Early sensory protection in reverse end-to-side neurorrhaphy to improve the functional recovery of chronically denervated muscle in rat: a pilot study

Abstract

Object Early innervation by sensory nerves has been proposed to prevent atrophy of chronically denervated muscle, but conventional end-to-end (ETE) neurorrhaphy has been demonstrated to have adverse effects on muscle contractile function. The aim of the present study was to investigate the potential for modified sensory nerve protection in reverse end-to-side (ETS) neurorrhaphy as a way of improving the functional recovery of denervated muscle. Methods Four groups of rats underwent surgical denervation of the tibial nerve projecting to the right hindlimbs (Group 1, unprotected controls; Group 2, positive control [immediate repair without delayed denervation]; Group 3, ETS protected; and Group 4, ETE protected). The proximal and distal stumps of the tibial nerve were ligated in all animals except for those in the immediate-repair group. Other animals underwent denervation without sural nerve protection, or with ETE or ETS neurorrhaphy. The ETE- and ETS-protected and unprotected groups underwent an additional surgery in which the trimmed proximal and distal tibial nerve stumps were sutured together. After 3 months of recovery, the tibial function index was determined, and electrophysiological, histological, and morphometric parameters were assessed. Results Significant muscle atrophy was observed in the unprotected group, while a well-preserved ultrastructure was observed for the gastrocnemius muscle in the ETE- and ETS-protected groups. Enhanced recovery in the ETS-protected group was indicated by the tibial function index, motor nerve conduction velocity, muscle contractile force tests, and the histological results. In contrast, early sensory nerve protection in ETE neurorrhaphy impaired the recovery of the regenerated axons and diminished the contractile force of the denervated muscle. Conclusions Early sensory protection in reverse ETS neurorrhaphy is an effective method for improving the functional recovery of chronically denervated muscle following peripheral nerve injury in rats.

Development of a Piezoelectric PVDF‐TrFE Fibrous Scaffold to Guide Cell Adhesion, Proliferation, and Alignment

“…[4] Neurorrhaphies are typically capable of repairing transections of shorter length yet lack the ability to fully rejoin nerve ends without inflammatory scarring or limited functional recovery. [5] For longer, more traumatic, injury gaps, nonsutured applications such as nerve conduits serve as mechanical guides for regenerative directionality while possessing interchangeable structural chemistry and a capacity for bioactive additives. [6] Nerve autografts, and in some cases allografts, are regarded as the consensus "gold standard" treatment for traumatic injury, but are hindered by availability of donor sites, risk of innervation, and more serious conditions such as neuroma.…”

Electromyography as an intraoperative test to assess the quality of nerve anastomosis – experimental study on rats

“…In two cases, a follow-up EMG after 4 weeks showed nerve conduction. This phenomenon was described previously by other authors who described the ingrowth of nerve fibers in the end-to-side [2,[4][5][6][7][8][9] or the side-toside anastomosis [3,10]. In the aforementioned studies, a nerve sheath was cut at the site before the anastomosis was made to ensure direct contact of nerve fibers between the end and the side of the fused nerves.…”

"Babysitting" procedures in proximal nerve trunk injuries: two case reports and a review

“…However, another consideration is that there is no consensus about the negative influence of sensate fibers. Some authors' [17,18] experience agrees with this last opinion, but several other and more recent experimental experiences [19][20][21][22] do not. In these studies, sensate fibers produce end-to-side regeneration and reinnervation of distal muscle.…”