ABSTRACT

Although Obstructive Sleep Apnea (OSA) patients usually exhibit a cranio-cervical extension in the natural head posture (NHP), individual variations can be observed. This study was carried out in 121 male OSA patients (Apnea+Hypopnea Index= AHI>10) to identify potential differences in upper airway, tongue, soft palate, hyoid, obesity and apnea severity variables between Craniocervical Extension (CCE) and Craniocervical Flexion (CCF) groups. Established NHP angles (NSLOPT and NSLCVT) were used to divide the patients into CCE (n= 86) and CCF (n= 35) groups, and t-tests were performed to test mean differences. Significant differences between groups were found for tongue (longer, p<0.001, and larger in CCE, p<0.05) hyoid (lower in CCE, p<0.001), and upper airway variables (smaller hypopharyngeal airway cross-sectional area in CCF, p<0.001), but the soft plate measurements were similar. OSA patients with CCE exhibited a slightly higher BMI (p<0.05). The apnea severity variables (AHI and Apnea Index) did not differ significantly between the two groups. We conclude that certain anatomic and demographic characteristics may trigger the adaptations in the NHP and that different factors may be responsible from OSA inpatients who exhibit a CCE and CCF in the NHP. Supported by MRC (Canada) Grant MT-3849.