Legal causation in Wisconsin is provided for on the WKC-16B form in Questions 11, 12 and 13. Question 11 deals with direct causation of a new injury or the definite breakage of a pre-existing condition. Question 12 addresses an aggravation of a pre-existing condition, which the Lewellyn case explains in category 3 below:
(1) If there is a definite "breakage" (a letting go, a structural change etc., as described by Professor Larson), while the employee is engaged in usual or normal activity on the job, and there is a relationship between the breakage and the effort exerted or motion involved, the injury is compensable regardless of whether or not the employee's condition was preexisting and regardless of whether or not there is evidence of prior trouble.
Example: 50 year old iron worker bends down to pick up a 75lb beam and feels a pop in his back. MRI shows a herniated disc at L5-S1, breakage.
(2) If the employee is engaged in normal exertive activity but there is no definite "breakage" or demonstrable physical change occurring at that time but only a manifestation of a definitely preexisting condition of a progressively deteriorating nature, recovery should be denied even if the manifestation or symptomization of the condition became apparent during normal employment activity.
Example: 50 year old iron worker (has some pre-existing degeneration given age and the work) bends down to pick up a 75lb beam, feels a pain in his back. MRI shows "normal degeneration" including some disc bulging, ligamentum flavum hypertrophy and facet disease. No discrete breakaage. Applicant should consider an occupational claim.
(3) If the work activity precipitates, aggravates and accelerates beyond normal progression, a progressively deteriorating or degenerative condition, it is an accident causing injury or disease and the employee should recover even if there is no definite "breakage."
Example: 50 year old iron worker (has some pre-existing degeneration given age and the work) bends down to pick up a 75lb beam and feels a pain in his back and leg. MRI shows "normal degeneration" including some disc bulging, ligamentum flavum hypertrophy and facet disease and some nerve root impingement. This seems very similar to an occupational claim, and it may go hand in hand with one, but the Lewellyn analysis applies to a claimed traumatic injury.
Lewellyn v. DILHR, 38 Wis. 2d 43, 155 N.W.2d 678 (1968). It may be safer if the doctor checks Q12 on the 16B rather than putting it in his or her own words as the three elements must all be met. Joseph Schlitz Brewing Co. v. DILHR, 67 Wis. 2d 185, 226 N.W.2d 492 (1975).
McCormick Law Office in Milwaukee, Wisconsin handles workers compensation causation.