A Prospective Study of the Intra- and Postoperative Efficacy of Intraoperative Neuromonitoring in Spinal Cord Stimulation.

Background: Accurate lead placement is critical for spinal cord stimulation (SCS) efficacy. The traditional gold standard of awake placement is often technically difficult. While there is retrospective evidence supporting the use of intraoperative neurophysiological monitoring (IOM) as an alternative, a prospective assessment has not yet been performed.

Objective: To prospectively evaluate pain and functionality outcomes for IOM-guided SCS, validate two IOM modalities as a means to lateralize lead placement and assess whether IOM can be useful for postoperative programming.

Methods: A total of 73 patients were implanted with SCS using electromyography (EMG) and somatosensory-evoked potential collision studies (SSEP-CS) to verify lead placement. Patient pain and function were assessed through serial administration of several validated questionnaires. Stimulation parameters at 6 months were documented.

Results: Statistically significant (p < 0.05) improvements were observed in the McGill Pain Questionnaire, Oswestry Disability Index, Pain Catastrophizing Scale, and Visual Analog Scale. EMG and SSEP-CS appropriately lateralized leads in 65/73 (89.0%) and 40/58 (69.0%) cases, respectively. EMG predicted active contacts in use at follow-up with 82.7% sensitivity.

Conclusions: We provide prospective evidence that IOM can be used to verify SCS placement. Additionally, EMG may help to streamline device programming and thereby improve outcomes by predicting the ideal stimulation contacts in many cases.