Intraoperative Neurophysiological Monitoring in Spine Surgery

Abstract

Intraoperative neurophysiological monitoring (IONM) is a rapidly developing medical field that plays a critical role in preventing neurological damage by detecting dysfunction before it reaches an irreversible stage during spine and other surgical procedures. This article focuses on the intraoperative application and clinical utility of somatosensory evoked potentials (SEP), motor evoked potentials (MEP), and both spontaneous and triggered electromyography (EMG). SEP monitoring was introduced several decades ago and has been widely used to prevent neurological deficits. However, motor compromises have occurred despite the preservation of SEP. As a result, MEP recording following transcranial electrical stimulation has emerged as a reliable technique for intraoperative assessment of the functional integrity of motor pathways. More recently, both spontaneous and triggered EMG have become widely utilized for monitoring nerve root function during spine surgery. Although IONM provides sensitive and specific indications of neurological injury, it has limitations that must be acknowledged and understood. The monitoring team must be highly trained, capable of providing real-time feedback to the surgeon, and able to coordinate activities effectively with both the surgical and anesthesia teams.