The effects of chronic electrical stimulation on laryngeal muscle reinnervation

The present study examined the effects of functional neuromuscular stimulat ion (FNS) on reinnervation of the posterior cricoarytenoid (PCA) muscle. In 4 canines, the recurrent laryngeal nerve (RLN) was sectioned and anastomos ed and a patch electrode array implanted for stimulation and recording at m ultiple PCA sites. Following implantation, FNS was applied to 2 canines for a period of 6 weeks. Two additional animals served as nonstimulated contro ls. In each animal, histomorphometric analysis of the RLN was used to asses s the quality of nerve regeneration and the potential for muscle reconnecti on. The magnitude of reinnervation was monitored by electromyographic (EMG) potentials evoked by RLN stimulation. The appropriateness of reconnection was determined by the pattern of spontaneous EMG activity and recovery of v ocal fold abduction. Results of this preliminary study indicated that FNS c aused an overall repression of reinnervation. However, the repression prefe rentially inhibited reconnection by foreign nerve fibers, promoting selecti ve reinnervation and preventing synkinesis. Copyright (C) 2000 S. Karger AG , Basel.