A Prospective Observational Study on the Accuracy of Transcutaneous Laryngeal Ultrasonography in Assessing Vocal Cord Mobility before and after Thyroid Surgery.

Abstract

Introduction: Recurrent Laryngeal Nerve (RLN) injury remains one of the significant complications associated with thyroidectomy, occurring in approximately 1% to 9% of cases. Vocal Cord (VC) function is typically assessed before surgery using laryngoscopy. However, Transcutaneous Laryngeal Ultrasonography (TLUS) has become a non-invasive alternative for evaluating VC mobility. This study was performed to compare the diagnostic accuracy of TLUS with traditional laryngoscopy in assessing vocal cord function in patients undergoing thyroid surgery.

Materials and methods: A total of 105 patients undergoing hemi- or total thyroidectomy were enrolled in a prospective observational study at a tertiary healthcare facility from October 2022 to June 2024. TLUS was conducted by endocrine surgeons using a Mindray UGW 11 device. VC mobility was categorised as usual (spontaneous, rhythmic, symmetrical movement) or unilateral VC paralysis (asymmetrical or absent movement on the affected side).

Results: In the preoperative setting, TLUS achieved 100% sensitivity, Positive Predictive Value (PPV), and overall diagnostic accuracy. Postoperatively, it maintained a high sensitivity of 99.02%, with specificity reaching 100% and an area under the curve (AUC) of 0.99. The PPV remained at 100%, while the Negative Predictive Value (NPV) was 75%, and the diagnostic accuracy declined slightly to 99.05%. These findings highlight TLUS as a reliable, economical, and patient-friendly modality for evaluating vocal cord mobility in thyroid surgery.

Conclusion: TLUS is an effective non-invasive method for assessing VC function, with high diagnostic accuracy. With further advancements in ultrasound technology and standardized protocols, TLUS can be incorporated into routine clinical practice as a supplement to traditional laryngoscopy techniques. This study supports the use of TLUS as a viable alternative for preoperative and postoperative VC assessment in thyroid surgery patients.