The use of transcranial motor-evoked potentials, somatosensory-evoked potentials and free-run electromyography for proper placement of paddle leads in chronic pain

Abstract

Introduction: As an alternative to those patients who cannot be performed an awake spinal cord stimulation (SCS) or had been percutaneously implanted with poor pain relief outcomes, neurophysiological monitoring through transcranial motor evoked potentials (MEPs), somatosensory-evoked potentials (SSEPs) and free-run electromyography (EMG) under general anesthesia allows the correct placement of surgical leads and provide objective responses.

Methods: An initial series of 15 patients undergoing SCS implantation for chronic pain. Physiologic midline was determined with 32-channel NIM-Eclipse System equipment. During neurophysiological monitoring, MEPs, SSEPs, EMG and CMAPs were recorded.

Results: MEPs, SSEPs, and EMG were able to target spinal cord physiological midline during SCS to all patients. Physiologic midline was deviated in 53% patients. No warning events in SSEPs, MEPs, or EMG were recorded in any patient.

Conclusions: Bilateral CMAPs recording allows placement of paddle leads in physiological midline, obtaining an accurate coverage, pain relief and avoid unpleasant or ineffective stimulation postoperatively. While these neurophysiological techniques are generally used to provide information on the state of the nervous system and prevent neurological injury risks during SCS, our work has shown that can accurate direct lead placement.

Keywords:

• Neuropathic pain
• spinal cord stimulation
• laminectomy
• compound muscle action potentials
• general anesthesia

Disclosure statement

José F. Paz serves as a consultant to Boston Scientific and Medtronic. The remaining authors have no conflicts of interest to disclose.

No potential conflict of interest was reported by the author(s).