Identifying Factors Predictive of Atlantoaxial Fusion Failure in Pediatric Patients

Lessons Learned From a Retrospective Pediatric Craniocervical Society Study

Douglas L. Brockmeyer, MD; Walavan Sivakumar, MD; Marcus D. Mazur, MD; Christina M. Sayama, MD; Hannah E. Goldstein, MD; Sean M. Lew, MD; Todd C. Hankinson, MD; Richard C.E. Anderson, MD; Andrew Jea, MD; Philipp R. Aldana, MD; Mark Proctor, MD; Daniel Hedequist, MD; Jay K. Riva-Cambrin, MD


Spine. 2018;43(11):754-760. 

In This Article

Abstract and Introduction


Study Design. Multicenter retrospective cohort study with multivariate analysis.

Objective. To determine factors predictive of posterior atlantoaxial fusion failure in pediatric patients.

Summary of Background Data. Fusion rates for pediatric posterior atlantoaxial arthrodesis have been reported to be high in single-center studies; however, factors predictive of surgical non-union have not been identified by a multicenter study.

Methods. Clinical and surgical details for all patients who underwent posterior atlantoaxial fusion at seven pediatric spine centers from 1995 to 2014 were retrospectively recorded. The primary outcome was surgical failure, defined as either instrumentation failure or fusion failure seen on either plain x-ray or computed tomography scan. Multiple logistic regression analysis was undertaken to identify clinical and technical factors predictive of surgical failure.

Results. One hundred thirty-one patients met the inclusion criteria and were included in the analysis. Successful fusion was seen in 117 (89%) of the patients. Of the 14 (11%) patients with failed fusion, the cause was instrumentation failure in 3 patients (2%) and graft failure in 11 (8%). Multivariate analysis identified Down syndrome as the single factor predictive of fusion failure (odds ratio 14.6, 95% confidence interval [3.7–64.0]).

Conclusion. This retrospective analysis of a multicenter cohort demonstrates that although posterior pediatric atlantoaxial fusion success rates are generally high, Down syndrome is a risk factor that significantly predicts the possibility of surgical failure.

Level of Evidence: 3


The use of spinal instrumentation and biological adjuncts in pediatric patients with atlantoaxial instability has grown significantly over the past two decades.[1–20] It is now routine in pediatric spine centers for patients to undergo posterior instrumented fusion during surgical procedures for atlantoaxial instability. Although previous reports of instrumented pediatric atlantoaxial fusion have demonstrated high rates of success,[1–9,11–21] the reports have been small, single-institution studies containing the usual inherent biases of these types of studies. Furthermore, some of those studies have reported results from mixed adult and pediatric cohorts.[8,16,21]

Despite technical advances, fusion failures and complications still occur in pediatric posterior atlantoaxial arthrodeses.[14,18] Clearly, there is a need to evaluate multicenter data to understand the clinical and technical factors that may contribute to surgical nonunion in pediatric patients. The aim of this article is to use data pooled from seven major pediatric spine centers to examine clinical and surgical variables predictive of surgical nonunion in patients undergoing posterior instrumented atlantoaxial arthrodesis.