269 Risk Factors for Fusion Failure in Children Undergoing Occipital to C2 Rigid Instrumentation and Fusion

Abstract

INTRODUCTION: Studies of pediatric occipital-cervical fusions have been limited, and there is substantial variation among surgical constructs with reported failure rates as high as 20%. METHODS: The Pediatric Spine Study Group (PSSG) registry was queried to identify patients </= 21-years-old who had: (1) O-C2 posterior rigid instrumentation and fusion, (2) 2-year clinical and radiographic follow-up, and (3) available post-operative lateral cervical radiograph or CT. Failure was defined as hardware revision surgery >30 days following the index procedure or the presence of screw haloing or breakage on the most recent imaging study. Univariate comparisons were made using Mann-Whitney U-tests, Chi-square tests, and Fisher’s Exact tests followed by multivariable logistic regression. RESULTS: 76 patients were included. The median age at surgery was 9 years (range, 0.2 to 17.2 years), and 51% of the cohort was male. 55% percent of patients had syndromic etiology (41/75), and the most frequent diagnosis was Down Syndrome (28%). Of the 74 patients with complete information, 28/74 (38%) had fusion failure (95% CI, 27%-50%). Rib autographs were used more frequently in patients with successful fusions compared to failures (52% vs 25%; p = 0.04). Multivariable logistic regression determined that patients with rib autograft have a 75% decrease in the odds of failure compared to those without rib autograft (OR = 0.25; 95% CI = 0.08-0.75; p = 0.01). Other variables did not influence the risk for failure. CONCLUSIONS: In this multicenter, international registry study of children undergoing O-C2 rigid instrumentation, fusion failure was seen in 38% of patients, a higher rate than previously reported. Based on this study, the use of structural rib autograft should be considered to reduce fusion failure.