Experimental study of polarity in reversing cable nerve grafts.

To evaluate the effect of cable nerve graft polarity, the bilateral common peroneal nerves in 12 rabbits were excised to create 20-mm nerve gaps. These gaps were repaired with cable grafts using three strands of 20-mm ipsilateral sural nerves. In the left leg, the sural nerves were grafted with the original orientation. In the right leg, the nerve graft polarity was reversed 180°. Six months later, motor conduction velocities were evaluated, and the bilateral anterior tibial muscles and extensor digitorum longus muscles were measured. The nerves were harvested and analyzed histologically. Motor conduction velocity was 37.4±4.1 m/s in the reversed group, and 36.6±5.5 m/s in the control group. The weight of the muscles was 7.2±0.8 g in the reversed orientation, and 7.0±1.0 g in the original orientation. None of the differences was statistically significant. Histologically, the axon counts and the axonal density distal to the nerve graft also showed no differences between groups. The sural nerves used did not have a major branch and their diameter was almost the same throughout its length. Reversing nerve graft polarity of a cable graft did not affect nerve regeneration electrophysiologically or histologically.