Background: The objectives of this study were to emphasize the importance of preoperative laryngeal examination before thyroidectomy by investigating the incidence of coincident abnormal laryngeal conditions that impair the quality of voice, and evaluate the usefulness of the "thyroidectomy-related voice questionnaire" as a screening tool.
Methods: Five hundred consecutive patients scheduled to undergo thyroidectomy underwent preoperative laryngeal examination and voice analysis and completed the questionnaire. According to the laryngeal examination results, patients were classified into normal and abnormal groups. Acoustic-analysis results and questionnaire scores were compared between the two groups, and correlations between acoustic parameters and questionnaire scores were evaluated. The cutoff score of the questionnaire that can effectively discriminate between the two groups was also determined.
Results: The incidence of abnormal laryngeal conditions was 35.8%. The most common finding was laryngopharyngeal reflux (27.2%) followed by vocal nodule (4.8%), vocal polyp (1.8%), vocal cord palsy (1.2%), Reinke's edema (0.4%), vocal cyst (0.2%), and vocal sulcus (0.2%). The perceptual grade of voice quality (0.33 ± 0.49 for normal group vs. 0.65 ± 0.62 for abnormal group, P = 0.000) and the questionnaire scores (3.21 ± 5.47 for normal group vs. 13.41 ± 11.67 for abnormal group, P = 0.000) of the two groups were significantly different, and there was a significant correlation between objective voice parameters and questionnaire scores. A questionnaire score of 5 showed the best sensitivity (74%) and specificity (71%) in discriminating between the two groups.
Conclusions: The incidence of coincident abnormal laryngeal conditions is relatively high; therefore, voice screening before thyroidectomy is important. The "thyroidectomy-related voice questionnaire" is a simple and effective screening tool to detect preexisting laryngeal disorders that can affect the quality of voice.