…………..………54
  7. Medical Treatment and Apportionment………..…………..…………84
  8. Medical Evidence of Apportionment and Vocational Evidence……..99 
  1. Labor Code §4662(a) …………………..……………………..…….123 
  2. Labor Code 4662(b)……………………………………………….. 138   
  3. Labor Code 4663……………………………………………………140  
  4. Labor Code 4664……………………………………………………156 
  5. Range of Evidence…………………..……………………..……….175   
  6. Discovery…………………..……………………..…………………177 

  

NOTICE TO READERS 

The content of this case law summary is not intended to provide legal advice. Distribution and use  of this material is for educational use only and is not intended as consideration for future business.  This document is the property of Pearlman, Brown & Wax and may not be distributed without  express written permission.

  1. Fundamental Analytical Principles 

Introduction: 

In my 2013 Apportionment Case Law update I included for the first time a section dealing with  “fundamental analytical principles,” based on the working assumption that it would provide an  ongoing resource to the workers’ compensation community as a reference and guide dealing with  the critical underlying fundamental analytical concepts and principles related to Labor Code §4663  and Labor Code §4664, as well as a separate commentary on substantial medical evidence and  correct legal standards. In subsequent outlines I intentionally eliminated or removed this section  based on the belief that most, if not all, workers’ compensation practitioners, judges, and  evaluating physicians for the most part understood the basic fundamental analytical principles and  concepts underlying the radical change in the law of apportionment effectuated by the passage of  SB899 and Labor Code §§4663 and 4664.  

However, in the intervening years since 2013, and after my review and analysis of numerous recent  apportionment cases, it is abundantly clear that a significant number of practitioners and evaluating  physicians still do not fully comprehend the fundamental core analytical principles and concepts  essential to understanding the correct application of Labor Code §§4663 and 4664 and related  substantial medical evidence standards. 

Graphic examples to support my decision to include this section once again in the outline are  exemplified by numerous cases that clearly show there is what appears to be a continuing and  unabated widespread misunderstanding of the fundamental principles underlying Labor Code  §§4663 and 4664. In the case of Caires v. Sharp Health Care (2014) Cal.Wrk.Comp. P.D. LEXIS  145 (WCAB panel decision), three different evaluating physicians in the same case all failed to  demonstrate a basic understanding of the core concepts and principles related to Labor Code §4663  apportionment. What is striking about the Caires case is the fact the apportionment issue was  fairly straightforward, involving whether or not there was valid legal apportionment related to  preexisting degenerative conditions. Caires also deals with an important issue related to whether  the AMA Guides can be used by reporting physicians to determine valid legal apportionment under  Labor Code §§4663 & 4664.  

Perhaps a more graphic example is the case of Pattiz v. SCIF/MTC Trucking, Inc. 2015  Cal.Wrk.Comp. P.D. LEXIS 541, 43 CWCR 201, in which a workers’ compensation judge in  issuing a joint Findings of Fact and Award in two cases incorrectly dealt with four separate  apportionment issues in the same case, including Benson, Labor Code §4663 nonindustrial  apportionment, the interaction of medical evidence of apportionment and vocational evidence, and  finally erroneously construed and applied the Labor Code §4662(b) determination of permanent  total disability “in accordance with the fact.” (sic). The fact that a judge ten years after the passage 

of SB899 and Labor Code §§4663 and 4664 could render an incorrect and erroneous decision on  a “quartet” of apportionment issues in a single case is troublesome. In Pattiz, the WCAB granted  defendant’s Petition for Reconsideration and rescinded the WCJ’s Award. These cases and similar  cases underscore the fact that the core concepts, standards, and fundamental analytical principles  underlying Labor Code §§4663 and 4664 require continued and repeated reemphasis. 

Labor Code Section 4663 

The following are three critical portions or provisions of Labor Code Section 4663 as enacted by  SB 899 on April 19, 2004: 

(a) Apportionment of permanent disability shall be based on causation.  

(b) Any physician who prepares a report addressing the issue of permanent  disability due to a claimed industrial injury shall in that report address the  issue of causation of the permanent disability. 

(c) “…A physician shall make an apportionment determination by finding what  approximate percentage of the permanent disability was caused by the direct  result of injury arising out of and occurring in the course of employment  and what approximate percentage of the permanent disability was caused  by other factors both before and subsequent to the industrial injury,  including prior industrial injuries.” 

Comments: As reflected in the cases in the outline dealing with causation of injury, AOE/COE  as opposed to causation of impairment or disability, Labor Code Section 4663 deals only with  causation of permanent disability and not causation of injury. 

The other significant issue is the net cast by Labor Code Section 4663 is extremely broad in terms  of what may constitute legal apportionment. You will note the reference to “other factors” and not  just to injuries or disability. The term “factors” is much broader than an injury whether that injury  occurred prior to or subsequent to the industrial injury in question. The critical legal and medical  questions to be resolved are to determine all the contributing causal factors of the applicant’s  permanent disability and impairment at the time of the MMI evaluation(s) in any case. A “factor”  or “factors” that can be a contributing cause of impairment or disability are myriad and contingent  on the specific medical record and facts. For example, in a psychiatric case, as indicated by cases  in the outline, a “factor” contributing to an applicant’s psychiatric impairment or disability may be  a pre-existing personality disorder or other mental condition that is a contributing cause of the  applicant’s current psychiatric or psychological disability. As is also demonstrated repeatedly in  the outline, a contributing “factor” to disability can be an asymptomatic pre-existing condition so 

long as that condition is a contributing cause or factor of the applicant’s present disability, i.e.,  making it worse than it would have been without the underlying causative factor.  

Radical Change 

Labor Code Section 4663 has been described in terms of its impact and change on pre-existing  apportionment law as “radical”, “a diametrical change”, and a “new regime”.  

From a historical perspective, it must be kept in mind that from 1932 to 1968, a period of 36 years,  the law of apportionment in California was basically the same as it is currently under SB 899, as  reflected in Labor Code Sections 4663 and 4664. For the period of 1968 to the enactment of SB  899 in 2004, a span of another 36 years, there was basically very little opportunity for a defendant  to obtain valid Labor Code Section 4663 apportionment since the case law during this period  essentially placed the burden on defendant to establish injuries and other factors that were labor  disabling as a basis for valid legal apportionment. From 1968 to 2004, there was no valid basis  for apportionment to pre-existing pathology and other factors that may have been a contributing  cause of the ultimate disability in a case if that contributing factor was not labor disabling in and  of itself. 

The California Supreme Court in Brodie v. WCAB (2007) 40 Cal. 4th 1313, 72 Cal Comp. Cases  565 discussed in detail the new “regime” of apportionment based on causation. The Brodie Court  discussed the distinction and differences in pre-SB 899 Labor Code Section 4663 apportionment  and post-SB 899 Labor Code Section 4663 apportionment as follows: 

Until 2004, former section 4663 and case law interpreting the workers’  compensation scheme closely circumscribed the basis for apportionment.  Apportionment based on causation was prohibited. (Pullman Kellogg v. WCAB (1980) 26 Cal. 3d 450, 454, 45 Cal. Comp. Cases 170) 

Under these rules, in case after case courts properly rejected apportionment of a  single disability with multiple causes (See, e.g., Pullman Kellogg v. WCAB, supra,  26 Cal. 3d at pp 454-455) no apportionment of lung injury between industrial  inhalation of toxic fumes and nonindustrial pack-a-day smoking habit]; Zemke v.  WCAB (1968) 68 Cal. 2d 794, 796-799, 33 Cal. Comp. Cases 358] [no  apportionment of back disability between industrial back injury and nonindustrial  arthritis]; Berry v. WCAB (1968) 68 Cal. 2d. 786, 788-790, 33 Cal. Comp. Cases  352] [no apportionment of knee disability where industrial knee injury triggered  “advancement” of previously dormant nonindustrial fungal disease]; Idaho  Maryland etc. Corp. v. IAC (1951) 104 Cal. App. 2d 567, 16 Cal. Comp. Cases  146] [no apportionment between industrial exposure to mine gas and nonindustrial  latent heart disease].” In short, so long as the industrial cause was a but-for

proximate cause of the disability, the employer would be liable for the entire  disability without apportionment. 

The Supreme Court, in contrasting current Labor Code Section 4663 with previous apportionment  law and principles under Labor Code Section 4663, the Court stated: 

The plain language of sections 4663 and 4664 demonstrates they were intended to  reverse these features of former sections 4663 and 4750. (Kleeman v. WCAB (2005)  127 Cal. App. 4th 274, 284-285, 70 Cal. Comp. Cases 133.) Thus, new sections  4663, subdivision (a) and 4664, subdivision (a) eliminates the bar against  apportionment based on pathology and asymptomatic causes. (E.L. Yeager  Construction v. WCAB (Gatten) (2006) 145 Cal. App. 4th 922, 71 Cal. Comp. Cases  1687; Escobedo v. Marshalls (2005) 70 Cal. Comp. Cases 604,617 (en banc)) 

Perhaps the most insightful comment or characterization the Supreme Court indicated in the Brodie decision as to the fundamental principle of applying Labor Code Section 4663 as enacted under  SB 899 was as follows: 

“…the new approach to apportionment is to look at the current disability and parcel  out its causative sources, nonindustrial prior industrial, current industrial, and  decide the amount directly caused by the current industrial source. This approach  requires thorough consideration of past injuries, not disregard of them.” 

Perhaps another way of characterizing the fundamental principles of new Labor Code Section 4663  in terms of causation of impairment is that in Brodie, Escobedo, and Gatten a reporting physician  under Labor Code Section 4663 must give an opinion and the WCAB to make a finding, on what  percentage of applicant’s current overall permanent disability is attributable to each contributing  cause industrial or non-industrial. As recognized by the Brodie court, multiple causes frequently  interact to cause permanent disability. In essence, the purpose of apportionment is to limit the  employer’s liability to that percentage of actual permanent disability caused by the industrial  injury, not to determine what the level of permanent disability would have been absent the non industrial cause. 

Basically, Labor Code Section 4663 comports with logic, common sense, and medicine in that  with respect to any disability or impairment there may be multiple contributing causes and not one  cause. These fundamental principles and concepts must be understood and applied by physicians,  lawyers, WCJs as well as the WCAB and the Court of Appeal. 

Given the radical change in apportionment under new Labor Code Section 4663, it was  understandable that immediately after the enactment of SB 899 there was a very unsettled period 

of time when both the applicant’s and defense bar expounded different theories and concepts as to  the meaning of Labor Code Section 4663 and how it should be applied. 

It was not until the WCAB issued its en banc decision Escobedo that the workers’ compensation  community had any clear guidance on how the new apportionment statutes should be implemented.  In Escobedo (2005) 70 CCC 604, the WCAB basically provided an analytical roadmap as to the  construction and application of the new apportionment statutes. However, a careful review of  numerous WCAB panel decisions in the immediate aftermath of the Escobedo en banc decision  demonstrated that both WCJs and the WCAB began to fully comprehend the dramatic and  sometimes harsh impact Labor Code Section 4663 would have on many cases. Unfortunately,  many of these early panel decisions and even recent decisions from line WCJs and the WCAB  continue to mistakenly apply the pre-SB 899 requirement that there had to be an injury or a factor  that was labor disabling in order to have valid apportionment under new Labor Code Section 4663.  (See, City of Petaluma et al., v. WCAB (Lindh) 2018 Cal.App. LEXIS 1137, at page 31 of this  outline as a prime example). 

And again in E.L. Yeager Construction v. WCAB (Gatten) (2006) 145 Cal. App. 4th 922, 71 CCC  1687 the Court reversed the WCAB reminding the Board of their own earlier en banc decision in  Escobedo and reaffirming the correct legal standards and principles in applying Labor Code  Section 4663 apportionment. 

The most significant case, as discussed hereinabove, was the California Supreme Court’s decision  in Brodie in 2007. (Brodie v. WCAB (2007) 40 Cal. 4th 1313, 72 Cal. Comp. Cases 565) The  California Supreme Court articulated a number of core principles with respect to their analysis of  Labor Code Section 4663, distinguishing and differentiating it from pre-SB 899 apportionment  law and principles.  

Labor Code §4664 

Labor Code §4664 has three critical provisions.  

Labor Code §4664(a) provides as follows: “the employer shall only be liable for the percentage of  permanent disability directly caused by the injury arising out of and occurring in the course of  employment.” 

Labor Code §4664(b) provides as follows: 

If the applicant has received a prior award of permanent disability, it shall be  conclusively presumed that the prior permanent disability exists at the time of any  subsequent industrial injury. This presumption is a presumption affecting the  burden of proof.

Labor Code §4664(c)(1) provides as follows: 

The accumulation of all permanent disability awards issued with respect to any one  region of the body in favor of one individual employee shall not exceed 100% over  the employee’s lifetime unless the employee’s injury or illness is conclusively  presumed to be total in character pursuant to §4662. As used in this section, the  regions of the body are the following: 

(A) Hearing. 

(B) Vision. 

(C) Mental and behavioral disorders. 

(D) The spine. 

(E) The upper extremities, including the shoulders. 

(F) The lower extremities, including the hip joints. 

(G) The head, face, cardiovascular system, respiratory system and all  other systems or regions of body not listed in sub paragraphs (a) to  

(f), inclusive. 

Labor Code §4664(c)(2) provides as follows “Nothing in this section shall be construed to permit  the permanent disability rating for each individual injury sustained by an employee arising from  the same industrial accident when added together from exceeding 100%.  

Comment: Subsequent to the enactment of Labor Code §4664, most employers and defendants  focused on Labor Code §4664(b) related to the conclusive presumption afforded/accorded to prior  awards of permanent disability. Unfortunately, through evolving case law, what appeared to be a  relatively straight forward concept became a quagmire related to burden of proof as to what  constitutes an award and defendant’s burden to prove overlapping factors of disability related to  prior awards.  

For example, many defendants and employers thought that if an applicant had a prior Findings &  Award or Stipulated Award to the lumbar spine of 25% under the 1997 Permanent Disability  Rating Schedule, and then suffered a subsequent injury to the lumbar spine under the AMA Guides  of 30% after adjustment for age and occupation, they would be entitled to a conclusive presumption  that the prior permanent disability, i.e., the 25% award existed at the time of the subsequent or  second injury. 

However, in 2006 the Court of Appeal in Kopping v. WCAB (2006) 142 Cal. App.4th 1099; 71  CCC 1229, in a well-reasoned decision held that with respect to Labor Code §4664(b) defendants  faced a difficult burden of proof. In Kopping, the Court of Appeal held that in each and every case 

involving Labor Code §4664(b), the defendant has the dual burden of proving the existence of a  prior award and more importantly the additional burden of proving the overlap of factors of  disability between the prior award and the current award.  

As set forth in the primary apportionment outline, dealing with cases up to 2011, under the section  dealing with overlap issues (burden of proof) and in this supplemental outline, defendants in case  after case have been basically unable except in a few unique cases, to meet their burden with  respect to proving or showing the overlap of factors of disability between a prior award under the  1997 Permanent Disability Rating Schedule and the 2005 Permanent Disability Rating Schedule.  However, the longer Labor Code §4664(b) remains in effect, the burden of proving overlapping  factors of disability will diminish since there will be a prior award under the same Permanent  Disability Rating Schedule, i.e., under the 2005 PDRS/AMA Guides. If there is an award and  disability is determined under the 2005 Permanent Disability Rating Schedule, and there is a  successive or later injury also under the 2005 Permanent Disability Rating Schedule/AMA Guides,  then defendant will have a much easier time proving overlapping factors of disability.  

Statutory Construction 

Labor Code section 3202’s requirement that workers’ compensation statutes be liberally construed  in favor of injured workers cannot supplant legislative intent as expressed in particular statutes  such as Labor Code sections 4663 and 4664. Davis v. Workers’ Comp. Appeals Bd. 145 Cal.  App.4th 324, 51 Cal.Rptr.3d 605, 2006 Cal.App. LEXIS 1893, review granted, depublished,  (2/14/07), 55 Cal.Rptr.3d 715, 153 P.3d 282, 2007 Cal. LEXIS 1481, review granted, depublished,  (4/4/07), 60 Cal. Rptr. 3d 31, 159 P.3d 507, 2007 Cal. LEXIS 3595. [See generally Hanna, Cal.Law  of Emp. Inj. And Workers’ Comp. 2d, sections 8.05[1], 8.07[2][d][i].]  

Substantial Medical Evidence and Correct Legal Standards  

As reflected and manifested in many of the decisions in this outline, reports from physicians  whether they are AMEs, primary treating physicians, QMEs, or SPQMEs repeatedly fail to apply  the correct legal standards with respect to apportionment determinations as outlined by the  California Supreme Court in Brodie, by the Court of Appeal in a certified for publication case in  Gatten, and the WCAB in their en banc decision in Escobedo. 

In terms of assessing and evaluating a physician’s opinion on apportionment it is critical to  determine whether or not the physician has applied the correct legal standard or standards as  articulated by the courts in the above referenced cases. In Gay v. WCAB (1979) 96 Cal. App. 3rd 555; 44 CCC 817, the Court stated, “physicians in workers’ compensation matters must  accordingly be educated by the parties of the correct legal standards.” It needs to be emphasized  repeatedly that physicians in workers’ compensation matters write “medical-legal reports” not just 

medical reports. Consequently, reporting physicians must understand and apply the correct legal  standards and principles in order to render an opinion that constitutes substantial medical evidence  whether that opinion is manifested in the form of a report or during a deposition. “A medical  opinion that refuses to accept correct legal principles does not constitute substantial medical  evidence.” (Hegglin v. WCAB (1971) 4 Cal. 3d 162; 36 CCC 93; Zemke v. WCAB (1968) 68 Cal.  2d 794, 33 CCC 358) 

In Cordova v. Sacramento Metropolitan Fire Dist., 2024 Cal.Wrk.Comp. P.D. LEXIS 329 based  on a petition by defendant for an Order for Replacement Panel, the WCAB found it was reasonable  and necessary for another QME evaluation in psychology and ordered the Medical Director to  issue a panel of QME’s in the field of psychology to replace the initial reporting QME in  psychology. There were multiple reasons articulated by the WCJ and the WCAB as to why a  multiplicity of actions of the first QME in psychology “significantly eroded the confidence of the  parties and the WCJ in the QME’s neutrality and impartiality.” Moreover, “[o]f central import to  the WCJ’s decision was the question of whether the QME would apply a correct theory of  apportionment to his analysis. The WCJ’s report observes that in his deposition, the QME stated  that unless a nonindustrial condition or factor of apportionment is symptomatic, “it doesn’t exist.” The QME was unwilling to apply a correct legal theory of apportionment that was mandated by  both applicable statutory and case law by refusing to apply apportionment based on preexisting  pathology unless the pathology was labor disabling or symptomatic before the current industrial  injury. 

In order for a medical report to constitute substantial evidence on the issue of apportionment, a  medical opinion “must disclose familiarity with the concepts of apportionment, describe in detail  the exact nature of the apportionable disability, and set forth the basis for the opinion.” (E.L.  Yeager Construction v. WCAB (Gatten) (2006) 145 Cal. App. 4th 992, 71 CCC 1687) A medical  opinion based upon an incorrect legal theory is not substantial medical evidence (Hegglin v. WCAB (1971) 4 Cal. 3d 162, 36 CCC 93; Place v. WCAB (1970) 3 Cal. 3d 372, 35 CCC 525)  

Also in Blackledge v. Bank of America (2010) 75 CCC 613, in footnote 10, the WCAB again  emphasized it was the duty of the parties to educate reporting physicians as to the utilization of the  correct legal standards in every single case. Thus, it is important for every evaluating physician  to understand all pertinent legal concepts so they may correctly apply those standards to the  specific facts of each case.  

In terms of reasonable medical probability and substantial evidence, the Court of Appeal in Gay  v. WCAB stated: 

We do not comprehend how the parties can expect any physician to properly report  in workers’ compensation matters unless he is advised of the controlling legal 

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principles. Physicians are trained to discover the etiology of an illness. Finding  the cause is important in preventative medicine and curing illness once developed.  Legal apportionment is not identical to theories of medical causation.  Physicians in workers’ compensation matters must accordingly be educated by the  parties in the correct legal standards of apportionment. (Emphasis added) 

Labor Code section 4663(c) also indicates that a physician in making an apportionment  determination may use an “approximate” percentage in determining industrial causes of permanent  disability and non-industrial contributing causal factors. The fact a doctor makes an “estimate” or  “approximation” does not render the opinion speculative. 

As stated in Anderson v. W.C.A.B. (2007) 149 Cal. App.4th, 1369, 72 Cal.Comp.  Cases 389, 398, the fact that “percentages [of causation of permanent disability that  the physician] provided are approximations that are not precise and require some  intuition and medical judgment…does not mean his conclusions are speculative  [where the physician] stated the factual bases (sic) for his determinations based on  his medical expertise.” 

See also, Utsey v National Courier Systems et al., 2024 Cal.Wrk.Comp. P.D. LEXIS 105 (WCAB  panel decision); City of Oakland v. WCAB (Utsey) (2024) 89 Cal.Comp.Cases 890 (writ denied).  In Utsey in a split panel decision both the WCJ and the WCAB found applicant to be 100% PTD  without apportionment under LC 4663 or under Benson related to three separate and consecutive  injuries. Commissioner Razo in dissent argued that the WCJ and the WCAB majority were  applying an incorrect legal standard of “scientific certainty” rather than an “approximation”  standard which is consistent with the reasonable probability standard in determining whether the  AME’s apportionment opinion constituted substantial medical evidence. In that regard  Commissioner Razo stated: 

Further, although the WCJ stated that she applied the requirements of substantial  evidence laid out in Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604 [Appeals  Board en banc], I believe the WCJ applied an even more exacting standard, again  requiring Dr. Mandell to be medically certain about his apportionment findings. This  was legal error on the part of the WCJ. As explained by the Court of Appeal in E.L.  Yeager v. Workers’ Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 930 [71  Cal.Comp.Cases 1687], Labor Code section 4663(c) requires no more than that the  reporting physician make an apportionment determination, based on his or her medical  expertise, of the approximate percentage of permanent disability caused by the non industrial condition.

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  1. Age, Gender, and Genetics 

Age and Gender Cases 

The issue of alleged gender or age discrimination related to apportionment determinations by  reporting physicians under Labor Code sections 4663 and 4664 is distinct from issues related to  apportionment determinations involving genetics and heritability. 

It is important to understand that pursuant to applicable statutes and related case law, there are  certain impermissible, invalid, and potentially unlawful nonindustrial contributing causal factors  of permanent disability that should not be used to establish nonindustrial apportionment under  sections 4663 and 4664. These impermissible and potentially unlawful factors would include but  are not necessarily limited to age alone and gender alone. There are two primary Government  Code sections applicable, section 12940(a) which deals with discrimination involving  compensation, and section 11135(a) dealing with age and gender discrimination. 

In general, the majority of workers’ compensation cases dealing with alleged age and gender  discrimination tend to support the premise that nonindustrial apportionment determinations where  age or gender is but one factor among a multiplicity of other factors reflected in an injured workers  medical history will not in and of itself serve to automatically render a nonindustrial apportionment  determination invalid or unlawful. Discussed hereinafter, is a sampling of cases dealing with  alleged age and gender discrimination. 

In Slagle v. WCAB (2012) 77 Cal. Comp. Cases 467 (writ denied) a 64 year old applicant suffered  a specific injury involving both his right knee and right hip. The AME determined that 80% of  applicant’s disability was industrial and the other 20% attributable to nonindustrial causative  degenerative factors. The MRI diagnostic testing showed applicant had a mild medial degenerative  joint disease process in the right knee and the operative report reflected a small interior patellar  osteophyte. The applicant had knee surgery less than three months after the specific injury date.  The operative report along with the MRI’s confirmed the osteophyte was related to degenerative  changes and not a specific injury. The AME noted that it was unremarkable for a 64-year-old person to have some degenerative changes in their knee. Applicant filed a Petition for  Reconsideration and argued the apportionment was invalid and also constituted age discrimination.  

