A MAGNETIC EVALUATION OF PERIPHERAL-NERVE REGENERATION - II - THE SIGNAL AMPLITUDE IN THE DISTAL SEGMENT IN RELATION TO FUNCTIONAL RECOVERY

Motor and sensory function in a healthy nerve is strongly related to t he number of neuronal units connecting to the distal target organs. In the regenerating nerve the amplitudes of magnetically recorded nerve compound action currents (NCACs) seem to relate to the number of funct ional neuronal units with larger diameters regenerating across the les ion. The goal of this experiment was to compare the signal amplitudes recorded from the distal segment of a reconstructed nerve to functiona l recovery. To this end, the peroneal nerves of 30 rabbits were unilat erally transected and reconstructed. After 6, 8, 12, 20, and 36 weeks of regeneration time the functional recovery was studied based on the toe-spread test, and the nerve regeneration based on the magnetically recorded NCACs. The results demonstrate that the signal amplitudes rec orded magnetically from the reconstructed nerves increase in the first 12 weeks from 0% to 21% of the amplitudes recorded from the control n erves and from 21% to 25% in the following 23 weeks. The functional re covery increases from absent to good between the 8th and the 20th week after the reconstruction. A statistically significant relation was de monstrated between the signal amplitude and the functional recovery (P < 0.001). It is concluded that the magnetic recording technique can b e used to evaluate the quality of a peripheral nerve reconstruction an d seems to be able to predict, shortly after the reconstruction, the e ventual functional recovery. (C) 1998 John Wiley & Sons, Inc.