Therapeutic approach to patients with a lower-pitched voice after thyroidectomy

A lower-pitched voice is one of the most common voice alterations after thyroidectomy without laryngeal nerve injury. The aim of this study was to evaluate the acoustic and stroboscopic changes and the treatment outcomes in patients with a lower-pitched voice with the goal of eventually establishing a therapeutic guideline.

Patients with a lower-pitched voice were selected according to the results of acoustic analysis among thyroidectomized patients. According to their pitch-gliding ability, patients were classified into a "gliding group" and "nongliding group," and direct voice therapy was performed. For those who did not respond, indirect voice therapy with subsequent identical direct voice therapy was performed. Video-stroboscopy, acoustic and perceptual analysis, and subjective analysis using a questionnaire were performed before and after treatment. The results of the two groups were compared.

Fifty patients were enrolled. Decreased vocal cord tension was the most common stroboscopic finding in these patients. After direct voice therapy, 87 % of patients in the gliding group showed restoration of pitch 2 months after thyroidectomy. None of the patients in the nongliding group showed improvement. After indirect voice therapy and subsequent direct voice therapy, these nonresponders finally showed improvement 4.5 months after thyroidectomy. Several characteristic stroboscopic findings of the nongliding group were identified.

The pitch-gliding ability and several specific stroboscopic findings were predictive of a response to direct voice therapy. Based on these findings, an individualized therapeutic approach could be applied, and the pitch of patients with a lower-pitched voice after thyroidectomy was restored earlier than expected.