I. Rozet, M.D.
Spinal cord injury resulting in neurological deficit is one of the most serious complications of spine surgery. To diagnose and potentially prevent an accidental injury of the spinal cord, special neurophysiologic monitoring called "evoked potentials" are used during the surgery. Evoked potential responses are very small electrical signals generated by the brain, spinal cord, or other nerves in response to a stimulus. The 3 most commonly used evoked potentials in our institution are: 1) somato-sensory evoked potentials (SSEPs), 2) motor evoked potentials (MEPs), and 3) visual evoked potentials (VEPs). The type of evoked potentials used for monitoring is based on the anatomical area of surgery, the nerve(s) at risk of injury, as well as the surgeon's and anesthesiologist's preferences. Generally, evoked potentials are checked immediately after the patient is put asleep (anesthetized) to obtain baseline signals, followed by continuous monitoring throughout the case. Unfortunately, all anesthesia medications can impair evoked potentials to some degree, depending on the particular kind of medication and the dose used. Therefore, the type and dose of anesthesia drugs in spine surgery depends on the type of neurophysiologic monitoring planned for the patient. The anesthesiologist occasionally has to adjust the depth of anesthesia to improve the quality of the evoked potential signals. The purpose of this research is to determine the effect of Dexmedetomidine (Dex) on evoked potential monitoring during spine surgery.