The WCAB in denying applicant’s petition for reconsideration and affirming the nonindustrial  apportionment determination indicated the AME did not apportion to age alone. Instead,  apportionment was based on the degenerative changes that were objectively demonstrated as well  as applicant’s medical records i.e., the operative report and the MRI’s. With respect to applicant’s  contention that apportionment constituted unlawful age discrimination under Government Code  section 11135, the WCAB noted “that while there may be a relationship between age and 

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degenerative changes, i.e., an increased probability for such changes, that does not mean that  apportionment to degenerative changes, when such apportionment is supported by  substantial evidence in the record, constitutes age discrimination in every case involving an  older person.” See also, Gerletti v. Santa Maria Airport District, 2009 Cal.Wrk.Comp. P.D.  LEXIS 300 (WCAB panel decision), where the WCAB affirmed 50% nonindustrial apportionment  of applicant’s cervical spine disability based on a degenerative condition which developed “in  response to both genetic and age-related factors.” The WCAB indicated this did not equate to  improper apportionment to those factors, but rather to the underlying degenerative condition itself.  

In Kos v. WCAB (2008) 73 Cal. Comp.Cases 529 (writ denied) applicant while employed as an office manager, suffered and admitted specific injury in 2002, to her back and legs. At the time of  injury applicant was 51 years old and weighed 340 lbs. and had diabetes with peripheral  neuropathy. The reporting a physician was an AME in Orthopedics. Based on MRI diagnostic  studies shortly after the injury the AME diagnosed applicant with severe multilevel degenerative  disc disease with disc desiccation. There was also a very severe loss of disc height at L 4-5  indicating bone-on-bone along with foraminal stenosis and active denervation. The AME  determined that most of the cause of applicant’s disc herniation was related to the degenerative  disease process and very little was related to applicant’s work activities since she was in a  sedentary type job. The AME indicated that 90% of applicant’s permanent disability was caused  by the aging process and by the degenerative disc disease. He did acknowledge that the simple act  of sitting at work on the day of her injury aggravated accelerated the underlying disc herniation to  the point that applicant became symptomatic at that time. 

Notwithstanding the AME’s opinion that 90% of the applicant’s lumbar spine disability was non industrial, the WCJ issued a Findings and Award that applicant was 100% permanently disabled  without apportionment. Defendant filed a petition for reconsideration which was granted by the  WCAB. The Board rescinded the WCJ’s decision on the basis the AME’s opinion constituted  substantial medical evidence that 90% of applicant’s permanent disability was apportionable to  non-industrial causative factors. The WCAB cited Escobedo as well as subsequent appellate cases  indicating that Labor Code section 4663 provides for apportionment of permanent disability  caused by other factors both before and subsequent to the industrial injury, including prior  industrial injuries and allows for apportionment of disability to pathology and asymptomatic prior  conditions as long as such apportionment is based on substantial medical evidence citing the  Supreme Court’s decision in Brodie. Applicant also argued on reconsideration that the AME  impermissibly and incorrectly assigned apportionment percentages to risk factors and also  apportioned based on applicant’s age. With respect to alleged age discrimination, the WCAB  stated “….that, even assuming that Labor Code section 4663 were (sic) inconsistent with the  provisions of Government Code sections 12940(a) and 11135( a) to the extent that Labor  Code section 4663 allows apportionment to age-related degenerative disc disease, the  WCAB’s decision would not be altered….” 

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The WCAB citing the California Supreme Court’s decision in Brodie indicated that the “legislative  intent of current section 4663 was to “eliminate the bar against apportionment based on pathology  and asymptomatic causes.” As a consequence “… therefore, the Legislature intended that  apportionment to causation under Section 4663 may be based on age – related disc disease…..”  citing E.L. Yeager Construction v. WCAB (Gatten) 2006 145 Cal.App.4th 922, 71 Cal.Comp.  Cases 1687. In Gatten the Court of Appeal remanded the case to the WCAB with specific  directions to apportion 20% to the employee’s disability age-related degenerative disc disease and stated that “apportionment may be based on pathology and asymptomatic prior conditions.” The  WCAB also noted that Labor Code section 4663 was a later enacted and more specific statute  then the “more general “age” discrimination provisions of Government Code sections  12940(a) and 11135(a). 

Allen v. Workers’ Comp. Appeals Bd. 2008 Cal.App.Unpub. LEXIS 10026 (Court of Appeal, Fifth Appellate District) 

This unpublished case from the Court of Appeal focuses on alleged age discrimination with respect  to the AME’s apportionment determination of 20% nonindustrial. The WCJ found the AME’s  apportionment opinion and determination did not constitute substantial evidence. However, based  on a defense petition for reconsideration, the WCAB reversed and found the AME’s opinion on  nonindustrial apportionment did constitute substantial medical evidence which was affirmed by  the Court of Appeal in this non-published opinion. 

Applicant suffered a 2003 specific back injury. She was 60 years old. As a consequence, she had  a surgical fusion. The reporting physician was an AME. There were two trials and the reason there  was a second trial related exclusively as to what PDRS should apply either the 1997 PDRS or the  2005 PDRS. The AME’s nonindustrial apportionment was attributable to pre-existing pathology  in the form of a moderate disc collapse at L 2-3 with related arthritis and stenosis. The AME  formed his opinion in part by reviewing x-rays taken in 2002 before applicant’s industrial injury  as well as recent x-rays which showed a compression fracture of L-4 which existed before the  injury. In terms of other diagnostic testing, applicant also had a positive discogram which disclosed  the basis for the stenosis and the need for surgical decompression. Also based on the operative  report and other diagnostic findings the AME was of the opinion the need for the surgery could  not have happened from or be related to one specific injury. The AME also indicated that some  people develop arthritis more than other people. There are some 60-year-olds that do not really  have much arthritis, but with respect to the applicant it was more advanced than usual. 

Notwithstanding the AME’s opinion that 20% of applicant’s lumbar spine disability was  nonindustrial and attributable to pre-existing pathology, the WCJ awarded applicant permanent  disability without apportionment. Defendant filed a petition for reconsideration that was granted. 

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The WCAB reversed the WCJ and found the AME’s opinion and report constituted substantial  medical evidence on apportionment under Brodie, Escobedo and Gatten and there was no age based discrimination. Applicant’s counsel specifically argued to the Court of Appeal that the  WCAB violated California’s prohibition against classification-based discrimination under  Government Code section 11135 by adopting the AME’s age-based apportionment findings. In  response both the WCAB and the Court of Appeal indicated as follows: 

We need not determine the relationship between the Government Code provision  and the workers’ compensation laws here because we are not persuaded the  WCAB’s apportionment was based on Allen’s age rather than her individual  medical health. “[T]he Legislature intended that apportionment of causation under  Section 4663 may be based on age – related degenerative conditions. (Kos v.  WCAB (2008) 73 Cal.Comp.Cases 529,536 (writ denied) Although Dr. Haider  mentioned Allen was 60 years old and that it was a “factor” in her pre-existing  pathology, he explained that arthritis was common among individuals her age and  added that “in this case I think it was more advanced than usual.” As the WCJ  found, “While the doctor did say age was a factor in the pathology, he meant that  people develop arthritis as they age. His apportionment was to [Allen’s] specific  medical conditions, not simply to her being 60 years old.” 

Vaira v. WCAB (2009) 72 Cal.Comp.Cases 1586 (not certified for publication) Although this case is not certified for publication, many of the cases cited in the opinion are.  Moreover, there were a large number of briefs filed by several amicus curiae participants. 

The AME confused causation of injury with causation of disability. Applicant also argued that the  AME impermissibly apportioned to applicant’s age and gender in violation of Government Code  section 11135(a). One of the amici also argued apportionment of disability to age is per se  unlawful and apportionment to osteoporosis is improper because it disproportionately impacts  women. 

With respect to the “disparate impact” argument related to osteoporosis even assuming it exists,  the court stated:  

Reducing permanent disability benefits based on a persisting condition that is a  contributing factor of disability is not discrimination. When the WCAB determines  a preexisting condition contributes to a given disability, and apportions  accordingly, this is merely recognition that a portion of the disability exists  independent of the industrial injury. The injured worker is being compensated only  for the disability caused by the industrial injury. To this extent the injured worker  is being treated no differently than an injured worker who does not suffer from the 

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preexisting condition. Both would be compensated for the amount of disability  caused by the industrial injury. This is no different than if the WCAB apportioned  disability to a prior industrial injury. Such apportionment is not discrimination  based on disability. 

The court also indicated that the facts of this case did “…not present a claim that the WCAB has  apportioned disability to a condition particular to women while failing to give equal treatment to  a condition peculiar to men that may also contribute to disability. Such unequal treatment of  disabling conditions peculiar to a particular race, ethnicity or gender may give rise to a claim of  discrimination.” 

As to the alleged age discrimination, the court stated: 

To the extent osteoporosis or some other physical or mental condition that might  contribute to a work-related disability arises or becomes more acute with age, we  see no problem with apportioning disability to that condition. However, in such  case, apportionment is not to age but to the disabling condition. In this case, when  Dr. Johnson mentioned petitioner’s age as a contributing factor of her disability, he  may have been referring to the fact that her osteoporosis has become more acute  with age. On the other hand, he may have been using the term “age’ as a shorthand  reference to the many other physical and mental conditions that tend to come with  age. 

Genetics 

City of Jackson v. Workers’ Compensation Appeals Bd. (Rice) (2017) 11 Cal.App. 5th 109, 82 Cal.Comp.Cases 437, 2017 Cal.App. LEXIS 383  

Issues: Whether 49% nonindustrial apportionment under Labor Code §4663 attributable in large  part to heredity and genetics, constituted valid legal apportionment under Labor Code §4663 and  was supported by substantial evidence contrary to the WCAB’s determination that such  apportionment was to, 1) “impermissible immutable factors; 2) apportionment to causation of  injury as opposed to disability and, 3) that the medical opinion finding such apportionment valid  was not based on substantial medical evidence. 

  

Holding: The Court of Appeal in a decision certified for publication, annulled the WCAB’s  decision, holding that valid legal apportionment under Labor Code §4663 even when in large part  based on heredity or genetics, constituted valid legal apportionment to nonindustrial contributing  causal factors when supported by a medical opinion constituting substantial medical evidence.  Applicant’s degenerative disc disease caused by genetic/hereditary factors did not reflect or 

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constitute apportionment to “impermissible immutable factors; apportionment to causation of  injury as opposed to causation of permanent disability, and the reporting physician’s opinion was  supported by substantial evidence. 

Overview and Discussion: Applicant was a police officer who had a short employment history  as well as being only 29 years old when he filed his cumulative trauma claim ending in April of  2009.  

Applicant worked as a reserve police officer in 2004 and became full time with the City of Jackson  in 2005. He filed a cumulative trauma injury ending on April 22, 2009. He never alleged any  specific mechanism of injury. 

Following trial, the WCJ found 49% valid nonindustrial apportionment based on the orthopedic  QME’s opinion that in large part there were genetic and hereditary factors contributing to  applicant’s cervical spine disability. However, the WCJ rejected alleged nonindustrial  apportionment of 17% based on applicant’s prior work activities and 17% to prior activities based  on a lack of substantial evidence. Applicant’s attorney filed a Petition for Reconsideration arguing  that 49% nonindustrial apportionment to genetic risk factors was not substantial medical evidence  since there was no evidence that applicant’s family had a history of cervical degenerative disc  disease and there was no genetic test for degenerative disc disease. 

The WCAB reversed the WCJ, finding applicant was entitled to an unapportioned award. The  WCAB cited three independent reasons for finding the Labor Code §4663 nonindustrial  apportionment invalid. They were:  

  1. Any attempt to assign nonindustrial causation of permanent disability to genetics was  deemed by the WCAB to be based on an “impermissible, immutable factor.” 
  2. Nonindustrial apportionment based on applicant’s genetic makeup reflects apportionment  to causation of injury and not causation of disability and; 
  3. The orthopedic QME’s apportionment determination did not constitute substantial medical  evidence. 

Medical Evidence: On November 7, 2011, prior to applicant undergoing cervical spine surgery,  applicant was evaluated by the QME in orthopedics. The QME reviewed medical records. Both  the QME and applicant believed applicant’s cervical pain symptomology was a consequence of  repetitive bending and twisting of his head and neck.

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The diagnostic pre-cervical spine surgery x-ray showed cervical degenerative disc disease. The  QME’s diagnosis was cervical radiculopathy as well as cervical degenerative disc disease. After  her first evaluation of the of the applicant, the QME made a preliminary apportionment  determination finding four contributing causal factors of the applicant’s cervical spine disability  consisting of 25% related to applicant’s work activities for the City of Jackson, 25% attributable  to the applicant’s work activities prior to his employment with the City of Jackson, 25% to  applicant’s personal activities consisting of prior injuries and recreational activities, and 25% to  what was described as applicant’s personal history consisting of inheritability and genetics, history  of smoking, and a diagnosis of lateral epicondylitis (tennis elbow).  

The QME reevaluated the applicant after he had cervical spine surgery in May of 2013. Her  diagnosis remained unchanged. However, the QME changed her apportionment determination.  She increased her prior 25% nonindustrial apportionment to 49% based on heritability and  genetics, history of smoking, and diagnosis of lateral epicondylitis based on specific medical  publications she indicated lent more support to nonindustrial causation based on “genomics,  genetics, and heritability issues related to applicant’s cervical spine disability. The QME cited  three studies that supported genomics as a significant causative factor in cervical spine disability.  As a consequence, the QME’s apportionment formula was revised to consist of 17% industrial  related to applicant’s employment with the City of Jackson. 17% related to applicant’s previous  employment, 17% related to applicant’s personal activities consisting of prior injuries and  recreational activities and 49% to applicant’s personal history including genetic issues. 

In a supplemental report the QME indicated she “could state to a reasonable degree of medical  probability that genetics had played a role in Mr. Rice’s injury.” This was despite the fact there  was no way to test for genetic factors. 

With respect to the cited scientific/medical publications, the QME indicated that with respect to  one study, heritability constituted 73% of the contributing causal factors of degenerative disc  disease with only smoking, age, and work contributing a small percentage of the contributing  causal factors that resulted in cervical spine disability.  

Another scientific journal/publication cited the role of heritability in disc degeneration as 75% and  another article at 73%. There was a fourth article consisting of twin studies that demonstrated that  degeneration in adults may be explained up to 75% by genes alone. The same study found  environmental factors to contribute little or not at all to disc degeneration.  

The QME concluded these articles supported nonindustrial apportionment of 75% to applicant’s  personal history. However, in an abundance of caution “she decided to err on the side of the patient  in case there was some unknown “inherent weakness” in the study and decided that 49% was the  “lowest level that could reasonably be stated.” 

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In terms of clarification the QME stated that even without knowing the cause of applicant’s father’s  background, the evidence that applicant’s degenerative disc disease having a predominantly  genetic cause was “fairly strong” especially where there is no clear traumatic (specific) injury as  in applicant’s case. 

Court of Appeal’s Analysis and Holding. 

The Court held that apportionment may be properly based on genetic/heritability as long as it is  supported by substantial medical evidence.  

The Court of Appeal noted the WCAB without explanation held that apportionment to “genetics”  opens the door to apportionment of disability to immutable factors.” In a way the WCAB was  hoisted on its own petard since the Court of Appeal indicated not only did they not perceive any  impermissible apportionment in this case based on genetics and heredity, but more importantly  there were several the WCAB’s own prior apportionment decisions under similar facts and  circumstances that undermined the validity of the WCAB’s reasoning. 

In holding under the particular facts of this case that valid nonindustrial apportionment under  Labor Code §4663 could be properly based on genetics and heritability, the Court discussed in  detail SB 899, and the California Supreme Court’s decision in Brodie. Also discussed was the  1968 California Supreme Court’s decision in Zemke, which had been clearly superseded by SB  899 as articulated by the California Supreme Court in Brodie. The Court noted that since the  enactment of Senate Bill 899 “…apportionment of permanent disability is based on causation and  the employer is liable only for the percentage of permanent disability directly caused by the  industrial injury.” (Brodie, supra, 40 Cal.4th at pp. 1324-1325).  

Apportionment may now be based on “other factors” that caused the disability,  including “the natural progression of non-industrial condition or disease, a  preexisting disability, or a post-injury disabling event [,]…pathology,  asymptomatic prior conditions, and retroactive prophylactic work preclusions…”  (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 617-618 (Escobedo).)  Precluding apportionment based on “impermissible immutable factors” would  preclude apportionment based on the very factors that the legislation now permits,  i.e., apportionment based on pathology and asymptomatic prior conditions for  which the worker has an inherited predisposition. (emphasis added) 

The Court cited a prior decision by the WCAB in Kos v. WCAB (2008) 73 Cal.Comp.Cases 529,  530. In Kos, the applicant developed back and hip pain while working as an office manager. She  was diagnosed with multi-level degenerative disease. The reporting physician in Kos indicated  applicant’s underlying degenerative disc disease was not directly caused by work activities but her 

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prolonged sitting at work “lit up” her preexisting disc disease. More importantly the reporting  physician testified that the worker’s “pre-existing genetic predisposition for degenerative disc  disease would have contributed approximately 75% to her overall level of disability.” (Ibid.)”.  Nevertheless, the ALJ found no basis for apportioning the disability. (Id. at p. 532.) The Board  granted reconsideration and rescinded the ALJ’s decision. (Id. at p.532.) The Board stated that in  degenerative disease cases, it is incorrect to conclude that the worker’s permanent disability is  necessarily entirely caused by the industrial injury without apportionment. (Id. at p.533.) Thus,  in Kos, the Board had no trouble apportioning disability where the degenerative disc disease was  caused by a “pre-existing genetic predisposition.”  

The Court also noted that in Escobedo, the WCAB found valid legal apportionment of 50% of the  worker’s knee injury to non-industrial causation based on the medical evaluator’s opinion that the  worker suffered from “significant degenerative arthritis.” In Escobedo, the Board stated: 

In this case, the issue is whether an apportionment of permanent disability can be  made based on the preexisting arthritis in applicant’s knees. Under pre-[Senate Bill  No.] 899 [(2003-2004 Reg. Sess.)] apportionment law, there would have been a  question of whether this would have constituted an impermissible apportionment  to pathology or causative factors. [Citations.] Under [Senate Bill No.] 899 [(2003- 2004 Reg. Sess.)], however, apportionment now can be based on non-industrial  pathology, if it can be demonstrated by substantial medical evidence that the non 

industrial pathology has caused permanent disability. Thus, the preexisting  disability may arise from any source—congenital, developmental, pathological, or  traumatic (Id. at pp. 617-619.) We perceive no relevant distinction between  allowing apportionment based on a preexisting congenital or pathological condition  and allowing apportionment based on a preexisting degenerative condition caused  by heredity or genetics. (emphasis added). 

In support of their decision the Court also discussed in depth Acme Steel v. WCAB (Borman) (2013)  218 Cal.App.4th 1137, where the Court of Appeal reversed the WCAB who had found no basis for  nonindustrial apportionment and awarded the applicant 100% PTD. The Court of Appeal in  Borman found 40% valid nonindustrial apportionment to the applicant’s hearing loss attributable  to “congenital degeneration” of the cochlea. The Court in discussing Borman stated “Again, we  see no relevant distinction between apportionment for a preexisting disease that is congenital and  degenerative, and apportionment for a preexisting degenerative disease caused by heredity or  genetics.”

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The reporting physician properly apportioned to causation of disability and not causation of  injury. 

Both applicant’s counsel and the WCAB erroneously determined the orthopedic QME had  invalidly apportioned applicant’s disability to causation of injury as opposed to causation of  disability. The Court held that the QME had properly apportioned to causation of disability. In  that regard the Court carefully distinguished what was being alleged as applicant’s injury and what  was being asserted as his resultant disability. In terms of injury, the Court described the  mechanism of injury as a cumulative trauma injury as opposed to a specific injury. Applicant’s  injury was based on and caused by repetitive motion of his neck and head. The Court pointed out  the QME did not conclude as the WCAB erroneously did, that this repetitive motion injury was  caused by genetics at all. In contrast to applicant’s injury, his disability consisted of “neck pain  and left arm, hand, and shoulder pain, which prevented him from sitting for more than two hours  per day, lifting more than fifteen pounds, and any vibratory activities such as driving long  distances. All of these activities were included in Rice’s job description.” 

The orthopedic QME properly concluded and opined applicant’s cervical spine disability as  described by the QME was caused only partially (17%) by his work activities for the City of  Jackson and was caused primarily, i.e., 49% by his genetics. As the Court succinctly stated,  “Contrary to the Board’s opinion, Dr. Blair did not apportion causation to injury rather than  disability.” 

The Orthopedic QME’s opinion was based on substantial evidence. 

The Court reviewed pertinent cases setting forth principles of substantial evidence. Based on these  standards, the QME’s opinion as to causation of the applicant’s cervical spine disability constitutes  substantial medical evidence. The QME explained in her initial apportionment determination, that  25% of the cause of applicant’s cervical spine disability was attributable to his personal history.  She also explained that studies taken from relevant medical literature indicated “heredity and  genetics are significant causes of degenerative diseases of the spine…”. The QME also “included  in the personal history category, Rice’s history of smoking and a previous diagnosis of lateral  epicondylitis.” 

The Court also indicated applicant had incorrectly argued that the QME had concluded that  genetics played a role in approximately 63% – 75% of degenerative disc disease cases. The Court  noted that the QME had instead “indicated that degenerative disc disease in adults may be  explained up to 75% by genes alone.” Explained another way, “Every case of degenerative disc  disease in adults is caused in part by genetics or heredity, and the other part by other factors.”

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Applicant also argued the QME had no way of knowing applicant’s degenerative disc disease was  caused by genetics because the QME had never researched applicant’s family medical history. 

The Court stated, “It was unnecessary for Dr. Blair to conduct such an analysis because her  research indicated that genetics or heredity was a majority factor in all cases of degenerative disc  disease.” 

The Court concluded that the QME’s reports met all of the requirements of Escobedo.  

Dr. Blair’s reports reflect, without speculation, that Rice’s disability is the result of  cervical radiculopathy and degenerative disc disease. Her diagnosis was based on  medical history, physical examination, and diagnostic studies that included X-rays  and MRI’s (magnetic resonance imaging scans). She determined that 49 percent of  his condition was caused by heredity, genomics, and other personal history factors.  Her conclusion was based on medical studies that were cited in her report, in  addition to an adequate medical history and examination. Dr. Blair’s combined  reports are more than sufficient to meet the standard of substantial medical  evidence. 

In addition, the WCAB stated the AME, 

“…[D]id not give one sentence of reasoning behind his opinion. He made bold,  conclusionary statements such as that the cause of degenerative disc disease has  been convincingly shown to be genetic, but he does not back that up with substantial  medical evidence; he does not state how, why, when or where the cause of  degenerative disc disease was shown to be genetic, he just makes the statement. He  does not list any research studies or facts pertinent to the instant case that support  causation outside the industrial exposure…” 

On appeal counsel for defendant cited the Rice case and the medical studies relied on by the doctor  in Rice. However, there was no evidence that the AME relied on these same studies to formulate  his opinion on apportionment. 

Editor’s Comment: There are a number of other decisions not cited by the Court that support  finding valid legal apportionment based on pathology caused by heredity, genetics, and congenital  factors. See Gerletti v. Santa Maria Airport District 2009 Cal.Wrk.Comp. P.D. LEXIS 300  (WCAB panel decision). WCAB found 50% of applicant’s cervical spine disability was  nonindustrial based on a cervical spine MRI confirming foraminal stenosis and degenerative  spondylosis consistent with both age and genetic changes in the applicant’s spine. Also, Costa v.  WCAB (2011) 76 Cal.Comp.Cases 261 (writ denied). In a 100% PTD cervical spine disability case, 

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valid nonindustrial apportionment of 20% attributable to “preexisting congenital cervical spinal  stenosis” causing applicant’s cervical spine disability to be greater than it otherwise would be.  

There is also Paredes v. WCAB (2007) 72 Cal.Comp.Cases 690 (writ denied) 10% valid  nonindustrial apportionment related to applicant’s cervical spine based on nonindustrial pathology  consisting of mild stenosis confined by x-rays and MRIs taken shortly after his first injury. It was  unnecessary for defendant to prove the nonindustrial pathology caused disability prior to the  industrial injury, or that the pathology alone would have caused a particular amount of PD, absent  the industrial injury. 

However, there is a significant issue as to whether the “approximate” percentage figure related to  nonindustrial contributing causal factors can be calculated or “quantified” directly from what  caused a particular pathology as opposed to the actual pathology itself especially in progressive  degenerative disease conditions that evolve over time. The article on page 24 discusses this  provocative “dual” causation issue in depth. 

