Intraoperative iatrogenic seizure induced by transcranial motor-evoked potential during spinal surgery: A case report and review of the literature.

Background: Intraoperative neuromonitoring is an essential tool for detecting early intraoperative neurological changes during spinal surgery. Only rarely do seizures occur during transcranial motor-evoked potentials (TcMEP).

Case description: A 44-year-old male presented with a magnetic resonance (MR)--documented L5-S1 T2-hyperintense intradural mass that heterogeneously enhanced with Gadolinium and extended through the right S1 neural foramen. Utilizing transcranial motor-evoked potential (Tc-MEP) before the skin incision, the patient developed the 1^st seizure that lasted for 2 min. The 2^nd seizure occurred after the initial incision and lasted for around 15 min; at this point, the procedure was terminated. After brain MR studies documented no structural lesion and other etiologies of seizures were ruled out, the patient underwent an uneventful resection of the L5-S1 spinal lesion.

Conclusion: Although the risk of seizures from Tc-MEP is very low, it is crucial to be aware of this potential side effect. If they occur, surgical procedures should be aborted and diagnostic studies performed to rule out the presence of structural lesions and/or other reasons for seizure activity.