Incidence, Risk Factors, and Functional Outcomes of Symptomatic Postoperative Spinal Epidural Hematoma: A Case-Control Study

Background: Symptomatic postoperative spinal epidural hematomas (PEDHs) are rare complications, with significant implications on patients' functional outcomes. Strategies for PEDH prevention are poorly understood. This study sought to evaluate preoperative and intraoperative variables predicting the risk of PEDH and patients' functional outcomes after PEDH evacuation.

Methods: This is a single institution study of all patients with PEDH requiring reoperation and matched controls over a 6-year period. The incidence of PEDH was calculated by region and operative technique. The preoperative and intraoperative parameters of 40 patients and 40 matched controls were compared.

Results: A total of 5941 spine surgeries and 40 patients with symptomatic PEDH requiring reoperation were identified (0.67% overall incidence). The highest incidence of PEDH was observed after minimally invasive lumbar laminectomies. Higher preoperative diastolic blood pressure was a risk factor for PEDH. Of the 17 PEDH patients in whom a drain was placed at the time of index surgery, 8 patients (47%) still had the drain in place at the time of diagnosis of PEDH. Among the posterior index approaches, 18 patients (51.43%) (1 cervicothoracic and 17 lumbar) did not develop paresis at the time of PEDH diagnosis. Seventeen patients (48.57%) (9 cervicothoracic and 8 lumbar) developed paresis. Ten of the patients with paresis had complete resolution of motor weakness, whereas 7 never achieved complete resolution.

Conclusions: Although the incidence of PEDH was less than 1%, nearly half of the patients developed motor weakness as a presenting symptom and a third of the patients never had resolution of the weakness.