Non-Neural Post-Thyroidectomy Dysphonia: Long-Term Voice Outcomes in 527 Patients

Area of Science:

• Otolaryngology
• Voice Science
• Surgical Outcomes

Background:

• Post-thyroidectomy dysphonia (PTD) is common, but non-neural causes are less understood.
• Evaluating long-term voice outcomes in patients with preserved nerve function is crucial for comprehensive PTD characterization.

Purpose of the Study:

• To characterize non-neural PTD by analyzing long-term voice outcomes.
• To identify factors influencing voice recovery in patients with no evidence of nerve injury post-thyroidectomy.

Main Methods:

• Retrospective cohort study of 527 post-thyroidectomy patients with normal vocal fold mobility and EMG.
• Comprehensive voice evaluations (acoustic, aerodynamic, VHI-10) conducted preoperatively and at multiple time points postoperatively.
• Linear mixed models and machine learning used to assess predictors of voice changes.

Main Results:

• Immediate declines in fundamental frequency (F0) and speaking fundamental frequency (SFF) post-surgery, with prolonged reduction in older patients and those with high preoperative F0.
• Voice Handicap Index-10 (VHI-10) increased early post-total thyroidectomy but returned to baseline by 6-12 months; older age correlated with delayed VHI-10 recovery.
• Preoperative F0 and age predicted F0/SFF, while surgical extent predicted VHI-10 and maximum frequency (Fmax) at 1 month.

Conclusions:

• Voice alterations can occur post-thyroidectomy despite preserved recurrent laryngeal nerve and superior laryngeal nerve function.
• Most voice parameters improve over time, but full recovery is not guaranteed, influenced by patient sex, age, surgical extent, and preoperative F0.
• Findings aid in counseling patients regarding non-neural PTD and expected voice outcomes.