Current trends in intraoperative neurophysiological monitoring among Asia-Pacific countries: an Asia-Pacific Spine Society survey

Study design: A prospective web-based survey.

Purpose: Although intraoperative neurophysiological monitoring (IONM) is critical in spine surgery, its usage is largely based on the surgeon's discretion, and studies on its usage trends in Asia-Pacific countries are lacking. This study aimed to examine current trends in IONM usage in Asia-Pacific countries.

Overview of literature: IONM is an important tool for minimizing neurological complications and detecting spinal cord injuries after spine surgery. IONM can be performed using several modalities, such as transcranial electrical stimulation-muscle evoked potentials (Tc-MEP) and somatosensory evoked potentials (SEP).

Methods: Spine surgeons of the Asia-Pacific Spine Society were asked to respond to a web-based survey on IONM. The questionnaire covered various aspects of IONM, including its common modality, Tc-MEP details, necessities for consistent use, and recommended modalities in major spine surgeries and representative surgical procedures.

Results: Responses were received from 193 of 626 spine surgeons. Among these respondents, 177 used IONM routinely. Among these 177 respondents, 17 mainly used SEP, whereas the majority favored Tc-MEPs. Although a >50% decrease is the commonly used alarm point in Tc-MEP, half of the Tc-MEP users had no protocols planned for such scenarios. Moreover, half of the Tc-MEP users experienced complications, with bite injuries being the most common. Most respondents strongly recommended IONM in deformity surgery for pediatric and adult populations and tumor resection surgery for intramedullary spinal cord tumors. Conversely, IONM was the least recommended in lumbar spinal canal stenosis surgery.

Conclusions: Spine surgeons in Asia-Pacific countries favored IONM use, indicating widespread routine utilization. Tc-MEP was the predominant modality for IONM, followed by SEPs.