In Sobol v. State of California Department of Corrections and Rehabilitation 2017 Cal.Wrk.Comp.  P.D. LEXIS 454 (WCAB panel decision), decided after Rice, both the WCJ and WCAB found that  an AME’s apportionment opinion of 25% to nonindustrial factors based on genetics did not  constitute substantial medical evidence. With respect to the genetic basis for apportionment the  AME stated, “[t]he cause of degenerative disease of the spine, particularly as it involves discs, has  been convincingly shown to be principally genetic in determination.” The WCAB characterized  this statement as “conclusory” and not “substantiated with sufficient medical rationale.” 

In Owens v. San Mateo County Transit District, 2017 Cal.Wrk.Comp. P.D. LEXIS 448 (WCAB  panel decision), the Board ruled there was 60% valid nonindustrial apportionment of applicant’s  overall cervical spine disability of 36% attributable to congenital osteoarthritis. The QME’s  opinion on apportionment was based on the medical record as well as on “studies and articles” on  the causes of spinal disc degeneration. With respect to the Rice decision, the WCAB stated: 

I remain persuaded that Dr. Piasecki has outlined his conclusions regarding  apportionment of impairment in a manner that is consistent with the law. I note as  well, as defendant has pointed out the recent published case of City of Jackson v.  Wkrs. Comp. Appeals Bd. (Rice) (April 26, 2007) 11 Cal.App. 5th 109 endorsing  apportionment to various causes other than the work-related injury; those factors  included “heritability and genetics.” There, also, the employee had argued that the  genetic finding amounted to an analysis of causation of injury, rather than disability  or impairment, and that the doctor’s opinions were not substantial medical  evidence, arguments also advanced in this case.

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In Schuy v. City of Yuba 2018 Cal. Wrk. Comp. P.D. LEXIS 136 (WCAB Panel Decision), the  WCAB reversed a WCJ’s Award of 29% PD lumbar spine permanent disability without  apportionment and found 50% valid legal apportionment. The WCAB relied on the apportionment  determination made by the orthopedic AME that applicant’s widespread degenerative disease of  the low back, for the most part, such changes are “genetically determined.” The AME in his  deposition reiterated that 50% of applicant’s lumbar spine permanent disability was due to non 

industrial causation factors that were “genetic in origin.”  

The WCAB cited a number of cases including City of Jackson v. WCAB (Rice) (2017) 11 Cal.  App. 5th 109 [82 Cal. Comp. Cases 437] that “established the principle that, under sections 4663  and 4664(a), apportionment of permanent disability is mandated where substantial evidence  established that some definable percentage of that disability was caused by, among other things,  pathology, an asymptomatic preexisting condition or genetic/hereditary factors.” 

Apportionment of Permanent Disability Related to Genetics and Heredity: Is It A Causational Diversionary Red Herring? 

The decision from the Court of Appeal in City of Jackson v. Workers’ Compensation Appeals  Board (Rice) (2017) 11 Cal.App. 5th 109, 2017 Cal.App. LEXIS 383 (certified for publication),  has justifiably engendered wide spread controversy in the workers’ compensation community as  evidenced by numerous articles and upcoming seminars related to analysis of the case as well as  proposed litigation strategies all focused on what may be a causational diversionary red herring.  Before I weighed in with my own analysis, commentary, and opinion, I wanted to wait for the dust  to settle. In my opinion as discussed in detail hereinafter, without further development of the  record, the orthopedic QME’s determination of 49% nonindustrial apportionment in Rice is invalid  and speculative. The nonindustrial apportionment in Rice reflects apportionment to the etiology  (genetics and heritability) expressed in percentage terms of what caused applicant’s pathology  (cervical degenerative disc disease and related radiculopathy) and not to the pathology itself and  more importantly the severity of the pathology after applicant’s neck surgery and when the QME’s  maximum medical improvement (MMI) examination took place. So no one is confused, I am not  talking about causation of injury versus causation of disability. The Court in Rice correctly  analyzed that issue. The issue I am raising is much different. Apportionment to etiology is in my  opinion not apportionment of or to disability as defined and discussed in Rice as “…actual  incapacity to perform the tasks usually encountered in one’s employment and the wage loss  resulting therefrom, and…physical impairment of the body that may or may not be incapacitating  and …[p]ermanent disability is the irreversible residual of an injury…” (citations omitted). 

While it may be interesting to know the etiology or cause of a particular underlying pathology  (congenital, developmental, genetic, heredity, etc.), it can be argued that whether genetics or  heredity may have played a “predominant” or “large part” in the actual causation or existence of 

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the underlying pathology, it should be carefully distinguished from the separate issue under Labor  Code Section 4663, as to what approximate percentage the extent or severity of the pathology or  disease process itself (as confirmed by diagnostic studies and supported by substantial evidence)  is a present contributing causal factor of the permanent disability at the time of the MMI  examination determining permanent disability and apportionment.  

It is extremely important to acknowledge that orthopedic related degenerative diseases and  conditions such as the one in Rice (cervical degenerative disc disease) are generally not static but are progressive over time and this progression over time can relate to both industrial and  nonindustrial causative factors. This principle is evidenced by hundreds (if not thousands) of  apportionment decisions involving degenerative disease pathology and orthopedic injuries decided  by the WCAB since SB 899 was enacted in 2004, along with scores of writ denied cases and  several published decisions by the Court of Appeal and the Supreme Court in Brodie. 

The Court of Appeal in Rice tacitly recognized the significance of the critical causational  distinction between etiology and pathology in stating that: “The QME concluded that the  employee’s disability—neck, shoulder, arm, and hand pain–was caused by cervical degenerative  disc disease, and the disease was, in turn, caused in large part by heredity or  genetics.”(emphasis added). So if I understand the Court, there are actually two separate and  distinct causal components. One related to causation of pathology and the other to the disability  attributable to a particular pathology. Therefore, pursuant to Labor Code 4663, an apportionment  analysis should focus on the pathology itself and not what caused the pathology.  

In Rice, the QME in her second report after the applicant’s neck surgery, used or relied on various  medical publications to justify and support her increasing the nonindustrial apportionment  percentage related to applicant’s cervical spine disability from 25% to 49%. The QME’s original  diagnosis of cervical radiculopathy and cervical degenerative disc disease remained unchanged.  While I agree with the QME that some approximate percentage of applicant’s neck permanent  disability is nonindustrial as being causally related to his cervical spine pathology, I question  whether her reliance on medical literature/studies alone warranted almost a doubling of the  nonindustrial apportionment from 25% to 49%. In my opinion merely establishing the etiology or  causation of the underlying pathology (cervical degenerative disc disease) as being attributable  “largely” or “predominantly” to genetics and heritability does not automatically or necessarily  translate into the degree or extent a particular pathology (the critical percentage approximation in  the apportionment equation) is actually manifested in an individual injured worker at a given point  in their life and more importantly at the time of the MMI examination assessing permanent  disability. This requires a separate analysis and determination to be made by the reporting  physician based upon a combination of a variety of factors including but not solely limited to  diagnostic studies, operative reports, medical records, clinical findings, clinical judgment, and a  complete and accurate medical history. In short, apportionment determinations and related 

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approximate percentages of industrial and nonindustrial contributing causal factors of permanent  disability based on and attributable to the etiology of a pathological disease or condition as opposed  to pathology itself is inherently speculative and unreliable. My opinion on this issue may perhaps  be viewed as “contrarian” or an “outlier” of sorts since it is radically different from the Court of  Appeal’s holding in Rice and that of many recent commentators. 

The Acme, Kos, and Escobedo Cases: The Court in Rice cited Acme Steel v. Workers’ Comp.  Appeals Bd. (2013) 218 Cal.App.4th 1137, 1139 in support of their holding that “apportionment  may be properly based on Genetics/Hereditability.” However, what must be emphasized is that in  Acme, the AME in hearing loss in finding 40% nonindustrial apportionment based upon pathology  consisting of a degenerative cochlea condition or disease process made this determination by  relying on diagnostic audio testing that clearly established a portion (40%) of the applicant’s  hearing loss was not related to industrial exposure. As to the nonindustrial component, the AME  indicated this form or aspect of hearing loss was suspicious but was “most consistent [with] a  congenital degeneration of the entire organ.” The AME did not base his nonindustrial  apportionment determination on the cause of the degenerative cochlea condition which was  congenital but on the pathology itself assessed by diagnostic testing which demonstrated the  severity of the hearing loss and causal components related to this worker at a particular point in  time. Etiology was of interest but was not directly relevant in determining or assessing the severity  of the pathology expressed as an approximate percentage for purposes of determining  nonindustrial apportionment based on Labor Code 4663. See also, Costa v. WCAB (2011) 76  Cal.Comp.Cases 261, 2011 Cal.Wrk.Comp. LEXIS 25 (In a 100% permanent total disability case  valid 20% nonindustrial apportionment related to applicant’s preexisting asymptomatic congenital  lumbar spinal stenosis, the severity of which was confirmed by significant findings on MRI, CT  studies.). 

The Court also discussed Kos v.Workers’ Comp.Appeals Bd. (2008) 73 Cal.Comp.Cases 529 (writ  denied) where the WCAB “….had no trouble apportioning disability where the degenerative disc  disease was caused by a pre-existing genetic predisposition. However, in Kos, diagnostic testing  in the form of an MRI taken less than six weeks after the applicant’s specific injury as well as her  pre-injury chiropractic records were critical in assessing and determining the extreme severity of  the applicant’s disc herniation/multi-level disc disease and in my opinion formed the basis for the  reporting physician to find that approximately 90% of applicant’s permanent total disability was  non-industrial. The reporting physician opined that the etiology or cause of the applicant’s  degenerative disc disease was largely attributable to her “genetic predisposition.” However, in my  opinion it was the extreme severity of the applicant’s degenerative disc disease as confirmed by  MRI diagnostic testing shortly after the injury and her pre-injury medical records that provided the  most compelling support for the valid 90% nonindustrial apportionment, not the etiology of the  multi-level disc disease. In Kos there was apportionment to pathology not to what caused the  pathology. Both Acme and Kos in my opinion support the argument that valid legal apportionment 

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pursuant to Labor Code 4663 can be based on pathology but not directly to the etiology or cause  of the pathology itself. 

The WCAB’s en banc decision in Escobedo v Marshalls (2005) 70 Cal.Comp.Cases 604 (WCAB  en banc) is also instructive on this issue. In Escobedo, the WCAB found valid non-industrial  apportionment of 50% based on the contributing causal factor of pre-existing pathology consisting  of degenerative arthritis in the applicant’s knees. In Escobedo, the actual cause or source of the  nonindustrial pathology whether congenital, genetic, or hereditary was essentially irrelevant in  determining valid nonindustrial apportionment since diagnostic tests in the form of an MRI and x 

rays confirmed both the existence and more importantly the severity of the degenerative arthritis  at a particular point in time. In Rice, the Court emphasized that in Escobedo the injured worker  had pathology in the form of significant degenerative arthritis to his knees. In Escobedo, the  “significant” degenerative arthritis noted by the Court was based primarily on diagnostic studies  not the etiology or cause of the significant degenerative arthritis itself. This is generally the  scenario in the majority of orthopedic injuries involving degenerative diseases and conditions. In  Escobedo, the reporting physician’s opinion constituted substantial medical evidence since he  explained in detail how and why applicant’s degenerative arthritis expressed as an approximate  percentage was a nonindustrial contributing causal factor of the applicant’s knee disability.  

Both Brodie and Escobedo found valid non-industrial apportionment based on pathology  and asymptomatic causes without reference to or reliance on heredity and genetics: The Court  of Appeal in Rice quoted extensively from both Brodie v. Workers’ Comp. Appeals Bd. (2007) 40  Cal.4th 1313 and Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604 (WCAB en banc) related  to apportionment based on an expansive set of contributing causal factors of permanent disability,  including pathology and asymptomatic causes. Prior to SB 899, apportionment to pathology and  asymptomatic causes as well as instances where an industrial injury aggravated or accelerated an  industrial injury were generally prohibited. As a consequence, employers were liable for the entire  resulting disability without apportionment to nonindustrial contributing causal factors. In Brodie,  the Supreme Court held that “[T]he plain language of new sections 4663 and 4664 demonstrates  they were intended to reverse these features of former sections 4663 and 4750.” In citing Brodie and the radical diametrical changes engendered by 4663 and 4664, the Court in Rice stated: 

Since the enactment of Senate Bill No. 899(2003-2004 Reg. Sess.), apportionment  of permanent disability is based on causation, and the employer is liable only for  the percentage of permanent disability directly caused by the industrial injury.  (Brodie, supra, 40Cal.4th at pp.1324-1325.) Apportionment may now be based on  “other factors” that caused the disability, including “the natural progression of a  non-industrial condition or disease, a preexisting disability, or a post-injury  disabling event[,]…pathology, asymptomatic prior conditions, and retroactive  prophylactic work preclusions….”(Escobedo v Marshalls (2005) 70 

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Cal.Comp.Cases 604, 617-618(Escobedo).) Precluding apportionment based on  “impermissible immutable factors” would preclude apportionment based on the  very factors that the legislation now permits, i.e., apportionment based on  pathology and asymptomatic prior conditions for which the workers has an  inherited predisposition. (emphasis added). 

Prior to SB 899, any apportionment to pathology would have been invalid. In contrast, under  current 4663 and 4664 the Court in Rice cited Escobedo in describing the expansive nature and  extent of valid non-industrial contributing causal factors of disability as follows: 

[H]owever, apportionment now can be based on non-industrial pathology, if it can  be demonstrated by substantial medical evidence that the non-industrial pathology has caused permanent disability. Thus, the preexisting disability may arise from  any source—congenital, developmental, pathological, or traumatic.”(Id. at pp.617- 619.) We perceive no relevant distinction between allowing apportionment based  on a preexisting congenital or pathological condition and allowing apportionment  based on a preexisting degenerative condition caused by heredity or genetics. (emphasis added). 

In Rice, it is undisputed that the 29-year-old applicant with a relatively short cumulative trauma  injury period, was diagnosed with cervical spine pathology consisting of cervical spine  radiculopathy and degenerative disc disease. In my opinion, based on 4663 and 4664 as well as  Brodie and Escobedo and a legion of related cases involving orthopedic injuries and degenerative  diseases and conditions, the existence of pathology (whether symptomatic or asymptomatic)  provides a potential viable basis for nonindustrial apportionment so long as it is supported by a  medical opinion that constitutes substantial medical evidence. The fact the QME in Rice identified  the primary source or etiology of the pathological degenerative condition itself as being primarily  caused by genetics and heredity to a “large” degree” is largely irrelevant in terms of substantial  medical evidence as to the approximate percentage the pathological degenerative condition or  disease process or condition is an actual contributing cause of permanent disability at the particular  point in time the applicant had his MMI examination after his neck surgery to determine his  permanent disability and any basis for apportionment.  

The Record in Rice should have been further developed in order for the QME to apportion  properly to pathology and not etiology: The QME’s determination that the pathology itself was  “largely” or “predominately” caused by genetics and heredity based on medical studies/literature  to between 73% and 75% or a reduced percentage of 49%, does not mean these same percentage  figures are at all relevant and somehow automatically equate to the approximate percentage the  actual underlying pathology is a contributing nonindustrial causal factor of the applicant’s cervical  spine disability. 

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Arguably applicant’s degenerative disc disease with related radiculopathy had progressed and was  severe enough to cause the need for neck surgery. However, when the orthopedic QME  reevaluated applicant after his neck surgery and issued her MMI supplemental report, it appears  she did not analyze or discuss the operative report findings and any closely related cervical spine  diagnostic testing. Such an analysis and detailed discussion of the diagnostic testing and operative  report findings would clearly establish to a reasonable medical probability the severity of the  applicant’s pathology at that point in time and could have been used by the QME to help her  “parcel out” all of the contributing industrial and nonindustrial contributing causal factors of  applicant’s cervical spine disability without reference to any medical literature related to the  etiology of the underlying pathology. As a consequence, based on the defective report of the QME  we have no way of knowing to what extent applicant’s underlying degenerative disc disease had  progressed at the time of his neck surgery and more importantly at the time of the later MMI  examination.  

I believe the Court of Appeal in Rice should have remanded the case back to the WCAB for further  development of the record. The QME should have been ordered to issue a supplemental report  based on her review of the operative report findings from applicant’s neck surgery and any closely  related cervical spine diagnostic testing in order for her to determine the severity of applicant’s  degenerative disc disease at the time of the MMI evaluation. This would provide a reliable basis  for her to determine the extent to which applicant’s cervical disc disease had progressed and enable  her to form an opinion as to what approximate percentage the underlying pathology (not the  etiology of the pathology) was a contributing causal factor of the applicant’s cervical spine  disability as required by Labor Code 4663. 

In Summary Important Points to Consider Are: 

  1. Pursuant to Brodie and Escobedo and related cases, the fact that pathology whether symptomatic  or asymptomatic is congenital or caused by genetics or hereditary is not a bar to valid legal  apportionment. 
  2. The “approximate” percentage figure representing the industrial and nonindustrial contributing  causal factors of an applicant’s permanent disability should be based on the pathology in question  based on diagnostic testing and not a questionable speculative percentage the underlying genetics,  hereditary, or congenital factors allegedly caused the pathology at issue. 
  3. The fact that genetics or heredity played a “large” or “predominant” role in causing the  pathology at issue does not automatically equate to nor is it synonymous with an approximate  percentage figure the pathology itself is a contributing causal factor under Labor Code 4663 of the  applicant’s permanent disability. 

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  1. Diagnostic studies, operative report findings, medical records, clinical findings, clinical  judgment, and a complete and accurate medical history are among but not the exclusive  components or factors to be used in assessing the extent to which a given underlying pathological  condition or disease process is a contributing causal factor of the applicant’s permanent disability  as reflected in many of the cases cited in the body of the article.  
  2. “RISK FACTORS”, PATHOLOGY, AND ASYMPTOMATIC PRIOR  CONDITIONS-CAUSATION OF INJURY VERSUS CAUSATION OF  PERMANENT DISABILITY 

City of Petaluma et al., v. WCAB (Lindh) (2018) 29 Cal. App. 5th 1175, 83 Cal. Comp. Cases 1869 (Petition for Review by Supreme Court denied 3/13/19). 

Issues & Holding: The Court of Appeal in reversing both the trial WCJ and the WCAB held that  when there are multiple contributing causal factors of an applicant’s permanent disability  apportionment is required so long as there is substantial medical evidence establishing valid legal  apportionment. 

Factual & Procedural Overview: Applicant was employed as a law enforcement officer. The  parties stipulated he sustained injury AOE/COE to his left eye, while engaged in canine training  suffering three to six blows to the left side of his head. Afterwards he suffered headaches that  would last between several hours and one or two days. However, over a month later on June 16,  2015, while he was off duty, applicant suddenly lost most of the vision in his left eye. He was  initially examined by treating physicians from two different facilities. Neither of the two treating  physicians believed the applicant’s vision loss was related to the blows that he suffered to his head  during canine training.  

Applicant was then examined by a neuro-ophthalmologist QME. The QME diagnosed applicant  with five different conditions. None of these conditions had caused disability prior to applicant’s  suffering the blows to his head during canine training. The QME also indicated that applicant had  an underlying condition which the QME identified as “vasospastic-type personality.” The QME  opined that this underlying condition put the applicant at higher risk of suffering a disability. The  QME also described the underlying condition of vasospasticity as a rare condition. The QME  indicated the applicant’s blood circulation to his left eye was defective. The QME repeatedly  stated the applicant did not have any disability prior to receiving the blows to his head during canine training. 

Injury AOE/COE: In terms of injury AOE/COE the QME indicated that the blows to the  applicant’s head contributed to his injury. He also indicated that as to causation of disability, he  would apply the same analysis. 

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Apportionment: With respect to the permanent disability related to applicant’s left eye, the QME  initially found there was non-industrial apportionment of 90%. However, following the QME’s  deposition and the issuance of a supplemental report, he modified the apportionment percentage  to 85% non-industrial and 15% industrial which equated to permanent disability of 40% if there  was no valid legal apportionment. If there was 85% valid non-industrial apportionment, the  applicant’s left eye permanent disability would be 6%.  

The WCJ’s and WCAB’s decisions: The WCJ rejected the QME’s apportionment analysis  concluding that it was not supported by substantial medical evidence and therefore awarded the  applicant 40% permanent disability without apportionment. The City of Petaluma filed a Petition  for Reconsideration which was denied by the WCAB who affirmed the WCJ’s decision. The  Board’s denial of defendant’s Petition for Reconsideration was based on the reasoning that the  applicant’s preexisting asymptomatic condition of hyperactive type personality and systemic  hypertension and vasospasm were “mere risk factors” that predisposed the applicant to having a  left eye injury, but that the actual resultant left eye disability based on partial left eye blindness  was entirely caused by industrial factors. The Board indicated that the QME had “confused  causation of injury with causation of disability and therefore, there was no valid legal basis for  apportionment”.  

The City of Petaluma filed a Writ with the Court of Appeal, which was granted, and the Court of  Appeal annulled the WCAB’s decision finding that the QME’s opinion constituted substantial  medical evidence and therefore ordered an apportioned Award of 6% permanent disability.  

Discussion: In a lengthy and well-reasoned decision with an in-depth analysis and discussion of  SB 899, Labor Code §4663 and 4664 and applicable case law, the Court of Appeal held that both  SB 899 and applicable case law clearly permitted valid legal apportionment based on preexisting  asymptomatic pathology as well as prior asymptomatic conditions. The WCAB also affirmed the  fact that unlike case law prior to SB 899, current Labor Code sections 4663 and 4664 and  applicable case law establish that when an industrial injury aggravates or accelerates an underlying  disease process whether that disease process is symptomatic or asymptomatic, there may be a basis  for valid legal apportionment that was now allowed prior to the enactment of SB 899. 

With respect to SB 899 and the enactment of Labor Code sections 4663 and 4664, the court in  citing the California Supreme Court’s decision in Brodie indicated that SB 899 “overhauled the  statutes governing apportionment.” The court also indicated that Labor Code §4663 provides and  requires that apportionment be based on causation. Under SB 899 a physician is required to make  an apportionment determination by finding “what approximate percentage of the permanent  disability was caused by the direct result of injury arising out of and occurring in the course of  employment and what approximate percentage of the permanent disability was caused by other  factors both before and subsequent to the industrial injury, including prior industrial injuries.” 

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More importantly the Court of Appeal indicated that Labor Code §4664 specifically and expressly  states “The employer shall only be liable for the percentage of the permanent disability directly  caused by the injury arising out of and occurring in the course of employment.” (Labor Code  §4664, subdivision (a), italics added.) 

The Court of Appeal focused on the fact that one of the significant changes to apportionment  effectuated by SB 899 enacted in 2004 was that “other factors” are required to be taken into  account for apportionment, “making clear that pathology and preexisting asymptomatic conditions  are among such factors”, that may provide a basis for valid legal apportionment.  

The Court’s Analysis of Applicable Case Law: The Court of Appeal analyzed a number of the  most significant cases decided by the California Supreme Court and the Court of Appeal  subsequent to the enactment of SB 899, as well as a number of WCAB decisions. These cases  included City of Jackson v. WCAB (2017) 11 Cal.App.5th 109 (Jackson), Brodie v. WCAB (2007)  40 Cal.4th 1313 (Brodie), Acme Steel v. WCAB (Borman) (2013) 218 Cal.App.4th 1137, Escobedo  v. Marshalls (2005) 70 Cal.Comp.Cases 604 (Escobedo), E.L. Yeager Construction v. WCAB (2006) 145 Cal.App.4th 922 (E.L. Yeager) and Costa v. WCAB (2011) 76 Cal.Comp.Cases 261 

(Costa). 

The Court of Appeal set forth the following key points and the holdings of prior cases that  supported its opinion that valid legal apportionment can be based on pathology and asymptomatic  conditions, so long as they were contributing causal factors of the applicant’s permanent disability  and there was substantial medical evidence to support the apportionment determination. 

  1. The Court of Appeal rejected applicant’s argument and the WCAB’s opinion that the  QME impermissibly apportioned to “risk factors” by citing from Costa. “Applicant’s  argument that the WCJ improperly apportioned to a risk factor ignores the medical  opinion that applicant’s preexisting congenital condition went beyond being a risk  factor to being an actual cause of his increased permanent disability, when applicant  sustained his industrial injury.” 
  2. The Court of Appeal rejected both the WCAB’s and Applicant’s repeated  mischaracterization of the applicant’s underlying pathology and asymptomatic  condition as simply or merely a “risk factor.” The Court also indicated that labeling or  characterizing an underlying condition whether symptomatic or asymptomatic as a  “risk factor” does not change the fact that it is still an “underlying condition” that can  be a contributing causal factor of the applicant’s resultant permanent disability.

