Cervical Spine Hyperextension and Altered Posturo-Respiratory Coupling in Patients With Obstructive Sleep Apnea Syndrome
FRONTIERS IN MEDICINE
Authors: Clavel, Louis; Remy-Neris, Segolene; Skalli, Wafa; Rouch, Philippe; Lespert, Yoann; Similowski, Thomas; Sandoz, Baptiste; Attali, Valerie
Abstract
Obstructive sleep apnea syndrome (OSAS) is associated with postural dysfunction characterized by abnormal spinal curvature and disturbance of balance and walking, whose pathophysiology is poorly understood. We hypothesized that it may be the result of a pathological interaction between postural and ventilatory functions. Twelve patients with OSAS (4 women, age 53 years [51-63] (median [quartiles]), apnea hypopnea index 31/h [24-41]) were compared with 12 healthy matched controls. Low dose biplanar X-rays (EOS (R) system) were acquired and personalized three-dimensional models of the spine and pelvis were reconstructed. We also estimated posturo-respiratory coupling by measurement of respiratory emergence, obtaining synchronized center of pressure data from a stabilometric platform and ventilation data recorded by an optico-electronic system of movement analysis. Compared with controls, OSAS patients, had cervical hyperextension with anterior projection of the head (angle OD-C7 12 degrees [8; 14] vs. 5 degrees [4; 8]; p = 0.002), and thoracic hyperkyphosis (angle T1-T12 65 degrees [51; 71] vs. 49 degrees [42; 59]; p = 0.039). Along the mediolateral axis: (1) center of pressure displacement was greater in OSAS patients, whose balance was poorer (19.2 mm [14.2; 31.5] vs. 8.5 [1.4; 17.8]; p = 0.008); (2) respiratory emergence was greater in OSAS patients, who showed increased postural disturbance of respiratory origin (19.2% [9.9; 24.0] vs. 8.1% [6.4; 10.4]; p = 0.028). These results are evidence for the centrally-mediated and primarily respiratory origin of the postural dysfunction in OSAS. It is characterized by an hyperextension of the cervical spine with a compensatory hyperkyphosis, and an alteration in posturo-respiratory coupling, apparently secondary to upper airway instability.
Magnetic Resonance Imaging Research of Thoracic Inlet Parameters in the Cervical and Cervicothoracic Spine in Degenerative Cervical Spondylosis
WORLD NEUROSURGERY
Authors: Li, Wanli; Li, Fangcai; Yang, Xiaobo; Yu, Shunjie; Chen, Weishan; Chen, Qixin
Abstract
OBJECTIVE: The purpose of this study was to examine the thoracic inlet angle (TIA) and its related parameters in the cervical and cervical-thoracic vertebrae in patients with degenerative cervical spondylosis (DCS) and explore the association of the TIA, tilt angle of the neck, and tilt angle of the first thoracic spine with the cervical degeneration score. METHODS: Patients with DCS were included from January 2014 to December 2017. The relevant parameters were assessed on T2-weighted magnetic resonance imaging. The association of cervical parameters with the cervical degeneration score was examined by multiple linear regression model. RESULTS: A total of 204 patients (126 men) were eligible and enrolled, with a mean age of 55-56 years. Men had significantly higher thoracic inlet parameters than women (all P < 0.05). Thoracic inlet parameters were positively correlated with age (all P < 0.05). After adjustment for age and sex, the significant association between the TIA and cervical or cervical-thoracic spine degeneration scores was not observed in all vertebrae. Meanwhile, men had higher vertebral height (VH) and intervertebral disk height (IVDH) than women. Only the VHs of C7, T1, and T2 and the IVDHs of C6-7, T1-2, and T2-3 were significantly and positively associated with the TIA (all P < 0.05). CONCLUSIONS: Age was positively correlated with thoracic inlet parameters in patients with DCS. Men had significantly higher thoracic inlet parameters than women because the men had higher VHs and IVDHs. However, the TIA was not associated with the level of cervical disk degeneration. The clinical relevance of these findings has not been established.