ABSTRACT
The revascularization of nerve grafts was investigated using histologic and morphometric
techniques. Small-diameter nerve grafts (sciatic in the rat and sural in adult ewes)
were studied, as was a large-diameter peroneal nerve graft in the ewe. Ninety-six
hours after sciatic nerve engraftment, rats were injected with an intravascular fluorescent
tracer, Evans blue albumin (EBA). Specimens were observed for the number of vessels
perfused. Analysis showed no difference in vascular pattern between the grafted nerves
and their control nerves, suggesting that spontaneous revascularization had occurred
to establish a vascular tree essentially identical to the native nerve.
Sural and peroneal nerve grafts were evaluated in adult ewes at 7 or 40 days post-nerve
grafting. Similar to the rat sciatic nerve, the small-diameter sural nerve grafts
were completely revascularized, with an equal number of perfused vessels at both time
periods, with respect to control specimens. In contrast, the larger-caliber peroneal
nerve grafts were not perfused at 7 days, and very poorly perfused at 40 days. This
correlated with scant neural regeneration at 40 days.
The finding suggests that small-diameter nerve grafts spontaneously revascularize,
and revascularization using microvascular techniques is not necessary. In contrast,
the larger-diameter nerve graft did not revascularize well. Such a large-diameter
nerve graft would provide a suitable model to investigate the potential merits of
a vascularized nerve graft.
