Translaryngeal ultrasound in thyroid surgery: state of the art review.

BACKGROUND: Clinical voice assessment prior to thyroid and parathyroid surgery is essential, but the paradigm of indirect laryngoscopy (IDL), when indicated, has been challenged by the risk of aerosolised SARS-Cov-2 during endoscopy of the aerodigestive tract. Translaryngeal ultrasound (TLUS) to assess the vocal cords has been proposed as a safe, non-invasive and sensitive alternative. The aim of this review was to verify TLUS as a viable tool for perioperative laryngeal assessment. METHOD: A literature review was performed using Medline, Embase, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials and Scopus with the following search strategy: (vocal cord OR vocal fold OR glottic OR glottis OR vocal ligaments OR rima glottidis) AND (ultras* OR sonograph* OR echography OR echotomography). RESULTS: Fifteen studies were included in this review. All studies compared TLUS to IDL in visualizing the vocal cords in adults. Ten studies compared pre-operative TLUS to IDL where 50.6-100% of vocal cords were successfully visualized. Nine studies compared post-operative TLUS to IDL and reported visualization between 39.6% and 100%. Pre- and post-operative negative predictive values ranged from 60% to 100%. CONCLUSION: Whilst promising, successful visualization of the cords is limited by inter-user variability, older age and male gender. Thus, we see the role of TLUS as an alternative to IDL in the post-operative setting in the young patient following uncomplicated surgery with a normal voice on clinical examination, to confirm recurrent laryngeal nerve integrity while minimizing the risk of aerosolization.

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

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.