Surgical Failure and Revision Strategy for Atlantoaxial Dislocation

Study Design. Retrospective study. Objective. To classify surgical failures following atlantoaxial dislocation, present strategies for revisions and evaluate the clinical results of revision surgery. Summary of Background Data. With the increase in atlantoaxial dislocation surgery, the number of surgical failures has gradually risen. However, current reports on atlantoaxial surgical revision are limited in scope. There remains a lack of summary regarding the causes of surgical failure, a detailed classification system, and no proposed strategy for revision surgery. Methods. 109 cases of failed surgery following atlantoaxial dislocation were classified according to the reduction immediately after surgery and the fusion status before revision. The reduction, decompression, fusion status and outcomes following revision surgery were evaluated by X-ray, CT, MRI and JOA score. The data were analyzed statistically with a paired-samples t test and multivaraible logistic regression analysis. Results. The 109 patients were classified into three categories of failure: non-reduction with non-fusion (NR-NF, 73 cases), non-reduction with fusion (NR-F, 19 cases), and reduction with non-fusion (R-NF, 17 cases). Sixty-four patients underwent anterior revision, 21 posterior revision, and 24 anteroposterior revision. Postoperative complications were the primary cause of early revisions. After revision, complete decompression was achieved in all cases, anatomical reduction in 89 cases, significant improvement of JOA score in 77 cases, and fusion achieved in 86 cases. Twelve cases experienced surgical complications and 3 underwent a second revision. Conclusions. We found that NR-NF was the most common type of failure following surgery for atlantoaxial dislocation. Revision strategies can be guided according to our descriptive classification of failure, and revision surgery should focus on achieving adequate reduction, appropriate fixation and reliable fusion to optimize post-surgical outcomes.