Surgical Evacuation for Subdural Hematoma: Predictors of Postoperative Hematoma Clearance, Reoperation, and Functional Outcome at Three Months

Introduction: Although subdural hematoma (SDH) incidence has increased, there is limited evidence to guide patient management after surgical evacuation. We aimed to identify predictors of reoperation, postoperative hematoma clearance, and functional outcome after SDH surgical evacuation.

Methods: We identified all patients with SDH between 2010 and 2018. Clinical and radiographic variables were collected from the medical records. Outcomes were reoperation within 90 days, poor (3–6) modified Rankin Scale score at three months, and the postoperative hematoma clearance rate.

Results: We identified 551 surgically treated SDH cases/hemispheres (482 patients). The mean age was 68.6 years and 30.9% were females. A total of 299 (54.3%) cases underwent burr hole evacuation, 188 (34.1%) craniotomy, and 64 (11.6%) craniectomy. Within 90 days 13.1% of cases underwent reoperation, whereas 29.4% had a poor functional status at three months. Multivariate analysis identified three independent predictors postoperative clearance: seizure absence on admission (P < 0.001), increased preoperative hematoma area (P < 0.001), and brain atrophy absence (P=0.028). The two independent predictors of reoperation within 90 days were: female sex (OR=1.815, 95% CI:1.042–3.162, P=0.035) and lower clearance rate (OR=0.601, 95% CI:0.3787–0.955, P=0.031). However, the performance of clearance in predicting no reoperation within 90 days was suboptimal. Only altered mental status on admission (OR=3.889, 95% CI:1.742–8.686, P=0.001) was an independent predictor of poor functional outcome at three months.

Conclusion : Careful management of patients with the above predictive factors may reduce SDH reoperation and improve radiographical and functional outcomes. However, larger randomized studies are necessary to assess long-term prognosis after surgical evacuation.