Evaluation of a tailored surgical site infection prevention bundle in instrumented spinal surgery using interrupted time series analysis

Surgical site infections (SSIs) are a major complication of instrumented spinal surgery, with incidence up to 16%. Although care bundles reduce SSIs across surgical specialties, prospective evidence in spinal surgery is limited. We conducted prospective surveillance (January 2023 – June 2025) in a tertiary care center. In June 2024 following structured operating room observations, we implemented a team-agreed five-component bundle covering skin preparation, hair removal, timely cefazolin prophylaxis, alcohol-based chlorhexidine antisepsis, and perioperative glycaemic control (<180 mg/dL) in diabetic and non-diabetic patients. Pre-bundle and post-bundle periods were compared. Primary outcome was SSI incidence assessed by interrupted time-series (ITS) analysis. Secondary outcomes included reoperations, re-hospitalizations, and healthcare costs savings. The pre-bundle period (18 months) included 203 surgeries, while the post-bundle phase (13 months) included 142 surgeries. SSI incidence decreased from 11.33% to 2.82%. (IRR 4.02; 95% CI 1.37–16.00; p=0.0065). ITS analysis estimated an immediate reduction of approximately 78% (​IRR 0.22, 95% CI 0.05–1.02), although the confidence interval included the null; uncertainty in the post-intervention trend precluded conclusions about durability.. Reoperations fell from 15 to 3 (70% reduction vs expected). Net estimated cost savings were €140,815. A tailored, team-developed SSI prevention bundle was associated with a large reduction in SSI incidence, reoperations, and healthcare costs in instrumented spinal surgery. Although the ITS estimate did not reach statistical significance, the magnitude of the observed reduction supports the potential clinical relevance of this approach.