Monitoring spinal nerve function with H-reflexes

H-reflexes have been used in the clinical neurophysiology laboratory for some time to assess patients with neuromuscular disorders. There are only a few reports for the application of H-reflexes for intraoperative neurophysiologic monitoring. The goals of this article are to review the intraoperative neurophysiologic monitoring of spinal nerve root function with H-reflexes. The following will be reviewed: (1) Introduction to H-reflexes, (2) pathophysiology of spinal nerve root function, (3) neurophysiologic basis of H-reflexes, (4) gastrocnemius H-reflex, (5) flexor carpi radialis H-reflex, (6) anesthetic technique and research, and (7) intraoperative applications of H-reflexes. H-reflexes are single sweep real-time recordings that provide immediate feedback to the surgeon. They can be used to monitor not only sensory and motor spinal nerve root function but also peripheral sensory and motor nerves, plexus, and postsynaptic spinal cord gray matter function.