Sleep Apnea Secondary to Service-Connected Cervical Spine Abnormalities
Patients with cervical spine abnormalities secondary to spondyloarthropathy or rheumatoid arthritis are known to have a very high incidence of obstructive sleep apnea. Sleep apnea is a risk factor for high mortality of rheumatoid arthritis (RA) patients.
In the research article, Sleep apnea in rheumatoid arthritis patients with occipitocervical lesions: the prevalence and associated radiographic features, Naoki Shoda et al. examined the prevalence of sleep apnea in RA patients with cervical lesions. Twenty-nine RA patients requiring surgery for progressive myelopathy due to occipito-cervical lesions were preoperatively evaluated. Twenty-three (79%) had sleep apnea, and all of them were classified as the obstructive type. The authors observed that:
“Obstructive sleep apnea was caused by the reduction of the airway space which is determined by an interaction between mechanical properties of the airway itself and neurological regulations of the dilator muscles.”
They suggested that both mechanisms could possibly be affected by RA with cervical lesions. First, the decrease of cervical length may give rise to a bending force and horizontal pressure on the soft tissues surrounding the airway, which, in turn, may cause the mechanical compression of the airway. Secondly, the vertical translocation caused by the RA occipitocervical lesions may “lead to compression of cranial nerves V, VII, IX, X, XII that are known to control the airway dilator muscles. The neurological dysfunction of the muscles may cause the collapse of the airway.”
Similarly, it has been proposed that spondyloarthrosis patients are at increased risk for OSA because of structural changes in the cervical spine. This hypothesis is supported by reports of improvement in OSA after surgical removal of excessively bulky, pathologic bone from the anterior cervical spine.
OSA has also been shown to be caused by anterior cervical spine fusion and the insertion of a plate. In the study Anterior cervical spine fusion and sleep disordered breathing, Guilleminault et al. reviewed 12 patients who developed OSA in association with anterior cervical spine fusion. Four subsequent patients were studied prospectively before C2 to C4 anterior fusion and documented to have OSA by questionnaire, visual analogue scales, polysomnography, and multiple sleep latency tests. The authors found that placement of the anterior cervical plates reduced the size of the upper airway. Symptoms and objective findings were controlled with nasal continuous positive airway pressure.
In addition, Krieger et al. reported cases of sleep apnea following spinal surgery in the Journal of Neurosurgery, Sleep-induced apnea 2. Respiratory failure after anterior spinal surgery (Journal of Neurosurgery, 1974 Feb; 40(2):181-5).