Evoked Potentials as a Complementary Tool for Tract-Level Functional Assessment in Postoperative Brown-Séquard Syndrome.

Brown-Séquard syndrome (BSS) is a rare neurological condition caused by a unilateral spinal cord injury. Although it is most commonly associated with trauma, several recent studies have reported BSS after spinal cord surgery. We describe a 53-year-old woman who developed acute BSS with symptoms of motor weakness and sensory impairment on the right side after C5 laminotomy performed via biportal endoscopic spine surgery. Postoperative cervical T2-weighted magnetic resonance imaging demonstrated a newly developed hyperintense lesion at C3-C4 and C4-C5. The diagnosis of BSS was supported by measurements of motor and somatosensory evoked potentials, which revealed tract-specific abnormalities in the right corticospinal and dorsal column-medial lemniscus pathways. This case highlights the potential for severe neurological complications after minimally invasive cervical spine surgery, and underscores the value of measuring evoked potentials as a complementary tool for tract-specific functional assessment and recovery monitoring.