Anatomical Characterization of the Upper Airway in the Indian Population: Implications for Laryngoscope Design

<title>Abstract</title> <p>Purpose This study highlights a key research gap in population-specific laryngoscope blade design, emphasising the lack of data on upper airway anatomy in the Indian population. The study aims to characterise the upper airway in the Indian population and evaluate the need for population-specific laryngoscope blade designs based on anatomical variations. Methods The upper airway profile, defined as the path traversed by the laryngoscope blade, was segmented into horizontal and vertical components. CT scans of 118 Indian adults were retrospectively collected from a tertiary-care institution, and analysed using four reproducible mid-sagittal landmarks. Comparative anatomical data from ten international populations were obtained from published literature. Independent t-tests with Holm–Bonferroni correction were used to evaluate differences in airway dimensions across populations, and Pearson's correlation was used to assess associations with age. Results The mean horizontal component was 77.8 mm and the mean vertical component was 50.95 mm, with males exhibiting larger dimensions than females for both components. The horizontal component differed significantly from the Austrian population, while the vertical component (upper airway length) was significantly shorter than all ten comparison populations. The vertical component showed a moderate positive correlation with age in both sexes, whereas the horizontal component did not. The measured lower incisor-to-vallecula working lengths for males (77.28 mm) and females (71.07 mm) were substantially shorter than the working lengths of standard C-MAC Mac 3 and C-MAC Mac 4. Conclusion This study demonstrates distinct gender-based and inter-population variations in the upper airway profile of the Indian population and highlights a mismatch with standard blade designs. These findings underscore the need for population-specific laryngoscope blade designs that account for anatomical diversity, particularly in terms of curvature and insertion length.</p>