Burr-Hole Drainage With or Without Irrigation for Chronic Subdural Hematoma, Postoperative Hematoma Volume, and Risk of Reoperation: A Post Hoc Analysis of the FINISH Trial.

Abstract

Burr-hole drainage with intraoperative irrigation of chronic subdural hematoma (CSDH) has recently been associated with decreased risk for reoperation, compared with the procedure without irrigation. Whether this benefit is mediated through greater hematoma volume reduction remains unknown. We conducted a post hoc analysis of the nationwide multicenter randomized FINISH study. We measured preoperative and 6-week postoperative CSDH volumes from the patient's head computed tomography images or magnetic resonance images using computer-assisted manual segmentation. We compared volumetric parameters between the irrigation and no-irrigation groups and analyzed their association with reoperation and functional outcome. This study included 573 of 589 the FINISH trial patients with preoperative and postoperative images available for volumetric assessment. Volume reduction was similar between the irrigation and no-irrigation groups: absolute reduction 86 mL (IQR 54-117) vs 81 mL (IQR 49-120; P = .46) and relative reduction 74% (IQR 50-91) vs 69% (IQR 42-94; P = .23). Among reoperated patients, volume reduction was only 15% in both groups (P = .93). Percentage volume reduction was the strongest predictor of reoperation, with an optimal threshold of 47% (area under the curve 0.88). Volumetric parameters were not associated with functional outcome at 6 months. Irrigation did not reduce postoperative hematoma volume compared with no-irrigation, suggesting that the previously reported reoperation benefit of irrigation is not mediated through volume reduction. Volumetric parameters predicted reoperation but not functional outcome, questioning the value of radiological end points in CSDH trials.