Floor plan - 2013 Annual Meeting - American Association for Hand ...

The Feasibility of Using Side-to-Side Nerve Grafts to “Protect” Nerve Pathways during Axon
Regeneration from Surgically Repaired Proximal Nerve Injuries
Institution where the work was prepared: University of Alberta, Edmonton, AB, Canada
P. Schembri, BSc, MD; A Ladak; N. Tyreman; J Olson; T. Gordon; University of Alberta
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). 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 Groups II and III. In the 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 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. All anastomoses were
performed using Tisseel fibrin glue and rats convalesced prior to backlabelling of TIB and CP regenerated axons 4 months later with
fluorescent retrograde dyes. Axonal regeneration through the contralateral CP nerve graft in Groups I and II showed exceptional recovery:
~90% of CP motoneurons regenerated axons through the 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. There was only one case of sprouting in 32 rats in Groups II, III and IV. 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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