Histologic examination of peripheral nerves elongated by tissue expanders

Histological changes induced by the slow stretch of peripheral nerves using a tissue expander were studied using a rat sciatic model. Tissue expanders were adapted to elongate the sciatic nerve in vivo. Nerves elongated over an eight week period using this method achieved an average increase in length of 88%. Light microscopic examination revealed that individual axons were separated but each axon and the myelin sheaths were stained well. Electron microscopic examination showed that the convoluted contour of the axons appeared and some loss of myelin was also observed, but the intraneural cytoskeleton elements were kept intact.