Remote Spinal Subdural Hematoma Following Lumbar Biportal Endoscopic Surgery : Two Case Reports.

Remote spinal subdural hematoma (SSH) following unilateral biportal endoscopic (UBE) spine surgery is rare, even without intraoperative dural injury. We report two such cases. A 76-year-old woman underwent anterior lumbar interbody fusion and UBE decompression for lumbar spinal stenosis. Intraoperatively, dense adhesions were noted, but no cerebrospinal fluid (CSF) leakage occurred. Postoperatively, she developed left leg monoplegia. MRI revealed a subdural hematoma at L2-3, remote from the surgical site. She recovered completely with steroid therapy and conservative management. An 88-year-old man underwent left-sided UBE laminotomy for central stenosis. The procedure was uneventful. Postoperative MRI revealed an incidental subdural hematoma from L2-4 without neurological deficits. He was observed conservatively. Both patients showed favorable outcomes without surgical evacuation. Remote SSH is a rare but important complication following UBE surgery. It should be considered when unexpected neurological deficits occur postoperatively, even in the absence of visible dural tears. Prompt diagnosis is essential for optimal management.