Prevalence of Intraoperative Tissue Bacterial Contamination in Posterior Pediatric Spinal Deformity Surgery

Study Design. Retrospective case control study. Objective. To determine prevalence and risk factors for intraoperative bacterial contamination in posterior spinal deformity surgery. Summary of Background Data. The prevalence of deep surgical site infection in pediatric spinal deformity surgery varies from 1% to 14%. Little evidence exists about the incidence and role of intraoperative bacterial contamination. Methods. A total of 114 cases of pediatric posterior instrumented deformity surgery were retrospectively identified. All patients received preoperative and every 4-hour intraoperative antibiotics and 3M Ioban 2 Antimicrobial Incise Drape. Preoperative photographs of patients' backs were used to correlate presence of back acne with contaminant bacteria. Laboratory cultures were obtained from paraspinal muscle debrided before closure. Results. Of the 114 cultures obtained, 26 (23%) were positive in 21% of idiopathic, 37% of neuromuscular (P = 0.02), and 14% of congenital patients. Contaminant bacteria included Propionibacterium acnes (69%), Staphylococcus (23%), Coryneform (4%), and Clostridium (4%). P. acnes was seen only in children 11 years or older (P = 0.02) and only with back acne (P < 0.0001). Eight of 19 (42%) patients with pelvic fusion had positive cultures (P = 0.04) and all 8 were neuromuscular patients. Eighty-one percent of culture-positive patients were older than 11 years (P = 0.01). Three of 114 (2.7%) patients developed an early deep surgical site infection, all with positive cultures (P = 0.01). Conclusion. Neuromuscular patients fused to the pelvis, children older than 11 years, and surgery duration greater than 6 hours were associated with positive cultures. Back acne is a preventable risk factor for P. acnes seeding. Intraoperative bacterial contamination indicates a need to consider the type of surgery and patient age to determine prophylactic antibiotics and other odalities to prevent infection.