OBJECTIVE: To determine whether shorter surgical delays for chronic subdural hematoma (CSDH) are associated with improved functional outcomes. METHODS: Post hoc analysis of the FINISH (The Finnish Study of Intraoperative Irrigation vs. Drain Alone After Evacuation of Chronic Subdural Hematoma) trial, a nationwide multicenter randomized controlled trial. The primary outcome was functional outcome at 6 months postsurgery assessed by the modified Rankin Scale (mRS). Secondary outcomes included dichotomized mRS (0-3 favorable, 4-6 unfavorable), mortality, adverse events, and reoperation rates within 6 months. RESULTS: This study included 589 patients (median age 78 years, interquartile range: 72-84
28.0% females) with a median surgical delay of 21 hours (interquartile range: 9-33). The optimal cut-off point for surgery delay in relation to favorable functional outcome was 22 hours. In the early surgery (≤22h) group, 10.0% had an unfavorable functional outcome versus 15.8% in the late surgery (>
22h) group (P = 0.06). After adjusting for confounding factors, the common odds ratio for mRS for late surgery versus early surgery was 1.42 (95% confidence interval: 1.01-2.00
P = 0.046). The probability of unfavorable functional outcome increased with surgical delay, peaking between 72 and 96 hours. There was no association between surgical delay, mortality, and adverse events after confounding adjustment. Reoperation rates were 17.5% in the early surgery groups and 13.1% in the late surgery group (P = 0.14). CONCLUSIONS: In this post hoc analysis, shorter surgical delays for CSDH were associated with improved functional outcome. Our findings suggest that symptomatic CSDH patients should be operated on as soon as reasonably possible.