Does Additional Bone Grafting of Atlantoaxial Joint Increase Bone Fusion Rate of Iliac Crest Autograft in Posterior Occipitocervical Fusion? Retrospective, Controlled Study with 2-Year Follow-up

Objective: We sought to explore whether additional bone grafting of the atlantoaxial joint increases the bone fusion rate of iliac crest autograft in posterior occipitocervical fusion surgery.

Methods: From January 2012 to January 2016, a total of 78 patients who had basilar invagination with occipitalization of the atlas came to our tertiary spine center. Except for those lost to follow-up (10 cases) or who had a follow-up time <2 years (20 cases), there were 48 patients retrospectively included in this study. In the control group, a piece of autogenous iliac corticocancellous bone was placed between the occipital and C2 vertebral lamina for fusion. In the hybrid fusion group, besides posterior occipitocervical autograft, some granular bone harvested from the iliac crest was packed into the bilateral atlantoaxial joint. X-ray imaging and cervical computed tomography (CT) were performed during follow-up.

Results: The operations were completed successfully in all patients without intraoperative complications. Only 21 (87.5%) patients in the control group had confirmed posterior bony fusion on CT, while 24 (100%) patients in the hybrid fusion group had confirmed posterior bony fusion. There were postoperative implant-related complications in 2 patients. Both cases belonged to the control group (8.3%). Three patients (12.5%) complained of transient numbness in the posterior occipital region: 2 patients in the hybrid group and 1 patient in the control group. The mean duration to posterior occipitocervical fusion was 5.5 months in the hybrid fusion group versus 6.1 months in the control group (P = 0.757). Of note, in the hybrid fusion group, the process of atlantoaxial joint fusion was faster than that of posterior occipitocervical fusion (5.1 months vs. 5.5 months, P = 0.823).

Conclusions: Additional bone grafting of the atlantoaxial joint could increase the bone fusion rate of iliac crest autograft in posterior occipitocervical fusion.