The value of transcranial motor-evoked potentials and free-running electromyography in surgery for cervical disc herniation.

The present study prospectively investigated the value of free-running electromyography (EMG) and transcranial motor-evoked potentials (TcMEP) during anterior cervical microdiscectomy and fusion for cervical disc herniation with radiculopathy. Thirty-eight patients were eligible for inclusion in the study. Pain was assessed using the visual analogue scale (VAS) score. Quality of life results were scored according to Odom's criteria in the postoperative period. Patients with at least a 41% increase in TcMEP amplitude had an excellent postoperative outcome. When the increase of TcMEP amplitude was ⩽ 11% the patient's outcome was fair. The VAS score decreased from a preoperative mean value of 6.39 ± 2.16 to a 3-month postoperative value of 2.39 ± 1.17. At 12-month follow-up the mean VAS score was 1.65 ± 0.90. TcMEP and free-running EMG are effective for monitoring the spinal cord during surgery and may hold an additional prognostic role.