Endoscopic and Computed Tomography Evaluation of Posterior Glottic Closure During Phonation.

OBJECTIVES/HYPOTHESIS: The anatomy of the posterior glottis, specifically the states of the posterior glottis during phonation, has not been thoroughly explored in laryngology. Conventional wisdom about the posterior glottis indicates that it tends to be completely closed in men but may be open in women. Furthermore, professional singers are expected to have a completely closed posterior glottis. The aim of this study was to investigate whether these generalizations are true by comparing rigid videolaryngostroboscopy results with high-resolution computed tomography (HRCT) and three-dimensional (3D) reconstruction findings. STUDY DESIGN: Prospective study. METHODS: Of the 90 volunteers (58 women, 32 men) examined, 48 were female professional singers, 10 were female nonsingers, 22 were male professional singers, and 10 were male nonsingers. Rigid videolaryngostroboscopy as well as HRCT scans were performed during singing at the average singing fundamental frequency. HRCT images of the larynx and air-column were 3D visualized using the software MIMICS®. The states of the posterior glottis were assessed in both examinations and compared among participants. RESULTS: The sensitivity of endoscopy was 67.5%. Complete closure of the posterior glottis was observed in 62.5% men and 52% women (P = .33). Complete closure of the posterior glottis was observed in 35% nonsingers and 61% professional singers (P = .036). CONCLUSIONS: The closure of the posterior glottis seen on videolaryngostroboscopy does not always correlate with actual closure. There seems to be no link between sex and complete closure of the glottis. However, there is strong evidence that posterior glottis closure can be influenced, to some degree, by vocal training. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:124-129, 2022.

How Age and Frequency Impact the Thyroid Cartilages of Professional Singers.

OBJECTIVES/HYPOTHESIS: Young professional singers can easily reach very high pitches. In contrast, older singers often complain that they have to exert substantially more laryngopharyngeal force to reach the same high pitch compared with their earlier years. Various factors such as the property changes of the mucosa and ossification that impact the singing apparatus were suggested as explanations in the literature. The aim of this study was to analyze thyroid deformation-and thereby stiffness indirectly-during singing as a potential reason for this phenomenon. STUDY DESIGN: Prospective study. METHODS/DESIGN: We examined 44 female professional singers. High-resolution computed tomography scans were performed during singing at the fundamental mean speaking frequency and the first and second octaves above it. Digital Imaging and Communications in Medicine scan data were rendered and visualized 3-dimensionally using MIMICS software. By superimposition of the different 3-dimensional images, different positions of the thyroid were visualized. The distance from the posterior border of the thyroid was measured in all the examinations. RESULTS: All laryngeal cartilages could be three-dimensionally visualized. The magnitude of the thyroidal deformation significantly depends on pitch and significantly correlates with age (r2 = 0.7, P < 0.001). CONCLUSIONS: The thyroid cartilage is flexible and its formability is especially important during singing. At higher pitches, the cartilage was more deformed. The larynx in older singers showed less thyroid cartilage deformation.