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|Title:||THE USE OF SIDE-TO-SIDE NERVE GRAFTS TO “PROTECT” DISTAL NERVE PATHWAYS DURING AXON REGENERATION FROM SURGICALLY REPAIRED PROXIMAL NERVE INJURIES |
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|Authors/Affiliations:||1 Adil Ladak*; 1 Paul Schembri; 1 Neil Tyreman; 1 Jaret Olson; 1 Tessa Gordon; |
1 University of Alberta, Edmonton, AB, Canada
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|Content:||Objectives: The goal in the surgical repair of peripheral nerve injuries is the precise union of the proximal and distal stumps of the transected nerve such that optimal nerve function is achieved. It has been established that there is a narrow window of opportunity for axonal regeneration so that with high ulnar nerve lacerations for example, long-term neuronal axotomy and chronic denervation of distal nerve stumps will progressively reduce regenerative potential to almost zero. In this study we used side-to-side nerve bridges on the distal nerve stump as a means to “protect” the distal nerve stumps and counted the number of motoneurons that regenerated their axons through the bridge(s). |
Methods: Sprague Dawley rats (n=43) were divided into 4 groups, all of which were subjected to unilateral excision of a 6mm segment of the common peroneal (CP) nerve to use as a side-to-side nerve bridge. In Group I, an 18mm contralateral CP nerve graft (cCPgraft) was harvested to bridge between the ipsilataral CP nerve stumps using end-to-end anastomoses. In Group II, a cCPgraft was again inserted between the ipsilateral CP nerve stumps AND a side-to-side ipsilateral CP nerve graft (6mm) joined the tibial and CP distal nerve stumps. In Groups III and IV, the CP nerve was transected and NOT bridged end-to-end by the cCP graft; one (Group III) or 3 (Group IV) side-to-side nerve CP graft(s) joined the tibial (TIB) and CP distal nerve stumps.
Results: Axonal regeneration through the contralateral CP nerve graft in Groups I and II showed exceptional recovery: ~90% of CP motoneurons regenerated axons through the end-to-end cCP graft. In Group III, there was minimal TIB axon regeneration with 8+3 (mean + SE) labeled motoneurons in 8 out of 15 rats in contrast to the significantly better regeneration of 76+30 backlabelled motoneurons in 7 out of 7 rats in Group IV.
Conclusions: Our data demonstrate the feasibility of using multiple rather than single side-to-side nerve bridges to “protect” the distal nerve stump after surgical repair of proximal nerve injuries.
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