Learning to Interpret Pediatric Vocal Fold Mobility: A Laryngeal Ultrasound Training Module

Abstract

Objectives/Hypothesis Vocal fold movement impairment (VFMI) in infants and children is most commonly evaluated by flexible nasolaryngoscopy (FNL). FNL in this population can be challenging due to movement, floppy supraglottic structures, or secretions. Laryngeal ultrasound (LUS) may be an alternative, less invasive means of evaluating VFMI that also decreases aerosolization during the COVID‐19 pandemic. The primary objective was to examine LUS interpretation proficiency for VFMI via an educational module. A secondary outcome was to determine whether quantitative measurements increase interpretation accuracy. Study Design Prospective cohort trial. Methods Medical students, residents, fellows, faculty, and staff were recruited to complete the module, composed of a 13‐minute teaching video followed by 20 cases. Participants determined both qualitatively (subjective assessment) and then quantitatively (through protractor measurements of the vocal fold to arytenoid angle) whether there was normal versus impaired vocal fold mobility. Results Thirty participants completed the LUS training module, and about one‐third were otolaryngology residents. On average, each participant correctly identified 18 cases. The mean rank percent correct for quantitative measurements was significantly higher than that of qualitative interpretations (P < .0001). Measurements significantly caused participants to change their answer correctly compared to incorrectly (P < .0001). As the module progressed, there was no significant trend of more correct interpretations (P = .30). The sensitivity was higher for quantitative interpretations (89.0% vs. 87.3%) but specificity remained unchanged (92.6%). Conclusion Quantitative measurements may increase LUS interpretation accuracy. There was not a specific number of cases interpreted to achieve learning proficiency. LUS is an easily learned method to evaluate for VFMI across all training levels. Level of Evidence 3 (local cohort study nonrandomized) Laryngoscope, 131:2545–2549, 2021

Laryngeal ultrasound for evaluation of paediatric unilateral vocal fold immobility -- a retrospective cohort study in Aotearoa New Zealand and a survey of clinicians around the world

“…Similarly, laryngoscopy combined with LUS is likely to clarify a diagnosis of suspected VFI compared to a single investigation. LUS has also been shown to be easy to learn for clinicians other than otolaryngologists (15,16,(19)(20)(21)(22), suggesting it may be a useful tool in remote areas where an otolaryngologist may not be available.…”

“…Our radiologists report LUS in a qualitative fashion, i.e., they report whether mobility is normal, reduced, or absent. Few studies have described quantitative measures such as maximum glottic angle and vocal fold-arytenoid angle to aid the interpretation of LUS (22,23). These authors concluded that the accuracy of LUS increases by using quantitative measures.…”

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

“…It may be a diagnostic alternative for the evaluation of laryngeal disorders, well tolerated by patients and parents and easy to perform. It also decreases aerosolization during COVID-19 pandemic and may serve as an alternative tool of visualizing the larynx in children who can not tolerate laryngoscopy [ 24 ]. During TLUGS patients are scanned with a linear probe, in the supine position, with the neck well extended.…”

“…No sedation or anesthesia is required [ 25 ]. Many authors have demonstrated that laryngeal ultrasound can be used to evaluate vocal cord function, allowing early detection of vocal fold paralysis in children [ 24 , 26 , 27 ]. The diagnostic criteria for vocal fold paralysis using TLUGS are: abnormal mobility, hyperechoic air-column band of the glottic rima during phonation, flaccid vocal fold and asymmetry of the glottal structures [ 26 ].…”

“…Vats and colleagues [ 27 ] reported the need to interpret with caution ultrasonographic findings in patients aged below 12 months (Concordance rate of 77.7% vs 89.5% in patients over 12 months). However, Alexander et al [ 24 ] investigated a quantitative laryngeal ultrasound interpretation by vocal fold-arytenoid angle measurement, using a digital protractor. He demonstrated that quantitative measurements may increase LUS interpretation accuracy, sensitivity, and negative predictive value.…”