Electromyographic study on end‐to‐end anastomosis of the recurrent laryngeal nerve in dogs

Abstract

The effectiveness of anastomosis of a divided recurrent laryngeal nerve was studied with electromyography as well as visual observation. Results obtained through this investigation permitted the following conclusions: 1. Regenerated potentials were recorded from both the involved thyroarytenoid and posterior cricoarytenoid muscles for an average of 5 to 6 weeks postoperatively. 2. Average onset of recovery of spontaneous adduction was 10 weeks following surgery, and four dogs regained complete recovery of adduction in 13 to 14 weeks. Average onset of recovery of spontaneous abduction was 11.8 weeks postoperatively, and none of the four dogs displayed complete recovery. 3. The time delay between the onset of regenerated potentials and onset of recovery of cord mobility averaged 4.2 weeks for adduction and 6.4 weeks for abduction. 4. Incomplete recovery of movements of the reinnervated vocal cord might be due to an inadequate number of effective motor units. 5. End-to-end anastomosis of the recurrent laryngeal nerve can be performed as one method of reinnervating the denervated intrinsic laryngeal muscles, and further histological studies should be carried out to determine if the regenerated nerve fibers actually have decreased.