Investigation of the impact of thyroidectomy on voice quality

Objective: Evaluation of the relationship of intraoperative neuromonitoring results with voice quality in cases of thyroidectomy. Method: Thirty-eight nerves at risk of 20 patients who had thyroid surgery and 20 patients who had surgery excluding larynx, pharynx and thyroid as a control group were recruited for the study. In thyroidectomy group, EMG responses of recurrent laryngeal nerve (RLN) were recorded before and after dissection. Voice quality of the patients in both groups were evaluated with subjective GRBAS (grade, roughness, breathiness, asthenia, strain) with VHI (voice handicap index) and objective tests (acoustic analysis) in preoperative and postoperative period. Results: While no statistically significant difference was found in the subjective analyses, statistically significant difference was found in all parameters of acoustic analyses of the control group. No statistically significant difference (p>0,05) was found in the intraoperative EMG responses of patients in thyroidectomy group before and after dissection and no vocal cord palsy was seen in any of the patients postoperatively. No statistically significant difference (p>0,05) was found in patients' videolaryngostroboscopy (VLS) scores between the comparisons made before and after the operation. Statistically significant difference was found in early postoperative period in Shimmer and Noise to Harmonic Ratio values of the acoustic analysis parameters of the patients, and this significant difference was found to return to normal at 3rd month. Conclusion: In thyroidectomies which are done with intraoperative neuromonitoring (IONM), no difference was found in neuromonitoring results and VLS and subjective evaluations posoperatively. Some alterations which are found at early period in objective evaluations, was seen to return to normal at 3rd month postoperatively. Keywords: Thyroidectomy, intraoperative neuromonitoring, voice, acoustic analysis