The Impact of Atlantoaxial Intra-Articular Fusion on Cervical Spine Curvature and Sagittal Balance.

Abstract

Aim: To investigate whether atlantoaxial intra-articular fusion (AIF) can maintain sagittal balance stability in the cervical spine during follow-up.

Material and methods: The data of 39 patients with anterior atlantoaxial dislocation who underwent AIF and 21 patients who underwent structural bone grafting (SBG) fusion were retrospectively reviewed. Radiographic variables, including T1 slope (T1S), C1?C2 angle, C2?C7 angle, C2?C7 sagittal vertical axis (SVA), and lateral atlantoaxial joint space height (LAAJSH), were measured preoperatively, postoperatively, and at the last follow-up. Analyzing the differences in cervical spine curvature and sagittal balance during the preoperative, postoperative, and follow-up periods, as well as identifying the influencing factors.

Results: In the AIF Group, compared to the preoperative measurements, there was a statistically significant increase in both the C1?C2 angle (p < 0.001) and LAAJSH (p < 0.001) at the final follow-up, while a significant decrease was observed in the C2?C7 angle (p < 0.001). At the final follow-up, there was a decrease in LAAJSH compared to immediately post-surgery (p < 0.001), but there were no significant changes in the C1?C2 angle (p=0.366), C2?C7 angle (p=0.502), T1S (p=0.082) and C2?C7 SVA (p=0.209).

Conclusion: Posterior AIF technique can effectively reconstruct the alignment of the atlantoaxial complex and avoid secondary imbalance and loss of lordosis of the subaxial cervical spine.