Spinal implant-associated infections: A prospective multicenter cohort study.

Margaryan, Donara; Renz, Nora; Bervar, Maja; Zahn, Robert; Onken, Julia; Putzier, Michael; Vajkoczy, Peter; Trampuz, Andrej

OBJECTIVES To evaluate the clinical, laboratory, microbiological, radiological and treatment characteristics of patients with early-onset and late-onset spinal implant-associated infections. METHODS Patients diagnosed with spinal implant-associated infections between 2015 and 2019 were prospectively included and treated according to a standardized algorithm. Infections were classified as early-onset (≤6 weeks) and late-onset (>6 weeks). RESULTS Among 250 patients, 152 (61%) had an early-onset and 98 (39%) late-onset infection. Local inflammatory signs was the most common manifestation in early-onset infections (84%), whereas late-onset infections presented mainly with persisting or increasing local pain (71%). Sonication fluid were more often positive than peri-implant tissue samples (90% vs. 79%, p=0.016), particularly in late-onset infections (92% vs. 75%, p=0.005). Predominant pathogens were coagulase-negative staphylococci, Staphylococcus aureus and Cutibacterium spp. Debridement and implant retention was the most common surgical approach in early-onset infection (85%), whereas partial or complete implant exchange was mainly performed in late-onset infections (61%). 218 patients (87%) received biofilm-active antibiotics, the median treatment duration was 11.7 weeks. 49 patients (20%) needed more than one revision for infection, six patients (2.4%) died during their hospital stay. CONCLUSIONS Most spinal implant-associated infections were acquired during surgery and presented within 6 weeks of surgery. Infections presented mainly with local inflammatory signs in early-onset and with persisting or increasing pain in late-onset infections. Sonication was the most sensitive microbiological method, particularly in late-onset infections. Debridement and implant retention was used in well-integrated implants without loosening implant parts, independent of the time of infection onset.