The external laryngeal nerve (ELN) is intimately associated with the superior thyroid vessels and may be stretched by a retractor or transected when these vessels are divided during thyroidectomy. Damage to the ELN causes paralysis of the cricothyroid muscle and changes to the voice that may include hoarseness, weakness, decreased range of pitch or volume and fatigue after extensive use’. These changes tend only to be a nuisance in most individuals but can be catastrophic in singers or professional speakers.
The use of a nerve stimulator during thyroidectomy has previously been described but there are no reports relating to singers. A nerve stimulator is a useful safeguard in these patients.
In a study in 1995, a nerve stimulator was used in a limited number of singer patients. During thyroidectomy, stimulation of the nerve produced obvious contractions of the ipsilateral cricothyroid muscle. Individual branches of the superior thyroid artery were tested with the nerve stimulator before ligation in order to exclude a closely associated ELN branch. Following exposure of the recurrent laryngeal nerve, total thyroid lobectomy was performed.
There were no postoperative complications in these patients. On the first two days after surgery their voices sounded normal; this impression was confirmed by the patients themselves. All the patients returned to natural singing within 6 weeks and reported that there were no changes in the pitch or range of their voices.
Choksy, S. and M. Nicholson, Prevention of voice change in singers undergoing thyroidectomy by using a nerve stimulator to identify the external laryngeal nerve. British journal of surgery, 1996.