Substantial Evidence of Causation Apportionment - 3

Saturday, September 24, 2005 | 0

The following is the third of a three part series of a medical-legal analysis on the new apportionment rules by Pamela W. Foust. The first part reviewed the recent Escobedo decision, the second part reviews the legal standard of "substantial evidence" and this third and final part looks at Escobedo as to non-industrial apportionment.

by Pamela W. Foust

Applying Escobedo to other types of nonindustrial apportionment The Escobedo case did not address the issue of a nonindustrial condition that was "lit up," by an industrial injury and otherwise would have remained asymptomatic and nondisabling. Neither did it deal with aggravation or acceleration of nonindustrial conditions. It is very likely that the issue of apportionment to causation of disability in these situations will be treated as legal and not medical questions, and the appellate courts will ultimately tell us whether apportionment is legally permissible or legally impermissible. In the meantime, the doctor can only use his best judgment.

Escobedo will have doubtful application to cases in which the nonindustrial condition makes the applicant more vulnerable to injury and disability. The QME's opinion that the arthritis would have caused 50 percent of the disability was found to be substantial evidence in light of the trivial nature of the injury, the substantial disability, and the rapid onset of the pain in the noninjured knee. This rationale could not possibly be used to support an opinion that an individual with diabetes would have had 50 percent or any percent of an amputated leg even if a box hadn't fallen on his foot at work. Nor could it be used to justify apportionment to pre-existing osteoporosis in an applicant who fell at work and fractured her hip.

In cases where an underlying pathology is both progressing naturally and being accelerated by industrial cumulative trauma, it may be impossible to separate out the percentages of industrial and nonindustrial causation such that the doctor could not make an apportionment determination without resorting to speculation. When an essential fact cannot be determined, the prevailing party is normally the one that was not required to carry the burden of proof. When this situation arose in pre-SB 899 cases, the applicant was entitled to an unapportioned award. Since the Appeals Board held in Escobedo that the applicant had the burden of proving the industrial causation and the defendant had the burden of proving the nonindustrial causation, it is not clear who would prevail if the percentages could not even be approximated.

Whether or not there can be an apportionment of permanent disability to risk factors or hereditary and familial factors is open to question. Many risk factors are associated with race and ethnicity for which apportionment may be prohibited as a matter of public policy. Also, it might open a vast can of worms to allow apportionment to physical characteristics that are genetic in origin simply because all individuals have their strengths and weaknesses and will tend to fall above or below the norm in any given area.

The potential for apportionment to obesity has been widely discussed. However, would it make a difference in terms of stress on the joints of the lower extremities if a 250 pound individual is 5'4" tall or 6'5" tall? Does it matter if an injured worker has a large bone structure or a delicate one? What about an employee who is 6'2" tall, weighs 135 pounds and injures his back doing heavy lifting? Is his body type a cause of the injury that would justify an apportionment?

In the cases involving pathology such as osteoarthritis, spondylolisthesis, congenital defects, and other physical abnormalities that were not caused by the industrial injury, there may be articles and studies that would shed light on the causal relationship of these conditions to disability with or without trauma. Reference to such studies might be helpful to doctors in justifying apportionment determinations, whether the doctor ultimately concludes that the underlying pathology is or is not a cause of the disability. For example, an article entitled "Knee Osteoarthritis" that appeared in the March/April 2005 issue of The Guides Newsletter, published by the American Medical Association, contains the following analysis:

"To opine that an injury caused osteoarthritis, the traumatized knee should show significant arthritis while the contralateral uninjured knee is radiographically normal. To opine that pre-existing arthritis was aggravated, the involved knee should show significantly more advanced osteoarthritis than the contralateral joint. If both the injured and contralateral knee have symmetrical osteoarthritis, the arthritis is probably primary (idiopathic) rather than secondary (posttraumatic). In the latter scenario, the injury may have involved soft tissues alone, resulted in exacerbation (temporary worsening) of the symptoms of pre-existing arthritis, or both but did not cause or aggravate (permanently worsen) the osteoarthritis."

Studies and articles such as this one might serve to provide valuable guidance to physicians who are trying to navigate the broad uncharted areas of the new apportionment rules.

The Escobedo case was somewhat of a bridge between the new and old versions of the law rather than an example of what we can expect in the post-SB 899 world. The language in the QME report that the Appeals Board relied on sounds suspiciously like the rules governing the old Labor Code section 4663 where pre-existing disability was not required as long as the nonindustrial disability would have manifested itself by the permanent and stationary date, even if no industrial injury had been sustained. The QME did not say that the injury and the pathology were equally responsible for causing the permanent disability and his report was written a month before SB 899 was enacted. Thus, the apportionment in Escobedo would have been technically correct under pre-SB 899 apportionment rules although it might have been invalidated as speculative.

In the final analysis, even assuming the decision in Escobedo is not altered or overturned by a higher tribunal, the case has very little application to other potential sources of nonindustrial apportionment beyond the enunciation of some general principles. At this point in time, the physician can only use his skills of medical judgment and scientific analysis to produce an opinion that complies with the requirements for substantial evidence expressed in the Appeals Board's opinion. Future decisions from the Appeals Board and the appellate courts will undoubtedly give us some more definitive guidelines, but right now, we are still groping around in the dark and probably will be for some time to come.

-------------------------------

The views and opinions expressed by the author are not necessarily those of workcompcentral.com, its editors or management.