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  1. The Court of Appeal also stated, “[m]ore importantly, the post-amendment cases do  not require medical evidence that an asymptomatic preexisting condition, in and of  itself, would eventually have become symptomatic. Rather, what is required is  substantial medical evidence that the asymptomatic condition or pathology was a  contributing cause of the disability. (citing Brodie, supra, 40 Cal.4th at page 1328).  Also citing Brodie, the Court of Appeal stated that under SB 899 [“the new approach  to apportionment is to look at the current disability and parcel out its causative sources nonindustrial, prior industrial, current industrial – and decide the amount directly  caused by the current industrial source”]. 
  2. The Court of Appeal flatly rejected applicant’s arguments and the Board’s erroneous  decision and related arguments that apportionment is required only “where there is  medical evidence the asymptomatic preexisting condition would invariably have  become symptomatic, even without the workplace injury.” The Court indicated these  arguments merely reflect the state of the law prior to the 2004 amendments in SB 899.  “Under the current law, the salient question is whether the disability resulted from both  nonindustrial and industrial causes, and if so, apportionment is required.” (citing  Brodie, Jackson, and Acme Steel) The Court of Appeal characterized as “immaterial”  whether or not an asymptomatic preexisting condition that contributes to an applicant’s  disability would, alone have inevitably become manifest and resulted in disability. 
  3. The Court of Appeal also rejected applicant’s argument that valid legal apportionment  can only be based on a preexisting degenerative condition. The Court citing Jackson indicated “[w]e perceive no relevant distinction between allowing apportionment based  on a preexisting congenital or pathological condition and allowing apportionment  based on a preexisting degenerative condition caused by heredity or genetics”. The  Court stated the key to understanding the principles and concepts of apportionment  based on Labor Code sections 4663 and 4664 is to “focus on whether there is substantial  medical evidence the disability was caused, in part, by nonindustrial factors, which can  include “pathology and asymptomatic prior conditions for which the worker has an  inherited predisposition.” (Jackson, supra, 11 Cal.App. 5th at p. 116; see Escobedo,  supra, 70 Cal.Comp.Cases at p. 617 [separately listing, and thus distinguishing  between, all the “factors” that are apportionable-including those apportionable prior to  2004 (“the natural progression of a non-industrial condition or disease, a preexisting  disability, or a post-injury disabling event”) and those apportionable after 2004  amendments (“pathology, asymptomatic prior conditions, and retroactive prophylactic  work preclusions”)].) 
  4. Lastly, the Court of Appeal rejected applicant’s argument that there can be no valid  apportionment to a condition that did not cause disability prior to the work-related  injury. The Court emphatically and unambiguously stated “[b]y definition, an 

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asymptomatic preexisting condition has not manifested itself, and thus, by definition  has not caused a prior disability. “Prior disability or evidence of modified work  performance is no longer a prerequisite to apportionment. If the presence of these  factors is necessary to constitute substantial evidence, there would have been no  purpose in changing the law.” (see E.L. Yeager, supra, 145 Cal.App.4th at p. 929). 

Editor’s Comments: The Court of Appeal’s decision in Lindh broke no new ground nor did it  establish any new concepts or principles related to apportionment law. Its importance is that it  expressly and unambiguously rearticulated and reaffirmed the radical diametrical change in prior  apportionment law reflected in SB 899 and Labor Code sections 4663 & 4664. The Court did this  by conducting a comprehensive review and analysis of appellate decisions ranging from the  Supreme Court’s decision on Brodie, numerous Court of Appeal decisions, and the WCAB’s en  banc decision in Escobedo, (affirmed by the Court of Appeal) and key panel decisions. In doing  so, the Court of Appeal rejected both the WCJ’s and WCAB’s misunderstanding and  misapplication of existing case law on apportionment. 

The Court of Appeal in Lindh, as it has done numerous times in other cases since the enactment of  SB 899, reminded the WCAB that SB 899 and Labor Code Sections 4663 & 4664 reflect a radical  and diametrical change in the law of apportionment that existed for 36 years prior to 2004. This  radical change in the law of apportionment based on causation (prior to 2004 apportionment based  on causation was prohibited) will frequently result in any given case to a potentially large reduction  of an applicant’s permanent disability award based on apportionment to non-industrial  contributing causal factors so long as there is substantial medical evidence to support such a  determination. 

In Lindh, the Court of Appeal annulled the WCAB’s decision since the WCAB erroneously  rejected the QME’s legally correct non-industrial apportionment analysis and opinion apportioning  85% of the applicant’s eye permanent disability to a preexisting asymptomatic non-disabling  underlying pathological condition that was aggravated and accelerated by applicant’s industrial  injury. The WCAB erroneously applied pre-SB 899 apportionment law in rejecting the QME’s  medically and legally correct opinion on apportionment resulting in an unapportioned award of  40% permanent disability. In annulling the WCAB’s decision, the Court of Appeal awarded  applicant 6% permanent disability after 85% valid nonindustrial apportionment. 

The Court of Appeal reaffirmed prior case law interpreting and applying Labor Code sections 4663  and 4664 that apportionment is required to be based on causation and that valid nonindustrial  contributing causal factors may include pathology as well as asymptomatic prior conditions even  if the underlying pathology is caused in large part by heredity and genetics. The Court flatly  rejected both the applicant’s and the WCAB’s attempts to nullify and eviscerate valid legal  apportionment based on the labeling and mischaracterization of pathology and prior asymptomatic  conditions as “mere risk factors” and also the WCAB’s erroneous finding that apportionment based 

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on asymptomatic pathology and prior conditions impermissibly related to risk factors of injury as  opposed to causation of permanent disability.  

The Court also stressed that the WCAB erroneously applied pre-SB 899 apportionment law by  requiring that any pre-existing pathology or asymptomatic prior conditions had to be disabling in  some form either prior to or subsequent to the current industrial injury or injuries. The Court of  Appeal said that with respect to post SB 899 apportionment this was simply “immaterial.” “If the  presence of these factors is necessary to constitute substantial evidence, there would be no purpose  in changing the law.” 

Substantial medical evidence issues: In Lindh, the WCAB applied the wrong legal apportionment  standard of pre-SB 899 apportionment law combined with its’ misinterpretation of Escobedo in erroneously assessing and determining the QME’s report did not constitute substantial medical  evidence of valid legal apportionment. There is no question both WCJ’s and the WCAB are vested  with the responsibility and authority to determine whether a medical report constitutes substantial  medical evidence to support legal apportionment. However, if the Board or a WCJ applies the  wrong legal principles and standards related to apportionment, even a medical report that has the  requisite “how and why” analysis pursuant to Escobedo combined with the correct legal analysis  will as evidenced by the WCAB’s decision in Lindh, be mistakenly and erroneously found to not  constitute substantial medical evidence. 

In Moreno v. Kern County Superintendent of Schools 2020 Cal.Wrk.Comp. P.D. LEXIS 98  (WCAB panel decision) decided by the WCAB after the Court of Appeal’s decision in Lindh, the  Board found that a QME’s apportionment determination of 40% nonindustrial based on a pre existing congenital condition did not constitute substantial medical evidence. In Moreno it was  undisputed that the applicant suffered from a pre-existing congenital condition in the form of  Chiari Malformation that was triggered and aggravated by her industrial injury. The Board rejected  the QME’s nonindustrial apportionment determination on the basis that the QME simply changed  his opinion on apportionment without providing an adequate explanation coupled with the fact that  the QME’s new opinion on apportionment was a mere conclusory one sentence statement reciting  the industrial and nonindustrial percentages without explanation, or insight into his conclusions.  

In rejecting the QME’s apportionment determination the WCAB stated: 

The decisions in Lindh and Rice do not alter the framework for making apportionment  determinations, in that all such determinations must be based upon medical evidence that  establishes how and why a non-industrial factor caused some portion of the resulting  disability. In both cases, substantial discussion of the medical evidence was provided by  the medical examiners that established a medical basis for apportionment to non 

industrial factors.

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See also, Mitchell v. Securitas Security Services, PSI 2019 Cal.Wrk.Comp. P.D. LEXIS 287  (WCAB panel decision) (Post Lindh decision where the WCAB rescinded a WCJ’s 98% award of  PD and found applicant was entitled to an unapportioned award of permanent total disability.  WCAB rejected AME’s apportionment of 10% of applicant’s left knee disability since the AME  impermissibly apportioned to applicant’s underlying preexisting arthritis when in fact applicant’s  left knee meniscus tear developed from traumatic arthritis caused by the industrial injury and not  the pre-existing arthritis.  

Garrison v. County of Los Angeles; PSI, Sedgwick Claims Mgt., Services, 2023  Cal.Wrk.Comp. P.D. LEXIS 51 (WCAB panel decision)  

Issues and Holding: In this case the WCAB affirmed a WCJ’s unapportioned award of 100%  PTD. The WCAB found that applicant’s vocational expert’s opinion rebutted the scheduled rating.  The WCAB also found that the IME in internal medicine’s apportionment determination in which he opined that 20% of applicant’s permanent disability related to his ulcerative colitis based on a  preexisting nonindustrial condition of rheumatoid arthritis did not constitute substantial medical  evidence. 

Factual & Procedural Overview: Applicant while employed as a firefighter filed a cumulative  trauma for the period of 9/20/99 through 10/18/17 claiming injury to his skin, psyche, knees, low  back, colon, and hernia, and in the form of hearing loss, anal leakage, and anemia. He also filed a  specific injury to his right knee and low back on October 17, 2017. In terms of medical legal  evaluations, based on an alternative Dispute Resolution Agreement between the defendant and  applicant’s union, both of applicant’s claims were evaluated by Independent Medical Evaluators  (IMEs) in five different medical specialties. Those specialties included orthopedics, internal  medicine, dermatology, psychology, and hearing loss. 

When the claims could not be resolved based on the medical reporting of the IME’s, the case  proceeded to trial with the WCJ awarding applicant 100% PTD without apportionment. Defendant  filed a Petition for Reconsideration that was denied by the WCAB. 

Defense Issues on Reconsideration: Defendant asserted that the reporting of applicant’s  vocational expert relied upon to rebut the scheduled rating did not constitute substantial evidence  and that the WCJ failed to consider evidence of nonindustrial apportionment.  

Issues Raised in Applicant’s Answer: Defendant contended the apportionment analyses of the  IMEs were conclusory and also failed to adequately explain the reasoning behind their  apportionment opinions. Applicant also alleged that the apportionment of the IME in internal  medicine based on applicant’s preexisting rheumatoid arthritis did not constitute substantial  medical evidence. 

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The WCAB’s Decision on Reconsideration 

The WCAB framed the issue presented on appeal as “…..whether the medical and vocational  evidence constitutes substantial evidence to support the conclusion that applicant is permanently  and totally disabled due to applicant’s inability to benefit from vocational rehabilitation.” 

  1. The Vocational Evidence: Applicant’s vocational expert determined that applicant was not  feasible to return to the open labor market as well as unable to participate in vocational retraining.  He reviewed all of the applicant’s relevant medical history and administered the standard vocational skills testing. Chronicling and synthesizing the plethora of applicant’s medical  problems and work restrictions especially those impacting his activities of daily living, as well as  his transferable skills and the results of the vocational interview and skills testing, applicant’s  vocational expert “concluded that applicant would not benefit from vocational services.” He also  concluded that the applicant was “not able to meet the minimum requirements of competitive  employment given his ongoing problems.”  

In contrast, the WCAB found the conclusions and opinion of the defense vocational expert who  opined that applicant was amenable to vocational rehabilitation and could compete in the open  labor market did not constitute substantial evidence. The Board identified several flaws in the  defense experts reporting including the fact that her analysis only focused and was limited only to  applicant’s orthopedic limitations and work restrictions ignoring any non-orthopedic work  restrictions. Her opinion was based on an incomplete review of the medical record as well as an  “incomplete understanding of applicant’s work restrictions.” 

The Board concurred with the WCJ’s conclusion that based on applicant’s vocational expert’s  opinion served to rebut the scheduled rating “by establishing that “due to the residual effects of  his work-related injuries [applicant] could not be retrained for suitable meaningful employment.”  (citations omitted).  

  1. Whether the IME in Internal Medicine’s Opinion that 20% of Applicant’s Permanent  Disability Related to his Ulcerative Colitis was Non-Industrial based on Applicant’s Pre Existing Rheumatoid Arthritis Constituted Substantial Medical Evidence: Applicant argued  that the Internal IME’s opinion on apportionment did not constitute substantial medical evidence  because applicant’s ulcerative colitis was triggered by exposure to workplace stress and more  importantly that there was no evidence that the pre-existing rheumatoid arthritis was a work  disabling condition or that applicant lost any time from work due to this condition. Applicant  further argued that there was no evidence that the pre-existing rheumatoid arthritis “had any impact  on the applicant’s inability to participate in vocational rehabilitation.”

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However, the WCAB agreed with the defense argument: 

….that the pre-existing conditions need not be labor-disabling to  appropriately form the basis of apportionment. (Petition, at 12:5;  Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604 [2005 Cal. Wrk.  Comp. LEXIS 71] (Appeals. Bd. en banc) [factors of apportionment may  include pathology, asymptomatic prior conditions, and retroactive  prophylactic work preclusions, provided there is substantial medical  evidence establishing that these other factors have caused permanent  disability].) 

Even though the Board acknowledged that valid apportionment could be based on pre-existing  conditions that were not labor disabling including pathology, asymptomatic prior conditions etc.,  the WCAB citing Escobedo indicated that the internal medicine IME failed to adequately explain  the nature of the non-industrial condition in this case the preexisting rheumatoid arthritis, and more  importantly how and why it is a cause or contributing causal factor of the applicant’s permanent  disability at the time of the evaluation, and how any why it is responsible for the assigned  percentage of disability.” 

The Board indicated the IME’s apportionment opinion and analysis is premised on a pre-existing  condition/pathology of rheumatoid arthritis which they describe as a “risk factor” “rendering  applicant more susceptible to the onset of ulcerative colitis in the presences of significant and  ongoing workplace stress.” The panel also noted that the IME testified that the colon surgery and  removal of applicant’s colon as well as the fact that applicant’s colitis does not allow him to absorb  iron leading to anemia were all in part the reason for his current impairment. 

In finding the internal IME’s opinion on apportionment did not constitute substantial medical  evidence the WCAB concluded by stating that: 

The record does not disclose how applicant’s rheumatoid arthritis, a cause of  applicant’s injury, caused the disability identified at the time of the evaluation,  following the removal of applicant’s colon. In the words of Escobedo, the  apportionment analysis fails to explain “how and why” applicant’s preexisting  rheumatoid arthritis caused permanent disability at the time of the evaluation, and  how and why it was responsible for approximately 20% of applicant’s residual  disability. (Escobedo, supra, 70 Cal.Comp.Cases 604.) 

Editor’s Comments: First, I agree with the WCAB’s ultimate conclusion that the internal  IME’s opinion on apportionment did not constitute substantial medical evidence. However, I  disagree with the analysis they applied in arriving at their conclusion. As I have pointed out  and emphasized in other case summaries in this section of the outline, many WCJ’s and some 

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WCAB panels apply either a wrong or incomplete analysis related to substantial medical  evidence under Escobedo, and more importantly based on the Court of Appeal’s decision in  Lindh dealing with apportionment to pathology and asymptomatic conditions and also  situations where an industrial injury aggravates and accelerates an underlying disease process.  

I find it incomprehensible that in a case like this, the WCAB did not cite to or refer to the  Lindh case at all which is the definitive dispositive case on apportionment to preexisting  pathology and asymptomatic conditions which the Board prefers to label as “risk factors.” In  Lindh, the Court of Appeal annulled the WCAB’s unapportioned award to applicant where the  Board erroneously determined that the QME’s report apportioning 85% of the applicant’s PD  related to loss of vision in applicant’s left eye did not constitute substantial medical evidence.  The Lindh court in reversing the WCAB found the QME’s 85% nonindustrial apportionment  constituted substantial medical evidence. The Court of Appeal in Lindh also noted that for  many years, the WCAB in numerous cases had been misinterpreting and misapplying the  Escobedo decision. The Court of Appeal held that the WCAB in their en banc decision in  Escobedo correctly found contrary to the WCAB’s subsequent misinterpretation of their own  en banc decision, that a preexisting pathology or condition (described by the WCAB as “risk  factors”) whether asymptomatic or not can be both a contributing cause of an applicant’s injury  as well as a contributing causal factor of the resultant permanent disability but in different  percentages.  

Defendant in this case during the deposition of the internal IME could have and should have  provided an analytical roadmap for the IME to follow in correctly applying both Escobedo and  Lindh so the IME would have the opportunity to cure the defects in his reports by providing a  revised opinion on apportionment that would have constituted substantial medical evidence. 

In the instant case, the WCAB correctly determined that the applicant’s preexisting rheumatoid  arthritis was at a contributing cause in part of applicant’s ulcerative colitis injury. In my  opinion the analytical methodology articulated by the Court of Appeal in Lindh, is applicable  not only to the instant case but also to any case where the issue involves potential  apportionment to preexisting underlying pathologies, conditions, or disease processes whether  symptomatic or not and also to those cases where an industrial injury aggravates, lights up, or  accelerates a pre-existing pathology or disease process. It also does not matter in the Lindh analysis and consistent with LC sections 4663 and 4664, whether the pre-existing pathology  or condition was labor disabling before the current injury or whether it caused any loss of time  from work or need for medical treatment. 

In terms of the applicant’s PD in this case, the initial analysis by a medical-legal evaluator in  explaining “how and why” the alleged non-industrial is a contributing causal factor of the  applicant’s PD at the time of the MMI evaluation is to identify each and every body part,  condition, or system is at issue in terms of assessing PD and possible apportionment. 

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The next step in the analysis is to determine what are all of the industrial and non-industrial  (if any) contributing causal factors of any resulting PD by assigning an approximate  percentage figure to each based on reasonable medical probability. The medical-legal  evaluator should also consider whether the applicant’s permanent disability would be as large  or great in the absence of any identified nonindustrial contributing causal factor or factors?  Also, did the non-industrial contributing causal factor or factors contribute to the applicant’s  need for surgery or any other medical treatment the applicant received for the body part,  condition, or system at issue? Also, in determining whether there is valid apportionment based  on preexisting pathology and asymptomatic conditions, prior disability is not required, nor  does it matter if the applicant did not receive medical treatment or lost any time from work  based on any preexisting pathology (whether symptomatic or not) or received any medical  treatment. 

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  1. The AMA Guides: Impairment versus Apportionment of  Disability: The AMA Guides under California’s workers’ compensation system are for  determining whole person impairment (WPI) and not apportionment under Labor Code  Labor Code §§4663 & 4664 unless an apportionment analysis or methodology used in the  AMA Guides is Consistent with Labor Code sections 4663 and 4664 and applicable case law. 

In three cases, Caires v. Sharp Healthcare (2014) Cal.Wrk.Comp. P.D. LEXIS 145 (WCAB panel  decision) and Hosino v. Xanterra Parks & Resorts 2016 Cal.Wrk.Comp. P.D. LEXIS 351 (WCAB  panel decision) and Pini v. WCAB (2007) 73 Cal.Comp.Cases 160 (writ denied), the WCAB held  that while whole person impairment and permanent disability are closely related, they should not  be equated nor are they synonymous when used by evaluating physicians to determine whether or  not there is valid nonindustrial apportionment under the AMA Guides to the Evaluation of  Permanent Impairment, Fifth Edition (AMA Guides).  

In Caires, the WCJ awarded 9% permanent disability relying on WPI and apportionment opinions  and determinations by a PQME in orthopedics, a primary treating physician in orthopedics, and an  AME in psychiatry. Applicant filed a Petition for Reconsideration contending that the opinions of  all three evaluating physicians on apportionment did not constitute substantial medical evidence.  The WCAB granted applicant’s Petition for Reconsideration, rescinded the award, and remanded  the case back to the trial level for further development of the record. The WCAB found that all  three reporting physicians’ opinions on apportionment were fundamentally flawed for different  reasons. Moreover, in light of what appeared to be a clear lack of familiarity with the basic  concepts and principles of valid legal apportionment under Labor Code §4663, the parties should  consider the use of an AME, or if they were unable to do so, the WCJ may consider appointing a  “regular physician” under Labor Code §5701. 

A large part of the WCAB’s decision focused on the opinion of the SPQME in orthopedics who  found that 87.5% of applicant’s 24% whole person impairment was related to nonindustrial  degenerative conditions, leaving only 3% permanent disability as industrial.  

In assessing and determining WPI, the SPQME in orthopedics utilized the range of motion method  (ROM). However, with respect to apportionment and causation of orthopedic permanent  disability, the SPQME used DRE lumbar Category IV. The SPQME was deposed by applicant’s  counsel. He was specifically questioned as to why he determined impairment using ROM and  then used DRE Category IV in determining apportionment. In trying to explain the methodology  he used, the SPQME specifically referenced an example in the AMA Guides as follows: 

  1. Well, to answer your question about using rating—using impairment—rating  impairment using range of motion and then apportionment using the DRE category  four, actually, there’s a classic example in the AMA guides using the same method  of analysis. It’s actually the [*7] book. It’s one of the examples in the book. They 

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rate a condition by range of motion, and then at the very end they say because there  is a degenerative condition, one might use the DRE method to apportion out the  preexisting condition. So it is within the AMA guides cited as one of the example  cases. So that’s how I followed this rule. (Exh. E, September 9, 2009 deposition  transcript, pp. 20:3-14.) 

The WCAB found the SPQME’s opinion on apportionment did not constitute substantial medical  evidence since he relied exclusively on an apportionment example in the AMA Guides as opposed  to rendering an opinion on apportionment in accordance with Labor Code §§4663 and 4664, which  the Board emphatically stated, “…defines apportionment without reference to the AMA Guides.”  In footnote 3, in Caires, the WCAB stressed, that the Guides acknowledge that “[m]ost states have  their own customized methods for calculating apportionment.” (Guides §1.6b, p.12). In a lengthy  two-and-a-half-page analysis and discussion, the WCAB made a careful distinction between a  determination of whole person impairment under the AMA Guides as opposed to a separate and  distinct determination of disability and apportionment.  

Initially, the WCAB indicated that under the Labor Code whole person impairment is merely a  component of permanent disability. In that regard the Board stated: 

Labor Code section 4660(b)(1) requires an evaluating physician to use the  descriptions, measurements, and percentages in the American Medical Association  Guides to the Evaluation of Permanent Impairment 5th Edition (AMA Guides) as  part of the basis for determining whole person impairment. (City of Sacramento v.  Workers’ Comp. Appeals Bd. (Cannon) (2013) 222 Cal.App.4th 1360 [79  Cal.Comp.Cases 1]; Blackledge v. Bank of America (2010) 75 Cal.Comp.Cases  613, 619-620 (Appeals Board en banc).) Whole person impairment is a component  of permanent disability. (Lab.Code § 4660; Schedule for Rating Permanent  Disabilities (Dept. of Industrial Relations, Div. of Workers’ Comp.’ January 2005),  p.1-5; AMA Guides, § 1.8, p. 13.) 

In Caires, the WCAB also indicated that if an evaluating physician uses an example from the AMA  Guides to make an apportionment determination, that example must be consistent with Labor Code  §4663 and requires a detailed explanation by the evaluating physician.  

“…[W]hen evaluating apportionment of permanent disability, a physician must  offer an opinion in accordance with Labor Code sections 4663 and 4664, which  define apportionment without reference to the AMA Guides. An example from the  AMA Guides may be utilized by a physician if he or she explains how the example  addresses the current cause of permanent disability under Labor Code section 4663  and Escobedo. (emphasis added).

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In Caires, the SPQME in orthopedics failed to provide any explanation as to why the  apportionment example he used from the AMA Guides was consistent with §4663 and applicable  case law.  

