Highlights of Anesthetic Considerations for Intraoperative

Though relatively new, intraoperative neurophysiologic monitoring (IONM) has become standard of care for many neurosurgical procedures. The use of IONM has substan-tially decreased the rate of paralysis after deformity sur-gery, and has been validated in cervical spine surgery, and thoracic and lumbar laminectomy.1-3 Prior to common use of IONM, surgeons relied on the Stagnara wake-up test or ankle clonus. The disadvantage of these tests is they are dis-ruptive to the surgery and potentially dangerous and trau-matic to the patient, and neither test can be done continually.4,5 In modern-day procedures, the spinal cord is tested continu-ally and with minimal risk to the patient throughout many neurosurgical procedures. IONM refers to a group of testing measures, which allow continual observation of the integ-rity of the spinal cord during surgery. The main modalities are: somatosensory-evoked potentials (SSEPs), motor-evoked potentials (MEPs), and electromyography (EMGs). Each test examines a functionally separate area of the spinal cord, which test is chosen depends on the location of the surgery and the patient’s preexisting injuries and deficits.