[Relations between donor nerve size and degree of neurotization in the nerve transplant--an experimental study]

The present study was undertaken to investigate whether the number of myelinated fibers in a sensory nerve used as an autograft influences the result of nerve fiber regeneration in the graft. In 30 rabbits, the left saphenous nerve was used as an autograft. It was coapted to the motor branch to the rectus femoris muscle. Biopsies from both ends of the graft were taken. Animals were separated into four investigation groups, which were reexamined 3, 6, 9 and 12 months after the grafting procedure. Biopsies for histological and morphometric examination were again taken from the proximal and the distal part of the grafts. Thus, the number of myelinated nerve fibers in the different specimens could be obtained by computer-assisted image analysis. At the proximal end of the original saphenous nerve, the number of fibers varied between 1032 and 3100 (mean 2145). Corresponding data obtained from the distal end ranged from 1044 to 3084 myelinated nerve fibers (mean 1724). Fiber numbers in the proximal and distal parts of the grafts before and after regeneration were correlated to each other. In the whole population of specimens (correlation coefficient +/-0) as well as in the experimental subgroups, the quantitative success of neurotization in the grafts did not depend to a high degree upon the fiber numbers in the original saphenous nerve. The correlation coefficient for the proximal part of the graft exceeded 0.5 to only three and twelve months after grafting, but did not reach a level of statistical significance. In the distal part of the graft, the coefficient for a linear correlation was always less than 0.45.