Kathleen Mears Lecture: Intraoperative Neurophysiologieal Monitoring—A Contemporary Perspective

Abstract

ABSTRACT.Intraoperative neurophysiologieal monitoring (IONM) has gained widespread acceptance over the past five years, due in part to the myriad publications demonstrating the reliability, validity, and clinical efficacy of this burgeoning specialty. In fact, monitoring of spinal cord function is now considered standard of care during surgical correction of scoliosis. Likewise, cranial nerve monitoring now enjoys similar universal acceptance during posterior fossa tumor surgery. Recent technological advances in spinal instrumentation systems, for both deformity correction and internal fixation, have broadened the scope of patients who can now benefit from complex spine surgery, far beyond scoliosis. Similarly, advances in neurosurgery have also given rise to broadened opportunity for neuromonitoring techniques and strategies to keep pace with advances in a multitude of surgical specialties. The increase in demand for spinal cord monitoring reflects the increase in the intricacy of corrective spine procedures and the subsequent risk of iatrogenic injury to the spinal cord, nerve roots, or both. The monitoring demands for these procedures extend far beyond the time-honored somatosensory evoked potential (SSEP) and the brainstem auditory evoked potential (BAEP). Newer techniques that assess central nervous system (CNS) function more directly, such as transcranial motor evoked potentials, nerve root mapping, motor and speech cortex mapping, transcranial microdoppler flow studies, and cerebral oximetry, are now included in the neuromonitoring armamentarium either to augment or replace historical indirect measures such as SSEPs and EEG. As the field of IONM approaches its third decade, we are forced to examine current and future perspectives relating to the broad-based knowledge demands required in neurophysiology, surgical anatomy, anesthesia, and the like that now far exceed that needed previously. The chalenge is indeed formidable.