We report the case of somatosensory evoked potential loss during a transforaminal interbody fusion during exposure following a transient rise in blood pressure. The topography of signal loss and elimination of technical causes led to the inference of left sided stroke which was confirmed as a left thalamocapsular hemorrhagic infarct on postoperative magnetic resonance imaging. Use of intraoperative neuromonitoring in this lumbar fixation surgery helped to identify it intraoperatively and prevented undue alternative surgical decision making.