Vocal dysfunction following thyroid surgery: a multidimensional subjective and objective study

Following thyroid surgery, vocal changes are a common complication and well-known morbidity that may be linked to neuronal and non-neuronal voice breakdown. Nevertheless, their effects on different voice characteristics are not fully understood, and their bases are still poorly characterized. In order to determine the diagnostic indicators that address the nature of such post-thyroidectomy voice alternations, this study was designed to provide a multidimensional assessment of vocal function after thyroid surgery. This research was a 1-year prospective cohort study conducted on 100 adult patients aged 40.19 (± 12.82) years who were recruited from the outpatient clinic of Phoniatric Unit, Assiut University Hospital, and scheduled to undergo thyroid surgery during the period from November 2020 to November 2021. All subjects underwent vocal assessment preoperatively and 15 days, 1 month, and 2 months postoperatively by filled in subjective evaluation of voice complaints via voice handicap index (VHI-30), auditory perceptual assessment (APA) of the voice, and videolaryngoscopy in addition to acoustic analysis using computerized speech lab (CSL). Statistical analysis was performed to compare multi-parameter voice assessment tools across different assessment time points. The voice changes were significantly decreased from 51.0% after 15 days postoperatively to 33.0% after 2 months of follow-up. Among these cases, 35.0% cases developed vocal fold paralysis and complained of a breathy voice (27% developed unilateral vocal fold paralysis, and 8% developed bilateral focal fold lesions), and the remaining 16.0% cases had no paralytic manifestations. Also, only one case developed gross lesion “bilateral vocal fold nodules.” The subjective evaluation of voice outcome after thyroidectomy showed significant improvement in VHI subscales and total score from 15 days postoperatively to 2 months of follow-up (P < 0.001). All of the acoustic parameters except HNR showed a significant difference across the different assessment settings (P < 0.001). Thyroidectomy can result in significant vocal alterations, even in cases where the laryngeal nerve is unharmed. These changes should be taken into consideration in patient having thyroid surgery, especially a total thyroidectomy because of malignant lesions. More efforts are needed in order to determine the extent and pathophysiological reasons for the vocal alterations following thyroid surgery in order to reduce the morbidity associated with one of the most popular surgical procedures performed globally.