Dorsal root entry zone stimulation for deafferentation pain.

Dorsal root entry zone (DREZ) stimulation was performed in 12 patients with chronic pain syndromes after extensive trials of medical therapy, sympathectomy or peripheral nerve stimulation had failed, with 50% of them obtaining excellent long-term benefit. Evoked potential monitoring to facilitate positioning of electrodes under either general or spinal anesthesia, and postoperatively to explore the mechanism of action, revealed findings distinct from those reported with conventional spinal cord stimulation (SCS). DREZ stimulation may function on a different neurophysiologic basis than conventional SCS, involving intersegmental processing and influencing tract of Lissauer functions or the dorsal horn directly.