Experimental Study on Reinnervation of Vocal Cord Adductors With the Ansa Cervicalis

Abstract

The purpose of this study was to reestablish the adduction of the paralyzed vocal cord through reinnervation of the adductor muscles for unilateral vocal cord paralysis. In nine dogs, the adductor branch of the recurrent laryngeal nerve was anastomosed to the main branch of the ansa cervicalis. Six months later, various techniques of observation showed that seven of nine cases had excellent to good adduction during whining. Adduction was caused by reinnervation of the adductor muscles from the ansa cervicalis as demonstrated by laryngeal spontaneous and evoked electromyography, contraction tension, and various histologic findings. Therefore, the new technique could be a good treatment of unilateral vocal cord paralysis.

Laryngeal Reinnervation Using Ansa Cervicalis for Thyroid Surgery-Related Unilateral Vocal Fold Paralysis: A Long-Term Outcome Analysis of 237 Cases

“…We firstly reported laryngeal reinnervation using main branch of ansa cervicalis in UVFP animal models in 1996, and satisfactory or good voice qualities were obtained by this procedure in a small sample of patients with UVFP [14], [16], [17]. The main branch of ansa cervicalis in our procedure possesses more motor fibers than a single branch.…”

“…Our previous anatomical study demonstrated that there is usually a main branch coming from the loop of ansa cervicalis, and it has two to three branches and innervates the inferior portions of the sternohyoid, sternothyroid and omohyoid muscles. The main branch almost has the same number of myelinated fibers and motor fibers to the number of the adductor branches of the RLN [13], [14]. The existence of the main branch of ansa cervicalis was later confirmed by Chhetri et al [15].…”

Changes in electrical response function and myosin heavy chain isoforms following denervation and reinnervation of bilateral posterior cricoarytenoid muscles in dogs

“…The ansa cervicalis best fits the criteria for reinnervating the PCA muscle, and is anatomically adjacent to the larynx [12]. The ansa-RLN anastomosis also demonstrated significant PCA muscle functional improvement in clinical and animal studies of unilateral vocal paralysis [10,13]. Although PCA muscle reinnervation can cause greater vocal fold mobility than denervation under functional electrical stimulation, research into bilateral PCA muscle reinnervation was limited due to the variability and complexity of nerve supply, especially in ansa-RLN anastomosis studies [2,6].…”

“…The resected laryngeal ends of the RLN were anastomosed to the ansa cervicalis branches with four or five epineurial stitches of nylon 11-0 thread. The wound was then closed in layers [10].…”

Modified arytenoid adduction for cancer-related unilateral vocal fold paralysis

“…Laryngeal reinnervation has been shown to be an effective intervention which restores physiological laryngeal phonatory and protective sphincteric function, by re-establishing the tension and mass of the paralysed vocal fold. 11,19,20 However, this method is not a good choice for patients with cancer-related unilateral vocal fold paralysis because of their short life expectancy, given the relatively lengthy reinnervation process. Vocal fold medialisation represents an alternative, palliative procedure which can improve voice quality and resolve aspiration while involving minimal intrusion into the patient's life, and it is accepted currently for the treatment of cancer-related unilateral vocal fold paralysis.…”