In Pini v. WCAB (2007) 73 Cal.Comp.Cases 160 (writ denied), the WCJ awarded applicant 46%  P.D. without apportionment. Applicant’s QME cited an example from the AMA Guides related to  the “aging process” and apportionment. The WCAB rescinded the award and remanded the case  for further development of the record on apportionment stating the opinion of applicant’s QME on  apportionment was not substantial evidence, “since it was based on the AMA Guides rather than  on Labor Code Labor Code §4663 and the applicable case law.”  

In the most recent case, Hosino v. Xanterra Parks & Resorts 2016 Cal.Wrk.Comp. P.D. LEXIS  351 (WCAB panel decision), the second and most recent case, the WCJ relying on the opinion of  an AME in orthopedics related to an October 26, 2011, specific injury, awarded applicant 34%  permanent disability after nonindustrial apportionment of 35%. Applicant filed for  Reconsideration, which was granted by the WCAB. The case was returned to the trial level for  further proceedings related to permanent disability and apportionment. The AME was deposed by  applicant’s counsel and the WCAB included in its lengthy Opinion seven full pages from the  AME’s deposition transcript.  

The WCAB indicated there were numerous ambiguities and conflicts in the AME’s deposition  testimony. The most significant flaw in the AME’s opinion and analysis was that the AME equated  apportionment of impairment with apportionment of disability which the WCJ also erroneously  adopted. The WCAB stated:  

We disagree with the WCJ’s statement that “the proper method of determining  apportionment was utilized,” because Dr. Wood and the WCJ apportioned  impairment not permanent disability. Of course impairment and permanent  disability are closely related, but they should not be equated to determine  apportionment. 

The WCAB then cited Caires to remind the WCJ on remand that the AMA Guides can be used to  evaluate whole person impairment but that with respect to determining apportionment, Labor Code  §4663 is “controlling.” As it did in Caires, the WCAB in Hosino stated: 

In contrast, when evaluating apportionment of permanent disability, a physician  must offer an opinion in accordance with Labor Code sections 4663 and 4664,  which define apportionment without reference to the AMA Guides.” In Caires, the  Board panel also noted in footnote 3 that “[t]he Guides acknowledge that [m]ost  states have their own customized methods for calculating apportionment.” (Guides  § 1.6b, p. 12).” 

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As a consequence, the Board found that the AME’s opinion on apportionment did not constitute  substantial medical evidence. While affirming parts of the WCJ’s Findings and Award the WCAB  amended the Findings of Fact, indicating that the issues of permanent disability and apportionment  should be deferred pending further proceedings and a new decision by the WCJ on remand with  jurisdiction reserved. (See also, subsequent decision Hosino v. Xanterra Parks and Resorts 2017  Cal.Wrk.Comp. P.D. LEXIS 341 (WCAB panel decision) (WPI does not directly equate to  permanent disability; when evaluating apportionment of permanent disability, a physician must  offer an opinion in accordance with Labor Code §§4663 and 4664, which define apportionment  without reference to the AMA Guides.) 

The critical lessons and practice pointers from Caires, Hosino and Pini are:  

1) While WPI and permanent disability are closely related, they are not synonymous. WPI  does not directly equate to permanent disability. As a general rule the AMA Guides cannot  be used by evaluating physicians or the parties to determine valid legal apportionment  under Labor Code §§4663 & 4664. 

2) Labor Code §4663 and related case law construing and applying §§4663 & 4664 define  apportionment without reference to the AMA Guides, including any references or  examples of apportionment in the Guides. 

3) If an evaluating physician attempts to utilize an example in the AMA Guides to determine  apportionment, he or she must explain in detail how the apportionment example in the  AMA Guides addresses the current causes of the applicant’s permanent disability under  Labor Code §§4663 and 4664 as well as Brodie. Escobedo and other cases construing and  applying §4663. The author believes very few, if any, evaluating physicians will be able  to provide such an explanation that will constitute substantial medical evidence. 

Editor’s Comment: In Ashman v. State of California Department of Rehabilitation Center (WCAB panel decision 1/31/22), the orthopedic QME based his determination of 89% non industrial apportionment attributable to the applicant’s previous fusions of 1998 and 2010 on a  formula or methodology based on the ratio between the pre-existing impairment and the post industrial impairment. The WCAB rejected this methodology because the QME treated  impairment as the equivalent of permanent disability without an adequate explanation. The WCAB  remanded the case back to the trial level for development of the record for the QME to clarify his  opinion on apportionment or in the alternative for the parties to have applicant evaluated by an  AME or if no agreement on an AME, for the WCJ to appoint a regular physician under LC 5701. 

The basis for the WCAB finding the formula or methodology used by the QME in this case was  not substantial medical evidence on apportionment was as follows: 

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Regarding the issue of apportionment, according to Dr. Pelton, there is 89%  apportionment to the non-industrial fusions of 1998 & 2010 under Labor Code section  4663 because the ratio between the pre-existing impairment and the post-industrial injury  impairment is 89% (25 [divided by] 28) = 89%.) In applying the ratio between the two  impairments to determine apportionment of permanent disability, it appears that Dr. Pelton  assumed the pre-existing impairment (25%) was subsumed within applicant’s impairment  at the time of the evaluation regarding the July 23, 2013 injury (28%). However, Dr.  Pelton did not provide an explanation for this assumption. Further, Dr. Pelton  treated impairment as the equivalent of permanent disability without explaining why  this produces an accurate evaluation of apportionment and an accurate description  of applicant’s disability caused by the motor vehicle accident. (emphasis added). 

Also, if as here, the doctor states that a portion of the injured worker’s disability is caused  by a pre-existing condition, the physician must explain the nature of the pre-existing  condition, how and why it is causing permanent disability at the time of the evaluation,  and how and why it is responsible for the percentage of the disability assigned by the  physician. (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621 (Appeals Board  en banc).) Dr. Pelton did not provide an explanation of his apportionment opinions, and  in turn did not comply with the requirements of Escobedo v. Marshalls, supra.  

For these reasons, the reports from Dr. Pelton do not constitute substantial evidence on  the issue of apportionment. Based on our review of the record, it appears there is no dispute  that applicant had undergone cervical fusion surgeries prior to his July 23, 2013 injury,  which would constitute pre-existing permanent disability factors. Permanent disability and  apportionment were issues submitted for decision and as discussed herein; the record does  not contain substantial evidence upon which those issues may be decided 

Editor’s Comment: In another case illustrating how some medical-legal evaluators come  up with some creative but questionable methods to determine apportionment is Jimenez v.  Pacific Cambria, Inc., 2022 Cal.Wrk.Comp. P.D. LEXIS 258 (WCAB panel decision).  Jimenez involved a knee replacement case with related permanent disability and  apportionment based on preexisting severe osteoarthritis that was a contributing causal  factor of the applicant’s left knee permanent disability. Instead of deciding what  approximate percentage of the applicant’s left knee permanent disability was caused by  the applicant’s preexisting osteoarthritis versus the specific left knee industrial injury, the  reporting physician based his apportionment determination on epidemiological studies  that demonstrated the percentage of people with osteoarthritis who are symptomatic or  asymptomatic. 

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Both the WCJ and the WCAB found the reporting physician’s opinion on apportionment  did not constitute substantial medical evidence since they were “unable to discern how  this relates to applicant’s permanent disability caused by factors other than the disability.”  As a consequence applicant received an award of 50% permanent disability without  apportionment. 

  1. Petitions to Reopen/Vargas 

Sykes v. Los Angeles County Metropolitan Transit Authority 2022  Cal.Wrk.Comp. P.D. LEXIS 175 (WCAB panel decision)  

Issues and Holding: Whether applicant sustained new and further disability related to her July  16, 2012 injury and whether her permanent disability was subject to apportionment pursuant to  Labor Code sections 4663 related to a 2016 non-industrial motor vehicle accident and based on  Labor Code 4664(b) related to a prior award involving applicant’s lumbar spine. On  Reconsideration, the WCAB affirmed the WCJ’s unapportioned award of 59% permanent  disability less credit for amounts previously paid by defendant.  

Factual & Procedural Overview: Applicant suffered two specific injuries in 2012 while  employed as a bus operator. On July 16, 2012 she suffered an injury to her cervical spine, lumbar  spine, right wrist, right ankle, left thigh and right shoulder. She also suffered a specific injury on September 20, 2012 to her psyche.  

The parties settled both specific injuries in 2015 by way of joint Stipulations with Request for  Award issued on December 21, 2015. It was stipulated that the July 16, 2012 specific injury caused  30% permanent disability with the parties including language that “ “SETTLEMENT IS FOR A  COMPROMISED 26% LUMBAR SPINE, 5% CERVICAL SPINE (MDT 30%) for 7/2012 DATE  OF INJURY.” As to applicant’s lumbar spine, the orthopedic AME, Dr. Angerman found 24%WPI  with apportionment to the lumbar spine of 10% related to non-industrial degenerative disease and  5% to a “prior industrial injury already stipulated to.” With respect to the specific psyche injury of  September 20, 2012, the parties stipulated that there was “No PD per QME Steiner as to the 9/2012  date of incident.” In March of 2017, the applicant filed a timely petition to reopen both claims. 

The Medical Evidence: Before the parties settled both specific injuries by way of the December  21, 2015 award, the parties used Dr. Angerman as an AME in orthopedics and Dr. Steiner as the  QME in psychiatry. With respect to the applicant’s Petition to Reopen, AME, Dr. Angerman re evaluated the applicant in November of 2017. The AME noted that applicant in the interim between  when he last evaluated her, gave a history of being involved in a non-industrial automobile accident  in February 2016. She provided details that the accident in 2016 had increased pain in her neck,  low back, left thigh and left knee. She also reported that she received physical therapy for 6 months 

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from February 2016 to August of 2016. She claimed that the therapy was beneficial and that her  neck, low back, and left thigh conditions “reverted to their previous state” by August 2016. Dr.  Angerman requested treatment records related to the February 2016 non-industrial auto accident. 

Treatment records were obtained and reviewed by Dr. Angerman confirming that applicant  complained of neck and back pain following the February 2016 auto accident. The records also  indicated applicant had increased neck and back pain after the auto accident. However, Dr.  Angerman was not provided with any of the orthopedic treatment records between the the non 

industrial traffic accident on February 16, 2016 and when a treating physician issued a report on  April 5, 2017, before Dr. Angerman’s re-evaluation of applicant in November of 2017. Dr. Angerman re-evaluated the applicant again on November 5, 2019, but the parties advised him  they were unable to procure any additional treatment records related to the February 16, 2016  nonindustrial traffic accident but still asked him to render an opinion on the applicant’s PD and on  apportionment. In that regard, Dr. Angerman stated: 

With regard to the February 2016 motor vehicle accident, it is noted that the patient took  six months off work. It is indicated she last worked on April 8, 2017 and officially retired  on February 1, 2018.  

…  

With regard to the lumbosacral spine, the medical evidence supports that she had  progressively worsening complaints even prior to the non-industrial motor vehicle  accident in February of 2016. Therefore, it is felt the patient has increased permanent  disability/impairment referable to her lumbosacral spine beyond the level already  stipulated to.  

… 

With regard to the lumbosacral spine, if the subtraction method is determined to be  applicable, it is then felt appropriate to state that, in all medical probability, 50% of the  patient’s increased level of disability/impairment would be attributable to the  nonindustrial motor vehicle accident occurring in February of 2016 with the remaining  portion attributable to the stipulated injury of July 16, 2012.  

If the subtraction method is not determined to be applicable, it is then felt appropriate to  state that, in all medical probability, 10% of the patient’s lumbosacral spine  disability/impairment would be attributable to underlying degenerative disease and her  history of obesity on a non-industrial basis, 30% would be attributable to the industrial  injury already stipulated to with the remaining portion split equally between the natural  progression of the July 16, 2012 industrial injury and the non-industrial motor vehicle  accident occurring in February of 2016.  

Dr. Angerman also provided impairment ratings including 28% WPI for the lumbar spine with a  3% add-on for pain. He also found applicant had sustained additional impairment to the right  shoulder but not to her cervical spine.

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The WCJ’s Decision: The WCJ issued a Findings and Award that applicant was entitled to an  unapportioned Award of 59% permanent disability for the July 16, 2012 injury, less credit for the  amounts previously paid by defendant. 

Defendant’s Petition for Reconsideration: On reconsideration, defendant argued that that  applicant’s permanent disability for the lumbar spine under LC 4663 should be apportioned based  on applicant’s 2016 non-industrial traffic accident and there must be apportionment for the lumbar  spine based on Labor Code section 4664(b) based on applicant’s prior award. 

The WCAB’s Decision on Reconsideration: With respect to defendant’s argument related to  apportionment of applicant’s lumbar spine PD based on her February 2016 nonindustrial traffic  accident the WCAB found that Dr. Angerman’s report did not constitute substantial medical  evidence. The Board noted that Dr. Angerman apportioned part of applicant’s lumbar spine PD to  the 2016 non-industrial automobile accident without a complete review of the medical records  pertaining to applicant’s treatment and condition related to the accident. “Furthermore, Dr.  Angerman does not explain how and why the non-industrial accident contributed to applicant’s  current level of disability for her lumbar spine.” Defendant also argued that the record should be  reopened for further discovery related to apportionment since Dr. Angerman did not adequately  address apportionment. However, the WCAB indicated defendant has the burden of proving a  valid basis for apportionment and that neither the WCJ nor the WCAB is “obligated to reopen  discovery where a defendant proceeds to trial on inadequate reporting on the issue of  apportionment.” 

Defendant also argued that there was a basis to apportion applicant’s lumbar spine permanent  disability under LC 4664(b) based on her prior award of December 21, 2015, which included her  lumbar spine. However, the WCAB noted that to support apportionment to a prior award under  LC 4664(b) the employer must prove more than just a prior award to the same body part, system,  or condition. 

The employer must make the following showing in order to prove apportionment for a  prior permanent disability award is warranted under section 4664:  

First, the employer must prove the existence of the prior permanent disability award.  Then, having established by this proof that the permanent disability on which that award  was based still exists, the employer must prove the extent of the overlap, if any, between  the prior disability and the current disability. Under these circumstances, the employer is  entitled to avoid liability for the claimant’s current permanent disability only to the extent  the employer carries its burden of proving that some or all of that disability overlaps with  the prior disability and is therefore attributable to the prior industrial injury, for which  the employer is not liable. (Kopping v. Workers’ Comp. Appeals Bd. (2006) 142  Cal.App.4th 1099, 1115; see also Pasquotto v. Hayward Lumber (2006) 71  Cal.Comp.Cases 223 (Appeals Board en banc).)  

The Board indicated that the parties initially stipulated that the applicant suffered 26% PD to her  lumbar spine in the 2015 award presumably based on Dr. Angerman’s report of June 24, 2015 in 

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which he apportioned applicant’s PD for the lumbar spine 10% to non-industrial degenerative disc  disease and 5% to a prior March 7 2007 award with the remaining PD attributable to the July 16,  2012 specific injury. Dr. Angerman in his subsequent report of November 5, 2019 related to  applicant’s petition to reopen for new and further disability discussed two possible scenarios for  apportionment of applicant of the applicant’s lumbar spine. However, the WCAB found Dr.  Angerman’s opinion to be unclear and ambiguous as to what he meant in one of the scenarios  when he states as to which “industrial injury already stipulated to” caused 30% of the PD in the  second scenario. Dr Angerman, while noting that there was a 2007 award of 16% for the neck,  back and shoulders but the specific level of PD attributed to the back, if any from this award is not  discussed by him. As a consequence the Board found that defendant failed to provide substantial  evidence establishing overlap between applicant’s prior disability and the 2007 award and her  current disability from the July 16, 2012 injury. 

The WCAB panel also pointed out that a review of the 2015 award reflects that the parties  stipulated to 26% PD for the lumbar spine “but there is no language in the award to indicate that  the parties stipulated that Dr. Angerman’s apportionment conclusions in 2015 would apply to a  claim for new and further permanent disability. A stipulation by the parties to specific  apportionment percentages may not be inferred when it is not contained in the 2015 award. 

Defendant also argued that under section 4664 there should be apportionment of the 26% PD for  the lumbar spine related to the July 16, 2012 injury that had been previously stipulated to.  However, while recognizing that the subtraction method advocated by defendant may be appliable  where there are two industrial injuries, in this situation the 2015 award the applicant received was  for the same injury for which the applicant has medically established new and further disability.  Therefore if cannot be defined as a “subsequent industrial injury” for purposes of section 4664(b).  

Defendant in this situation is only entitled to take a credit for the dollar amount previously paid  under the 2015 award related to the lumbar spine. Applicant is entitled to a new permanent  disability award reflecting the total level of disability resulting from the July 16, 2012 injury and  defendant is entitled to credit for amounts previously paid as permanent disability. (Shedelbowersupra.) This is precisely what the F&A reflects. Therefore the WCAB affirmed the unapportioned  award of 59% less credit for amounts previously paid by defendant. 

Editor’s Comment: It is important for practitioners to take note and to be wary of the WCAB’s  concern related to the distinction and legal effect in the 2015 Joint Stipulations with Request for  Award between the parties stipulating to 26% PD related to the applicant’s lumbar spine but that  the actual specific apportionment percentages referenced in the stipulation cannot be inferred since  was not contained in the actual Award signed and issued by the WCJ on December 21, 2015. “A  stipulation by the parties to specific apportionment percentages may not be inferred when it is not  contained in the 2015 award.” 

Determining apportionment with respect to new and further disability can be both problematical  and challenging if the parties and the WCJ are not familiar with the controlling case law and correct  methodology to use. In Corente v. Aetna; Ace America Insurance Co. 2023 Cal.Wrk.Comp. P.D. 

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LEXIS ___, (Corente II) The WCJ issued three separate Findings and Awards all of which failed  to apply the correct analysis for determining any applicable non-industrial apportionment related  to the applicant’s new and further disability of 26% related to a prior award of 7% PD after 50%  valid non-industrial apportionment. Defendant without citing to any post 2004 controlling case  law especially the Vargas WCAB en banc decision, argued it was entitled to have the 50% non 

industrial apportionment that applied to the original 7% award carried over and subtracted from  applicant’s new and further disability of 26%. The WCAB granted reconsideration and remanded  the case back for a correct determination/calculation of what if any non-industrial apportionment  should apply to the new and further disability of 26%. See also, Corente v Aetna, Ace America  Insurance Co. (Corente I) 2022 Cal.Wrk.Comp. P.D. LEXIS 358. 

Wilson v. 20/20 Administrative Services, The Hartford Insurance Company 2016  Cal.Wrk.Comp. P.D. LEXIS 654 (WCAB panel decision) 

Issues: What is the proper methodology to determine apportionment related to Petitions to Reopen  for New and Further Disability under the WCAB’s en banc decision in Vargas v. Atascadero State  Hospital (2006) 71 Cal.Comp.Cases 500 (WCAB en banc). In addition, whether the defendant  properly and timely raised the issue of apportionment. 

Holding: The proper methodology to determine whether there is valid legal apportionment under  Labor Code §§4663 and 4664 related to a Petition to Reopen for New and Further Disability under  the Vargas case is to determine whether there are any nonindustrial contributing causal factors of  the applicant’s increased permanent disability from the time of the prior award until the time of  the P&S/MMI evaluation related to the Petition to Reopen for New and Further Disability. The  fact permanent disability was identified as a disputed issue for trial is generally sufficient to raise  the related issue of apportionment.  

Overview and Discussion: Following trial the WCJ issued an amended Findings and Order  related to a cumulative trauma from April 2007 to April 2008, where applicant sustained industrial  injury to her neck, back, upper extremities, psyche, internal system, high blood pressure/nervous  system, and sleep, with permanent disability of 68% after apportionment. 

Applicant had also received a prior Stipulated Award on January 25, 2012, for 68%. Given the  prior Award, the WCJ found the present permanent disability of 68% was no greater than the prior  award of 68%, and that applicant take nothing further related to her Petition to Reopen for New  and Further Disability. 

Applicant filed a Petition for Reconsideration arguing that the AME in psychology and the PQME  in internal medicine had both found new and further permanent disability and that any  apportionment related to the new and further disability found by the WCJ was not supported by 

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substantial medical evidence. Applicant also argued defendant had not timely raised the issue of  apportionment before the case was tried and submitted. 

Whether defendant properly raised apportionment as an issue before the case was tried and  submitted. 

On Reconsideration the WCAB found that defendant had properly and timely raised the issue of  apportionment. In that regard the WCAB stated: 

Even though the “apportionment” box on page three of the Pretrial Conference  Statement of July 13, 2015 was not checked, the “other issues” box at the bottom  of the same page was checked, and “LC 4664” was handwritten within the list of  “other issues.” Secondly, the issue of permanent disability was identified in the  “Stipulations and Issues” statement in the Minutes of Hearing at trial on February  3, 2016, and although “apportionment” was not specifically raised, the  identification of permanent disability as a disputed issue was sufficient to raise the  issue of apportionment. (See Bontempo v. Workers’ Comp. Appeals Bd. (2009) 173  Cal.App.4th 689, 704 (74 Cal.Comp.Cases 419): (Raising the issues of permanent  disability (Lab. Code §4660) and apportionment (Lab. Code, §§4663, 4664) was  sufficient to raise the 15% increase in permanent disability under Labor Code  section 4658(d).].)  

The reporting physicians in psychiatry and internal medicine and the WCJ failed to properly  determine apportionment related to applicant’s Petition to Reopen for New and Further  Disability.  

In every case involving a Petition to Reopen for New and Further Disability the methodology for  calculating nonindustrial apportionment related to any purported new and further disability is set  forth in the controlling case of Vargas v. Atascadero State Hospital (2006) 71 Cal.Comp.Cases  500 (WCAB en banc). Vargas requires that any new and further disability should be determined  commencing from the day after any prior award up to the MMI/P&S evaluation determining  whether any new and further disability exists. Any alleged or purported nonindustrial  apportionment related to any new and further disability must be assessed over this specific limited  period of time. Any reference to apportionment that may have existed prior to the date of the  Award is not to be considered. 

Under the facts of this case, the reporting physician in orthopedics determined there was no new  and further disability. However, the AME in psychiatry found there was new and further disability,  but also applied 12% nonindustrial apportionment to applicant’s psychiatric disability. The PQME  in internal medicine found there was 80% nonindustrial apportionment to applicant’s 

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cardiovascular disability related to the Petition to Reopen for New and Further Disability. There  was no indication by either of these reporting physicians that the percentage of nonindustrial  apportionment was determined related to the specific time frame from immediately after the prior  Stipulated Award of January 25, 2012, up until each of their respective MMI/P&S evaluations and  related reports. 

Moreover, the WCAB determined that the PQME in internal medicine’s opinion on apportionment  did not comply with the Escobedo standards since he did not describe in detail the exact nature of  the apportionable disability caused by applicant’s preexisting hypertension and that the physician  was “opaque” in setting forth the basis for his apportionment opinion. The WCAB also took issue  with the fact that the AME in psychology may have derived his apportionment percentage  determination from the flawed apportionment opinion of the PQME in internal medicine. 

As a consequence, the Board found good cause to develop the record further on the issue of  apportionment and remanded the case for supplemental opinions consistent with their analysis.  The WCAB stressed in Footnote No. 2 that, “the question for both physicians is whether there is  a medical basis to apportion applicant’s present new and further permanent disability, if any,  without reference to any apportionment that may have existed at the time of the prior Stipulated  Award.” 

Editor’s Comment: In the first few years after SB 899 and Labor Code §§4663 and 4664 were  enacted, physicians, attorneys, and trial judges had an exceedingly difficult time determining how  to properly calculate and determine apportionment in cases involving Petitions to Reopen for New  and Further disability. This led to the WCAB’s en banc decision in Vargas v. Atascadero State  Hospital (2006) 71 CCC 500, which provides explicit guidance with respect to the correct  methodology in determining and applying valid legal apportionment under Labor Code §§4663  and 4664 related to Petitions to Reopen For New and Further Disability. For a medical opinion to  constitute substantial medical evidence an applicant has suffered new and further disability over  and above a prior award, the determination of valid legal apportionment must be based on a focal  timeline between the date the prior Stipulated Award issued and the MMI/P&S evaluations in any  related medical specialty. It is only during this defined and limited timeframe that any contributing  nonindustrial causal factors of the applicant’s new and further disability must be determined  without reference to any apportionment or basis for apportionment that may have existed at or  before the date of the prior Stipulated Award. 

Another case illustrating the problem of physicians and a workers’ compensation judge not using  the correct methodology mandated in the WCAB’s en banc decision in Vargas is Condit v. Panama  Buena Vista Unified School Dist. PSI 2018 Cal. Wrk. Comp. P.D. LEXIS 232 (WCAB Panel  Decision). 

