High rate of late revision with multiple Cutibacterium acnes tissue isolates in paediatric spinal deformity suggesting implant-associated infection

Background Postoperative spinal implant infection (PSII) causes significant morbidity and suffering and can occur long after surgery.Objectives Our purpose was to investigate the incidence and time to reoperation for PSII following adolescent deformity surgery. We also aimed to identify causative microorganisms, resistance to antibiotics and the influence of risk factors and evaluate resolution of infection.Methods Retrospective review on all adolescent idiopathic scoliosis (AIS) and neuromuscular scoliosis(NMS) spinal fusion patients aged 10–18 at a university hospital between 2015 and 2021, with a 2-year follow-up of two.Results A total of 207 AIS and 55 NMS patients were included. Among AIS patients, 38 cases of confirmed and 2 cases of likely PSII were identified. Among NMS patients, 11 confirmed and 1 likely case were found. The median time from primary surgery to reoperation was 20.0 months (range 0–63) for AIS and 14.0 months (range 0–79) for NMS. The most frequently isolated microorganism in AIS patients was Cutibacterium acnes (78.9%, n = 30). In NMS patients, polymicrobial infections dominated. Among infected patients, only 1 of 38 AIS patients (2.6%) and 3 of 11 NMS patients (27.3%) required a second reoperation within 24 months.Conclusion The predominance of Cutibacterium acnes as the presumtive causative agent for the elevated rate of late revisions due to PSII in this paediatric deformity cohort highlights important challenges in current diagnostic frameworks and the definition of PSII. Despite a high rate of successful single surgery treatment of infection, targeted prevention strategies against C. acnes are warranted in this or similar populations.