Neurophysiology of complex spinal cord untethering.

Surgery of complex spinal dysraphisms can be challenging. A number of surgical maneuvers can place the conus and the cauda equina at risk for neurological injury during cord untethering, and the identification of functional neural structures within the lumbosacral region is often not possible solely on the basis of anatomy. Therefore, the assistance of intraoperative neurophysiological monitoring can be invaluable during these procedures. We describe the intraoperative neurophysiological monitoring strategy developed at our institution over the past 12 years when dealing with tethered cord surgery. Monitoring and mapping techniques are described, with a focus on the invaluable role played by neurophysiological mapping. This latter, for a neurosurgeon, impacts tethered cord surgery at least as strongly as neurophysiological monitoring. Our results suggest that the combination of monitoring and mapping techniques increases the safety of these procedures, minimizing long-term morbidity and improving the degree of cord untethering.