Spinal Cord Herniation After Posterior Cervical Spine Surgery in a Middle-Aged Man.

Spinal cord herniation is a rare condition arising from idiopathic or traumatic dural defects or fragility. Here we present a case of early-onset spinal cord herniation following cervical posterior decompression and fusion surgery for ossification of the posterior longitudinal ligament (OPLL). The patient, a 55-year-old male, presented with upper and lower extremity weakness and gait disturbance. Cervical spine MRI and CT scans revealed spinal canal stenosis due to OPLL at the C3-C5 level, leading to a diagnosis of cervical OPLL. The patient subsequently underwent a C3-C5 laminectomy, C2-C7 posterior spinal fusion, and C2 dome-like laminectomy. No intraoperative dural injury was identified, and postoperative drainage did not indicate cerebrospinal fluid (CSF) leakage. Immediately after surgery, the patient exhibited impaired deep sensation in the left upper and lower extremities, along with deficits in fine motor function. A cervical spine MRI performed on postoperative day 19 showed spinal cord deviation and strangulation at the C3-C4 level within the epidural space, leading to a diagnosis of spinal cord herniation. The patient underwent urgent surgical intervention on the same day. Intraoperative findings revealed posterior deviation of the spinal cord through a dural defect resulting in significant strangulation. A dural incision was extended at the site of injury, allowing for spontaneous repositioning of the spinal cord, followed by dural repair through suturing. Postoperatively, the patient exhibited marked improvement in deep sensation and regained ambulatory function. Although mild fine motor impairment persists, the patient was able to walk independently, including climbing stairs, and now continues outpatient follow-up. In this case, no evident intraoperative dural injury was observed; however, the onset was presumed to have occurred immediately after surgery. Particularly in young to middle-aged men, this condition should be considered if symptoms worsen, even in the absence of obvious dural injury or CSF leakage, and early imaging studies should be performed.