Intraoperative neuromonitoring reduces vocal cord injury in open thyroid cancer surgery: results from a randomized controlled trial.

BACKGROUND

Intraoperative neuromonitoring (IONM) has been increasingly used in thyroid surgery, yet its clinical value remains controversial.

OBJECTIVES

This randomized controlled trial aimed to evaluate the efficacy and safety of IONM in thyroid cancer surgery.

METHODS

The standardized four-step monitoring protocol was used in the IONM group. Primary endpoints included RLN injury rates and postoperative voice function recovery. Secondary endpoints included surgical parameters (operation time, blood loss), complication rates, and oncological outcomes. Voice function was assessed using VHI-10 scoring and maximum phonation time (MPT). Patients were followed up for a median of 6 months.

RESULTS

The IONM group demonstrated significantly lower rates of temporary vocal cord paralysis (2.0% vs 10.0%, P = 0.038) and higher nerve identification rates (100% vs 96.0%) compared to the control group. Voice function recovery was notably faster in the IONM group, with smaller changes in VHI-10 scores (Δ = 4.2 ± 1.5 vs 7.6 ± 2.1, P < 0.001) and shorter MPT recovery time (14.2 ± 3.5 vs 25.6 ± 5.2 days, P < 0.001). Although operation time was longer in the IONM group (125.6 ± 18.3 vs 108.4 ± 15.7 min, P < 0.001), no significant differences were found in blood loss (45.3 ± 12.6 ml vs 48.7 ± 13.2 ml, P = 0.183), complication rates, or oncological outcomes between the groups.

CONCLUSION

IONM technology greatly lowers the risk of temporary recurrent laryngeal nerve injury and speeds up voice function recovery in thyroid cancer surgery. Although operation times are slightly extended, the technique is safe and preserves oncological integrity.