Analysis of Temporal Change in Voice Quality After Thyroidectomy: Single-institution Prospective Study

Objectives: This study analyzed the temporal changes of voice quality after thyroidectomy and assessed the predictive perioperative parameters of postthyroidectomy voice disorder (PTVD). Study design: This is a prospective cohort study. Methods: From March 2011 to July 2014, 559 patients who underwent thyroidectomy with or without central neck dissection were prospectively enrolled. All patients underwent prospective voice evaluation using the subjective and objective comprehensive battery of assessments, preoperatively and postoperatively at 1 week, 1 month, 3 months, 6 months, and 12 months. Results: Fundamental frequency (F0) was not significantly decreased during the postoperative follow-up. Maximal vocal pitch (MVP) and maximal intensity were not recovered, even at 1 year postoperatively, whereas the Grade, Roughness, Breathiness, Asthenia, Strain scale reached preoperative value at postoperative 3-6 months and voice handicap index at 1 year. Postoperative 1-month MVP was the best predictor for PTVD, and the cut-off value was 80% of preoperative value. Wide surgical extent and high preoperative F0 were the parameters that significantly correlated with PTVD (P = 0.021 and P <0.001, respectively), and large tumor, higher preoperative MVP, and lower postoperative 1-month F0 were significantly associated with permanent PTVD (P = 0.028, P <0.001, and P = 0.003, respectively). Conclusions: Different recovery patterns of voice parameters should be considered in preoperative counseling. Intensive voice therapy may be needed for patients with the ability to produce higher pitch than normal preoperatively and wide surgical extent.