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In the Condit case, applicant received a prior Award in July 2013, which in part was based upon a  compromise of psychiatric permanent disability from two psychiatrists. One psychiatrist indicated  a GAF of 52 which equated to a 27% WPI with 20% non-industrial apportionment resulting in 45% psychiatric permanent disability after apportionment. The other psychiatrist found a GAF of  41, equal to a 48% WPI without apportionment equating to 81% PD. On the Petition to Reopen,  the same reporting physicians agreed that applicant now had a GAF of 31 with equated to 69 WPI.  One psychiatrist found 40% of the increased psychiatric permanent disability was attributable to  non-industrial factors. The WCJ found that applicant did not suffer any new and further disability  despite the fact both psychiatrists found increased psychiatric permanent disability. The WCAB  rescinded and remanded the WCJ’s decision. 

  

The WCJ erroneously relied on the reporting of one of the physicians since the doctor did not  specify the non-industrial apportionment of the increased psychiatric disability occurred during  the time frame of the date of the prior Award issued on July 9, 2013, and the MMI evaluation in  December of 2014. Both the WCJ and the reporting physician are prohibited from changing any  nonindustrial apportionment to applicants’ entire Award, which includes the disability found  previously. See also Corente v. Aetna: Ace American Ins. Co., 2022 Cal.Wrk.Comp. P.D. LEXIS  358 (Corente I)(WCAB panel decision) (In a case involving a Petition to Reopen, the WCAB  granted the defense petition for reconsideration and remanded the case back to trial level for the  WCJ to correctly determine whether applicant actually suffered any new and further disability and  if so, the proper methodology to use in calculating whether or not a prior award of 7% PD after  apportionment of 50% could or should be applied and calculated against any new and further  disability.) (caution superseded by Corente II, see pages 48 & 49 of outline.) 

In Knapp v. Department of Social Services 2019 Cal.Wrk.Comp. P.D. LEXIS 102 the WCJ as well  as both defense and applicant’s counsel used the wrong methodology to calculate apportionment  involving a Petition to Reopen involving a pre-SB899 combined award involving three separate  spine injuries (two specifics and one CT) that resulted under the Wilkinson case in a combined  award of 25% PD. Applicant filed a timely Petition to Reopen the combined PD award of 25%.  The parties did not dispute applicant suffered new and further PD. However, in calculating the  value of the new and further disability factoring in 30% nonindustrial apportionment to be applied  to the nonindustrial portion of applicant’s increased PD, the WCJ and the parties failed to use the  correct methodology. The WCAB concluded that the 30% nonindustrial apportionment must be  applied to applicant’s increased percentage of disability, not to the overall dollar value of the  nonindustrial portion of the increase in the PD award. The WCAB characterized this case as unique  since the Vargas en banc decision involved a post SB 899 petition to reopen case involving only  a single injury and the instant case involved a pre-SB 899 combined award related to three separate  injuries under the old Wilkinson case that was essentially abrogated by SB 899 as reflected in the  Benson WCAB en banc decision. 

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For other cases illustrating the correct application of the methodology under the WCAB’s en banc  decision in Vargas, see Charon v. WCAB (Ralph’s Grocery Company (2013) 78 Cal.Comp.Cases  869 (writ denied) (Valid 10% nonindustrial apportionment in a Petition to Reopen in a psychiatric  case based on applicant’s nonindustrial issues and interactions with her daughter and grandchildren  that all occurred after the original Stipulated Award of 48% in February of 2000. Applicant’s  award of 100% PTD on the Petition to Reopen was reduced to 90%), see also, Rocha v. TTX  Company 2008 Cal.Wrk.Comp. P.D. LEXIS 348 (WCAB panel decision); Bunnie Orange v.  Hilton Hotel Corp., Specialty Risk Services 2008 Cal.Wrk.Comp. P.D. LEXIS 14 (WCAB panel  decision); Cruz v. Santa Barbara County Probation Dept. 2008 Cal.Wrk.Comp. P.D. LEXIS 427  (WCAB panel decision); Milivojevich v. United Airlines (2007) 72 Cal.Comp.Cases 1415, 2007  Cal.Wrk.Comp. LEXIS 322 (writ denied); Wilson-Marshall v. WCAB (2007) 72 Cal.Comp.Cases  1736 (writ denied); Johnson v. City of Los Angeles (2009) 74 Cal.Comp.Cases 1, Court of Appeal (not certified for publication, 18 ½ page decision!); Rowe v. County of San Diego 2009  Cal.Wrk.Comp. P.D. LEXIS 470 (WCAB panel decision); Balderas v. GTE Corporation 2010  Cal.Wrk.Comp. P.D. LEXIS 270 (WCAB panel decision); Tull v. General Lighting Service  (CIGA) 2010 Cal.Wrk.Comp. P.D. LEXIS 391 (WCAB panel decision); Ortiz v. Orange County  Transportation Authority, PSI 2012 Cal.Wrk.Comp. P.D. LEXIS 429 (WCAB panel decision);  Bates v. WCAB (2012) 77 Cal.Comp.Cases 636; 2012 Cal.Wrk.Comp. LEXIS 80 (writ denied). 

  1. BENSON 

Vior v. The Regents of the University California (Vior I) 2023 Cal.Wrk.Comp.  P.D. LEXIS 288 (WCAB panel decision); see also, Vior v. The Regents of the  University California (Vior II) 2023 Cal.Wrk.Comp. P.D. LEXIS 370 (WCAB  panel decision)(WCAB on removal by applicant reaffirmed its prior decision  in Vior I) as well as Vior v. WCAB (Vior III) (2024) 89 Cal.Comp.Cases 493;  2024 Cal.Wrk.Comp. LEXIS 13 (writ denied). 

Issues and Holding: This case involves multiple issues including Benson apportionment, the LC  4664(b) conclusive presumption related to a prior award, and the applicability of LC 4664(c)(1)(E)  dealing with the accumulation of all permanent disability awards issued with respect to one region  of the body not exceeding 100%. The third issue in the case was whether the defendant was entitled  to the conclusive presumption under LC 4664(b) related to applicant’s prior award of 68.5%. The  WCJ found that with respect to one cumulative trauma claim, applicant was entitled an award of  permanent total disability without apportionment to applicant’s prior Stipulated Award of 68.5%  PD. In addition, the WCJ with respect to a second CT injury awarded applicant an unapportioned  award of 13%. The WCJ failed to address the Benson issue as well as the 4664(c)(1)(E) issue.

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The WCAB granted defendant’s Petition for Reconsideration and remanded the case for further  development of the record on permanent disability and apportionment with a detailed analysis  designed to provide guidance to the parties on remand. 

Factual Overview: Applicant filed two separate cumulative trauma injuries ending in 2015, both  involving the upper extremities. In addition, applicant had received a prior award on 9/10/10 for  68.5% PD under the 1997 PDRS. The prior award involved a CT for the period of March 1995  through February 29, 1996. The reporting physician in the case was appointed by the WCJ as a  “regular physician”. In terms of apportionment, the “regular physician” apportioned 50% of  applicant’s right elbow PD to the old 1996 CT and 50% to the second CT. With respect to  applicant’s left elbow PD, he apportioned all of the PD to the 1996 CT. He apportioned applicant’s  left-hand PD 50% to the 1996 CT and 50% to the second CT injury. Defendant argued that the  regular physician’s apportionment findings constituted substantial medical evidence to apply  either or both Labor Code 4663 and Benson apportionment of the applicant’s disability between  multiple injuries. 

The LC 4663 and Benson Issues: The WCAB noted that the WCJ’s report on reconsideration  failed to address and was “not responsive” to defendant’s apportionment arguments related to  Benson and LC 4663. As a consequence, these issues must be revisited on remand. However, the  WCAB found the physician’s apportionment determination did not constitute substantial medical  evidence based on the following analysis:  

In this regard, we note that page two of Dr. Newton’s December 17, 2019 report  offers what appears to be some “boilerplate” medical language that nonetheless  includes some reasoning about “how and why the [applicant’s disabilities are]  causally related to [each of her] industrial [injuries],” consistent with Escobedo v.  Marshalls (2005) 70 Cal.Comp.Cases 604, 621 (Appeals Board en banc). The  WCJ must revisit and resolve whether Dr. Newton’s reporting constitutes  substantial evidence of apportionment under section 4663, pursuant to the  standards set forth in Escobedo. 

The 4664(b) and 4664(c)(1) (E) Issues: The Board identified several issues concerning  apportionment under LC 4664. The first related to applicant’s prior award dated September 21,  2010 in which she received an award of 68.5% PD under the 1997 PDRS for injuries to her elbows,  wrists and thumbs related to a cumulative trauma injury. Citing the Kopping case, the WCAB  indicated that defendant had met the first prong of their burden related to 4664(b) by proving up  the existence of the prior award. However, the Board indicated there had to be further inquiry on  remand on the issue of whether there was any overlap and the extent of the overlap, if any, between  applicant prior disability related to the prior award under the 1997 PDRS and her current disability  under the 2005 PDRS. 

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To provide guidance to the WCJ and the parties the Board stated: 

Therefore, we conclude that the issue of overlapping disabilities (if any)  occasioned by the prior and subsequent cumulative traumas requires further  inquiry and resolution by the WCJ. We agree with the approach taken by the  Board in Richard v. City of Los Angeles (2022) 2022 Cal. Wrk. Comp. P.D.  LEXIS 287, wherein the panel explained:  

We have previously held that a permanent disability rated under the 1997  PDRS would be properly apportioned to an award of permanent disability  rated pursuant to the 2005 PDRS, if the prior disability could be converted  to an impairment under the 2005 PDRS utilizing the same method as the  current disability. (See Robinson v. Workers’ Comp. Appeals Bd. (2011)  76 Cal.Comp.Cases 847, 851 (writ den.).) The parties need to ask the  doctor to review the available medical records regarding the previous  injuries, and then, if possible, to rate applicant’s left ankle disability,  caused by each of the injuries, using factors identified in the 2005 PDRS,  and then to address apportionment as appropriate. 

The WCAB on remand indicated the WCJ should request and advise the reporting “regular  physician” to “review the available medical records regarding the prior cumulative trauma injury  and if possible, rate the disabilities caused by each of the two cumulative trauma injuries, using  factors identified in the 2005 PDRS so as to address the issue of apportionment under section  4664(b).” 

The 4664(c)(1)(E) Issue: This issue is the most challenging both medically and legally. On  remand the WCAB stated the following as guidance for the WCJ and the parties: 

…….the WCJ must address whether or not section 4664(c)(1)(E) applies. The  prior stipulated Award of 68.5% permanent disability for the earlier cumulative  trauma injury – all to the upper extremities – must be considered, unless the WCJ  determines that applicant has lost the use of both hands, which would generate a  conclusive presumption of permanent and total disability pursuant to section  4662(a)(2). Otherwise, it appears that only 31.5% permanent disability (100%- 68.5%) may be available to award for the subsequent cumulative trauma in  ADJ9828972. Further, if section 4664(c)(1) does apply, it appears there would be  no basis for apportionment under section 4663 because the prior Stipulated Award  already accounts for it. However, the WCJ also must consider that if he finds  applicant has lost the use of both hands, which justifies a presumed permanent  and total disability, then there can be no apportionment of that disability. 

In conclusion the WCAB also opined that with respect to whether the applicant suffered one CT  or two CT’s, the WCJ and the parties should be mindful of the fact that the parties stipulated at 

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trial that there were two separate CT’s and not one CT. The Board reminded the parties that as a  general rule stipulations are binding on the parties absent a showing of good cause citing Robinson  v. Workers’ Comp. Appeals Bd. (1987) 194 Cal.App.3d 784 [52 Cal.Comp.Cases 419]; Brannen  v. Workers’ Comp. Appeals Bd. (1996) 46 Cal.App.4th 377 (61 Cal.Comp.Cases 554) [party not  permitted to withdraw from stipulation absent showing of good cause]. 

In Vior III, the Court of Appeal in a writ denied case affirmed the WCAB’s development of the  record order on the 4663 apportionment as well as the L.C, 4664(c)(1)(e) issue of the application  of the life time cap limitation on PD related to the applicant’s prior award of 68.5% involving the  upper extremities leaving only 31.5% that may be available to the applicant related to any award  for the most recent CT injury. 

Editor’s Comment: This case graphicly illustrates the parties, the reporting medical-legal  evaluator (appointed by the WCJ) and the WCJ all struggling with how to correctly analyze and  apply the correct legal principles and standards and applicable case law related to three challenging  apportionment issues under Labor Code sections 4663 and 4664. What the WCAB did not discuss  is that even if the defendant failed to prove overlap of the applicant’s disabilities related to the  prior award and her current disability under LC 4664(b) the prior injuries that formed the basis for  the Stipulated Award of 68.5% i.e., to her bilateral wrists, bilateral thumbs and bilateral elbows  could still be considered and analyzed under LC 4663 as to whether they were contributing causal  factors of applicant’s current disability related to those same body parts if part of the new CT under  the 2005 PDRS.  

Unlike, 4664(b), under a 4663 analysis, proof of overlapping disability is not required. The issue  under LC 4663 is whether the prior injuries to the same body parts were a contributing cause of  the applicant’s current PD at the time of the MMI/P&S evaluation. 

Johnson v. State of California, Department of Corrections, Inmate Claims 2020  Cal.Wrk.Comp. P.D. LEXIS 57 (WCAB panel decision).  

Issues & Holding: The WCAB rescinded the WCJ’s single combined award of permanent total  disability without apportionment related to applicant’s two specific injuries and one cumulative  trauma claim and remanded for further proceedings. The WCJ failed to apply apportionment of  disability pursuant to Benson among applicant’s three separate industrial injuries even though the  AME in orthopedics consistently provided separate permanent disability ratings for applicant’s  three injuries.  

The WCJ also erroneously relied on the opinion of applicant’s vocational expert in concluding  applicant was permanently totally disabled based on her not being amenable to vocational  rehabilitation and inability to return to the labor market. However, the WCAB held that the opinion  of applicant’s vocational expert did not constitute substantial evidence sine the vocational expert  did not consider or adequately address the orthopedic AME’s apportionment of applicant’s right 

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knee disability to nonindustrial arthritis pursuant to Acme Steel v. Workers’ Comp. Appeals Bd. (2013) 218 Cal.App.4th 1137.  

Factual and Medical Overview: Applicant was employed as a firefighter inmate by the  Department of Corrections. The parties stipulated that applicant sustained three separate admitted  industrial injuries. Applicant suffered two specific injuries on April 26, 2001 and February 15,  2002 to her lumbar spine and hepatitis C. She also suffered a cumulative trauma injury to her left  knee, left shoulder, and neck over the period of April 6, 2001 to March 6, 2002. Also based on the  reporting of the AME in orthopedics, applicant suffered a compensable consequence injury to her  right knee with related disability based on applicant shifting her weight from her left knee ACL  reconstructed knee. 

Medical Reporting: There were AME’s in internal medicine and orthopedics. The AME in  orthopedics prepared numerous reports over a twelve-year period from 2007 through 2019. With  respect to applicant’s lumbar spine disability, the orthopedic AME consistently opined that the  28% WPI related to the lumbar spine was equally apportioned between applicant’s two specific  injuries. When asked whether the disability caused by applicant’s injuries were “inextricably  intertwined” the AME indicated his previous opinion on apportionment remained essentially  unchanged.  

When the AME reevaluated applicant in 2017 he determined that she suffered a compensable  consequence injury to her right knee and the right knee impairment should be apportioned 50% to  the cumulative trauma injury and 50% to applicant’s underlying degenerative arthritis.  

In 2017 the AME agreed with applicant’s vocational expert that applicant was permanently totally  disabled due to her pain medication usage combined with the fact of her worsening condition  manifested by a significant limitation on her ability to sit and stand intermittently. Also, a trial  spinal cord stimulator was not successful and made her substantially worse. 

The Vocational Evidence: Applicant’s vocational expert concluded the applicant did not have the  functional capacity to compete in the labor market and was unable to perform work on a sustained  basis, and not amenable to vocational rehabilitation sustaining a 100% loss of future earning  capacity. With respect to medical apportionment, the expert stated he found no basis for  apportionment in the medical records and therefore no basis for apportionment of the vocational  impact of the applicant’s disability, impairments, and work restrictions related to the orthopedic  body parts of cervical spine, left shoulder, and low back as determined by the AME. The vocational  expert did not address or consider applicant’s right knee disability and the AME’s nonindustrial  apportionment of applicant’s right knee disability as being 50% attributable to her underlying  degenerative arthritis. 

The WCAB’s Decision: The WCAB in a short two sentence introductory paragraph set for the  reasons why it was rescinding the WCJ’s single combined award of permanent total disability  without apportionment of applicant’s permanent disability among her three separate injuries. “The 

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WCJs award of permanent total disability arising out of applicant’s three separate claims of  industrial injury is not sustainable without further evidence and analysis. The medical and  vocational reporting is not sufficient to support the award.” 

Citing to Benson the WCAB stated:  

The WCJ issued a single combined award of permanent total disability for all three dates  of injury. Absent a finding that the medical evidence establishes that applicant’s disability  cannot be parceled out between his separate injuries, applicant’s disability must be  apportioned between his separate dates of injury. (Benson v. Workers’ Comp. Appeals  Bd. (2009) 170 Cal.App.4th 1535, 1560 [74 Cal.Comp.Cases 113].) 

The Board stressed the fact that there was no evidence that the orthopedic AME could not parcel  out the approximate percentages of disability related to each of applicant’s separate and successive  injuries. 

The WCJ issued a single combined award of permanent disability without reference to  whether the medical record justified this determination. We note that Dr. Scheinberg was  asked to opine on this issue, but we have not seen, or been directed to, a report where he  stated that he could not parcel out the approximate percentages of the overall permanent  disability caused by each industrial injury. In fact, Dr. Scheinberg has consistently  provided separate permanent disability ratings for applicant’s three industrial injuries.  There is no legal basis for the issuance of a joint award of permanent disability in the  absence of a finding by the WCJ that the medical record does not support the  apportionment of permanent disability between the separate industrial injuries. 

The WCAB also explained why applicant’s vocational evidence was not substantial evidence and  therefore could not support the WCJ’s unapportioned award of permanent total disability. 

Here, the WCJ relied on Mr. Van Winkle’s opinion to find that 100% of applicant’s  permanent disability is due to her industrial injuries. However, Mr. Van Winkle’s report  is not substantial evidence that applicant is totally permanently disabled on an entirely  industrial basis. This is because Mr. Van Winkle’s expert opinion did not account for the  apportionment of applicant’s permanent disability. Where the medical disability, on  which a vocational expert’s report is based, is apportionable, a vocational expert cannot  simply say that “there does not appear to be a basis for apportionment of the vocational  impact of Ms. Johnson’s industrial medical disability” as Mr. Van Winkle did here, when  the medical evidence is to the contrary. An expert opinion that disregards or ignores  relevant facts does not constitute substantial evidence. (citations omitted). 

The WCAB’s Rescission and Remand: The Board rescinded the WCJ’s Joint Findings of Fact  and Order and returned the matter to the trial level to resolve the issues discussed herein and for  issuance of a new final award. With respect to applicant’s permanent disability, the WCAB stated, 

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“[t]herefore, we will return this matter to the trial level for further determination of the proper  rating of the disability caused by each date of injury and apportionment between the dates of injury,  per Benson, supra. 

Editor’s Comments: Understanding and navigating apportionment of permanent disability  between and among separate and successive injuries is challenging and inherently problematical  due primarily to the “limited exception” apportionment escape hatch available to try and avoid  diminishment of an applicant’s recovery inherent in separate awards of PD as opposed to one  combined award if of PD related to multiple injuries which is always beneficial to an applicant. After reading scores of Benson apportionment cases it is the editor’s opinion that many judges and  various WCAB panels do not favor the requirement i.e., general rule under Benson that permanent  disability related to separate and successive injuries is required to be apportioned among and  between separate injuries except in limited circumstances. 

This can be readily seen in Philpot v. Performance Dairy Services Inc., 2023 Cal.Wrk.Comp. P.D.  LEXIS 43; 51 CWCR 51 In Philpot it was undisputed applicant was 100% permanently totally  disabled based primarily on a traumatic brain injury resulting from two separate specific industrial  traffic injuries on 4/26/10 and 7/14/11. The reporting physicians were two AME’s and one IME.  Following trial the WCJ found the applicant based on Benson and applicable 4663 apportionment,  was to received two separate awards of 70% and 30% as opposed to one combined award of 100%  PTD. Applicant filed for Reconsideration that was granted by the WCAB who reversed the WCJ’s  two separate PD awards implicitly finding that the Benson exception applied resulting in applicant  receiving a combined unapportioned award of 100% PTD. In finding the medical reporting on  Benson apportionment did not constitute substantial medical evidence, the WCAB indicated in  their opinion all of applicant’s PD related to his traumatic brain injury was primarily attributable  to the first specific injury and that the PD from both injuries was “probably” inextricably  intertwined thus justifying application of the Benson “limited circumstances” exception. NOTE: The Editor has been informed that defendant intends to file a writ in this case so please make sure  to check subsequent case history for developments. 

Also in Caravez v. Red Bluff Meadows and National Union Fire Ins., Co., 2023  Cal.Wrk.Comp.P.D. LEXIS 314; 89 Cal.Comp.Cases 510, granted defendant’s Petition for  Reconsideration and rescinded the WCJ’s combined award of 64% PD related to a specific and  separate CT injury. Applicant had a prior significant low back injury in 2000 involving his low  back that resulted in surgery and ongoing medical treatment. While the WCAB agreed with the  WCJ that the AME’s report did not constitute substantial medical evidence on LC 4663  apportionment and, even if all of the applicant’s PD was entirely industrial without a basis for LC  4663 apportionment a Benson analysis/opinion is still required as to whether the applicant’s PD  can or cannot be parceled out between the current CT and specific injuries. The WCAB also gave  the AME an opportunity to revisit the issue of overlap of PD between applicant’s prior low back  injury and the two separate issue currently at issue.

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The WCAB in the case of Sanchez (Jaime) v. California Dept. of Corrections, SCIF (2022) 87  Cal.Comp.Cases 344; 2022 Cal.Wrk.Comp. P.D. LEXIS 35 (WCAB panel decision) dealt with an  issue of first impression related to Benson apportionment involving a specific injury and a  cumulative trauma injury. The unique issue in this case was that it was the defendant and not the  applicant who was trying to prove an exception to Benson in arguing that applicant should only  receive one combined award of PD rather than two separate awards. 

In Sanchez, the WCJ awarded applicant 100% permanent total disability related to a specific injury  and 85% PD related to a CT injury. Defendant filed for reconsideration and one of the issues they  raised was that the medical evidence warranted a single combined award of permanent disability  for applicants two separate and successive injuries. The WCAB described this situation as a  “peculiar circumstance” In that regard the WCAB stated, “[s]ince defendant would be the  beneficiary of the reduced liability inherent in a single award, we believe that defendant has the  burden of proof to establish the applicability of the Benson exception.”  

In rescinding the WCJ’s Findings and Award and remanding back to the trial level for further  proceedings on a variety of issues including the Benson issue raised by defendant, the WCAB  noted that there was a subsidiary issue not addressed by the WCJ related to the Benson issue. The  WCAB noted that inconsistent with defendant’s argument that the medical evidence establishes  applicant’s two injuries are “inextricably intertwined” defendant stipulated at trial that applicant  sustained two distinct and separate industrial injuries, “even though it appears the medical  evidence shows a significant relationship between the two injuries.” The Board stated that “the  general rule is that stipulations are binding on the parties absent a showing of good cause.”  (citations omitted).  

In providing guidance to the WCJ on remand the Board indicated that: 

Under the circumstance of the instant matter, we are persuaded that the WCJ must  address the issue of whether defendant’s attempt to establish the Benson exception of one  award, on the premise that the two injuries are “inextricably intertwined,” requires  defendant to make a showing of good cause to disregard its stipulation to two distinct  injuries. Again we express no final opinion on this issue. 

