Temporal recovery in motor evoked potential during evacuation of cervical spontaneous epidural hematoma: illustrative case.

backgroundIntraoperative neuromonitoring (IONM) is primarily used to prevent irreversible motor deficits during spinal surgery. However, the prognostic significance of intraoperative waveform recovery-particularly its correlation with postoperative neurological improvement-remains controversial. The authors report a rare case of cervical spontaneous spinal epidural hematoma in which motor evoked potentials (MEPs) were absent at baseline but recovered following surgical decompression. OBSERVATIONS: Reports describing the emergence of MEP waveforms after complete baseline absence are extremely limited. In the present case, the short interval between symptom onset and surgical intervention, along with the nontraumatic nature of the injury, likely minimized direct spinal cord damage, thereby permitting waveform recovery after decompression. Previous studies have suggested that improvement in MEP amplitude is associated with favorable neurological outcomes, and the appearance of MEPs in this case may reflect the functional efficacy of decompression. LESSONS: Even in the absence of baseline MEP responses, the intraoperative emergence of waveforms may serve as an indicator of effective decompression. These findings support the continued use of IONM during surgery, as it may provide valuable real-time prognostic information. https://thejns.org/doi/10.3171/CASE251007.