Obstructive sleep Apnea's association with the cervical spine abnormalities, posture, and pain: a systematic review

Objectives: While obstructive sleep apnea (OSA) is associated with several chronic health conditions such as hypertension, obesity, and chronic hypoxia, there is limited information on its association with neuromuscular and spinal pathologies that may be of interest to a musculoskeletal (MSK) medicine or pain management clinician. The objective of this study was to perform a systematic literature review to examine the association between OSA and cervical spine pathologies, postural changes, and pain. Design: We systematically reviewed PubMed and Embase databases up to 4/15/2019. We included studies that explored associations between OSA and a) pain, b) postural characteristics or changes, or c) cervical spine morphology. Systematic reviews, meta-analysis, randomized control trials, cohort studies, and case–control studies were included. Case reports, narrative reviews or expert opinion papers were excluded. From the articles that met selection criteria, information regarding type, direction and magnitude of such associations was extracted. The OSA-pain association studies were further divided into 3 subgroups: neuropathic, temporomandibular, and chronic pain. Results: 21 articles that met our study criteria were selected for this review. Two studies were on cervical spine pathologies, eight on postural changes, and eleven on pain associated with OSA. Exploring the association between OSA and cervical spine pathologies, postural changes, and pain in this systematic review we found: (1) Cervical spine lesions, fusions, and abnormalities that reduce retropharyngeal space are associated with OSA, likely by way of worsening posture and decreasing range of motion. (2) Head extension and anteriorization are associated with OSA likely as a compensatory mechanism. Extension may improve airway function, while anteriorization helps to maintain visual sense. (3) Head-of-bed-elevation may improve OSA symptoms and can possibly supplement other conservative treatment measures. (4) Neuropathic pain is associated with OSA, likely by way of inflammatory pathways. (5) Oral appliance use (eg mandibular advancement/protruding device) in OSA likely contributes to transient temporomandibular pain. (6) There is little association between OSA and chronic pain prevalence. (7) Increased pain intensity and decreased pain tolerance are somewhat associated with OSA, likely by way of hypoxemia and sleep fragmentation. Conclusions: Clinicians in MSK and pain medicine need to consider these associations and consider obtaining imaging studies and/or making referrals for management of their OSA to better provide appropriate care to these patients.