Histologic analysis of Schwann cell migration and peripheral nerve regeneration in the autogenous venous nerve conduit (AVNC)

Over the last two decades, the autogenous venous nerve conduit (AVNC) has been established as an effective treatment modality for the repair of nerve gaps less than 3 cm. In this study, the spatial-temporal progression of Schwann-cell migration and peripheral-nerve regeneration across a 10-mm gap bridged by a venous conduit was examined, using immunoctyochemical techniques. Histologic analysis revealed that the process of nerve regeneration through an AVNC occurs in four phases: the hematoma phase, cellular migration phase, axonal advancement phase, and myelination and maturation phase. The authors found that: 1) the lumen of the vein conduit remains patent throughout the process of nerve regeneration; 2) Schwann cells migrate into the vital space of the vessel lumen from the proximal and distal nerve stumps; 3) axonal growth into the conduit lags behind Schwann-cell migration; 4) Schwann cells migrate to the regenerating axons to form mature nodes of Ranvier when the distal stump is present; and 5) mechanical injury alone is sufficient to induce axonal outgrowth from the proximal nerve stump.