After removal of 1 metatarsal pad and formation of a granulation tissu
e bed, free segmental 6- x 8-mm grafts from digital pads were sutured
into recessed same-size recipient sites in the granulation tissue. In
5 dogs, the grafted area had been denervated by excision of a segment
of the tibial nerve at the level of the tarsus. The grafted area was n
ot denervated in the remaining 5 dogs. In both groups of dogs, the gra
fts placed around the periphery of the wound healed, blocked ingrowth
of delicate epithelium from the surrounding skin, and provided a tough
keratinized epithelium that covered the wound's center. As healing pr
ogressed, the grafts coalesced as the wounds contracted. Weight bearin
g resulted in graft expansion to provide functional weight-bearing tis
sue. Dogs of the denervated group had clinical and histologic evidence
of collateral sensory reinnervation of the denervated area. However,
with the exception of 1 dog, results of sensory nerve action potential
tests indicated that reinnervation may not have been by way of regene
ration across the excisional gap in the nerve. Evaluation of reinnerva
tion of the tibial autonomous zone in 2 additional dogs revealed clini
cal evidence that collateral reinnervation began between 19 and 28 day
s after nerve excision and progressed proximad to distad. Results of s
ensory nerve action potential tests indicated that reinnervation may n
ot have been via regeneration across the excision site. Results of flu
orescent tracer studies did not have positive findings regarding the r
oute of collateral reinnervation. Segmental paw pad grafts can be used
effectively to provide weight-bearing tissue on a dog's limb. With lo
cal nerve damage on the distal portion of the limb, collateral innerva
tion can grow into the area to reinnervate tissues, including pad graf
ts.