The morphology of the nasopharyngeal inlet in obstructive sleep apnea.

Routine flexible optic laryngoscopy (FOL) can visualize the airway from the nasopharynx to the hypopharynx in obstructive sleep apnea (OSA). With the tip of a flexible endoscope at the nasopharyngeal inlet (NPI), we can visualize the morphology of this area. We evaluated the effect of NPI morphology on OSA severity. Videos were obtained during FOL examinations of the NPI in 83 patients (11 females, 72 males; mean age 42.1 ± 9.5 years) and NPI morphology was examined. Two main morphologies were seen: wide and narrow. The narrow NPI group (n = 45) was further subdivided into kidney-shaped (n = 34), elliptical (n = 6), and circumferential (n = 5) groups. The wide NPI group (n = 38) was subdivided into circumferential (n = 20) and kidney-shaped (n = 18) groups. Mean Respiratory Disturbance Index (RDI) values were 30.38 ± 22.36 and 14.51 ± 13.9 in the narrow and wide groups, respectively. Mean RDI values were 45.32 ± 30.6, 23.74 ± 10.8, and 28.72 ± 21.5 in the narrow circumferential, elliptical, and kidney-shaped groups, respectively. Mean RDI values were 11.58 ± 12.91 and 17.8 ± 14.6 in the wide circumferential and kidney-shaped groups, respectively. RDI values were significantly lower in the wide morphology group (p < 0.0005). NPI morphology might predict OSA during routine FOL examination. Further analysis of the subgroups supported evidence of narrowing, reflected as higher RDI values.