The usefulness of cephalometric measurement as a diagnostic tool for obstructive sleep apnea syndrome: a retrospective study.

OBJECTIVE

Obstructive sleep apnea syndrome (OSAS) is a disorder characterized by apnea and hypopnea maintained for over 10 seconds and occurring at least 5 times per hour, with at least 30 episodes during 7 hours of nocturnal sleep. The most important pathophysiology in OSAS is the obstruction of the upper airway during sleep. The aim of this study was to identify the correlations between lateral cephalometric parameters, which seemed to be related to OSAS severities, and polysomnography (PSG) indices and to thus determine the cephalometric parameters reflecting OSAS severity.

PATIENTS AND

METHODS

A total of 140 participants (122 males, 18 females) were evaluated by lateral cephalography and PSG. A total of 29 measurements (24 distances and 5 angles) were made on lateral cephalography. Cephalometric and PSG parameters were evaluated statistically to select and validate the cephalometric parameters reflecting OSAS severity.

RESULT: OSAS has a significant relationship with the anatomic deformities of craniofacial and soft tissues. Lateral cephalometry revealed that patients with OSAS have a significant vertical airway length, a regrognathic mandible, a thick uvula, a large tongue, and a long mid-face length. The position of the hyoid bone had a tendency to displace inferiorly and/or posteriorly. Using the discriminant variable combination, including tongue base-posterior nasal spine (T1-PNS), sella-nasion-B point angle (SNB), maximum uvula thickness (Max U), tongue base-tongue tip (T1-TT), and nasion-anterior nasal spine (N-ANS), 102 of 140 (72.9%) patients were correctly assigned to the normal-to-mild and moderate-to-severe apnea-hypopnea index (AHI) groups.

CONCLUSIONS

Lateral cephalometric radiography may be an accessible and suitable tool for evaluation of craniofacial and soft tissue deformities in their correlations with OSAS severity. Further research on the cephalometric parameters reflecting OSAS severity is needed.