Lessons Learned After 1000 Cases of Transcutaneous Laryngeal Ultrasound (TLUSG) with Laryngoscopic Validation: Is There a Role of TLUSG in Patients Indicated for Laryngoscopic Examination Before Thyroidectomy?

INTRODUCTION

Patients with hoarseness of voice, previous neck operation, or suspicion of malignancy are at high risk of having pre-thyroidectomy vocal cord (VCP) palsy. Therefore, vocal cord (VC) functions should be evaluated before surgery. This study aimed to evaluate the accuracy of hoarseness, a voice-related questionnaire (Voice Handicap Index [VHI]-30), and transcutaneous laryngeal ultrasound (TLUSG) in diagnosing VCP, as well as the role of TLUSG in the evaluation of high-risk patients.

METHODS

A total of 1000 patients undergoing thyroidectomy or other endocrine-related neck procedures were prospectively included. Symptoms of hoarseness, the VHI-30 score, and TLUSG were evaluated. Validation laryngoscopies were performed by a separate endoscopist after performing TLUSG. All the assessments were performed one to seven days before surgery. The findings of hoarseness, the VHI-30 score, and TLUSG were correlated with laryngoscopic findings to evaluate the diagnostic accuracy.

RESULTS

Of 1000 patients, nine preoperative VCP were diagnosed with laryngoscopy. Sensitivity in detecting VCP by hoarseness, the VHI-30 score, and TLUSG were 33.3%, 62.5%, and 88.9%, respectively. A total of 342 patients were considered as high risk, and eight preoperative VCP were confirmed with laryngoscopy. Despite it not being possible to visualize the VCs in 26 (7.7%) patients, TLUSG had a higher accuracy in detecting VCP than the VHI-30 did (96.8% vs. 74.2%; p < 0.001). If patients had been selected who were unassessable or who had had VCP on assessment for confirmatory laryngoscopy, TLUSG saved more patients from laryngoscopic examinations than the VHI-30 did (87.7% vs. 71.3%; p < 0.001). A history of neck operation and suspicion of malignancy did not affect the assessment by TLUSG (p > 0.05).

CONCLUSION

TLUSG is a feasible, non-invasive, and sensitive tool in detecting VCP in high-risk patients. It has safely precluded 87.7% high-risk patients from laryngoscopy. TLUSG should be incorporated as a part of the ultrasound examination of the thyroid.