Endocrine Head & Neck Surgery

Stanford Head & Neck Center

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Voice Evaluation and Preservation in Thyroid and Parathyroid Surgery

Surgery on the thyroid and parathyroid glands requires special attention and expertise because of the close proximity of these glands to the laryngeal nerves (nerves that control movement of the vocal cords). The vocal cords are located within the larynx or voicebox just above the thyroid gland in the neck. The vocal cords move during speech, swallowing, and breathing. If the nerves that control the muscles within these structures are damaged during thyroid surgery, one’s ability to speak, swallow and breathe can be significantly affected.

Injury to the dominant nerve of the vocal cords, the right or left recurrent laryngeal nerve, occurs in up to 5-10% of thyroid surgeries nationally. Nerve injury may be unavoidable, but at the Stanford Endocrine Head & Neck Surgery Program, particular emphasis is placed on preoperative assessment of vocal cord function, intraoperative nerve monitoring and nerve awareness, and follow-up postoperative assessment of nerve functioning and preservation. Only through pre- and post-operative evaluation and feedback can surgeons truly know and use what techniques are most successful at preserving and maximizing nerve function.

Injury can occur on either side during thyroid or parathyroid surgery. This can lead to temporary or permanent vocal cord paralysis.

If the nerve is injured on only one side, patients typically experience a reduction in the power of their voice. They may also experience swallowing problems, termed “dysphagia.” Patients with dysphagia can cough when they drink and sometimes when they eat solid food. Since a functioning vocal cord also serves to protect the airway, coughing can also occur when saliva mistakenly travels into the airway, even when the patient is not eating.

If the recurrent laryngeal nerve is injured on both sides, breathing can be severely impaired. In these cases, patients often require tracheotomy tubes to breathe. 

In addition to the dominant recurrent laryngeal nerves, there are more minor superior laryngeal nerves, that are also susceptible to injury. These nerves mainly influence voice loudness and pitch. In our practice, we focus on the evaluation and presentation of both nerves before, during, and after surgery to ensure the best outcome for our patients.