Transcranial Electric Motor Evoked Potential Monitoring During Spine Surgery

In Brief Study Design. Retrospective review. Objective. To report on the safety of repetitive transcranial electric stimulation (RTES) for eliciting motor-evoked potentials during spine surgery. Summary of Background Data. Theoretical concerns over the safety of RTES have hindered broader acceptance of transcranial electric motor-evoked potentials (tceMEP), despite successful implementation of spinal cord monitoring with tceMEPs in many large spine centers, as well as their apparent superiority over mixed-nerve somatosensory-evoked potentials (SSEP) for detection of spinal cord injury. Methods. The records of 18,862 consecutive patients who met inclusion criteria and underwent spine surgery with tceMEP monitoring were reviewed for RTES-related complications. Results. This large retrospective review identified only 26 (0.14%) cases with RTES-related complications; all but one of these were tongue lacerations, most of which were self-limiting. Conclusions. The results demonstrate that RTES is a highly safe modality for monitoring spinal cord motor tract function intraoperatively. Review of 18,862 consecutive spine procedures conducted with tceMEP monitoring of spinal cord and/or spinal nerve root function revealed few stimulation-related complications, largely limited to a low incidence of tongue lacerations. With proper technique, tceMEPs triggered by repetitive transcranial electric stimulation appear to be safe in both children and adults.