Sleep apnea in rheumatoid arthritis patients with occipitocervical lesions: the prevalence and associated radiographic features

Abstract

Since sleep apnea is a risk factor for high mortality of rheumatoid arthritis (RA) patients, this study examined the prevalence in RA patients with occipitocervical lesions, and the associated radiographic features. Twenty-nine RA patients requiring surgery for progressive myelopathy due to occipitocervical lesions (3 males, 26 females, average age 65 years) were preoperatively evaluated. Twenty-three (79%) had sleep apnea defined as apnea-hypopnea index >5 events per hour measured by a portable monitoring device, and all of them were classified as the obstructive type. Among gender, age, bone mass index (BMI), and radiographic parameters related to occipitocervical lesions: atlantodental interval (ADI), cervical angles (O/C1, C1/2, and C2/6), and cervical lengths (O-C2 and O-C6), the ADI and cervical lengths were shown to be significantly associated with the presence of sleep apnea by parametric statistical analysis. Since there were positive correlations between the ADI and cervical lengths by Pearson's test, we performed a multivariate logistic regression analysis after adjustment for confounding factors and found that small ADI was the principle parameter associated with sleep apnea. We therefore conclude that the prevalence of sleep apnea is higher than that in a general RA population that was reported previously, and believe that occipitocervical lesions are an independent risk factor for this condition. Small ADI and short neck, secondary to the vertical translocation by RA, may cause obstructive sleep apnea, probably through mechanical or neurological collapse of the upper airway.

Sleep apnea and cervical spine pathology

“…Involvement of these joints may cause subluxation of the vertebrae and vertical translation, leading to reduced neck width and a decreased angle of the craniovertebral junction. Reduced neck width and decreased craniovertebral angles, such as the O/C2 angle, may crowd the retropharyngeal space and increase the propensity for a horizontal bending force on the upper airway, especially during neck flexion, leading to apneic events [15]. This mechanism may help account for the larger prevalence of sleep apnea in RA patients when compared to the general population [14].…”

“…Since that time, multiple case reports have described RA patients presenting with combinations of OSA and CSA. In separate studies, the prevalence of sleep apnea in RA patients was reported to be 53 and 79 % in those with occipito-cervical lesions [14,15]. A crosssectional study of OSA in RA patients with occipito-cervical lesions was performed by Shoda et al [15].…”

“…In separate studies, the prevalence of sleep apnea in RA patients was reported to be 53 and 79 % in those with occipito-cervical lesions [14,15]. A crosssectional study of OSA in RA patients with occipito-cervical lesions was performed by Shoda et al [15]. They cataloged the radiographic features of 29 RA patients by measuring the atlanto-dental interval, cervical angles (O/ C1, C1/2, and C2/6), and cervical lengths (O-C2 and O-C6 distance).…”

“…On imaging, small atlanto-dental intervals (4.9 vs. 9.5 mm in controls) and cervical lengths (O-C2: 24.8 vs. 32.9 mm in controls; O-C6: 87.0 vs. 104.6 mm in controls) were shown to be significantly associated with the presence of sleep apnea. The horizontal atlantoaxial subluxation typically seen in RA may explain the vertical translocation and shortening of these radiographic parameters [15].…”

The Michel Benoist and Robert Mulholland yearly European Spine Journal Review: a survey of the “medical” articles in the European Spine Journal, 2009

“…This paper by Shoda et al [20] published in the June issue deals with the prevalence of sleep apnea in a subgroup of rheumatoid patients with occipito-cervical lesions. The patient population comprised 29 subjects planned to undergo surgery for severe occipito-cervical lesions causing myelopathy.…”