California Labor Code § 4664

Determinative passage · p.4(c) (1) 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 percent over the employee's lifetime unless the employee's injury or illness is conclusively presumed to be total in character pursuant to Section 4662. As used in this section, the regions of the body are the following:

The Board reviewed the application of section 4664(c) to prior awards and apportionment in this case.

Determinative passage · p.6In addition, section 4664 provides that "[i]f 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." (Lab. Code, § 4664 (b).) "Section 4664(b) creates a conclusive presumption of the continued existence of a prior permanent disability when the claimant received an award of permanent disability benefits based on that disability," and that defendant "has the burden of proving overlap between the current disability and the previous disability in order to establish its right to apportionment...." (Kopping v. Workers' Comp. Appeals Bd. (2006) 142 Cal.App.4th 1099, 1115 [71 Cal.Comp.Cases 1229].)

The WCAB found the medical opinions did not meet the substantial evidence standard for apportionment because they lacked adequate explanation of causation and overlap.

Determinative passage · p.16A physician must determine apportionment based on causation, because an employer is liable solely for the portion of permanent disability directly attributable to an injury arising out of and occurring in the course of employment. (Lab.Code, § 4663(a) and 4664(a).) "The plain reading of `causation' in this context is causation of the permanent disability." (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 611 (Appeals Board en banc) (Escobedo).) Apportionment now includes pathology, asymptomatic prior conditions, and retroactive prophylactic work preclusions, provided there is substantial evidence establishing that these other factors have caused permanent disability. Pursuant to Escobedo, a physician's opinion must constitute reasonable medical probability, must not be speculative, rely on pertinent facts and/or an adequate examination and history, and must set forth the reasoning in support of the conclusions. (Id. at p.621.) That is, a physician must explain the "howand why" of their apportionment opinion and consider all potential causes of disability, whether from a current, prior or subsequent industrial or nonindustrial injury or condition. (Ibid.; Benson v. Permanente Med. Group (2007) 72Cal.Comp.Cases 1620, 1622 (Appeals Board en banc).)

Applied to reject Dr. Sussman's apportionment opinion as speculative and lacking adequate reasoning.

Determinative passage · p.3The WCJ's opinion found that apportionment was not appropriately addressed per the standards outlined in Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 611 (en banc) because the physician did not clearly outline the pre-existing conditions nor did he adequately address with particularity how those conditions caused the current impairment. He accepted the QME's opinion that the impairment to the right and left shoulder should be added instead of combined. The WCJ also found that the correct occupational code is 330 based on the job description provided (Defendant's Exhibit A.)

The WCJ applied these standards to reject the QME's apportionment opinion for lack of adequate explanation and to rate permanent disability without apportionment.

Determinative passage · p.20Therefore, apportionment is allowed by the subtraction method to the prior Award of 22% permanent disability pursuant to the case of Kopping v. Workers' Comp. Appeals Bd.

The WCAB applied section 4664(b) to allow apportionment by subtraction of prior awards overlapping the current award using the same AMA Guides method.

Determinative passage · p.11II. APPORTIONMENT Apportionment is the process utilized to segregate permanent disability or the residuals caused by an industrial injury from those attributable to other industrial injuries or to nonindustrial factors, to allocate legal responsibility fairly. (Brodie, supra, 40 Cal.4th at p. 1321; Marsh v. Workers'Comp. Appeals Bd. (2005) 130 Cal.App.4th 906, 911 [70 Cal.Comp.Cases 787.].) The mere fact that a medical report assigns approximate percentages of industrial and nonindustrial causation does not make the report reliable medical evidence by itself. (E.L. Yeager Construction v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 927-928 [71Cal.Comp.Cases 1687].) Instead, apportionment of permanent disability is "based on causation" and 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." (Lab.Code, § 4663(a) and 4664(a).) "The plain reading of `causation' in this context is causation of the permanent disability." (Escobedo v.

Applied to evaluate and reject nonindustrial apportionment in this case.

Determinative passage · p.7Section 4664(a) states that, "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." Section 4664(b) states that, "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." However, in Kopping v. Workers' Comp. Appeals Bd. (2006) 142 Cal.App.4th 1099 [71 Cal.Comp.Cases 1229], the Court of Appeal held that in order to apportion permanent disability pursuant to Labor Code section 4664, a defendant must

The Board found that the employer must prove overlap between prior and current disabilities to apply apportionment under LC 4664.

Determinative passage · p.9The mere fact that a medical report assigns approximate percentages of industrial and nonindustrial causation does not make the report reliable medical evidence by itself. (E.L. Yeager Construction v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 927-928 [71Cal.Comp.Cases 1687].) Instead, apportionment of permanent disability is "based on causation" and 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." (Lab.Code, § 4663(a) and 4664(a).) "The plain reading of `causation' in this context is causation of the permanent disability." (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 611 (Appeals Board en banc) (Escobedo).) Apportionment now includes pathology, asymptomatic prior conditions, and retroactive prophylactic work preclusions, provided there is substantial evidence establishing that these other factors have caused permanent disability. Pursuant to Escobedo, a physician's opinion must rely on reasonable medical probability, cannot be speculative, must rely on pertinent facts and/or an adequate examination and history, and must set forth the reasoning in support of its conclusions. (Id. at p.621.) That is, a physician must explain the "howand why" of their apportionment opinion (Ibid.) and

Applied to the issue of permanent disability apportionment.