Functional Reconstruction for Unilateral Recurrent Laryngeal Nerve Paralysis Caused by Thyroid Cancer

Abstract

Surgery for unilateral recurrent laryngeal nerve paralysis, which is caused by thyroid cancer, appearing within the past six months, should be aimed at improvement of the asymmetrical vocal cord and preservation of the stiffness and the mass of the vocal fold. To accomplish these aims, reconstructive surgery of the neuromuscular systems is available and it should be performed at the same time as thyroidectomy. Our surgical procedures for unilateral recurrent laryngeal nerve paralysis caused by thyroid cancer are reported along with some experimental investigations in dogs. Experimentally, muscle atrophy was prevented by neurorrhaphy or by free nerve grafting of the recurrent laryngeal nerve, although movement of the vocals cord was not recovered due to misdirected reinnervation and reduction of the end plates. In our study of functional reconstruction for unilateral recurrent laryngeal nerve paralysis, end-to-end anastomosis or free nerve grafting between the recurrent laryngeal nerve after extirpating the abductor muscle branch of this nerve was the most effective and practical method for improvement of the adductor function. Clinically reconstructive surgery was performed on five females suffering from thyroid cancer with unilateral recurrent laryngeal nerve paralysis. The abductor branch was cut selectively in four cases, followed by free nerve grafting of the ansa cervicalis and pedicle nerve muscle graft of the thyrohyoid muscle implanted in one case. Vocal cord atrophies were not observed and phonations were good in all cases six months after of operation. However, obvious adduction of the operated vocal fold at phonation was obtained only in two cases and other two cases showed slight adduction.