Surgical site infection following spinal instrumentation for scoliosis: a multicenter analysis of rates, risk factors, and pathogens.

BACKGROUND: Surgical site infection following correction of pediatric scoliosis is well described. However, we are aware of no recent multicenter study describing the rates of surgical site infection, and associated pathogens, among patients with different etiologies for scoliosis. METHODS: A multicenter, retrospective review of surgical site infections among pediatric patients undergoing spinal instrumentation to correct scoliosis was performed at three children's hospitals in the United States. Study subjects included all patients undergoing posterior spinal instrumentation from January 2006 to December 2008. Surgical site infections were defined according to the Centers for Disease Control and Prevention's National Healthcare Safety Network case definition, with infections occurring within one year after surgery. RESULTS: Following the analysis of 1347 procedures performed in 946 patients, surgical site infection rates varied among procedures performed in patients with different scoliosis etiologies. Procedures performed in patients with neuromuscular scoliosis had the highest surgical site infection rates (9.2%), followed by those performed in patients with syndromic scoliosis (8.8%), those performed in patients with other scoliosis (8.4%), those performed in patients with congenital scoliosis (3.9%), and those performed in patients with idiopathic scoliosis (2.6%). Surgical site infection rates varied among procedures in patients undergoing primary spinal arthrodesis based on etiology, ranging from 1.2% (95% confidence interval, 0.1% to 1.3%) in patients with idiopathic scoliosis to 13.1% (95% confidence interval, 8.4% to 17.8%) in patients with neuromuscular scoliosis. Surgical site infection rates following primary and revision procedures were similar among patients with different etiologies. In distraction-based growing constructs, rates were significantly lower for lengthening procedures than for revision procedures (p = 0.012). Multivariate analysis demonstrated that non-idiopathic scoliosis and extension of instrumentation to the pelvis were risk factors for surgical site infections. The three most common pathogens were Staphylococcus aureus (25.0% [95% confidence interval, 17.8% to 32.2%]), coagulase-negative staphylococci (17.1% [95% confidence interval, 10.9% to 23.3%]), and Pseudomonas aeruginosa (10.7% [95% confidence interval, 5.6% to 15.8%]). Overall, 46.5% (95% confidence interval, 35.5% to 57.5%) of surgical site infections contained at least one gram-negative organism; 97.0% (95% confidence interval, 90.8% to 100.0%) of these infections were in patients with non-idiopathic scoliosis. CONCLUSIONS: Surgical site infection rates were significantly higher following procedures in patients with non-idiopathic scoliosis (p < 0.001). Lengthening procedures had the lowest rate of surgical site infection among patients with early onset scoliosis who had undergone instrumentation with growing constructs. Gram-negative pathogens were common and were most common following procedures in patients with non-idiopathic scoliosis. These findings suggest a role for targeted perioperative antibiotic prophylaxis to prevent surgical site infection following pediatric scoliosis instrumentation procedures.