Schroeder v. Illinois Workers' Compensation Comm'n, 79 N.E.3d 833

Nanette Schroeder, a long‑haul truck driver with preexisting severe degenerative lumbar disease and prior back surgeries, returned to work for Swift in May 2013 after declining recommended surgery and passing required physicals.
On December 19, 2013, Schroeder slipped on ice at work, injuring her right side and later developing increased back and left‑leg symptoms; she stopped over‑the‑road driving and ultimately underwent lumbar fusion on April 10, 2014.
Treating neurosurgeon Dr. Yazbak attributed a symptomatic aggravation of Schroeder’s preexisting condition to the December 2013 fall and said the accident made surgery more appropriate; respondent’s physician Dr. Lami testified post‑accident imaging and exam showed no objective change and opined the ongoing problems were unrelated to the fall.
The arbitrator found the fall produced only a temporary aggravation and denied causation for Schroeder’s current condition; the Illinois Workers’ Compensation Commission reversed, finding causation based on deterioration after the accident and other evidence.
The McLean County circuit court set aside the Commission’s award (applying de novo and manifest‑weight standards); the appellate court reinstated the Commission, applying the manifest‑weight standard and deferring to the Commission’s medical fact‑finding.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether claimant proved her current condition of ill‑being was causally related to the December 19, 2013 work accident	Schroeder argued the accident aggravated her preexisting lumbar condition, precipitated symptom worsening, and accelerated the need for fusion surgery	Swift argued objective testing showed no change pre‑ and post‑accident and the post‑accident symptoms were unrelated or transient, so causation was not proved	The appellate court held the Commission’s finding of causation was not against the manifest weight of the evidence and reinstated the award
Proper standard of review for causation	N/A (Schroeder relied on Commission deference to medical findings)	Trial court applied de novo, saying facts undisputed	Appellate court found material factual disputes (conflicting medical opinions) and applied manifest‑weight review, deferring to the Commission’s medical expertise

International Harvester v. Industrial Comm’n, 93 Ill. 2d 59 (supreme court applied chain‑of‑events inference where claimant’s condition worsened after intervening work event)
Durand v. Industrial Comm’n, 224 Ill. 2d 53 (standard: reverse only if opposite conclusion clearly apparent under manifest‑weight review)
Long v. Industrial Comm’n, 76 Ill. 2d 561 (courts defer to Commission on medical questions)
Sisbro, Inc. v. Industrial Comm’n, 207 Ill. 2d 193 (an employment cause need not be sole or primary to recover for aggravation of preexisting condition)
Caterpillar Tractor Co. v. Industrial Comm’n, 92 Ill. 2d 30 (employer takes employee as found; aggravation or acceleration of preexisting condition is compensable)