Postoperative Spinal Epidural Hematoma After Microscopic Lumbar Decompression A Prospective Magnetic Resonance Imaging Study in 89 Patients

Study Design: A prospective case series. Objective: To prospectively analyze the incidence, characteristics, clinical outcomes, and risk factors of postoperative spinal epidural hematoma (SEH) after microscopic lumbar decompression using magnetic resonance imaging (MRI). Summary of Background Data: Studies prospectively focusing on postoperative SEH after microscopic lumbar decompression alone are rare. Methods: Eighty-nine patients who underwent microscopic lumbar decompressive surgery for herniated disc and/or stenosis between January 2007 and June 2007 were prospectively followed. Decompression was carried out using unilateral or bilateral laminotomy in all patients. Postoperative MRI was taken at 24 hours after surgery in all patients. Using operative report, chart, and MRI, the incidence, characteristics, and risk factors of postoperative SEH were evaluated. Clinical outcomes were evaluated 2 years after surgery using Visual Analogue Scale score and Oswestry Disability Index. Results: Postoperative SEH developed in 13 patients (14.6%). There were 5 males and 8 females. The mean age of these patients was 57.1 years. Postoperative SEH occurred at the index level in 6 cases, and at the index level with extension toward nondecompressed adjacent levels in 7 cases. Eleven patients were asymptomatic and 2 patients complained of leg pain and/or mild weakness. No patients underwent revision surgery owing to postoperative SEH. There was no significant difference in improvements of Visual Analogue Scale and ODI scores, and clinical success rate between patients with and without SEH. Patient's age 50 years old or more was the only significant risk factor for the development of postoperative SEH (P = 0.024; odds ratio = 5.12). Conclusions: The incidence of postoperative SEH after microscopic lumbar decompressive surgery was 14.6%. Postoperative SEH did not delay clinical improvements. Age 50 years old or more was strongly associated with the development of postoperative SEH.