ABSTRACT
Adequate vascularization is essential for a successful nerve graft. Theoretically,
immediate vascularization will minimize fibroblast infiltration and support axonal
regeneration. In this study, histomorphologic and morphometric studies were carried
out to determine whether vascularized grafts are beneficial, in terms of axonal regeneration.
In a rabbit model, 4-cm segments of sciatic nerve were obtained and placed as a non-vascularized
graft on one side, and as a pedicled vascularized graft fed by the inferior gluteal
vessel on the contralateral side. Histomorphologically, the distribution of myelinated
nerve fibers and Schwann cells was evaluated after toluidine blue staining, at 2-,
3, and 4-month intervals. The following results were obtained. 1) Myelinated nerve
fibers were more abundant in the proximal, middle, and distal segments of the vascularized
nerve group at 2 and 3 months. 2) The average nerve-fiber diameter was greater in
the vascularized nerve graft group at 2, 3, and 4 months (2 to 10 μm). 3) Schwann
cells were more abundant in the proximal, middle, and distal segments of the vascularized
nerve graft group at all time points.
Based on the above findings, the immediate restoration of circulation in the vascularized
nerve graft can be accountable for the increased number of surviving Schwann cells,
the rapid clearing of axons, and myelin-sheath changes that occur during Wallerian
degeneration, thus enabling ``morphologically'' optimal regeneration.
