Craniofacial skeletal architecture and obstructive sleep apnoea syndrome severity

Obstructive sleep apnoea syndrome (OSAS) is a sleep related breathing disorder caused by pharynx obstruction that often terminates in abrupt arousals and is capable of disrupting physiological sleep profile. Its' severity has been associated, among others, with craniofacial skeletal morphology. To investigate this relationship and elucidate craniofacial skeleton patterns in individuals without obvious maxillofacial abnormalities, 171 OSAS patients were studied with nocturnal polysomnographic record and chephalometric X-ray (24 variables). Chephalometric variables were compared between three apnoea/hypopnoea index (AHI) groups (AHI ≤ 15; 15 < AHI < 30; AHI ≥ 30) and uni/multivariate analysis between chephalometric variables and AHI were performed.The patients were predominantly men (83%), with a mean age of 48.1 years. Mean BMI and AHI were 28.4 kg/m2 and 26.2, respectively. Most chephalometric variables differed among the three AHI groups. Fifteen chephalometric variables showed a correlation with AHI. Five chephalometric variables and BMI were independent AHI predictors. Chephalometric variables were better AHI predictors in normal weight patients.Significant evidence of craniofacial skeleton influence was found on OSAS severity, caudalization of the hyoid and lower sagittal facial projection being the most important patterns. From the chephalometric variables analysed, the hypopharynx calibre demonstrated a higher predictive value for AHI, independently of BMI.