The Morphology of Nasopharyngeal Inlet in Obstructive Sleep Apnea

Objective: Routine flexible optic laryngoscopy (FOL) displays obstructive sleep apnea (OSA) related airway passages from nasopharynx to hypopharynx. Tip of the flexible endoscope awaiting at the nasopharyngeal inlet allows us to visualize the morphology of this area. We wanted to evaluate the impact of nasopharyngeal inlet (NPI) morphology on OSA severity. Method: The videos obtained during FOL examinations of NPI were examined in 83 patients (10 women, 73 men). Two main morphologies, wide and narrow, were depicted. The narrow NPI group was further divided into kidney-shaped, elliptical, and circumferential. The wide NPI group was divided into circumferential and kidney-shaped. Results: Forty-five patients had narrow NPI morphology, and 38 had wide NPI morphology. The wide NPI group had 20 circumferential and 18 kidney-shaped morphologies. The narrow NPI group had 34 kidney-shaped, 6 circumferential, and 5 elliptical morphologies. Mean RDI of the narrow group was 30.378 ± 22.358, and the wide group was 14.511 ± 13.901. Mean RDI of the narrow circumferential group was 45.317 ± 30.56, the narrow elliptical group was 23.74 ± 10.787, and the narrow kidney-shaped group was 28.718 ± 21.47. Mean RDI of the wide circumferential group was 11.3 ± 13.203, and the mean RDI of the wide kidney-shaped group was 17.772 ± 14.586. The wide morphology groups had lower RDI levels compared to the narrow morphology groups (P < .0005). Conclusion: Morphology of nasopharyngeal inlet may be evidence of OSA during routine FOL examinations. Further analysis of the subgroups supported evidence of narrowing by means of increased RDI levels.