Wouthuyzen‐Bakker, Marjan

Study Design. Modified Delphi consensus process Objective. To establish a standardized, consensus-driven definition for postoperative spine infection (PSI) for research, diagnosis, and management. Summary of Background Data. Postoperative infection is a devastating and common complication following spine surgery. Rates of PSI in the literature range from 0% to over 20% depending on surgical indication and invasiveness. Despite the implications of PSI, there is no universally accepted diagnostic standard or consensus definition for infection following spine surgery, hindering research and treatment of this challenging clinical condition. Methods. A multispecialty workgroup convened by the Musculoskeletal Infection Society (MSIS) conducted a systematic literature review. Using data from the systematic review, an expert panel completed a modified Delphi process to achieve consensus. The panel included nine fellowship-trained, board-certified physicians with expertise in infectious diseases, orthopaedic and neurologic spine surgery, and musculoskeletal radiology. Iterative rounds focused on criterion selection, importance ranking, categorical grouping, and final constellation development for PSI diagnosis. Consensus was defined as a 2/3 majority, with a target of 100%. Results. The workgroup achieved 100% consensus on a new PSI definition, which incorporates six clinical domains: wound features, microbiology, imaging, inflammatory biomarkers, intraoperative findings, and histology. A single microbiological stand-alone criterion—identification of a phenotypically indistinguishable organism from two or more deep operative site specimens—was established as pathognomonic for postoperative spine infection. Additional primary and secondary supporting criteria were defined, with specific combinations required to classify cases as definite or probable PSI. Final definitions were ratified by the boards of MSIS and the European Bone & Joint Infection Society (EBJIS) Conclusion. This consensus-based definition provides a standardized framework for diagnosing postoperative spine infection, facilitating research and clinical management. The criteria balance sensitivity and specificity across diverse clinical scenarios and represent the first multispecialty, society-endorsed definition for PSI.

Abstract Spinal implant infections are a serious complications of instrumented spinal fusion surgeries, carrying high morbidity and complex management challenges. Early postoperative infections may manifest with wound-healing issues, back pain, and fevers. Magnetic resonance imaging (MRI) is the preferred imaging modality, but can be limited by metal artifacts. For cases with stable implants, surgical debridement with implant retention combined with at least 12 weeks of antibiotics is currently considered appropriate treatment. Staphylococcal infections are ideally treated with biofilm-active antibiotics. Suppressive antibiotic therapy can be considered when surgical debridement has been delayed or is incomplete, and for those who are poor surgical candidates for another surgery. Chronic infections may present insidiously with implant failure or pseudarthrosis; implant removal or revision is generally pursued. As current guidance is heavily based on the periprosthetic joint infection literature and low-level studies on spinal implant infections, further research on optimizing diagnostic and treatment approaches is needed.

Abstract Background The first-line management strategy for acute periprosthetic joint infections (PJIs) is debridement, antibiotics, and implant retention (DAIR). Suppressive antibiotic therapy (SAT) after DAIR is proposed to improve outcomes, yet its efficacy remains under scrutiny. Methods We conducted a multicenter retrospective study in patients with acute PJI of the hip or knee who were treated with DAIR in centers from Europe and the United States. We analyzed the effect of SAT using a Cox model landmarked at 12 weeks. The primary covariate of interest was SAT, which was analyzed as a time-varying covariate. Patients who experienced treatment failure or were lost to follow-up within 12 weeks were excluded from the analysis. Results The study included 510 patients with 66 treatment failures with a median follow-up of 801 days. We did not find a statistically significant association between SAT and treatment failure (hazard ratio, 1.37; 95% CI, .79–2.39; P = .27). Subgroup analyses for joint, country cohort, and type of infection (early or late acute) did not show benefit for SAT. Secondary analysis of country cohorts showed a trend toward benefit for the US cohort (hazard ratio, 0.36; 95% CI, .11–1.15; P = .09), which also had the highest risk of treatment failure. Conclusions The utility of routine SAT as a strategy for enhancing DAIR's success in acute PJI remains uncertain. Our results suggest that SAT's benefits might be restricted to specific groups of patients, underscoring the need for randomized controlled trials. Identifying patients most likely to benefit from SAT should be a priority in future studies.

AimDebridement, antibiotics, and implant retention (DAIR) is a viable treatment option for acute periprosthetic joint infections (PJI). The landmark DATIPO trial of Bernard et al. concluded that six weeks is not non-inferior to 12-week antibiotic therapy for DAIR. However, it is unknown if suppressive antibiotic treatment (SAT) would improve patient outcomes. Therefore, our study aims to evaluate the utility of SAT after 12 weeks of therapy.MethodWe performed a retrospective study of patients with acute hip or knee PJI managed with DAIR at five institutions; in the U.S. (n=1), Netherlands (n=3), and Spain (n=1) from 2005–2020. We analyzed the effect of SAT using a Cox model among patients after 12 weeks of antibiotic treatment. The primary covariate of interest was whether the patient was on antibiotics after week 12, which was coded as a time-varying covariate. We decided a-priori to control for the clinically important risk factors such as age, sex, type of infection, modular exchange, joint, and presence of bacteremia and Staphylococcus aureus. We excluded patients who died, had treatment failure, or were lost to follow-up before 12 weeks. We defined treatment failure as infection recurrence (same or different organism), unexpected reoperation, or death due to infection.ResultsThere were 504 patients included in the study. The majority were female (58%, n=292), with a mean age of 70 years ago (SD 11). Hips and knees were equally proportioned. Primary arthroplasties represented 69% of the total cohort (n=349). Treatment failure was 11.9% in the total cohort (n=60). There was no statistically significant association between SAT after 12 weeks and treatment failure (HR 1.25, p=0.45, 95% CI 0.70–2.24). This finding was consistent across different subgroups, including hip or knee joints, early or late acute infections, cohort, and a subgroup of knee joints after 180 days.ConclusionsSAT after 12 weeks of antibiotic treatment for acute PJI managed with DAIR does not appear to improve patient outcomes.

Abstract Background Cutibacterium species are common pathogens in periprosthetic joint infections (PJI). These infections are often treated with β-lactams or clindamycin as monotherapy, or in combination with rifampin. Clinical evidence supporting the value of adding rifampin for treatment of Cutibacterium PJI is lacking. Methods In this multicenter retrospective study, we evaluated patients with Cutibacterium PJI and a minimal follow-up of 12 months. The primary endpoint was clinical success, defined by the absence of infection relapse or new infection. We used Fisher’s exact tests and Cox proportional hazards models to analyze the effect of rifampin and other factors on clinical success after PJI. Results We included 187 patients (72.2% male, median age 67 years) with a median follow-up of 36 months. The surgical intervention was a 2-stage exchange in 95 (50.8%), 1-stage exchange in 51 (27.3%), debridement and implant retention (DAIR) in 34 (18.2%), and explantation without reimplantation in 7 (3.7%) patients. Rifampin was included in the antibiotic regimen in 81 (43.3%) cases. Infection relapse occurred in 28 (15.0%), and new infection in 13 (7.0%) cases. In the time-to-event analysis, DAIR (adjusted hazard ratio [HR] = 2.15, P = .03) and antibiotic treatment over 6 weeks (adjusted HR = 0.29, P = .0002) significantly influenced treatment failure. We observed a tentative evidence for a beneficial effect of adding rifampin to the antibiotic treatment—though not statistically significant for treatment failure (adjusted HR = 0.5, P = .07) and not for relapses (adjusted HR = 0.5, P = .10). Conclusions We conclude that a rifampin combination is not markedly superior in Cutibacterium PJI, but a dedicated prospective multicenter study is needed.