Antibiotic Duration and Suppressive Antimicrobial Therapy After DAIR for Early Postoperative Spinal Implant Infection in Adults: A Systematic Review and Meta-Analysis

Background/Objectives: The optimal duration of systemic antibiotic therapy and the role of suppressive antibiotic therapy (SAT) after debridement, antibiotics and implant retention (DAIR) for early postoperative spinal implant infection remain uncertain. Methods: PubMed and Europe PMC were searched through 27 September 2026 for studies with at least ten identifiable adult retained-implant cases, duration or suppression data and a post-discharge infection-control outcome. Risk of bias was assessed with the JBI checklist and ROBINS-I; treatment failure was pooled with random-effects models and explored in subgroup, sensitivity, meta-regression and within-study analyses. Results: Fifty-three of 9199 records were eligible. Pooled treatment failure in 39 retained-implant cohorts (2114 patients) was 12.2% (95% confidence interval 9.5–15.6%; prediction interval 3.9–32.2%; I2 = 64%; 7.7% with a generalized linear mixed model) and varied with the endpoint used. Pooled failure was lowest in cohorts treated for six weeks or less, but this between-study contrast is observational and susceptible to confounding by indication, and within-study comparisons of shorter versus longer courses were imprecise (pooled odds ratio 1.52, 0.71–3.26; adjusted hazard ratio 1.05, 0.67–1.65). Most studies were at moderate or high risk of bias. Conclusions: The available observational evidence, which is imprecise and at moderate to high risk of bias, does not demonstrate a benefit from courses beyond six weeks or from routine suppression, nor does it establish that shorter courses are equivalent. A planned six-week course after prompt debridement may be a reasonable option for selected patients with susceptible pathogens and adequate source control.