Related Experiment Video
Updated: Dec 16, 2025
Drug-Induced Sleep Endoscopy DISE with Target Controlled Infusion TCI and Bispectral Analysis in Obstructive Sleep Apnea
Published on: December 6, 2016
A radiologic parameter that could be applied in the development of sleep apnea in rheumatoid arthritis patients
Gong Long1, Zhang Hu2, Zhang Jiao3
1Department of Orthopedic, China-Japan Friendship Hospital, Peking Union Medical College, Chinese Academy of Medical College, Beijing, 100853, China.
Background:
The prevalence of sleep apnea in rheumatoid arthritis (RA) patients with occipitocervical lesions was 79%. Occipitocervical fusion (OCF) could incur sleep apnea or worsen this condition. Recent studies reported that this complication is caused by stenosis of the oropharyngeal airway accompanying a decrease in the occipitoaxial angle (O-C2a). However, there are several limitations to the application of the O-C2a, which decreases its effectiveness. Therefore, we aimed to evaluate the association between a new radiologic parameter, the CVT/NSL angle (CVT: craniocervical inclination in the second and fourth vertebrae; NSL: Nasion-Sella line), and sleep apnea in RA patients accepting OCF.
Methods:
A total of 35 patients who underwent OCF due to upper cervical lesions secondary to RA and had sleep apnea before surgery were analyzed. Those who have a postoperative apnea-hypopnea index (AHI) < 15 and a ΔAHI ≥50% were considered "responders"; patients were otherwise considered "non-responders." They were analyzed whether pre- and postoperative radiologic parameters and their differences in plain lateral radiographs were correlated to the parameter related to sleep apnea.
Results:
The included patients have a mean AHI of 21.9 (range, 10 to 52) before surgery. The mean postoperative CVT/NSLa, ΔCVT/NSLa, andΔO-C2a in complete responders were significantly greater compared with non-responders (p < 0.05). Both the changes in the CVT/NSLa and O-C2a were linearly correlated within patients. However, the R2 value for the CVT/NSLa was greater compared with the O-C2a (0.403 vs. 0.203).
Conclusions:
The usefulness of the new craniovertebral angle, CVT/NSLa, as an intraoperative indicator during OCF, is more valuable in comparison with the conventional method of measuring the O-C2a. Measuring the craniovertebral angle is extremely important in the planning of surgical treatment for the development of sleep apnea in rheumatoid arthritis patients undergoing occipitocervical fusion.
