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

Original Article Iranian Journal of Otorhinolaryngology, Vol.37(5), Serial No.142, Sep-2025 A Prospective Observational Study on the Accuracy of Transcutaneous Laryngeal Ultrasonography in Assessing Vocal Cord Mobility before and after Thyroid Surgery Harjinder Singh1, Thirugnanasambandam Nelson1, *Kamal Kataria1, Ankita Agarwal2, Uttam Kumar Thakur1, Arvind Kairo3, Hitesh Verma3, Shuchita Singh Pachaury3, Amarinder Singh Malhi2, Yashwant Rathore1, Yashdeep Gupta4, Shivam Pandey5, Rajesh Khadgawat4, Shipra Agarwal6, Sunil Chumber1, Anita Dhar1 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. Keywords: Transcutaneous Laryngeal Ultrasonography, Vocal Cord Function, Laryngoscopy, Thyroidectomy Received date: 9 May 2025 Accepted date: 26 Jul 2025 *Please cite this article; Singh H, Nelson T, Kataria K, Agarwal A, Thakur UK, Kairo A, Verma H, Pachaury SS, Malhi AS, Rathore Y, Gupta Y, Pandey S, Khadgawat R, Agarwal S, Chumber S, Dhar A. A Prospective Observational Study on the Accuracy of Transcutaneous Laryngeal Ultrasonography in Assessing Vocal Cord Mobility Before and After Thyroid Surgery. Iran J Otorhinolaryngol. 2025:37(5): 253-259. Doi: 10.22038/ijorl.2025.86965.3949 1Department of Surgical Disciplines, All India Institute of Medical Sciences, New Delhi, India. 2Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India. 3Department of Otorhinolaryngology, All India Institute of Medical Sciences, New Delhi, India 4 Department of Endocrinology, All India Institute of Medical Sciences, New Delhi, India 5Department of Biostastics, All India Institute of Medical Sciences, New Delhi, India. 6Department of Pathology, All India Institute of Medical Sciences, New Delhi, India. *Corresponding author: E-mail: Copyright©2025 Mashhad University of Medical Sciences. This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 International License https://creativecommons.org/licenses/by-nc/4.0/deed.en 253 Singh H, et al Introduction Thyroidectomy is one of the most commonly performed endocrine surgeries globally, primarily undertaken for conditions such as thyroid cancer, benign goiters, and hyperthyroidism (1,2). Recurrent laryngeal nerve (RLN), injury is a well-recognized complication of thyroidectomy, with incidence rates ranging from 1% to 9% (3). RLN damage can lead to vocal cord paralysis, presenting with symptoms such as hoarseness, difficulty swallowing, breathing difficulties, and in severe cases, life-threatening airway obstruction (4,5). Assessment of vocal cord mobility before surgery is conventionally undertaken using laryngoscopic techniques, which include indirect mirror laryngoscopy and flexible fiberoptic laryngoscopy (FFL) (6). Although FFL remains the standard approach, it is invasive, may cause discomfort, and requires both specialized equipment and trained personnel resources that may not be accessible in all clinical environments (7). Transcutaneous laryngeal ultrasonography (TLUS) has emerged as a practical, non-invasive modality for evaluating vocal cord function (8). It is easy to perform, well-tolerated by patients, and removes the need for sedation or radiation exposure, making it appropriate for both pre- and postoperative assessments (9). Since its initial application for laryngeal imaging in 1992 (10), TLUS has gained attention as a viable substitute for traditional laryngoscopic evaluations in the perioperative setting. Additionally, intraoperative neuromonitoring (IONM) of the RLN has become increasingly common, wherein lowvoltage electrical stimulation of the nerve produces vocal cord muscle contraction. This is detected via electromyographic (EMG) signals, characterized by specific latency and amplitude, along with an audible sound output (6,11). Previous research has demonstrated that TLUS offers high diagnostic accuracy in identifying vocal cord paralysis after thyroid surgeries (12,13). This study was therefore designed to compare the effectiveness of TLUS with laryngoscopy in evaluating vocal cord function in patients undergoing thyroid surgery. Materials and Methods This prospective observational study was conducted at a tertiary care center between October 2022 and June 2024, following approval from the Institutional Ethics Committee. A total of 105 patients presenting to the surgical outpatient department with thyroid disorders requiring either hemithyroidectomy or total thyroidectomy were recruited. All participants underwent a comprehensive clinical assessment, which included a detailed history-taking and a thorough physical examination. Radiological assessment was performed using neck ultrasonography by experienced radiologists, and thyroid function tests were obtained for the biochemical evaluation. Fine-Needle Aspiration Cytology (FNAC) and other relevant diagnostic investigations were conducted with established institutional protocols. Following confirmation of diagnosis, preoperative evaluation of vocal cord (VC) mobility was performed by otolaryngologists using indirect lary (...truncated)