☆Comparison of transcutaneous laryngeal ultrasound with video laryngoscope for assessing the vocal cord mobility in patients undergoing thyroid surgery

Abstract

ObjectiveWe evaluated the accuracy and feasibility of transcutaneous laryngeal ultrasonography as an alternative to videolaryngoscopy for assessing vocal cord mobility to rule out recurrent laryngeal nerve injury following thyroidectomy. MethodsForty-five adult patients scheduled to undergo elective thyroidectomy under general anesthesia were included. Preoperatively, indirect laryngoscopy and transcutaneous laryngeal ultrasonography was done for assessing vocal cord mobility. Intraoperatively, following induction, patients were intubated using videolaryngoscope. On completion of the surgical procedure, one anesthetist performed videolaryngoscopy so as to record vocal cord mobility while the patients were being extubated in deep plane of anesthesia. Simultaneously another anesthesiologist performed transcutaneous laryngeal ultrasonography.Vocal cord mobility, changes in hemodynamics and total time duration for the two procedures was recorded. Indirect laryngoscopic assessment and flexible fiberoptic laryngoscopy was done on postoperative day 1 and 7 respectively. ResultsPostoperative videolaryngoscopy picked up bilaterally mobile vocal cords in 88.8% cases. Transcutaneous laryngeal ultrasonography could correctly identify 39(86.6%) of these patients, with 1(2.5%) patient being misdiagnosed as having bilaterally immobile vocal cords. Further, videolaryngoscopy identified 5 patients of vocal cord palsy, of which transcutaneous laryngeal ultrasonography correctly identified 3 (60%) patients. Hence, in comparison to videolaryngoscopy, the sensitivity, specificity, positive predictive value, and negative predictive value of transcutaneous laryngeal ultrasonography for assessment of vocal cords was 75%, 95.1%, 60%, and 97.5% respectively. ConclusionIn patients undergoing thyroidectomy, transcutaneous laryngeal ultrasonography can serve as a non-invasive, bedside screening tool for assessing vocal cord palsy postoperatively.