Intraoperative neuro-monitoring corner editorial: The need for preoperative sep and mep baselines in spinal surgery: Why can’t we and our monitoring colleagues get this right?

BACKGROUND: The majority of spinal surgeons now utilize intraoperative neurophysiological monitoring (IONM) during spinal procedures to limit the risk of inadvertent injury. Nevertheless, probably the most frequent error is the failure of the surgeon and IONM to obtain adequate preoperative baselines (e.g. before intubation or positioning). METHODS: Intraoperative neural monitoring should begin with the spinal surgeon, anesthesiologist, and monitoring technician/neurologist reviewing the patient's neurological deficits, the operative approach, the most anticipated risks and complications as well as the type of monitoring to be used (e.g. somatosensory evoked responses [SEP], motor evoked potential [MEP] monitoring, and electromyography [EMGs]). Baseline data should accurately reflect the preoperative status of the patient, and provide the appropriate data to be monitored and maintained throughout surgery. RESULTS: Significant but transient changes from the established preoperative baseline SEP and MEP often reflect alterations in the anesthetic technique (e.g. hypotension/hypoperfusion). However, when these changes persist, and resuscitative maneuvers have been exhausted (e.g. removing an oversized graft to avoid ischemia, utilizing total intravenous anesthesia [TIVA] correctly, reversing hypotension, changing the patient's cervical position, checking the electrode placement, checking the position of the limbs, and other factors), significant MEP/SEP changes may signal a major impending neural injury. CONCLUSION: IONM is only as good as how competently it is implemented by the technologist/neurologist, and understood by the surgeon and anesthesiologist. If any team member does not understand what and how the monitoring should be performed, then it becomes a useless adjunct to spinal surgery.