- Permanent impairment {NEL} (degree of impairment) (back)
- Permanent impairment {NEL} (rating schedule) (AMA Guides)
- Apportionment (non-economic loss) (preexisting conditions)
- Board Directives and Guidelines (apportionment) (pre-existing condition) (measurable impairment)
The worker suffered a non-compensable low back injury in 2006, for which he required surgery. He suffered a compensable low back injury in 2010, for which he required further surgery. The Board rated the worker's permanent impairment at 11% but reduced the rating by 10% due to the pre-existing condition, resulting in a 1% NEL award. The worker appealed regarding both the quantum of the NEL rating and the apportionment due to the pre-existing condition.
Under the AMA Guides, a back rating involves three separate parameters, which are then combined. The first parameter is specific disorders of the spine, under Table 53. The second parameter is abnormal range of motion, under Tables 60 and 61. The third parameter is peripheral nerve impairment, under Tables 10, 11 and 49.The NEL assessor found that range of motion was within normal limits. The assessor rated neurological impairment at 2% under Table 49, which converts to 1% impairment of the whole person. The assessor rated specific disorder of the spine at 10%, under Table 53, section II, part E, for surgically treated disc lesion residual pain and rigidity. The 10% rating under Table 53 was then combined with the 1% rating under Table 49, resulting in whole person impairment of 11%. The Board then deducted 10% for a measurable pre-existing, non-compensable low back injury, resulting in the 1% NEL award.Board Operational Policy Manual, Document No. 18-05-05, on effect of a pre-existing impairment, details determination of the rating for a new injury affecting the same area of the body, depending on whether the pre-existing impairment is measurable. If the pre-existing impairment is measurable, it is determined and deducted. If it is not measurable, a deduction is made depending on the severity of the pre-existing impairment. In the case of a pre-existing, non-compensable impairment, there is no prior NEL rating. Therefore, the policy instructs the decision-maker to determine whether the pre-existing impairment can be rated under the AMA Guides and to determine the rating. Thus, the policy directs what is in essence a hypothetical exercise to consider what the NEL rating would have been had the prior impairment been compensable.In this case, the worker had a pre-existing back injury, for which he required surgery. The Vice-Chair found that the pre-existing condition would have qualified as a permanent impairment had it been compensable and that the impairment would have been rated under Table 53 of the AMA Guides. Thus, the worker had a measurable pre-existing impairment. Table 53, section II, part D, provides an 8% rating for surgically treated disc lesion with no residual signs or symptoms. The Vice-Chair found that this was the applicable rating for the pre-existing impairment, as the first surgery was extremely successful and the worker was able to regain a very high level of function. The Vice-Chair concluded that the worker's NEL rating should be reduced by 8% rather than 10%.As to the rating of the permanent impairment, the Vice-Chair confirmed the 1% for neurological impairment and no rating for range of motion, as determined by the Board. The Vice-Chair also confirmed the 10% rating for the surgically treated disc lesion with residual pain and rigidity under Table 53, section II, part E, but also added an addition 2% under part G for a second operation. The AMA Guides do not specify that the additional 2% applies only if the two surgeries arise only from the same accident, and the Vice-Chair did not interpret Table 53 as including such a requirement.The 12% rating under Table 53 is combined with the 1% rating under Table 49, resulting in a 13% rating, from which 8% is deducted for the measurable pre-existing impairment, resulting in a 5% NEL award. The appeal was allowed in part.