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J Reconstr Microsurg 2022; 38(09): 711-720
DOI: 10.1055/s-0042-1757208
Original Article

Nerve-End Capping Treatment with a Polyglycolic Acid Conduit for Rat Sciatic Neuroma: A Preliminary Report

Authors

  • Ema Onode

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan

  • Takuya Uemura

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan
    2   Department of Orthopaedic Surgery, Osaka General Hospital of West Japan Railway Company, Osaka, Japan

  • Shunpei Hama

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan

  • Takuya Yokoi

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan
    3   Department of Orthopaedic Surgery, Seikeikai Hospital, Osaka, Japan

  • Mitsuhiro Okada

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan

  • Kiyohito Takamatsu

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan
    4   Department of Orthopaedic Surgery, Yodogawa Christian Hospital, Osaka, Japan

  • Hiroaki Nakamura

    1   Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan

Funding This work was supported by MEXT/JSPS KAKENHI Grant Number JP21K07300.
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Abstract

Background The treatment of painful neuroma remains challenging. Recently, a nerve-end capping technique using a bioabsorbable nerve conduit was newly introduced to treat amputation neuroma. A collagen-coated polyglycolic acid (PGA) conduit has been commercially available for the reconstruction of peripheral nerve defects, yielding successful clinical outcomes. However, no experimental research has been conducted using this PGA nerve conduit as capping device for treating amputation neuroma. The purpose of this study was to investigate nerve-end capping treatment with the PGA conduit in the rat sciatic nerve amputation model, focusing on histological scar formation and neuroinflammation.

Methods Forty-seven rats were divided into two groups: no capping (transected nerve stump without capping; n = 25) and capping (nerve-end capping with collagen-coated PGA nerve conduit; n = 22). Twelve weeks after sciatic neurectomy, neuropathic pain was evaluated using the autotomy score. Stump neuromas were histologically evaluated or perineural scar and neuroinflammation.

Results While autotomy scores gradually exacerbated in both groups, they were consistently lower in the capping group at 4, 8, and 12 weeks postprocedure. Twelve weeks after surgery, the transected nerve stumps in the no-capping group had formed macroscopic bulbous neuromas strongly adhering to surrounding tissues, whereas they remained wrapped with the PGA nerve conduits loosely adhering to surrounding tissues in the capping group. Histologically, distal axonal fibers were expanded radially and formed neuromas in the no-capping group, while they were terminated within the PGA conduit in the capping group. Perineural scars and neuroinflammation were widely found surrounding the randomly sprouting nerve end in the no-capping group. In capped counterparts, scars and inflammation were limited to closely around the terminated nerve end.

Conclusion Nerve-end capping with a collagen-coated PGA conduit after rat sciatic neurectomy might prevent neuroma formation by suppressing perineural scar formation and neuroinflammation around the nerve stump, potentially relieving neuropathic pain.

Keywords

nerve conduit - pain - peripheral nerve


Publication History

Received: 26 May 2021

Accepted: 30 January 2022

Article published online:
19 September 2022

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