Cervical Spine Angles, Craniocervical Posture, Neck Length, and Oropharyngeal Airway Analyses of Sleep Apnea Patients in Both Supine and Upright Positions: a Retrospective 3-D Imaging Study

Obstructive sleep apnea (OSA) is one of the most common respiratory disorders. Previous airway studies of OSA subjects have largely relied on 2-D radiographs. The purpose of this study is to use 3-D imaging to the analyze the relationships among cervical spine angles, craniocervical posture, cervical spine length and the oropharyngeal airway volume in OSA patients in both the supine and upright positions. Twenty-eight OSA subjects with 3-D imaging were included. Airway, craniocervical posture, spine angles, and spine length were assessed using Dolphin 11.8. Correlation analyses were utilized to detect associations among the recorded and measured variables. Mean differences were determined between the supine and upright subjects. A p \u3c 0.05 was considered statistically significant. Significant associations were found: positive associations between apnea-hyponea index (AHI) and age, craniocervical posture and airway volumes, craniocervical posture and cervical vertebrae C1-C2 spinal angle, and spine length and airway volumes. Negative associations were found between craniocervical posture and body mass index (BMI), C2-C3 and C1-C4 angle and age. A 1.767 odds ratio for retrolingual to retro-uvula was found with each increase in spine length. McGregor and McRae angles are nearly perfectly correlated. Subjects in the supine position had significantly greater BMI and oropharyngeal airway dimensions than subjects in the upright position. Craniocervical extension is positively correlated with increased BMI and negatively correlated with airway volumes; however, spinal angles are not. Subjects in the supine position demonstrated smaller airway volumes than upright subjects. Subject positioning and posture are important consideration in the evaluation of OSA