A simulation study on the effects of the bent length and angle of lightwand: based on the upper airway on computed tomography images

Abstract

Objective To investigate the effects of angle and length of lightwand in three-dimensional reconstruction images of the upper airway based on computed tomography. Methods A total of 245 patients, aged 18-86 years, were scanned by helical computed tomography in the head and neck.Reconstructed images, obtained by Aw4.4 Workstation, were printed out by the ratio of 1∶1. The tracheal tube was used to investigate the anatomic structure of the upper airway. The length L and angle α of the tracheal tube were recorded. And two distances (D1, D2) and one angle (β) were recorded: D1, the distance between the upper central incisor and root of epiglottis; D2, the distance between the root of epiglottis and midpoint of glottis; angle β, the angle of line D1 and D2. Results The α value in male patients was significant higher than that in female patients: (70.02 ± 15.49)° vs. (55.84 ± 14.70)°. The β value in male patients was significant higher than that in female patients: (129.74 ± 14.82)° vs. (120.40 ± 14.19)°. The L value in male patients was significant higher than that in female patients: (12.80 ± 0.85) cm vs. (11.50 ± 0.65) cm. The D1 and D2 value in male patients were significant higher than those in female patients: (7.53 ± 0.66) cm vs. (6.76 ± 0.53) cm, (3.13 ± 0.52) cm vs. (2.45 ± 0.32) cm. There were significant differences (P<0.05). The 245 patients were classified to 2 groups by using the function of hierarchical cluster analysis in the statistical software. The α value in group 2 was significanthigher than that in group 1: (75.45 ± 9.53)° vs. (48.17 ± 9.29)°. The β value in group 2 was significant higher than that in group 1: (136.27 ± 9.86)° vs. (112.31 ± 8.64)°. The age in group 2 was significant higher than that in group 1: (53.92 ± 19.64) years vs. (36.93 ± 17.21) years. Correlation analysis showed that in 245 patients, angle α was positively correlated to angle β and age (P<0.05), and angle β was positively correlated to age (P<0.05). Conclusions The bent length and angle on lightwand can be affected by both the patients′ gender and ages. Key words: Three-dimensional computed tomography reconstruction; Anatomical feature of upper airway; Lightwand; Shaping