Dorsal root entry zone lesioning for pain after brachial plexus avulsion: results with special emphasis on differential effects on the paroxysmal versus the continuous components. A prospective study in a 29-patient consecutive series.

Pain after brachial plexus avulsion (BPA) is generally characterized by 2 main different components: paroxysmal (electrical shooting-like) pain, and continuous (burning) pain. Dorsal root entry zone (DREZ) lesioning, namely, the microsurgical DREZotomy (MDT) used in our practice, has proved to be a worthwhile neurosurgical treatment for this indication. However, according to previous studies, the method does not seem to demonstrate as good effectiveness in patients in whom the continuous background of pain was predominant as in patients with the paroxysmal component predominating. To obtain more insight into this problem, a prospective study on an eventual differential effect of the MDT procedure on the 2 components was undertaken. The presented series included 29 consecutive patients affected with pain after BPA who underwent an operation over the 10 last years. Pain intensity was evaluated using a visual analogue scale (VAS). At last evaluation of the 26 patients followed for 12 to 122 months (60 months on average) after MDT, 76.9% had a good or excellent global pain relief after surgery, ie, pain control with or without additional nonopioid medications, respectively. According to the component types of pain, 84.6% of patients had good or excellent control of the paroxysmal pain, and 73.1% of the continuous pain. Kaplan-Meier prediction of lasting global pain control at 120 months of follow-up was calculated at 41.1%. Comparison of the 2 corresponding Kaplan-Meier curves at long term, namely, pain control in 76.2% for the paroxysmal component and in 43.1% for the continuous component, showed a statistically significant difference (P=.038). Hypotheses for this relative differential effect are discussed.