Long-term functional voice outcomes after thyroidectomy, and effect of endotracheal intubation on voice

The aim of this study was to evaluate long-term functional voice outcomes after thyroidectomy, and the effect of endotracheal intubation on post-operative voice impairment.

We prospectively analyzed the voice outcomes of 155 serial thyroidectomy patients for up to 2 years. The control group consisted of 69 patients who underwent parotidectomy. Patients with post-operative recurrent laryngeal nerve palsy or palsy of the external branch of the superior laryngeal nerve were excluded. Self-assessment voice symptom scores (VSS) by questionnaire, and objective acoustic parameters and maximum phonation times, were evaluated pre-operatively and 1 day, 3 days, 1 week, 1 month, 3, 6, 12, 18, and 24 months after surgery.

VSS increased from day 1 after surgery in both groups, and returned to pre-operative levels by 24 months in the thyroidectomy group and after 1 week post-operatively in the parotidectomy (control) group. The post-operative VSS of the thyroidectomy group was significantly higher than that of the control group up to 12 months post-operatively. Highest frequency decreased immediately after surgery in the thyroidectomy group, and recovered to pre-operative levels by 12 and 18 months in females and males, respectively, whereas it recovered to pre-operative levels after the first week in the control group.

Impairment of voice function may persist for more than 18 months after thyroidectomy even in patients without RLN palsy. Endotracheal intubation can affect voice outcomes adversely for 1 week post-operatively.