Acute postoperative spinal epidural hematoma following unilateral biportal endoscopic.

Objective: To report a rare case of acute postoperative epidural hematoma (PEDH) following unilateral biportal endoscopic (UBE) unilateral laminotomy with bilateral decompression (ULBD) for L3-4 spinal stenosis, presumably caused by muscular hemorrhage, and to explore its potential etiology through a review of the literature. Methods: The clinical data, including pre- and postoperative Visual Analog Scale (VAS) and Japanese Orthopaedic Association (JOA) scores, were recorded at key timepoints: preoperatively, pre-surgical drain removal, post-surgical drain removal, and post-emergency debridement. A literature review was conducted to contextualize the findings. Results: A 56-year-old male presented with left lower limb pain (VAS 6), intermittent claudication (walking distance: 100 meters), and a JOA score of 10 preoperatively. After undergoing the UBE-ULBD surgery at the L3-4 level, the patient reported significant relief of lower limb neurological symptoms upon regaining consciousness from anesthesia. However, three minutes after drain removal on the 24th hour postoperatively, the patient experienced sudden severe left lower limb pain (VAS 10), which was refractory to routine analgesics. Administration of morphine provided only partial relief (VAS 7). Physical examination disclosed localized swelling at the surgical site, and subsequent MRI imaging confirmed the presence of hematoma signals within the operative channel. Emergency debridement revealed continuous bleeding from a small muscular artery within the operative tract, which had led to hematoma accumulation and subsequent compression of the dural sac and nerve roots. The bleeding artery was successfully ligated, and the hematoma was meticulously evacuated. Following debridement, the patient's pain improved significantly (VAS 3), and he was discharged without any sequelae. Conclusion: Spinal postoperative epidural hematomas have been reported in 0.1%-3% of cases, however, this represents the first documented instance following UBE-ULBD surgery. Hemorrhage from the muscular layer is identified as a potential etiology, underscoring the necessity for meticulous intraoperative hemostasis, particularly after restoration of baseline blood pressure prior to wound closure. Routine placement of a drainage tube is therefore recommended. Immediate surgical intervention, preferably within 24 h, is crucial for alleviating neurological compression, as emphasized by expert consensus, and significantly improves functional outcomes.