Surgical Neurolysis for Atypical Neuropathy Diagnosed via Physical Examination Significantly Improves Chronic Pain Despite Negative Workup.

BACKGROUND: Many patients experience chronic pain, especially after trauma or surgery, despite a negative workup. We hypothesize that underdiagnosed peripheral neuropathy may be contributing to their intractable symptoms. METHODS: This is a retrospective cohort of patients who underwent surgical neurolysis for chronic pain that was neuropathic in nature, in the distribution of a peripheral nerve, with a positive scratch collapse test. Before surgery, patients were administered a corticosteroid injection at the lesion. The principal outcome was a self-reported visual analog scale pain score. Multivariate logistic regression identified predictors of poor response, defined as a relative pain reduction of less than 20% or increase in pain. RESULTS: A total of 302 patients were included, involving neurolysis of the following nerves: radial (101), peroneal (54), saphenous (39), axillary (38), median (45), tibial (16), femoral (2), sural (2), and brachial plexus (2). Average age was 51. Fourty six percent presented with an attributable mechanism, whereas 54% had negative electrodiagnostics, and 80% endorsed relief following injection. Following neurolysis, average pain decreased from 6.6 to 2.8, whereas 10% responded poorly. Worker's compensation patients were more likely to respond poorly, whereas positive injection response and longer follow-up duration were less likely to respond poorly. CONCLUSIONS: Patients with intractable conditions experiencing chronic pain despite a normal workup may benefit substantially from surgical neurolysis of underrecognized lesions identified via physical examination. Patients should be counseled that a positive response to injection and longer follow-up signify a beneficial prognosis, but worker's compensation status may predict a poor response.