ABSTRACT
This experiment evaluated the electrical and histologic differences between two groups
of rats, one of which underwent same-length bilateral resection of posterior tibial
nerves prior to being repaired with grafts of different lengths, while the other group
underwent different-length resections with same-length graft repair. In this rat model,
18 animals were used and divided into two groups. The first group of animals underwent
bilateral resection of 8-mm segments of posterior tibial nerve. To repair these nerves,
one leg received two 8-mm sural nerve grafts (Group A), while the other leg received
two 16-mm sural nerve grafts (Group B). The second group of rats underwent posterior
tibial nerve resections of 8 mm and 16 mm, respectively. The leg with the 8 mm of
posterior tibial nerve resected, received two side-by-side 16-mm sural nerve grafts
(Group C); the other leg with 16 mm resected, received two 16-mm sural nerve grafts
(Group D).
Electrophysiologic comparison of nerve conduction velocity for Groups A and B showed
a significant difference (p < 0.05), as did the same comparison for Groups C and D (p < 0.05). Histologic studies showed that Groups A and D had marked extrafascicular
escape of the regenerating nerve axons, disorganizational growth of minifascicles,
and loss of integrity of the donor fascicles, while Groups B and C had very minimal
extrafascicular escape of regenerating axons.
Results suggest that, in clinical situations, redundant nerve graft lengths are preferable
to nerve grafts that produce even the slightest tension on the suture line: producing
tension on the suture line seems to have a greater negative influence on axon regeneration
in the rat than does either doubling the gap length or doubling the graft length.
