Transient neuromonitoring changes and delayed vertebrobasilar infarction following anterior cervical discectomy and fusion: illustrative case.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) is a common spinal procedure with a well-established safety profile. While direct vertebral artery injury is rare and typically recognized intraoperatively, delayed posterior circulation stroke is an even less common but major complication. In patients with risk factors for vascular disease, vascular stress from surgical manipulation may predispose them to thromboembolic events that are not immediately apparent. Transient intraoperative neuromonitoring (IONM) changes may represent early, underrecognized indicators of such vascular compromise. OBSERVATIONS: The authors present the case of a 61-year-old male who underwent elective three-level ACDF for degenerative cervical myelopathy. During cage placement, transient right-sided somatosensory evoked potential signal attenuation occurred, while other IONM signaling remained stable. On postoperative day 1, the patient developed dysarthria, hemiparesis, and hoarseness (National Institutes of Health Stroke Scale score 7). MRI revealed bilateral cerebellar and pontine infarcts, and CT angiography showed right vertebral artery occlusion. He was treated with antiplatelet and anticoagulation therapy, followed by intensive rehabilitation. The patient achieved full motor recovery within 1 year. LESSONS: This case highlights the need for vascular risk stratification in ACDF patients with comorbidities, where preoperative vascular imaging may be beneficial. Transient, lateralized IONM changes, although reversible, may indicate early vascular compromise and warrant heightened postoperative vigilance for delayed stroke. https://thejns.org/doi/10.3171/CASE25587.