Peripheral nerve elongation by laser Doppler flowmetry-monitored expansion : an experimental basis for future application in the management of peripheral nerve defects

Nerve grafting often fails to achieve optimal functional results and is always associated with donor-site morbidity. Peripheral nerve elongation by the use of a tissue expander may provide a useful adjunct in the management of segmental nerve loss. In the present study, rabbit sciatic nerve (n = 40) was elongated by expansion while nerve blood flow was monitored by laser Doppler flowmetry. Elongation was possible up to 40 percent with preservation of clinical nerve function. Nerve conduction velocity of the expanded nerves decreased in a linear relation to elongation. The reduction in nerve conduction velocity may be secondary to the observed widening of the nodes of Ranvier and altered membrane properties after remyelination. Demyelination and remyelination of whole internodes and axonal degeneration occurred only sporadically. Thus laser Doppler flowmetry-monitored expansion provides a safe method for elongation of intact rabbit sciatic nerve while nerve function and axonal continuity are preserved. Further studies are needed before clinical use is considered. This technique may represent a favorable alternative to nerve grafting for the treatment of peripheral nerve defects.