Incidence, Risk Factors, and Functional Outcomes of Symptomatic Postoperative Spinal Epidural Hematoma: 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 PEDH cases requiring a reoperation and matched controls over six year period. The incidence of PEDH was calculated by region and operative technique. The preoperative and intraoperative parameters of 40 cases and 40 matched controls were compared.

Results: 5,941 spine surgeries and 40 symptomatic PEDH cases requiring reoperation were identified (0.67% overall incidence). The highest incidence of PEDH was observed after minimally invasive lumbar laminectomimes. Higher preoperative diastolic blood pressure was a risk factor for PEDH. Of the 17 PEDH cases that had a drain 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 cases (51.43%), one cervicothoracic and seventeen lumbar, did not develop paresis at the time of PEDH diagnosis. 17 cases (48.57%), nine cervicothoracic and eight lumbar, developed paresis. Ten of the patients with paresis had complete resolution of motor weakness, while seven never achieved complete resolution.

Conclusion: While the incidence of PEDH was below one percent, nearly half of the patients developed motor weakness as a presenting symptom and a third of the patients never had resolution of the weakness.