For another case dealing with Benson the WCAB rejected and rescinded a WCJ’s unapportioned  award of 74% PD related to three specific injuries based on the AME’s conclusory determination  that the disabilities from all three injuries were “inextricably intertwined” see, Cargile v. State of  California, Department of Transportation (2020) 48 CWCR 136. The WCAB issued their own  amended findings of fact and awarded the applicant three separate awards for each of three specific  injuries of 28%, 33%, and 20% PD as opposed to a single unapportioned award of 74% PD. The  three separate awards had a combined dollar value of approximately $93,000 versus $144,000 for  the single unapportioned award resulting in the applicant receiving $51,000 less due to three  separate awards versus one unapportioned single joint award.

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See also, Navarrete v. Sectran Security, Inc., 2020 Cal.Wrk.Comp. P.D. LEXIS 281 (WCAB  affirmed WCJ unapportioned award of 46% PD on the basis the QME’s report with respect to  Benson apportionment related to a specific and CT injury as well as injuries applicant incurred in  a nonindustrial automobile accident did not constitute substantial evidence. The QME failed to  explain the nature of the preexisting condition and how and why the preexisting condition and any  related disability was responsible for a percentage of applicant’s permanent disability at the time  of the QME evaluations. Also, the QME did not explain why each of the two separate and  successive industrial injuries caused a portion of the total PD he found.) 

However, there are still many cases where the WCAB has found that the Benson “limited  circumstances” exception is applicable, and therefore the applicant was entitled to a single  combined award as opposed to separate awards for each separate and distinct industrial injury.  

In Vizcarra v. Master Toys and Novelties, 2023 Cal.Wrk.Comp. P.D. Lexis 311 the Board on  Removal reversed a WCJ’s order to further develop the record on Benson apportionment related  to a specific and CT injury. The WCAB found that further development of the record on Benson  apportionment was unwarranted since the QME’s in psychiatry and internal medicine both  provided a reasonable and detailed explanation of why based on reasonable probability they were  unable to parcel out the approximate percentages related to applicant’s specific and CT injury  contributed to the applicant’s overall permanent disability thus satisfying the Benson “limited  circumstances” exception to the general rule that apportionment is required among separate and  successive injuries. As a consequence, defendant was unable to meet its burden of proof under  Benson and applicant would be entitled to a combined award of PD. 

See, Carter v. City of Los Angeles, PSI, 2021 Cal.Wrk.Comp. P.D. Lexis 39 (single joint award of  79% of PD related to a specific and CT injury when presumptive heart condition/injury  “inextricably linked” to other non-presumptive injuries); Schieffer v State of California, Salinas  State Prison 2021 Cal.Wrk.Comp. P.D. LEXIS 48 (single joint award of 100% PTD for a specific  and CT injury based on Benson exception that disability attributable to each injury was  “inextricably intertwined.”); Bullard v. County of Los Angeles 2020 Cal.Wrk.Comp. P.D. LEXIS  104 (single joint award of 100% PTD based lack of unanimity of opinion by three AME’s on  Benson apportionment of PD between a CT and specific injury. Psychiatric AME indicated  disability was inextricably intertwined while both the orthopedic and internal medicine AME’s  found Benson apportionment between both injuries); Peters v. Bank of America 2021  Cal.Wrk.Comp. P.D. LEXIS 122 (100% single joint 100% PTD award where AME was unable to  apportion disability between a specific and CT injury and therefore case came within “limited  circumstances” exception to Benson.); Lopez v. Hartnell Packing, Inc., 2021 Cal.Wrk.Comp. P.D.  LEXIS 85 (single joint award of 100% PTD related to two specific injuries and one CT injury  based on lack of unanimity on Benson apportionment by reporting evaluators. QME able to  apportion applicant’s disability between the separate injuries but psychiatric AME opined  disability was inextricably intertwined. QME in internal medicine deferred apportionment to  orthopedic specialist.). 

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Alea North American Ins. Co., v. W.C.A.B. (Herrera) (2018) 84 Cal. Comp.Cases  17, 2018 Cal.Wrk.Comp. LEXIS 123 (writ denied on 12/5/18), prior history, U.S.  Fire Insurance Company v. Workers’ Compensation Appeals Board (Herrera) (2018) 83 Cal.Comp.Cases 1829, 2018 Cal. Wrk. Comp. LEXIS 98 (Writ  Denied); Herrera v. Maple Leaf Foods, 2018 Cal. Wrk. Comp. P.D. LEXIS 430  (WCAB Panel Decision); and Herrera v Maple Leaf Foods, 2018 Cal. Wrk.  Comp. P.D. LEXIS 284 (WCAB Panel Decision) 

Issues: Whether there is a valid exception to the requirement under the Benson, “limited  circumstances” exception when two of the three reporting physicians were unable to parcel out  permanent disability between applicant’s specific and cumulative trauma injuries, based on the  fact there were some aspects of the industrially caused permanent disability that could be parceled  out and others that could not.  

Holding: The WCAB rescinded the WCJ’s separate awards of permanent disability for applicant’s  specific injury and cumulative trauma injury since two of the three reporting physicians could not  parcel out the applicant’s gastrointestinal and psychiatric permanent disabilities between the  specific and cumulative trauma injuries with reasonable medical probability. The WCAB in these  circumstances concluded this would satisfy the Benson “limited circumstances” exception and that  applicant was entitled to a combined award of 83% permanent disability.  

Factual & Procedural Overview: This case has a very complex procedural history. Before the  Writ was filed with the Court of Appeal there were two prior WCAB panel decisions.  

The applicant suffered two injuries, both involving orthopedic, internal, and psychiatric injuries.  He suffered a specific injury on October 15, 2002, and a cumulative trauma injury for the period  of October 15, 2002 through January 2, 2003. The applicant alleged injuries to the same body  parts and conditions for both injuries. The reporting physicians were AME’s in the fields of  orthopedics, internal medicine, and psychiatry.  

The WCJ awarded the applicant two separate awards, consisting of 39% permanent disability for  the specific injury of October 15, 2002, and 68% permanent disability for the cumulative trauma  injury from October 15, 2002 through January 2, 2003. Both the applicant and defendant filed  Petitions for Reconsideration, challenging the WCJ’s permanent disability award, as well as  apportionment findings.  

The WCAB initially granted reconsideration and rescinded the WCJ’s separate awards of 39% and  68% for applicant’s two dates of injury and remanded and instructed the DEU rater to issue a  combined permanent disability rating for applicant’s two injuries based on the factors of disability  described by the AMEs without apportioning disability between the injuries pursuant to Benson

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The rater found that applicant’s combined PD for the specific and cumulative injuries after 20%  non-industrial apportionment related to applicant’s gastrointestinal disability was 83%. On remand, defendants objected to the WCAB’s rating instructions on several grounds as follows: 

  1. The rating instructions were contrary to Labor Code §4663 and the “cannot parcel out”  exception outlined in Benson.  
  2. That apportionment of applicant’s psychiatric and gastrointestinal disability should be  in accordance with the orthopedic apportionment found by the orthopedic AME who  had apportioned all of applicant’s right finger, right shoulder and cervical spine  permanent disability to the October 15, 2002, specific injury, and the lumbar spine  disability 40% to the October 15, 2002, specific injury and 60% to the cumulative  trauma injury.  
  3. With respect to the psychiatric apportionment, defendant argued that the AME report  in psychiatry expressly indicated that the AME would apportion 80% of applicant’s  psychiatric disability to his orthopedic condition, and this should be apportioned along  the lines of orthopedic apportionment. 
  4. Defendants also argued that with respect to gastrointestinal disability, the AME in  internal medicine attributed applicant’s gastrointestinal complaints to medications  taken for the orthopedic injury and therefore, gastrointestinal permanent disability  apportionment should follow the orthopedic apportionment. 

In response the WCAB rescinded the WCJ’s separate awards and followed the recommended  combined rating of 83% permanent disability after non-industrial apportionment of 20%. In  reaching its decision the WCAB explained “under Labor Code §4663 and Benson, apportionment  of PD must be based on causation, except in those cases where the contribution of separate  industrial injuries to PD cannot be parceled out by the evaluating physician, in which  circumstances a combined award is justified.” Citing Benson, the Board indicated that in most  circumstances there is generally medical evidence that will enable each distinct industrial injury  to be separately rated based on its individual contribution to the employee’s permanent disability.  

The Board also noted in the Benson decision by the Court of Appeal that there could be “limited  circumstances”, when an evaluating physician cannot parcel out, with reasonable medical  probability, the approximate percentages to which each distinct industrial injury causally  contributed to the employee’s overall permanent disability. The Board noted that in such “limited  circumstances” when the employer has failed to meet its burden of proof, a combined award of  permanent disability may still be justified. 

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In terms of the reasoning used by the AMEs in internal medicine and psychiatry where they  indicated they could not “parcel out” the applicant’s permanent disability in their respective fields,  the AME in internal medicine indicated that applicant’s gastrointestinal permanent disability was  “not amendable to separation based on various dates of injury,” and that “[i]t would require  speculation to allocate specific levels of apportionment to each date of injury,” supported  application of the Benson “cannot parcel out” exception.” 

The WCAB rejected defendant’s argument that apportionment of applicant’s gastrointestinal  disability was somehow mandated by the internal AME’s conclusion that the gastrointestinal  injuries resulted from applicant’s use of pain medication to treat his orthopedic pain. The Board  indicated that this relates to causation of injury and is not equivalent to causation of disability. 

The rationale for the Board to find that the applicant’s permanent disability related to his internal  and psychiatric disability could not be reasonably “parceled out” between the two dates of injury  was “that where, as here, some aspects of the industrially-caused permanent disability from two or  more separate industrial injuries cannot be parceled out because the disability is inextricably  intertwined (in this case, the psychiatric and gastrointestinal disability), then a combined PD award  must issue even though other aspects of the industrially-caused permanent disability from those  injuries can be parceled out with reasonable medical probability (in this case, the orthopedic  disability).”  

Editor’s Comment: The primary holding in Herrera is that there can be no valid apportionment  under Benson among and between multiple separate and successive injuries unless there is  unanimity among all of the reporting physicians that they are able to parcel out and apportion the  disability between multiple and successive injuries. A case applying the Herrera requirement of  “unanimity” of all reporting medical-legal evaluators on Benson apportionment is Khammash v.  State of California Dept. of Transportation (2023) 89 Cal.Comp.Cases 270; 2023 Cal.Wrk.Comp.  P.D. LEXIS 307. In Khammash, applicant suffered four injuries consisting of three specific  injuries and one cumulative trauma injury. While the orthopedic AME was able to apportion  applicant’s orthopedic disability among and between the four injuries, the AME in psychiatry in a  non-conclusory detailed analysis and explanation opined he was unable to apportion applicant’s  psychiatric disability among and between the four separate injuries. Since there was no unanimity  among the reporting physicians on Benson Apportionment, under Herrera, applicant was entitled  to a combined award of 100% permanent total disability.  

Another case applying the holding in Herrera is Mills v. American Medical Response 2019  Cal.Wrk.Comp. P.D. LEXIS 84 (WCAB panel decision). In Mills the WCAB affirmed a WCJ’s  award of 100% PTD related to four specific injuries and one cumulative trauma injury. In applying  the Benson “limited circumstances” exception the WCAB held that even though five of six AME’s  were able to apportion applicant’s disability under Benson, the internal AME was unable to do so. 

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Since there was no unanimity amongst all of the reporting AME’s indicating valid apportionment  between the multiple dates of injury, defendant failed to meet their burden and the WCJ correctly  awarded a single combined disability award of 100% PTD. 

While the author understands and agrees that it is always the defendant’s burden to prove valid  legal apportionment, the WCAB in Mills should have also considered that the six reporting  physicians were all AME’s and therefore should be held to a higher standard since technically they  are reporting to the WCAB and not the parties. Something seems fundamentally wrong where five 

of six reporting AME’s had no problem apportioning under Benson and yet defendant was unable  to meet their burden in proving apportionment. Perhaps the WCAB in Mills should have  considered remanding the case in order for the single holdout AME to try to persuasively explain  why unlike his colleagues, he could not apportion applicant’s PD among the five separate injuries 

as in Chavez v. Chief Auto Parts, AutoZone, Inc. 2018 Cal. Wrk. Comp. P.D. LEXIS 257 (WCAB  Panel Decision). Alternatively, as the Board did in Chavez, they could have remanded the case  back to the trial level and recommended that the WCJ appoint a regular physician under Labor  Code 5701 to replace the one AME who could not apportion properly under Benson. 

In a safety member case involving a deputy sheriff, Bates v. County of San Mateo 2019  Cal.Wrk.Comp. P.D. LEXIS 72; 47 CWCR 82 (May 2019), apportionment under Benson of PD  related to successive CT injuries was precluded based on the combined applicability of Labor Code  sections 3212 and 4663(e). Applicant received a combined award for separate 3212 presumptive  heart injuries without apportionment of PD between the two injuries. In Bates, applicant suffered  a CT from May 10, 2009 through May 10, 2010 and received a stipulated award of 41% PD in  December of 2013 related to his heart and circulatory/cardiovascular injuries. He filed a timely  Petition to Reopen. He continued to work for the same employer in the same job, and filed a second  CT injury up to his last date of employment to the exact same body parts as in the first CT. The  AME opined that 75% of applicant’s current PD related to the original CT injury and 25% to the  new CT injury.  

At trial, the parties stipulated that if there was a finding of new and further disability only for the  first 2010 CT, the rating would be 80% less the dollar amount of the prior award, and if there was  finding of apportionment pursuant to Benson, the rating would be 60% to the 2010 CT and 20%  for the second CT injury. Following trial, the WCJ ruled that the applicant was entitled to the LC  3212 heart presumptions for both CT injuries which caused 80% PD with defendant to receive  credit for the dollar value of the 41% Award for the first CT. The WCJ also found that LC 4663(e)  precluded Benson apportionment of PD between the two CT injuries. Defendant’s Petition for  Reconsideration was denied. The WCAB indicated that defendant’s argument on reconsideration  disregarded 4663(e)’s provision that the apportionment to the causation provisions of 4663 do not  apply to injuries or illnesses covered under LC sections 3212-3213.2. The WCAB also relied on  Department of Corrections and Rehabilitation v. WCAB (Alexander) (2008) 166 Cal.App. 4th 911,  73 CCC 1294 and subsequent cases holding that 4663(e) prohibits the application of the 

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apportionment provisions of 4663 to injuries or illnesses covered by 3212.2. “Accordingly, the  WCAB concluded that applicant was entitled to a combined award and that Benson apportionment  was precluded. It would be “inconsistent with the Legislature’s unified scheme of apportionment  based on causation to conclude that 4664(a) somehow overrides the specific and later enacted  provisions of 4663(e).” 

Gonzalez v. EDCO Disposal Waste and Recycling Services 2019 Cal.Wrk.Comp.  P.D. LEXIS 199 (WCAB Panel Decision) 

Issues & Holding: In this case involving three separate dates of injury the WCAB rescinded a  WCJ’s finding that applicant was 100% permanently totally disabled in accordance with the fact  under L.C. 4662(b). The WCAB also held that the WCJ could not issue a combined award for  three separate specific injuries absent a finding that the medical evidence establishes that  applicant’s disability cannot be parceled out between the three separate specific injuries pursuant  to Benson v. Workers’ Comp. Appeals Bd. (2009) 170 Cal.App.4th 1535, 1560 [74 Cal.Comp.Cases  113].) 

Procedural & Factual Overview: Applicant suffered three specific injuries involving various  body parts and conditions. The strict AMA Guides impairment ratings supported a 73% permanent  disability rating. However, the WCJ found applicant was entitled to a permanent total disability  award based on part on Labor Code 4662(b) in accordance with the fact (sic). In addition, the WCJ  issued a joint combined award of permanent total disability without a finding by the WCJ that the  medical record did not support the apportionment of permanent disability between the three  separate specific injuries. Defendant filed a Petition for Reconsideration that was granted by the  WCAB who rescinded the WCJ’s combined Findings and Award and returned the matter to the  trial level for further proceedings necessary to correct the errors identified by the WCAB. 

Discussion: With respect to the Benson issue, the WCAB reiterated the holding in Benson that  “[A]bsent a finding that the medical evidence establishes that applicant’s disability cannot be  parceled out between his separate dates of injury, applicant’s disability must be apportioned  between his separate dates of injury.” Ordinarily and except in limited circumstances, “there will  be medical evidence that will enable each distinct industrial injury to be separately rated based on  its individual contribution to the employee’s permanent disability.” (Benson, supra, 170  Cal.App.4th at p. 1560.) In this case the WCJ issued a combined award of permanent total disability  without any reference to whether the medical record justified this determination. “There is no legal  basis for the issuance of a joint award of permanent disability in the absence of a finding by the  WCJ that the medical record does not support the apportionment of permanent disability between  the separate industrial injuries.” 

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With respect to the WCJ’s finding that applicant was entitled to a permanent total disability award  under 4662(b) in accordance with the fact (sic) as opposed to the 73% AMA Guides impairment  rating, the WCAB reversed and rescinded the WCJ’s PTD award. The WCAB held that the WCJ  could not independently rely on 4662(b) but must instead base a finding of an award of PTD only  through impairment ratings by application of the AMA Guides pursuant to Labor Code section  4660 pursuant to the Court of Appeal decision in Department of Corrections & Rehabilitation v.  Workers’ Comp. Appeals Bd. (Fitzpatrick) (2018) 27 Cal.App.5th 607 [83 Cal.Comp.Cases 1680].  In Fitzpatrick, the Court of Appeal held that Labor Code section 4662(b), “in accordance with the  fact,” does not provide “a second independent path to permanent total disability findings separate  from section 4660.” 

Langley v. 101 Casino, Mitsui Sumitomo Marine Management 2019  Cal.Wrk.Comp. P.D. LEXIS 293 (WCAB split Panel Decision) 

Issues & Holding: WCJ in a case involving a cumulative trauma and specific injury found  applicant to be totally permanently disabled but with no apportionment of disability between the  two injuries under Benson based on the fact that one of four reporting physicians, an orthopedic  PQME opined that the two injuries were inextricably intertwined based on the alleged complexity  of the two injuries as well as the medical record. The orthopedic PQME also testified in deposition  that he was unable to apportion between the specific and CT injury primarily because the applicant  was asymptomatic at any time prior to suffering her specific injury almost five months into the  cumulative trauma injury period. The WCAB in a split panel decision denied defendant’s Petition  for Reconsideration and affirmed the WCJ’s award of permanent total disability. 

Overview & Discussion: There were four reporting physicians in this case in different medical  specialties. There was an SPQME in orthopedics, an AME in psychiatry, as well as a neurologist  and internist. Both the neurologist and AME in psychiatry were able to apportion the applicant’s  permanent disability between the specific and cumulative injuries.  

On Reconsideration, the WCAB rejected the defense argument that the orthopedic SPQME reports  did not constitute substantial evidence on apportionment. The WCAB held that the orthopedic  SPQME was able to provide non-conclusory reasons as to why he could not apportion the  applicant’s permanent disability between the specific and cumulative trauma injuries and that the  PD from both injuries was inextricably intertwined. Commissioner Lowe, in a lengthy dissent  argued that the medical record needed to be further developed on the Benson issue based on her  assessment that the orthopedic SPQME’s opinion on apportionment was “confusing and  contradictory on causation of injury and causation of permanent disability/apportionment.”

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Chavez v. Chief Auto Parts, AutoZone, Inc. 2018 Cal. Wrk. Comp. P.D. LEXIS  257 (WCAB Panel Decision) 

Issues & Holding: The WCAB rescinded the WCJ’s award of 100% permanent total disability  without apportionment. The Board found the WCJ improperly merged three separate and distinct  injuries into one cumulative trauma. The WCJ also failed to apportion to nonindustrial causative  factors of the applicant’s permanent disability under Labor Code §4663. The WCJ erroneously  relied solely on the opinion of one of three AMEs that applicant’s permanent disability was  “inextricably intertwined.” The Board held that two of the three AMEs were able to apportion the  applicant’s permanent disability among the three separate and successive injuries under Benson. The Board rejected the opinion of the AME in internal medicine whose opinion they characterized  as not constituting substantial evidence when he opined he could not apportion among the three  injuries, because applicant’s internal permanent disability was “inextricably intertwined.”  

Procedural & Factual Overview: The applicant suffered two specific injuries, one on May 24,  1995 and the other August 7, 1997, as well as the cumulative trauma from March 28, 1983 through  September 28, 1998.  

The evaluating physicians consisted of three AME’s in orthopedics, internal medicine, and  psychiatry. All three of the AMEs found a basis for nonindustrial apportionment under Labor  Code §4663. In addition, the AME’s in orthopedics and psychiatry were also able to apportion  applicant’s permanent disability among the three dates of injury.  

The AME in internal medicine found that 20% of the applicant’s permanent disability caused by  internal conditions was attributable to non-industrial factors. However, the AME in internal  medicine, unlike the other two AMEs in orthopedics and psychiatry, opined he could not parcel  out applicant’s internal medicine permanent disabilities among the three separate and successive  injuries because they were “inextricably intertwined”.  

The WCJ issued a Joint Findings Award and Orders, finding all of applicant’s 100% permanent  total disability was attributable to the cumulative trauma and none to the two specific injuries  notwithstanding the medical reporting of the AMEs in orthopedics and psychiatry to the contrary.  

Defendant filed a Petition for Reconsideration arguing in part that the WCJ committed error by  relying upon the medical opinion of the AME in internal medicine, to find that the internal  permanent disability from applicant’s three injuries was “inextricably intertwined”. Defendant  also contended the record needed to be further developed on the issue of apportionment under both  Labor Code §4663 and Benson. The WCAB granted defendant’s Petition for Reconsideration and  rescinded the WCJ’s 100% Award of permanent disability without apportionment. 

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The WCAB’s Decision and Analysis  

Improper Merger of Separate and Successive Injuries: The WCAB found there was no factual  or legal basis for the WCJ to rely on the Benson “limited circumstances” exception to merge the  two specific injuries of May 24, 1985, and August 7, 1997, into one cumulative trauma injury.  The WCAB indicated this was clear error. In that regard the Board stated, although Benson may  authorize the combining of permanent disabilities in “limited circumstances”, it does not authorize  the merger of distinct industrial injuries. 

On remand the WCAB specifically instructed the WCJ that “before deciding whether this case  falls within the “limited circumstances” exception, the WCJ must proceed from the fact that  applicant sustained three distinct industrial injuries, one of which is a cumulative trauma injury.”  The Board indicated that what the judge needed to do on remand was to “consider each of the three  injuries and the nature of the permanent disability attributable to each injury, before considering  whether applicant’s disabilities fall within Benson’s “limited circumstances” exception. “The  merger of injuries is not part of this analysis.”  

Apportionment to Non-industrial Factors Under Labor Code §4663: On remand the WCAB  also instructed the WCJ that based on the present medical record there was a basis for nonindustrial  apportionment under Labor Code §4663 as well as apportionment of disability between the  industrial injuries under Benson. With respect to Labor Code §4663, the WCAB noted that the  AME in internal medicine apportioned 20% of the applicant’s internal medicine permanent  disability to nonindustrial factors. The WCAB noted the other AMEs in orthopedics and  psychiatry also found a basis for non-industrial apportionment. As a consequence, the WCAB  indicated they were not persuaded an Award of 100% permanent total disability without  apportionment was warranted based on Labor Code §4663 without considering apportionment of  the applicant’s residual industrial permanent disability in all three medical specialties among the  three separate and successive injuries. 

Benson Apportionment: The WCAB indicated it was difficult for them to understand why the  two AMEs in orthopedics and psychiatry were able to apportion the applicant’s permanent  disability in their respective fields among the three separate injuries and why the AME in internal  medicine was unable to do so. They described the AME’s opinion in internal medicine that the  permanent disability caused by the various internal injuries as “inextricably intertwined” was not  credible. The Board stated the AME’s opinion “on this point disregards the medical history and  the findings of the other medical evaluators who apportioned permanent disability to prior work  injuries as well as the specific and cumulative trauma injuries.  

Considering the fact, the AME’s in both orthopedic and psychiatric medicine were able to find  Benson apportionment but the AME in internal medicine could not, the Board concluded that  further resort to the internal AME to provide a “supplement opinion would be unfruitful.” The 

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WCAB then suggested that the WCJ appoint a regular physician under Labor Code §5701 in the  specialty of internal medicine.  

