J Reconstr Microsurg 2021; 37(07): 559-565
DOI: 10.1055/s-0040-1722762
Original Article

Histologic and Functional Outcomes of Conduit Wrapping for Peripheral Nerve Repair: Early Results in a Rat Model

1  Department of Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
,
Christopher J. Dy
1  Department of Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
,
Tony Y. Lee
1  Department of Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
,
Dana Rioux-Forker
2  Division of Plastic Surgery, University of Missouri, Columbia, Missouri
,
Jason Wever
1  Department of Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
,
Fraser J. Leversedge
3  Department of Orthopedic Surgery, University of Colorado, Aurora, Colorado
› Author Affiliations
Funding This work was supported in part by a KL-2 Career Development Award awarded to D.M.B. from the University of Missouri.

Abstract

Background The concept of utilizing a nerve conduit for augmentation of a primary nerve repair has been advocated as a method to prevent neural scarring and decrease adhesions. Despite clinical use, little is known about the effects of a nerve conduit wrapped around a primary repair. To better understand this, we investigated the histologic and functional effects of use of a nerve conduit wrapped around a rat sciatic nerve repair without tension.

Methods Twenty Lewis' rats were divided into two groups of 10 rats each. In each group, unilateral sciatic nerve transection and repair were performed, with the opposite limb utilized as a matched control. In the first group, direct repair alone was performed; in the second group, this repair was augmented with a porcine submucosa conduit wrapped around the repair site. Sciatic functional index (SFI) was measured at 6 weeks with walking track analysis in both groups. Nonsurvival surgeries were then performed in all animals to harvest both the experimental and control nerves to measure histomorphometric parameters of recovery. Histomorphometric parameters assessed included total number of neurons, nerve fiber density, nerve fiber width, G-ratio, and percentage of debris. Unpaired t-test was used to compare outcomes between the two groups.

Results All nerves healed uneventfully but compared with direct repair; conduit usage was associated with greater histologic debris, decreased axonal density, worse G-ratio, and worse SFI. No significant differences were found in total axon count or gastrocnemius weight.

Conclusion In the absence of segmental defects, conduit wrapping primary nerve repairs seem to be associated with worse functional and mixed histologic outcomes at 6 weeks, possibly due to debris from conduit resorption. While clinical implications are unclear, more basic science and clinical studies should be performed prior to widespread adoption of this practice.

Note

Ethical approval for this study was obtained from the Institutional Animal Care and Use Committees at Washington University in St. Louis and at the University of Missouri.




Publication History

Received: 13 July 2020

Accepted: 19 November 2020

Publication Date:
31 January 2021 (online)

© 2021. Thieme. All rights reserved.

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA