AIRWAY DIMENSIONS AND HEAD POSTURE IN OBSTRUCTIVE SLEEP-APNEA

The present cephalometric study aimed to describe the antero-posterior diameters of the pharyngeal airway in a sample of 50 male obstructive sleep apnoea (OSA) patients and a reference sample of 103 male studen ts, and to examine the relationship between these diameters and the po sture of the head and the cervical column. Subjects were recorded in t he cephalometer standing with the head in its natural position (mirror position). Pharyngeal airway diameters were measured at seven levels ranging from the maxillary tuberosity to the vallecula of the epiglott is. The largest difference was observed at the level behind the soft p alate where the diameter was 50 per cent narrower in the OSA sample th an in the reference sample. Extension of the cranio-cervical angle and forward inclination of the cervical column were correlated with an in crease in the three most caudal airway diameters in the OSA sample: at the uvula, the root of the tongue, and the epiglottis, but only to in crease in the lowest diameter in the reference sample. The findings we re considered to reflect a compensatory physiological postural mechani sm that serves to maintain airway adequacy in OSA patients in the awak e erect posture, most efficiently so at the lowest levels of the oroph aryngeal airway.