Application of Translaryngeal Ultrasound (TLUS) in Patients with Neck Surgery—A Single-Centre, Prospective Cohort Study on Technique Evaluation

Abstract

Purpose: The primary objective of this study was to assess the value of translaryngeal ultrasound (TLUS) in assessing vocal fold (VF) function in patients after thyroid, parathyroid and neck lymph node surgery. Methods: A total of 219 patients that underwent 230 surgical procedures were enrolled in this prospective study. The study was conducted from October 2020 to October 2021. Patients’ VFs were analysed independently with TLUS and laryngoscopy before and after the surgery. Various TLUS variables, such as vocal folds displacement velocity (VFDV), arytenoids symmetry and angle between VFs, were measured. The questionnaire evaluating discomfort caused to patients by both methods was conducted. Results: Of the 230 surgeries in this study, 85% were from oncological indications. The incidence of RLN injury was 10.4%. The accuracy of TLUS compared to laryngoscopy was 98.3%, with sensitivity 98.1%, specificity 100%, PPV 100% and NPV 83.3%. Laryngoscopy was found to cause significantly more discomfort than TLUS. VF visibility was lower in men; smokers; and patients with higher BMI (32 vs. 28 kg/m2), multifocal cancer, higher left lobe volume and higher fT3 levels. Arytenoid symmetry VFDV was lower for “e” and “i” right side and “i” left side in injured/disabled VFs/RLN. Conclusions: TLUS can be an excellent and non-invasive method of VF evaluation in most patients. There are some technical aspects that can improve its accuracy. Sometimes, RLN injury after the surgery, especially among oncological patients, is unavoidable. Therefore, it is vital to diagnose dysphonia early with convenient methods, such as TLUS.

Clinical usefulness of transcutaneous laryngeal ultrasonography in otolaryngology practice during COVID-19 pandemic: a literature review

“…The diagnosis of vocal fold paralysis is based on the asymmetric abduction and adduction movements of the vocal folds [ 10 ]. A recent study [ 11 ] showed that the movement of vocal folds are best assessed during whispering the vowel “e”. If the vocal folds are not visible from a midline approach due to acute shape or calcification of the thyroid cartilage, each vocal fold can be assessed laterally to the cartilage [ 12 ].…”

“…According to Dedecjus et al[ 13 ], by applying Doppler gate to real-time B scan of vocal folds, signals corresponding to tissue motion were observed in the vibratory area of vocal folds during phonation. In contrast, another author [ 11 ] considered Doppler wave pattern a not necessary component of the TLUSG evaluation, being unable to replace the observation of vocal folds movement during phonation and respiration. Recently, TLUSG has been proposed as a promising noninvasive tool for routine preoperative and postoperative vocal cord examination in thyroid surgery.…”

“…Wong et al [ 22 ] evaluated what factors affected assessability and accuracy of TLUSG: older age, male sex, tall in height, and incision closer to the thyroid cartilage were independent contributing factors for unassessable vocal cords. The above mentioned study by Wolff [ 11 ] showed unsatisfying vocal cords visibility by TLUSG in men (vocal cords visualization in women: 82.0%; men: 7.7%), smokers, patients with higher BMI (32.34 vs. 27.65 kg/m 2 ), secondary surgery, multifocal or T2 cancer, higher left lobe volume and higher free T3 levels.…”

“…The results regarding the diagnostic accuracy of TLUSG in the assessment of laryngeal function are controversial. Accordingly there is a tendency to consider TLUSG as just a screening method for vocal cord paralysis, followed by diagnostic confirmation with laryngoscopy, if required [ 11 ].…”

“…Success rate of palpation identification of the CM: 8% 29 Vats [ 27 ] 2004 UK Diagnosis of laryngeal disorders in infants and children Assessment of vocal fold paralysis in children 55 Concordance rate TLUSG—laryngoscopy: 81.2%. In patients aged over 12 months: 89.5% 30 Wang [ 26 ] 2011 China Diagnosis of laryngeal disorders in infants and children Assessment of vocal fold paralysis in children using measurement of the maximum glottic angle (MGA) 45 Mean value of MGA: 61.4 ± 9.00 in the normal larynx; 42.25 ± 10.41 in the paralyzed larynx 31 Wang [ 38 ] 2020 China Assessment of laryngeal cancer and other laryngeal lesions Diagnosis of vocal fold polyps 87 The rate of detection of vocal fold polyps: 88.0% 32 Wolff [ 11 ] 2022 Poland Evaluation of vocal cords function Assessment of vocal fold function in patients after thyroid, parathyroid and neck lymph node surgery 219 Sensitivity 98.1%. Specificity 100% 33 Wong [ 14 ] 2017 China Evaluation of vocal cords function Assessment of vocal folds function before thyroidectomy 1000 Sensitivity: 88.9% 34 Wong [ 18 ] 2014 China Evaluation of vocal cords function Vocal cord asymmetry detection after thyroidectomy …”