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Symptomatic Postoperative Spinal Epidural Hematoma after Spinal Decompression Surgery: Prevalence, Risk Factors, and Functional Outcome.

OBJECTIVE
 Postoperative spinal epidural hematoma (pSEH) with symptomatic compression of nervous structures after spinal decompression surgery is a rare complication. Delayed evacuation may result in severe neurologic impairment. We present a large single-center analysis of the prevalence, potential risk factors, and functional recovery after pSEH.


METHODS
 A retrospective review of our institutional database of spinal decompression surgery over 15 years yielded 6,024 consecutive patients. A total of 42 patients who had undergone surgical revision due to postoperative neurologic deterioration or intractable radiating pain and radiographically confirmed pSEH were allocated to the pSEH group. A matched 3:1 control group was formed (126 patients with the same surgical procedure, same year, same sex, and similar age). Charts, surgical reports, and radiographic data were reviewed for demographics, duration of symptoms, history of medical treatment, medication, comorbidities, radiographic extension, surgical strategy, and pre- and postoperative neurologic performance. Median follow-up was 3 months. Risk factors for pSEH, complete recovery, and recovery of neurologic symptoms were analyzed with univariable and multivariable logistic regression models.


RESULTS
 The prevalence of pSEH in this population was 0.69% (n = 42) with these locations: 7 of 1,284 (0.54%) cervical, 1 of 774 (0.12%) thoracic, and 34 of 3,966 (0.85%) lumbar. Use of anticoagulants (p = 0.003), pathologic coagulation values in the preoperative blood test (p = 0.034), and cigarette smoking (p = 0.003) were identified as independent risk factors of pSEH. Surgery in more than one level showed a trend toward an increased risk of pSEH. Pain as the only symptom (p = 0.0001) was a significant predictor of complete recovery. Patients symptomatic with paraplegia (p = 0.026) had a significantly higher risk of a poor neurologic outcome without full recovery of neurologic symptoms.


CONCLUSION
 The prevalence of pSEH was lower than previously reported incidences. Use of anticoagulants, pathologic coagulation values, and cigarette smoking were identified as independent risk factors of pSEH. Functional outcome was related to the duration between hematoma evacuation and the clinical presentation of symptomatic pSEH.