Delayed laryngeal reinnervation

Abstract

Objective. To test the feasibility of selective abductor reinnervation with a delay period of 9 months after transectionof the recurrent laryngeal nerve (RLN). Successful laryngeal abductor function restoration has been achieved in the cat model, using the phrenic nerve (PN) to reinnervate the abductor muscle, in the acute phase, but in clinical practice there is usually a considerable period of delay between the time of injury to the RLN and the moment the patient presents for treatment. Materials and methods. The right RLN was severed in 12 cats. Nine months later the PN was anastomosed to the distal RLN stump and all its branches were diverted to the posterior cricoarytenoid (PCA) muscle. Ten weeks after the reconstruction, electromyography, videolaryngoscopy and histological analysis were performed. Results. Eleven cats could be evaluated. Videolaryngoscopyshowed adequate to good abduction in only four cats although inspiratory EMG activity was found in the right PCA muscle in 10 cats. A high correlation was found between reduced mobility of the cricoarytenoid joint and poor restoration of abduction movement. Conclusion. Selective laryngeal abductor reinnervation has proved possible in the cat model even after a delay of 9 months, but restoration of abduction appears to be negatively influenced by reduced mobility of the cricoarytenoid joint.