The Long-Term Prognosis of Voice Pitch Change in Female Patients After Thyroid Surgery

Background: Relatively large numbers of patients complain of lower-pitched voices after thyroidectomy. However, little is known about the risk factors for, prognosis of, or progression over time of, such changes, in female patients. Methods: We analyzed the data of 217 patients who underwent thyroid surgery and postoperative (2 weeks, and 3, 6, and 12 months after surgery) voice work-ups. To identify patients with lower-pitched voices, speaking fundamental frequencies (SFFs) were compared before and after surgery. The change was calculated for all patients (postoperative change in SFF, ΔSFF). Results: The mean ΔSFF was 8.35 ± 17.06 Hz and significant changes in voice pitch (ΔSFF ≥12 Hz) were evident in 93 (42.85 %) patients after surgery, mostly within 6 months, and only 18.4 % of patients had lower-pitched voices 1 year after surgery. On multivariate analysis, age (≥52 vs. <52 years) and extent of surgery remained significant predictors of lower-pitched voice after surgery. The ΔSFFs of older patients (≥52) were significantly greater than those of younger patients (<52) at the 2-week follow-up, but not at the 3-, 6-, or 12-month follow-ups. The ΔSFFs of patients who underwent total thyroidectomy were significantly higher than those who underwent lobectomy at the postoperative 2-week follow-up, but did not differ at the 3-, 6-, and 12-month follow-ups. Conclusions: Patients frequently experience a lower-pitched voice after thyroid surgery. Such problems develop more frequently in the early postoperative period, in aged patients, and in those who had undergone total thyroidectomy. However, over time, the changes usually decrease to levels similar to those of patients without these risk factors.