Comparison between atlantoaxial and occipitocervical fusion: clinical implications of restoring the atlanto-occipital joint

Background context: Cervical myelopathy originating from high cervical pathology is typically managed through stabilization constructs, with the most common options being atlantoaxial fusion (AAF) and occipitocervical fusion (OCF). However, a well-established comparison of the 2 techniques in terms of clinical and radiological outcomes has not been made.

Purpose: Compare the surgical outcomes of AAF and OCF with a minimum follow-up period of 2 years.

Study design: Retrospective cohort study.

Patient sample: A total of 64 patients who underwent AAF (n=46) and OCF (n=18) to treat cervical myelopathy were retrospectively reviewed.

Outcome measure: Neck pain Visual Analogue Scale (VAS), Neck Disability Index (NDI), Japanese Orthopedic Association (JOA) scores and postoperative complications were assessed as clinical outcomes. For the radiological outcomes, cervical sagittal parameters including C0-2 lordosis, C2-7 lordosis, C0-7 lordosis, neck range of motion (ROM), C2-7 sagittal vertical axis, C2 sagittal tilt, T1 slope, chin brow vertical angle and McGregor slope were evaluated.

Methods: Continuous variables between AAF and OCF were compared using either the Mann-Whitney U test or an independent T-test. The Wilcoxon signed-rank test was utilized to compare variables across preoperative, 1-month postoperative, and final follow-up periods.

Results: Both the AAF and OCF groups did not show any significant differences in the total NDI score, VAS for neck pain, and JOA score when comparing preoperative and postoperative evaluations. However, at 1 month postoperatively (AAF group, 2.63; OCF group, 8.00: p=.006) and final follow-ups (AAF group, 3.08; OCF group, 7.82: p=.003), the OCF group showed a significant decline in the lifting function compared to the AAF group. Furthermore, the decrease in neck ROM was significantly more severe in the OCF group compared to the AAF group (AAF group, -6.4°; OCF group, -20.1°: p=.010).

Conclusions: The OCF has the potential to limit neck movement and impede lifting capabilities after the surgery. Hence, the AAF is advisable over the OCF, especially for younger individuals or those involved in strenuous physical work.