ABSTRACT
End-to-side neurorrhaphy is a technique that may provide a solution for the problem
of distal target reinnervation without injury to the original donor nerve. The technique
drew extensive attention after Viterbo reported his experiments in 1992; however,
to date, the animal models used to elucidate the process of lateral axon sprouting
had the disadvantage of substantial injury to the donor nerve, raising questions about
the origin of axons reinnervating the nerve graft. In this report, a new model in
the rat is introduced, in which the donor nerve is not damaged and an additional target
can be innervated via a nerve graft.
The saphenous nerve represents the axonal conduit; the proximal end is coapted end-to-side
to the sciatic nerve at the site of a perineurial window. The distal end is passed
through the adductor muscles and coapted distally in an end-to-end fashion with the
obturator nerve. In one group, a partial neurec-tomy was performed at the site of
coaptation, which led to a lower Sciatic Functional Index (SFI). In the second group,
the creation of a perineurial window yielded a normal SFI after end-to-side neurorrhaphy.
Compared to the partial neurectomy group, the perineurial window end-to-side neurorrhaphy
resulted in significantly less axons in the graft.
The new model has the following advantages: (a) minimal injury to the donor nerve;
(b) provision of a single additional target (gracilis) whose functional recovery can
be assessed morphologically and be-haviorally; (c) an opportunity to understand lateral
sprouting by providing a non-injury model in which axonal invasion of the graft can
originate from nodal axonal outgrowth; and (d) establishment of a non-injury model
that can have widespread clinical applications.
