The Role of Internal Nerve Splinting on the Repair of Peripheral Nerve Injury

Abstract

Background: Neuropathic pain, produced by symptomatic neuromas, is an important problem following peripheral nerve injury. Anastomosing the stump nerves end-to-end for peripheral nerve injury is a well-established but can’t avoid neuroma in-continuity forming efficiently. Methods: Seventy-two rats were randomly divided into four groups: rats with anastomosis sites supported by silicone tubes represented the internal nerve splinting (INS, n = 18) group, rats with simple anastomosis represented the control group I (CON 1, n = 18), and rats with the same silicone tube beside the anastomosis site represented the control group II (CON 2, n = 18), and rats with the same surgical procedures for skin and muscle operations, but without sciatic nerve injury (Norm, n = 18). Gross evaluation of anastomosis sites, gastrocnemius muscle atrophy, axonal regeneration and remyelination, neuropathic pain and scar hyperplasia of neuromas, as well as motor function evaluation, were assessed and compared among all groups. Findings: The results of the INS were similar to the CON 1, and both of these groups were better than CON 2 with respect to axonal regeneration, remyelination and gastrocnemius muscle atrophy. However, in INS, neuropathic pain and scar hyperplasia, evaluated by the expression of anti-sigma-1 receptor antibodies and anti-α-smooth muscle actin, respectively, as well as the weight ratios of neuromas, were reduced compared to those in CON 1 or CON 2. Interpretation: Application of an internal nerve splint in nerve repair effectively prevented traumatic in-continuity neuromas forming and inhibited neuropathic pain while with no influence on nerve regeneration in rats. Funding Statement: This study was supported by Wenzhou Municipal Science and Technology Bureau (grant numbers Y2020040) and National Natural Science Foundation of China (grant numbers 81571185). Declaration of Interests: The authors have declared no conflict of interest. Ethics Approval Statement: All experiments involving animals were conducted according to the ethical policies and procedures approved by the animal care committee of Wenzhou Medical University, China (Approval: wydw2019-0954).