Cephalometric Indicator of Obstructive Sleep Apnea in Relation to Severity and Sites of Obstruction in Non-Obese Male Patients

Obstructive Sleep Apnea (OSA) is characterized by episodic cessation of breathing during sleep. Upper airway patency is determined by an interactive role of anatomic and neuromuscular factors. Craniofacial skeletal and upper airway soft tissue morphology, obesity, sleeps position represents a few of the determinant factors. Cephalometric characteristics for OSA patients include mandibular deficiency, bimaxillary retrusion, and reduced cranial base angle, decreased mandibular length and increased lower anterior facial height. Treatment of OSA depends mainly on the severity and site of obstruction and is either surgical or non-invasive treatment. Objective: The study evaluated the dentofacial characteristics of (OSA) patients in Lebanese non obese male population and compared them with normal group according to severity and sites of obstruction. Materials and Methods: A total of 67 subjects were recruited for the study, 42 subjects were diagnosed with OSA by previous polysomnography tests at the American University in Beirut Medical Center Sleep Laboratory. 25 non-OSA subjects were recruited as controls. Based on Apnea-Hypopnea index (AHI) value, the patients were divided into mild-to-moderate and severe group. Cephalometric measurements and physical examination of the tonsils were used to classify the OSA patients into groups according to sites of obstruction. Cephalometric X-rays were taken and digitized for linear and angular values. Results: Regarding severity groups, no statistically significant differences were observed in age, BMI, or angular measurements between the three severity groups except for the angular measurement (C3-H-Me). However, for linear measurements; the soft palate length, the soft palate thickness, Jarabak facial ratio; the distance between the PNS and point V; and the distance between the hyoid and the following : tongue base, mandibular plane and C3-Me were found significant. As for sites of obstruction, no statistically significant differences were observed in angular measurements between the three groups except for C3- H-Me. However, the soft palate thickness, the distance between the PNS and point V; and the distance between the hyoid and the following: tongue base, mandibular plane and C3-Me were found significant. Conclusion: This study revealed that certain Craniofacial and upper airway soft tissue characteristics exist in relation to severity of OSA and sites of obstruction. (C3-Me perpendicular to the hyoid bone) is a significant predictor of OSA in non-obese Lebanese male subjects.