Flexion Dysfunction of Atlanto‐Occipital Joint Associated with Cervical Spondylosis

Abstract

Objective To investigate the association between atlanto‐occipital radiographic alignment in flexion and cervical spondylosis (CS). Methods This is a retrospective case‐control study. CS patients were recruited from our hospital, and the age/gender/body mass index (BMI)‐matched healthy controls were selected from the subjects in health examinations at the same hospital between January 2015 and May 2019. A total of 464 subjects was included in the study. There are 282 males and 182 females. The ages of patients were 20 to 67 years, and the mean age was 33.9 years. CS patients were considered the case group. Based on surgical treatments, they were subdivided into non‐operation group and operation group. The operation group and non‐operation group had 45 and 187 patients, respectively, while 232 subjects were included in the control group. The angle between McGregor's line and C1 line (O‐C1 angle) was evaluated on images taken in flexion (F‐OC) and neutral positions (N‐OC) independently. The relationship between the FOC (FOC=F‐OC—N‐OC) and Neck Disability Index (NDI) was examined, and the involvement of the FOC in the onset of CS was analyzed. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut‐off for detecting an increased risk of CS. Results The median follow‐up time was 51.6 months (25–115 months). The case groups, especially the operation group, tended to be older (55.8 ± 11.2 vs 41.6 ± 13.8 vs 23.5 ± 5.5 years, P < 0.001), have a higher NDI score (12.2 ± 4.5 vs 6.2 ± 2.1 vs 3.2 ± 1.2, P < 0.001), and longer medical history (10.5 ± 9.5 vs 6.8 ± 11.2 years, P < 0.001). One‐way analysis of variance showed statistically significant differences in FOC between the control and case groups (1.4° ± 1.2° vs 3.6° ± 1.9° vs 7.2° ± 2.0°, P < 0.001). Besides, a post‐hoc Tukey test showed a lower FOC in the operation group compared with that in the non‐operation group (1.4° ± 1.2° vs 3.6° ± 1.9°, P < 0.001). Using FOC as a radiological predictive model to predict CS, the cut‐off value was 4.2°. Using FOC as a radiological predictive model to predict CS, the area under the curve (AUC) was 0.86 (95% CI: 0.78–0.92, P < 0.001). In the univariable risk analysis model, conditional logistic regression showed that the FOC level was an independent factor with an important role in the risk of CS. The odds rose to 8.2 times when FOC reached the level under 4.2° (OR = 8.2; 95% CI: 6.4–10.0; P < 0.001). There existed a significant negative correlation between FOC levels and NDI (r = −0.451, P = 0.016). Conclusions Stiff O‐C1, which is defined as FOC ≤ 4.2°, represented decreased flexion dysfunction of atlanto‐occipital joint and is closely associated with high risk for the occurrence of CS. This finding could show a possible relationship between upper and lower cervical spine and help spine surgeons to understand the pathological process of CS and implement appropriate management.

Two‐level Anterior Cervical Corpectomy and Fusion versus Posterior Open‐door Laminoplasty for the Treatment of Cervical Ossification of Posterior Longitudinal Ligament: A Comparison of the Clinical Impact on the Occipito‐Atlantoaxial Complex

“…Changes in the SCS and adjacent segment sagittal parameters have long been a focus of research in cervical spine surgery. However, atlantooccipital flexion dysfunction has been shown to be associated with spinal cervical spondylosis, emphasizing the important role of the UCS 16 . To our knowledge, there are no studies to compare the effects of anterior t‐ACCF and posterior ODLP on sagittal parameters and ROM of the UCS, atlantooccipital and atlantoaxial joints.…”

Cervical Alignment of Patients with Basilar Invagination: A Radiological Study

“…The correlation between craniocervical alignment (O-C 2 angle and C 2 -C 7 angle) and the development of dysphagia after surgical treatment in BI patients was also discussed, finding that the change in the O-C 2 angle was significantly lower in patients with postoperative dysphagia than in patients without 10 . Another study revealed that the stiffer O-C 1 angle, which was measured and calculated in flexion and neutral positions, indicated the dysfunction of atlanto-occipital joint and correlated with risk of cervical spondylosis 11 . However, to the best of our knowledge, the cervical curvature and the sagittal alignment changes in neutral, extension, and flexion positions in BI patients have not been reported.…”