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Papers of the Week

Papers: 28 May 2022 - 3 Jun 2022

Animal Studies

2022 May 28


Editor's Pick

Resurgent neuropathic discharge: an obstacle to the therapeutic use of neuroma resection?


Ectopic discharge ("ectopia") in damaged afferent axons is a major contributor to chronic neuropathic pain. Clinical opinion discourages surgical resection of nerves proximal to the original injury site for fear of resurgence of ectopia and exacerbated pain. We tested this concept in a well-established animal neuroma model. Teased fiber recordings were made of ectopic spontaneous discharge originating in the experimental nerve-end neuroma and associated dorsal root ganglia (DRGs) in rats that underwent either a single transection (with ligation) of the sciatic nerve, or two consecutive transections separated by 7, 14, 21 or 30 days. Ectopia emerged in afferent A- and C-fibers after a single cut with kinetics anticipated from prior studies. When resection was carried out during the early period of intense A-fiber activity a brief period of resurgence was observed. However, resection of neuromas of more than 14 days was followed by low levels of activity with no indication resurgence. This remained the case in trials out to 60 days after the first cut. Likewise, we saw no indication of resurgent ectopia originating in axotomized DRG neuronal somata and no behavioral reflection of resurgence. In summary, we failed to validate the concern that proximal resection of a problematic nerve would lead to intense resurgent ectopic discharge and pain. As the well-entrenched concept of resurgence is based more on case-reports and anecdote than on solid evidence, it may be justified to relax the stricture against resecting neuromas as a therapeutic strategy, at least within the framework of controlled clinical trials.