Sensory changes in the chin and lower lip after transoral endoscopic thyroidectomy

Minimally invasive thyroid surgery offers cosmetic benefits over traditional approaches, but mental nerve injury risk affecting the chin and lower lip persists. Transoral endoscopic thyroidectomy within a defined safety zone is a scarless alternative that may cause transient sensory changes.

In this prospective observational study, 77 patients with benign thyroid conditions were enrolled; after exclusions, 37 underwent transoral endoscopic thyroidectomy and 40 underwent conventional transcutaneous thyroidectomy. Baseline chin and lower lip sensation was quantified preoperatively and postoperatively at 1 week, 1 month, and 2 months using a monofilament evaluator, measuring the area of sensory deficit at 1 mm intervals. The conventional group served as a control, as this approach is not associated with mental nerve injury.

Baseline sensation was normal in both groups. The mean patient age was 32.5 ± 8.9 years (53% female). Operative times were significantly longer in the transoral group. All 37 transoral patients experienced transient sensory disturbances immediately postoperatively. The area of sensory deficit decreased at 1 and 2 months compared with 1 week (p = 0.028), and 5 of 37 patients achieved complete recovery by 2 months, while the remaining patients demonstrated progressive reduction in affected area. No sensory changes occurred in the conventional group at any time point.

Transoral endoscopic thyroidectomy within a defined safety zone induces early transient sensory disturbances that improves or resolves by 2 months postoperatively. These findings support its use as a safe, cosmetically superior alternative to conventional thyroidectomy, with minimal long-term compromise to mental nerve integrity.