Longer upper airway lengths in Robin Sequence: A case-control study using computed tomography

Background: Direct laryngoscopy and intubation are often difficult in children with Robin Sequence. Previous research characterizing anatomic airway differences has focused on parameters influencing airway patency; there is a paucity of data pertaining to intubation trajectories and depth. Such information could impact airway management approaches and decrease the incidence of endotracheal tube malpositioning.

Aim: The study goal was to examine whether longitudinal airway parameters pertaining to intubation are different in children with Robin Sequence compared with age-matched controls.

Method: This case-control study compared patients with RS <4 years of age who had computed tomography scans of the head and neck to age- and sex-matched controls. Measurements were made of the nasopharynx, oropharynx, hypopharynx, tongue, hyoid, and the front teeth to vocal cord, nares to vocal cord, and nasion-basion distances. Statistical analysis was performed using multiple ANCOVA models with the categorical predictor of Robin Sequence vs control and potential covariates including subject height/length, weight, and age.

Results: Thirty-three patients with Robin Sequence and 33 control subjects were included. After controlling for subject height/length, mean front teeth to vocal cord distance was 1.2 cm longer (95% CI: 0.9 to 1.6 cm, P < .001) and mean nares to vocal cord distance was 0.8 cm longer (95% CI: 0.4 to 1.2 cm, P < .001) in patients with Robin Sequence than in controls. The tongue was positioned on average 0.5 cm higher (95% CI: 0.3 to 0.8, P < .001) and 0.9 cm more posterior (95% CI: 0.6 to 1.0 cm, P < .001) in cases than in controls. Moreover, in patients with Robin Sequence, the hyoid was positioned on average 0.5 cm more inferiorly (95% CI: 0.2 to 0.8 cm, P < .001) and 0.2 cm more posteriorly (95% CI: 0.1 to 0.4 cm, P < .01) than controls.

Conclusion: In patients with Robin Sequence under 4 years of age, the mean front teeth to vocal cord distance was found to be 1.2 cm longer while the mean nares to vocal cord distance was found to be 0.8 cm longer controlling for subject length. Clinicians should account for these differences when selecting and placing endotracheal tubes, particularly those with a preformed bend.