Imad v. Galpin Ford; Virginia Surety Company, administered by Sedgwick CMS;  Miller Honda; Zurich North America 2018 Cal. Wrk. Comp. P.D. LEXIS 919  (WCAB Panel Decision) 

Issues & Holding: Whether the workers’ compensation judge’s (WCJ) joint findings, award, and  order, awarding the applicant 100% permanent total disability without apportionment constituted  substantial medical evidence where the reporting AME in psychiatry indicated he could not  apportion the applicant’s psychiatric disability between two specific injuries because the  psychiatric disability was “inextricably intertwined.” 

With respect to the psychiatric permanent disability apportionment aspect of the case, the WCAB  granted defendant’s Petition for Reconsideration and rescinded the WCJ’s award of 100%  permanent total disability and remanded the case for further development of the record on the issue  of both Labor Code §4663 nonindustrial apportionment and Benson apportionment. 

Procedural & Factual Overview: The applicant filed two separate cumulative trauma injuries  against different employers that were consolidated for hearing. In ADJ2768261 applicant filed a  cumulative trauma from December 1997 to March 7, 2002 against Galpin Ford. In case number  ADJ562166 he filed a separate cumulative trauma injury for the period of March 8, 2002 to  October 11, 2004 while employed by Miller Honda. The applicant alleged injury to the same body  parts and conditions in both cumulative trauma claims. One of the reporting physicians in the case  was an AME in psychiatry. The AME in psychiatry evaluated the applicant several times and was  deposed at least four times.  

The AME opined applicant sustained a catastrophic industrial CT injury to his psyche and found  him to be 100% permanent totally disabled. In his MMI report dated April 17, 2013, based on his  evaluation of the applicant of November 29, 2012, with respect to apportioned, the AME in  psychiatry apportioned half of applicant’s permanent impairment to be split equally between non 

industrial factors and the remaining 50% to be equally divided between the two cumulative trauma  injuries. The matter was set for trial in August 2016. However, it was taken off calendar for  further development of the record with the WCJ ordering the parties to obtain supplemental  reporting from the AME in psychiatry and for the AME to clarify his apportionment findings  specifically in respect to “inextricably intertwined” related to each of the two CT injuries. 

The AME in psychiatry issued a supplemental report in which he concluded that his determination  of the applicant being 100% permanent totally disabled was based on his own definition of  reasonable medical probability, based on an 85% level of reliability and confidence. With respect  to apportionment of the applicant’s psychiatric permanent disability between the two cumulative  trauma injuries, he used an 85% level of reliability. The AME indicated that the applicant’s 

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psychiatric WPI is not likely to be accurate with any degree of reasonable medical probability and  that the psychiatric disability from the two injuries was “inextricably intertwined”. 

Both CT claims were consolidated for hearing. The WCJ issued a Joint Findings Award and Order,  finding applicant suffered two cumulative trauma injuries while employed by Galpin Ford and  Miller Honda to the same body parts and conditions. The WCJ found the applicant to be 100%  permanent totally disabled and there was no substantial evidence to apportion psychiatric disability  between the two cumulative traumas based on the psychiatric AME’s October 31, 2016,  supplemental report. 

Defendant Galpin Ford filed a Petition for Reconsideration which was granted by the WCAB. In  his report on reconsideration the WCJ acknowledged that the psychiatric AME’s findings and  apportionment did not constitute substantial medical evidence and since defendant failed to meet  its burden of proof, the applicant was entitled to a joint award, as opposed to separate awards for  each CT under Benson.  

The WCAB’s Decision and Analysis: The WCAB in rescinding the WCJ’s joint 100% total  disability award without Benson apportionment focused on a number of cases dealing with what  constitutes substantial medical evidence. In terms of one of the reasons a medical report may not  constitute substantial evidence is that the medical report or opinion is based on an incorrect legal  theory. Hegglin v. Workmen’s Comp. Appeals Bd. (1971) 4 Cal.3d. 162, 169 [36 Cal.Comp.Cases  93, 97]. 

The WCAB also noted the two burdens that an applicant must meet. The first is the burden of  proving injury AOE/COE, and the second is the level of permanent disability caused by the injury.  (South Coast Framing v. Workers’ Comp. Appeals Bd. (Clark) (2015) 61 Cal.4th 291, 297-298,  302; Labor Code §§5705; 3600(a); Escobedo, supra, at p. 612). 

More importantly in terms of applicant’s burden with respect to proving AOE/COE, the employee  need only show that the “proof of industrial causation is reasonably probable, although not certain  or “convincing.” (McAllister v. Workmen’s Comp. Appeals Bd. (1968) 69 Cal.2d 408, 413 [33  Cal.Comp.Cases 660].) More importantly the WCAB indicated that the burden on applicant  proving AOE/COE is a burden that “manifestly does not require the applicant to prove causation  by scientific certainty.” (Rosas v. Workers’ Comp. Appeals Bd. (1993) 16 Cal.App.4th 1692, 1701  [58 Cal.Comp.Cases 313].) 

The WCAB also reaffirmed that defendant always has the burden of proof on apportionment of  permanent disability. To meet this burden, defendant “must demonstrate that, based upon  reasonable medical probability, there is a legal basis for apportionment.” (Gay v. Workers’ Comp.  Appeals Bd. (1979) 96 Cal.App.3d 555, 564 [44 Cal.Comp.Cases 817]; see also Escobedo, supra,  at p. 620.) 

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Moreover, with respect to defendant’s burden of showing a legal basis for apportionment, it is  based on reasonable medical probability. Among other things and in the context of apportionment  determinations, a medical opinion must disclose familiarity with the concepts of apportionment,  etc. (Escobedo, supra, at p. 621, citations omitted.) 

With respect to a physician applying correct legal standards in the context of an opinion  constituting substantial medical evidence. The WCAB cited the Court of Appeal in Gay

Physicians are trained to discover the etiology of an illness. Finding the causes is  important in preventive medicine and curing illness once developed. Legal  apportionment is not identical to theories of medical causation. Physicians in  workers’ compensation matters must accordingly be educated by the parties on the  correct legal standards of apportionment. (Gay, supra at p. 563, citations omitted.) 

The WCAB also reaffirmed that contrary to common misconception “apportionment is a factual  matter for the Appeals Board to determine based upon all the evidence.” (Gay, supra at p. 564,  citations omitted.) As a consequence, both the WCJ and the Board have the authority to determine  the appropriate amount of apportionment, if any. The Board further stated “however, as outlined  above, in order for a decision by the Appeals Board to be supported by substantial evidence, the  underlying medical opinions relied upon by the WCJ must be substantial evidence, which includes  a correct application of the law by the physician.” 

The WCAB rejected the opinion of the psychiatric AME both on permanent disability and  apportionment since it was not based on substantial medical evidence. The Appeals Board has  never previously quantified “reasonable medical probability” as a specific percentage of certainty  and it declined to do so in this case. The psychiatric AME defined reasonable medical probability  as an opinion that achieves at least an 85% level of reliability and confidence. Even seeking  scientific certainty to support the AME’s medical opinion that applicant is permanently totally  disability is an incorrect legal standard.  

With respect to the psychiatric AME’s opinion that the applicant’s permanent psychiatric disability  was “inextricably intertwined” which allegedly prevented him from apportioning the psychiatric  disability between the two cumulative trauma injuries, the Board referenced Benson

Defendant’s Burden of Proof on Apportionment under Benson: The WCJ in his report on  reconsideration to the Board indicated that he found the psychiatric AME’s opinion on  apportionment was not substantial medical evidence, and because it is defendant’s burden to prove  apportionment, defendant failed to meet its burden.  

In response, the WCAB reaffirmed it is defendant’s burden to prove apportionment under Benson.  However, the record in the form of the AME’s deposition and medical reporting indicates the AME  in psychiatry “may have applied an improper legal standard to his opinions regarding both  permanent disability and apportionment.” His opinions therefore did not constitute substantial 

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medical evidence, and it is required that his findings comply with established legal precedent and  proper legal standards.  

Development of the Record: Given the fact the AME’s opinion with respect to apportionment  and Benson was based on his application of improper legal standards and precedent, the Board  determined that the record needed to be developed. “The Appeals Board has a duty to develop the  record when there is not substantial medical evidence in the record to support a finding.” (citations  omitted) The WCAB indicated the preferred procedure for developing a deficient record under  the applicable case law, was to allow supplementation of the medical record by the physicians who  have already reported in the case. The Board indicated the parties should attempt to return to the  psychiatric AME for a supplemental opinion in order to provide the AME with an opportunity to  address permanent disability and apportionment pursuant to a correct application of the law.  However, the WCAB also indicated that if the psychiatric AME cannot cure the defects in his  opinion, then the selection of another AME should be considered by the parties. If the parties  cannot agree on another psychiatric AME then the WCJ could appoint a “regular physician  pursuant to Labor Code §5701.” 

Editor’s Comment: In Fanning v. Workers’ Compensation Appeals Board (2022) 87 Cal.Comp.  Cases 91; 2022 Cal.Wrk.Comp. LEXIS 2 (writ denied), the case was submitted for decision at  trial. The WCJ ordered the case “unsubmitted” in order to develop the record on apportionment.  The PQME in the case issued 6 reports and was deposed but still could not determine if applicant’s  3 injuries were inextricably intertwined or apportion the disability between them. The WCJ  ordered development of the record on apportionment through appointment of a “regular physician”  (LC 5701) to replace the PQME since all of his six medical reports and deposition testimony did  not constitute substantial evidence. So, defendant got a second bite of the apple on the issue of  apportionment. Applicant filed for removal which was denied by the Board who affirmed the  WCJ’s decision. Applicant then filed a writ which was also denied. 

McClendon v. Home Pest Defense (Rollins Inc.) 2018 Cal. Wrk. Comp. P.D.  LEXIS 436, 46 CWCR 248 (November 2018) (WCAB Panel Decision) 

Issues: Whether the opinion, of an AME in orthopedics constituted substantial medical evidence  where the AME in his deposition testified he could not apportion applicant’s back disability  between two specific injuries because the two injuries occurred close in time and the first injury  was not yet permanent and stationary when the second injury occurred. 

Holding: The WCAB rescinded the WCJ’s Joint Findings Award and Order, for 100% permanent  disability without any Benson apportionment on the basis that the AMEs opinion on Benson apportionment did not constitute substantial medical evidence. The mere fact the two injuries  occurred close in time, and even when one injury was not yet permanent and stationary, when the  second injury occurred is not a proper basis to find that the injuries cannot be rated and apportioned  separately as required under Benson

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Factual and Procedural Overview: The applicant was employed as a salesperson for a pest  control company when he suffered two separate specific injuries on June 12, 2012 (neck, back,  psyche), and on September 27, 2012 (back, psyche, left lower extremity). After the first injury of  June 12, 2012, he received some medical treatment and returned to work. After the second injury  on September 27, 2012, he received medical treatment which included surgery on March 7, 2014.  

The reporting physician was an AME in orthopedics. The applicant was initially evaluated by the  AME on June 16, 2014. With respect to the applicant’s back injuries and related permanent  disability, the AME indicated that even though the applicant was not MMI with respect to his back  permanent disability, 60% would be non-industrial related to pre-existing pathology and 40%  would be industrial. Of the 40% industrial permanent disability, he indicated that under Benson,  50% would be apportioned to the June 12, 2012 specific injury, and 50% to the September 27,  2012 specific injury. After the Initial Evaluation of June 16, 2014, the AME indicated “that the  apportionment issue is complex and wrought with speculation.” 

The AME reexamined the applicant almost two years later and indicated applicant’s WPI was  60%. However, he also opined the applicant was unable to be gainfully employed in the open  labor market and was 100% permanently totally disabled. 

The AME in his MMI report indicated that with respect to the applicant’s back permanent  disability, 40% was non-industrial and 60% was industrial. As to the industrial back permanent  disability, he opined that 80% of the 60% industrial back permanent disability was attributable to  the June 12, 2012 injury and 20% to the September 27, 2012 specific injury.  

The AME was deposed and recanted his prior Benson apportionment and indicated it would be  speculative to attempt to apportion the applicant’s back permanent disability between the two  specific injuries. He testified during his deposition that since the applicant’s two specific injuries  were only three months apart he would be unable to separately rate the disability to the back from  the first injury because it would not have reached permanent and stationary status prior to the onset  of the second injury. “He testified that it would be speculative to rate the back disability from the  initial injury because it might have improved if it had not been impacted by the second injury….”  He also stated there was synergy between the effects of both specific injuries and it was hard for  him to separate the disability attributable to each specific injury. 

The WCJ issued a Joint Findings Award and Order finding the applicant 100% permanent total  disability without any Benson apportionment. Defendant filed a Petition for Reconsideration  contending there should be two separate awards based on apportionment between the two specific  injuries and that a Joint Award was not appropriate under Benson. Defendant also argued that the  opinion of the AME was not substantial medical evidence to support a finding the applicant was  permanently totally disabled. 

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The WCAB’s Decision and Analysis: The WCAB in a split panel decision granted defendant’s  Petition for Reconsideration and rescinded the WCJ’s 100% Findings Award and Order and  remanded the case back to the trial level for further development of record and to issue a new  decision. 

The WCAB rejected the orthopedic AME’s apportionment determination where he opined in his  deposition that he could not apply Benson apportionment of the applicant’s back disability between  the two specific injuries, because the two injuries occurred close in time, and where the first injury  was not yet permanent and stationary when the second injury occurred. The WCAB indicated this  is not a proper basis to determine that the injuries cannot be separately rated.  

The WCAB acknowledged that while the WCAB and the Court of Appeal in Benson indicated  “[T]here may be “limited circumstances” when the evaluating physician cannot parcel out with  reasonable medical probability, the approximate percentages to which each distinct industrial  injury causally contributed to the employee’s overall permanent disability.” It is only in such  limited circumstances, when the employer has failed to meet its burden of proof, that a combined  award of permanent disability may still be justified.  

The Court of Appeal in Benson affirmed the WCAB’s en banc decision “wherein the Appeals  Board held that when multiple industrial injuries combine to cause permanent disability, the  permanent disability caused by each injury must be separately calculated – unless the evaluating  physician cannot parcel out, with reasonable medical probability, the approximate percentages of  the overall permanent disability caused by each industrial injury.” In its en banc decision in  Benson, the WCAB “held that if a physician renders an opinion that the approximate percentages  of disability caused by each industrial injury cannot reasonably be parceled out, then this  constitutes an apportionment determination within the meaning of §4663 (b).” In essence  “successive injuries must be rated separately except when physicians cannot parcel out the  causation of disability.” (See State Comp. Ins. Fund v. Workers’ Comp. Appeals Bd. (Dorsett)  (2011) 201 Cal.App. 4th 433, 453 [76 Cal.Comp.Cases 1138]). 

As to the issue of whether there is some exception that would allow a joint award in a scenario  where the first injury reaches permanent and stationary status, prior to the onset of the second  injury, the WCAB rejected this as a viable basis for an exception to Benson stating:  

The determination of whether the Benson exception allowing a single joint award  applies does not depend on whether the first injury reaches permanent and  stationary status prior to the onset of the second injury. Prior to Benson, the Court  in Wilkinson v. Workers’ Comp. Appeals Bd. (1977) 19 Cal.3d 491 [138 Cal. Rptr.  696, 564 P.2d 848], allowed a single joint award, holding that when two separate  work-related injuries become permanent at the same time, neither permanent  disability is previous to the other and the employee therefore is entitled to a single 

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permanent disability rating. (Id. At p. 497.) However, the court in Benson concluded that “the clear change in the statutory language” of sections 4663 and  4664 as a result of SB 899 indicates a legislative intent “to invalidate Wilkinson.”  (Benson, supra, 170 Cal.App.4th at p. 1550.) Now, “the plain language of §4663,  subdivision (c), read in conjunction with the statutory scheme as a whole,  specifically requires a physician to determine what percentage of disability was  caused by each industrial injury, regardless of whether any particular industrial  injury occurred before or after any other particular industrial injuries.” (Benson,  supra, at p. 1552 italics added.)  

Tapia v. City of Watsonville, PSI 2017 Cal.Wrk.Comp P.D. LEXIS 50 (WCAB panel decision) 

Issue: Whether the AME where there were five separate and successive injuries consolidated for  trial impermissibly combined and merged the disability from each separate injury into a single  cumulative trauma without parceling out the approximate percentages to which each separate and  distinct injury causally contributed to the applicant’s overall permanent disability. 

Holding: Both the AME and the WCJ in his decision and Award in the five consolidated cases,  impermissibly merged separate and successive injuries into one cumulative trauma without  parceling out the approximate percentages to which each separate and distinct injury causally  contributed to the applicant’s overall permanent disability contrary to Labor Code section 4663  and Benson v. Workers’Comp.Appeals Bd. (2009) 170 Cal App.4th 1535, 74 Cal.Comp.Cases 114). 

Overview and Discussion: Applicant, a fire captain, filed five Applications for separate industrial  injuries, including two cumulative traumas and three specific injuries. The parties agreed to use an  AME. Following trial, the WCJ awarded applicant 73% permanent disability without any  apportionment and indicated that all of applicant’s disability was attributable to a single cumulative  trauma period ending in 2014. Defendant filed a petition for reconsideration. 

The AME, by way of a supplemental report was asked to explain his opinion that applicant had  sustained only a single cumulative trauma injury through 2014. In essence he stated:  

The first question had to do with apportionment referable to the multiple dates of  injury. As you can see from the information in the introductory portion of the report,  the patient has a CT exposure through 2008 and then a CT exposure through 2014  with at least three dates of injury in between. The injuries in 2012 are only seven  months apart. I had also noted on page 1 of my November 24, 2015 report that the  situation of the patient’s left hip worsening after his surgery as well as his findings 

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of bilateral carpal tunnel syndrome (CTS) warranted looking at this as a CT  exposure. The number of injuries involves speaks for itself. This is a very common  finding in fireman, policeman, and transit bus drivers. Multiple injuries occur over  the course of their career and when they are looked at in retrospect represent a CT  exposure. As I have noted on page 1 of my last report, I would look at all of these  events intertwined and feel that it is best looked at as a single CT event. I’m not  able to break out individual dates and levels of impairment. 

Defendant filed a Petition for Reconsideration raising a number of issues but primarily that both  the WCJ and the AME had impermissibly merged multiple separate and successive injuries in  violation of Labor Code §4663 and Benson. The WCAB granted defendant’s Petition for  Reconsideration and rescinded the 73% award and remanded the consolidated cases for further  proceedings in the form of either supplemental reporting or a deposition of the AME on permanent  disability and the Benson apportionment issue. 

The WCAB noted pursuant to Benson that “The only instance in which a combined award a  permanent disability may be justified is where the evaluating physician is unable, with reasonable  medical probability, to parcel out the approximate percentages to which each distinct industrial  injury causally contributed to the employee’s overall permanent disability.” Moreover, the WCAB  indicated that the AME’s opinion that all of applicant’s disability should be attributable to a single  cumulative trauma did not constitute substantial evidence since: 

Notwithstanding the clear evidence that applicant sustained three distinct industrial  injuries …..Dr. Anderson does not assign specific levels of disability to these  separate injuries or explain why he is unable to do so. Instead, he states, “I am not  able to break out individual dates and levels of impairment.” The only attempt at  an explanation is the suggestion that with police officers, firefighters and transit  drivers it is common to find multiple injuries over the course of their careers that  actually represent a cumulative trauma exposure. That commentary is insufficient  to meet the requirements of section 4663(c). Dr. Anderson must either assign a  specific level of disability to each of applicant’s industrial injuries or expound as to  the exact reasons he is unable to do so. 

Editor’s Comment: See also, Guerrero v. Walker Corporation 2017 Cal.Wrk.Comp. P.D. LEXIS  195 (WCAB panel decision) (WCAB affirmed WCJ’s finding that applicant suffered two periods  of cumulative trauma since there was a lengthy break in applicant’s need for industrially-related  medical treatment from 7/5/2011 to 12/26/2011, which the WCAB regarded as significant in  separating the two distinct periods of cumulative trauma and is thus consistent with the Coltharp case and distinguishable from Western Growers v. WCAB (Austin)(1993) 16 Cal.App.4th 227, 58  Cal. Comp. Cases 323.

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Singh v. State of California 2017 Cal.Wrk.Comp. P.D. LEXIS 204 (WCAB panel  decision) 

Issues: Whether the WCJ improperly calculated the permanent disability from applicant’s four  separate successive injuries under Benson by using a complicated mathematical formula to  increase the permanent disability apportionment to each injury as well as the permanent disability  apportioned to nonindustrial factors until the combined disability for three of the four injuries and  nonindustrial disability under the Combined Values Chart totaled 100%. 

Holding: The WCAB reversed the WCJ finding that the WCJ had erroneously calculated  applicant’s permanent disability under both Benson and under Labor Code §4663 and amended  the joint Findings and Award to reflect that fact. 

Overview and Discussion: Applicant, a heavy equipment mechanic, suffered and filed four  separate successive injuries consisting of three specific injuries and one cumulative trauma injury.  The WCAB noted that it was uncontested that the scheduled permanent disability ratings would  have rendered an award of 53% for one specific injury, 47% for another specific injury, and 67%  for the cumulative trauma injury. However, the WCJ elected not to employ the scheduled ratings  because “combining the scheduled disabilities, before apportioning to each injury and to  nonindustrial factors, yielded overall 95% permanent disability. 

Also, the WCJ found that the overall 95% permanent disability had been rebutted by applicant’s  vocational expert who had rendered an opinion that the applicant was unable to compete in the  open labor market.  

Defendant filed a Petition for Reconsideration indicating that the WCJ had committed error in  making disability findings at variance with the scheduled disabilities and that applicant’s  vocational expert’s opinion did not constitute substantial evidence. 

The WCAB granted defendant’s Petition for Reconsideration. At the outset, the WCAB found  that applicant’s vocational expert’s opinions did not constitute substantial evidence under either  Ogilvie or Dahl.  

With respect to the Benson and Labor §4663 issue, the WCAB indicated that even if the evidence  supported a conclusion that applicant was unable to compete in the open labor market solely as a  result of his various work injuries both Labor Code §4663 and Benson were applicable. Labor  Code §4663 and Benson would require applicant’s permanent disability to be apportioned among  his various industrial injuries. The Board noted that “it is settled that disability is caused by  separate injuries or non-industrial factors are separated by subtracting percentages of disability.”  (citations omitted).

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Consequently, after applying Benson the WCAB indicated that the scheduled ratings with  consideration of both apportionment and Benson equated to separate awards of 53% for one  specific injury, 47% for the other specific injury, and 67% for the cumulative trauma injury, all to  be awarded applicant separately. 

Philpot v. Performance Dairy Services, Inc., et al. 2017 Cal.Wrk.Comp. P.D.  LEXIS 174 (WCAB panel decision); see subsequent decision Philpot v.  Performance Dairy Services, Inc., et al. at 2023 Cal.Wrk.Comp. P.D. LEXIS 43  (Philpot II). 

Issue: In a situation where there are two separate and successive specific injuries related to  multiple body parts and conditions does apportionment under Benson require apportionment for  each body part and condition with the resultant disability for each body part and condition to be  allocated or apportioned to the separate and successive specific injuries. 

Holding: Where there are multiple separate and successive injuries, each reporting physician and  their respective specialties must make an independent apportionment determination related to each  and every body part and condition and then under Benson the resultant disability for each separate  body part and condition should be apportioned between the separate and successive injuries unless  in limited circumstances the evaluating physician or physicians cannot parcel out with reasonable  medical probability the approximate percentage as to which each distinct industrial injury causally  contributed to the employee’s overall permanent disability. 

Facts and Discussion: Applicant, while employed as a utility dairy service truck driver suffered  two separate successive specific injuries. The first was on April 26, 2010, as a result of an  industrial motor vehicle accident in which he suffered injury to his right shoulder, brain, left knee,  left shoulder, right knee, and psyche. Applicant received extensive treatment, especially with  respect to his serious brain injury. Following treatment, he did return to work, but with some  physical restrictions and with simplified tasks. However, he did not have any driving restrictions. 

On July 14, 2011, he suffered his second separate specific injury also as a result of an industrial  motor vehicle accident with injuries to his brain, right shoulder, lumbar spine, left shoulder, right  knee, and psyche. Following trial, the WCJ found that the solvent insurer’s liability for one of the  specific injuries was 70% and that CIGA’s share was 30%. Both CIGA and the solvent insurer,  Imperium Insurance Company, filed Petitions for Reconsideration. 

CIGA argued that there should have only been a joint award rather than separate awards since the  applicant’s disability resulting from both separate and successive injuries was inextricably 

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