Acute Brown-Sequard syndrome from an intradural C5–C6 disc herniation: Case report and literature review

Brown-Sequard syndrome (BSS) is a rare spinal cord hemisection syndrome characterized by ipsilateral weakness with contralateral loss of pain and temperature. Cervical intradural disc herniation (CIDH), an extremely rare phenomenon, is an uncommon etiology of BSS. Only around 50 cases of CIDH have been reported in the literature to date, including our own. A previously healthy 45-year-old man presented with sudden right-sided hemiparesis and contralateral sensory loss, consistent with incomplete BSS. MRI revealed a large C5-C6 disc extrusion penetrating the posterior longitudinal ligament and breaching into the intradural space, compressing the right anterolateral spinal cord. Urgent anterior cervical discectomy and fusion (ACDF) was performed, with intradural disc removal and dural repair. Neurological improvement was immediate. At 12 months, the patient had fully recovered motor and sensory function. BSS is the most frequent presentation of CIDH, yet preoperative diagnosis is uncommon (around 13 %). Suggestive MRI features include the Y-sign (bifid ventral dura) and a CSF halo around the fragment, but confirmation is often intraoperative. An anterior approach (ACDF) allows definitive decompression, intradural fragment removal, and dural repair; early surgery is associated with favorable outcomes, as mirrored by this patient's course. CIDH presenting as BSS is exceedingly rare but should be considered in lateralizing cervical myelopathy. Prompt anterior decompression with dural repair can result in excellent outcomes. All the information in this manuscript has been reported in accordance with SCARE criteria.