A randomized controlled trial to evaluate the effects of topical intraoperative corticosteroid application on voice quality in thyroid surgery with preserved recurrent laryngeal nerves

Background: The effect of topical intraoperative corticosteroid application on voice quality in thyroid surgery with preserved RLN remains unclear. This randomized controlled trial aimed to evaluate the efficacy and safety of this intervention. Methods: Between January 2023 and June 2024, 134 patients scheduled for thyroid surgery were screened for eligibility. Patients who developed loss of signal (LOS) during surgery or who had postoperative impaired vocal cord motility on laryngoscopy were not included in the final analysis. Fourteen patients were excluded (six for previous thyroid/parathyroid surgery, four for preoperative vocal cord paralysis, and four for corticosteroid allergy), leaving 120 patients who were randomized equally to receive either topical intraoperative corticosteroids (n = 60) or standard treatment (n = 60). Baseline demographic and clinical data were comparable between the groups. Dynamic function of the larynx was monitored intraoperatively using electromyography (EMG), and vocal outcomes were assessed 1 week postoperatively using the Voice Handicap Index (VHI) and voice-related quality of life (V-RQOL). Laryngeal findings and adverse events were also recorded. Results: No EMG signal was recognized in any patient. The EMG amplitudes and latencies of the vagus nerve (V1 and V2) did not differ significantly between the groups. EMG signal changes between V1 and V2 were observed in 16% of RLNs in the control group and in 18% in the corticosteroid group, but these were not associated with clinically significant decreases in amplitude or increases in latency. Postoperatively, the corticosteroid group had significantly lower (better) mean VHI scores (12.4 ± 3.2 vs. 19.6 ± 4.7; p < 0.01) and higher V-RQOL scores (88.3 ± 6.1 vs. 77.5 ± 8.8; p = 0.02) than the control group. The subgroup analysis of patients with EMG changes showed similar trends. Vocal fold edema occurred in 2 patients in the corticosteroid group and 5 in the control group, with complete resolution of stroboscopic abnormalities in all patients after 4 weeks. No local or systemic complications related to the use of corticosteroids were observed, and the postoperative courses were uneventful in both groups. Conclusions: Topical intraoperative use of corticosteroids in thyroid surgery with preserved RLN is safe and associated with improved early postoperative voice outcomes. No significant adverse events were observed, and RLN function was preserved in all cases. Further studies are needed to assess the long-term clinical relevance of these results.