Nelson, Sandra B.

Abstract Background Postoperative spinal implant infections (PSIIs) are a serious complication of instrumented spinal fusion. Although debridement with implant retention is standard for early infection, the optimal duration of antimicrobial therapy remains uncertain. Methods We conducted a multicenter retrospective cohort study across 10 US academic centers, including adults with early PSII (≤90 days after fusion surgery) from 2017 to 2021. We excluded patients who experienced treatment failure within 6 weeks of debridement. The primary outcome was treatment failure. Antibiotic therapy effect was analyzed as a time-varying exposure using adjusted Cox proportional hazards models. Secondary analyses included 12-week landmark and clone-censor-weighted models to compare durations ≤ 12 weeks versus >12 weeks. Results A total of 116 patients out of 499 (23.2%) experienced treatment failure during a median follow-up of 3.2 years. Among patients who remain failure-free 6 weeks from debridement, being on antibiotics was not associated with treatment failure (adjusted hazard ratio [aHR] 0.71; 95% CI .48–1.07; P = .10). In a 12-week landmark analysis limited to 359 patients who were not on indefinite suppressive antibiotic therapy, treatment durations > 12 weeks did not significantly reduce the risk of failure (aHR 1.01; 95% CI .62–1.64; P = .99). Results were consistent in the clone-censor-weight sensitivity analysis (aHR 0.85; 95% CI .62–1.16; P = .30). Conclusions Prolonged antibiotic therapy was not associated with improved outcomes in early PSII managed with debridement and implant retention. These results support shorter, individualized antibiotic courses in patients with adequate surgical source control.

Abstract Background Spinal implant infections (SII) are serious complications following instrumented spinal fusion. Debridement with implant retention requires antibiotic therapy, yet the optimal duration remains unclear. We assessed whether longer antibiotic duration is associated with reduced risk of treatment failure. Methods We conducted a multicenter retrospective cohort study of adult patients diagnosed with acute postoperative SII (≤90 days from index surgery) between January 1, 2017, and December 31, 2022. All patients underwent debridement with implant retention. Treatment failure was defined as unplanned reoperation, clinical recurrence, or infection-related death. A Cox proportional hazards model assessed whether being on antibiotics was protective, treating antibiotic use as a time-dependent covariate, adjusting for relevant clinical variables, and including death not attributable to infection as a competing event. A second Cox model evaluated whether shorter antibiotic duration was associated with increased risk of failure with landmark analysis at six weeks. Results There were 531 patients included in the study. Patient demographics are described in Table 1. During a median follow-up of 1,168 days (IQR 576-1,817), 151 patients experienced treatment failure. There was a non-significant trend toward decreased hazard of failure while on antibiotics (HR 0.70; 95% CI 0.46–1.05; p=0.087). Among 363 patients without early failure, 60 (16.5%) received ≤6 weeks of antibiotics and 303 (83.5%) received >6 weeks. Longer antibiotic duration was not associated with a differential risk of failure (HR 0.75, 95% CI 0.43–1.33; p=0.34). Conclusion Continuing antibiotic therapy after debridement and implant retention may help reduce the risk of treatment failure in SII. However, it remains unclear whether extending antibiotic treatment beyond a certain duration continues to offer additional benefits. Prospective studies are needed to better define the optimal duration and approach to antibiotic therapy in these scenarios. Disclosures Sandra B. Nelson, MD, UpToDate Wolters Kluwer Health: Author, Editor

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.

SUMMARY Periprosthetic joint infection (PJI) is a significant complication of arthroplasty. Implicit in the diagnosis of PJI is the presence of organisms in what should be a sterile milieu. Given limits to culture-based PJI diagnosis, optimal utilization of culture in the diagnostic approach to PJI needs clarification. Culture is important in confirming a PJI diagnosis and characterizing the infecting microorganism(s) to inform management. As part of the development of a unified definition of PJI (by a group representing multiple scientific societies), a systematic review was performed to inform the role of culture in the definition of PJI. In addition, a comprehensive review on synovial fluid and periprosthetic tissue collection for culture, and associated culture methodology and results interpretation, was performed to inform best practices. Gaps in the literature were identified to develop research priorities.

Abstract Over the last several decades, periprosthetic joint infection (PJI) has been increasing in incidence and is occurring in more complex patients. While there have been advances in both surgical and medical treatment strategies, there remain important gaps in our understanding. Here, we share our current approaches to the diagnosis and management of PJI, focusing on frequent clinical challenges and collaborative interdisciplinary care. The more detailed review including diagnosis, surgical considerations, and a detailed antimicrobial discussion is presented in the online version.

Abstract Over the last several decades, periprosthetic joint infection has been increasing in incidence and is occurring in more complex patients. While there have been advances in both surgical and medical treatment strategies, there remain important gaps in our understanding. Here, we share our current approaches to the diagnosis and management of periprosthetic joint infection, focusing on frequent clinical challenges and collaborative interdisciplinary care.