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Abstract
Partial nerve recovery either after expectant observation following an injury in-continuity or after nerve repair is not an uncommon occurrence. Historically, treatment strategies in these situations-late repair, revision repair, or acceptance of a mediocre result-were unsatisfying. The reverse end-to-side, or supercharging, nerve transfer was conceived to offer a more palatable option. Partially validated primarily through small animal research, supercharging has been rapidly translated to clinical practice. Many have extended the indications beyond the original intent, though the final place of this technique in the peripheral nerve surgeon's armamentarium is still yet to be determined.
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Affiliation(s)
- Jonathan Isaacs
- Virginia Commonwealth University Medical Center, Richmond, USA
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Isaacs J, Patel G, Mallu S, Ugwu-Oju O, Desai A, Borschel G, David D, Protzuk O, Shah S, Semus R. Effect of Reverse End-to-Side (Supercharging) Neurotization in Long Processed Acellular Nerve Allograft in a Rat Model. J Hand Surg Am 2019; 44:419.e1-419.e10. [PMID: 30172450 DOI: 10.1016/j.jhsa.2018.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 05/06/2018] [Accepted: 07/11/2018] [Indexed: 02/02/2023]
Abstract
PURPOSE Processed acellular nerve allograft (PNA) has been suggested as a convenient tool for overcoming short and medium nerve defects. Although the clinical implications are unclear, animal data suggest that PNA becomes less effective at longer lengths. Although reverse or supercharging end-to-side nerve transfer may improve the neurotrophic potential in chronically denervated nerve tissue, the application of this strategy to long acellular nerve allograft has not been previously investigated. We hypothesized that supercharging acellular nerve allograft would increase its effective length. METHODS Sprague-Dawley and Thy1-green fluorescent protein Sprague-Dawley rats underwent transection of the tibial nerve, followed by immediate repair with 20-, 40-, or 60-mm acellular nerve allografts processed identically to commercially available human acellular nerve allograft (AxoGen, Inc., Alachua, FL) or isograft. Half of the allograft group was supercharged with a reverse end-to-side transfer from the ipsilateral peroneal nerve. At 10 weeks, the reconstructed nerve in the Thy1-green fluorescent rat groups were exposed and examined under a fluorescence-enabled microscope. At 20 weeks, the remaining rats underwent motor testing and tissue harvest for morphological examination. RESULTS In comparison with a nonenhanced allograft, supercharging had a statistically significant positive impact on the reinnervated muscle normalized force generation and distal axon counts for all graft sizes. Muscles in the supercharged group were heavier than those in the allograft group for the 40-mm-length grafts and G-ratio measurements were higher in the supercharged allograft group for 60-mm-length grafts only. CONCLUSIONS This study supports that hypothesis that supercharging nerve transfer improves axon regeneration within PNA. CLINICAL RELEVANCE When an appropriate donor nerve is available, supercharging nerve transfer may improve nerve regeneration in PNA across long nerve defects.
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Affiliation(s)
- Jonathan Isaacs
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA.
| | - Gaurangkumar Patel
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Satya Mallu
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Obinna Ugwu-Oju
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Anish Desai
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Gregory Borschel
- Division of Plastic Reconstructive Surgery, Department of Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Dylan David
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Omar Protzuk
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Shalin Shah
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Rachel Semus
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
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Isaacs J, Mallu S, Shall M, Patel G, Shah P, Shah S, Feger MA, Graham G, Pasula N. Does partial muscle reinnervation preserve future re-innervation potential? Muscle Nerve 2017; 56:1143-1148. [PMID: 28073145 DOI: 10.1002/mus.25571] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2017] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Late revision nerve surgery for incomplete motor recovery due to partial reinnervation would improve muscle function if all muscle fibers were protected from developing denervation atrophy. METHODS Sixty immature Sprague-Dawley rats underwent the following tibial nerve manipulations (n = 15/group): group A, partial denervation (two thirds of nerve resected and the remaining one third crushed), revision repair at 8 months; group B, partial denervation; group C, complete denervation, immediate reconstruction; group D, complete denervation, reconstruction at 8 months; and group E, control. Final testing at 11 months included muscle force, weight, and histology. RESULTS Muscle weight was significantly (P < 0.05) different among all groups (highest to lowest: E > B > C > A > D), and force was significantly lower in groups A and D compared with E. Muscle fiber cross-sectional area was statistically smaller in group A than in groups B, C, or E. DISCUSSION Partial reinnervation still allowed substantial muscle recovery, but it did not preserve the non-innervated muscle fibers. Muscle Nerve 56: 1143-1148, 2017.
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Affiliation(s)
- Jonathan Isaacs
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Satya Mallu
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Mary Shall
- Department of Physical Therapy, Virginia Commonwealth University Medical Center, Richmond, Virginia, USA
| | - Gaurangkumar Patel
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Pooja Shah
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Shalin Shah
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Mark A Feger
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Gordon Graham
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
| | - Nikhil Pasula
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, 1200 East Broad Street, Richmond, Virginia, 23298, USA
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Pulley BR, Luo TD, Barnwell JC, Smith BP, Smith TL, Li Z. A chronically-denervated versus a freshly-harvested autograft for nerve repair in rats. HAND AND MICROSURGERY 2016; 5:124-129. [PMID: 30828670 DOI: 10.5455/handmicrosurg.215015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Objectives Autologous nerve grafting remains the gold standard for repair of peripheral nerve injuries. Its use, however, is limited by donor nerve availability and donor site morbidity. This is especially problematic after failure of an initial autograft that requires a repeat nerve graft, resulting in a second surgical site with associated morbidity. Based on the molecular differences in nerve degeneration in the proximal and distal segments after transection, we hypothesized that a chronically-denervated proximal stump may be viable for autologous nerve repair. Methods 20 Sprague-Dawley rats underwent right sciatic nerve excision and sural nerve transection. After 8 weeks, nerve repair was performed by harvesting the proximal segment of the sural nerve (n=10) or a fresh sural nerve (n=10) from the contralateral hind limb. Electrophysiological changes were analyzed to compare the fresh and denervated grafts. Results Electrophysiological testing demonstrated higher compound motor action potential in the denervated group compared to the fresh autograft group, however this difference was not statistically significant (p=0.117). Conclusion The proximal segment of a chronically-denervated sural nerve can be as effective as a fresh sural nerve for autologous repair of peripheral nerve injuries in a rodent model.
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Affiliation(s)
| | | | | | - Beth P Smith
- Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
| | - Thomas L Smith
- Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
| | - Zhongyu Li
- Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
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Abstract
Major peripheral nerve injuries in the upper extremities can result in significant morbidity. Understanding the pathophysiology of these injuries aids in the assessment and planning of appropriate treatment. With limited nerve mobilization, tension-free repairs can often be performed using sutures, fibrin glue, or nerve connectors. Acellular allograft and autograft reconstruction are better for bridging any gaps greater than a few millimeters. Adherence to proper principles of nerve repair improves the chances of achieving a favorable result, although in general these injuries portend a guarded prognosis.
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