Changes in spontaneous dorsal horn potentials after dorsal root entry zone lesioning in patients with pain after brachial plexus avulsion.

OBJECTIVES This study investigated spontaneous dorsal horn potentials in patients with pain after brachial plexus avulsion and determined the effect of dorsal root entry zone (DREZ) lesioning on these potentials and on pain levels. METHODS Electrospinography (ESG) recordings were undertaken in seven patients using a noninvasive electrocorticography strip electrode. Measurements were taken from the DREZ on the intact side of the spinal cord before lesioning of the injured DREZ and from the injured DREZ before and after lesioning. RESULTS DREZ lesioning had a significant positive effect on pain at 12 months postoperatively. At 15.0 Hz, the mean ESG power from the injured DREZ before lesioning was significantly higher than that from the intact DREZ. In addition, the mean ESG power from the injured DREZ after successful DREZ lesioning was significantly lower than that from the intact DREZ and that from the injured DREZ before lesioning. CONCLUSIONS The ESG power from the injured DREZ increases in patients with pain after brachial plexus avulsion compared with that of the intact DREZ; this increase is reduced by successful DREZ lesioning.