Tailored infection bundle sharply reduced surgical site infections after instrumented spinal surgery
Instrumented spinal surgery carries a stubborn infection burden because implants, longer operative times, and deeper tissue planes create an environment where bacteria can persist and biofilm can form. In this prospective single-center evaluation from Galliera Hospital in Genoa, a team-developed surgical site infection prevention bundle was associated with a marked drop in infections after June 2024, when the protocol was introduced following structured operating-room observations.
The bundle was built around five concrete steps: skin preparation, hair removal, timely cefazolin prophylaxis, alcohol-based chlorhexidine antisepsis, and perioperative glycaemic control below 180 mg/dL in both diabetic and non-diabetic patients. Each element targets a different point in the chain of contamination. Skin antisepsis reduces microbial burden at the incision site, antibiotic timing improves tissue concentrations during the highest-risk window, and glucose control blunts the immune dysfunction that follows perioperative hyperglycaemia. In implant surgery, those mechanisms matter because once organisms attach to hardware, eradication becomes far more difficult.
The pre-bundle period ran for 18 months and included 203 surgeries. The post-bundle phase covered 13 months and included 142 surgeries. During those periods, SSI incidence fell from 11.33% to 2.82%. The reported incidence rate ratio was 4.02, with a 95% confidence interval of 1.37 to 16.00 and a p value of 0.0065. In practical terms, the infection rate dropped substantially after the bundled measures were adopted.
The time-series analysis told a more cautious story. Interrupted time-series modeling estimated an immediate reduction of about 78%, with an IRR of 0.22 and a 95% confidence interval of 0.05 to 1.02. The point estimate was large, but the confidence interval crossed the null, so the statistical signal was not definitive. The post-intervention trend also remained uncertain, limiting claims about how durable the effect would be over time. A sharp early drop is visible; long-term persistence is not yet settled.
Why the bundle may have worked at the bedside
Surgical infection prevention rarely depends on one intervention alone in high-risk orthopaedic and spine procedures. The physiology is layered. A clean incision is not enough if the antibiotic arrives too late, if skin flora remain abundant after preparation, or if intraoperative glucose rises high enough to impair neutrophil function. In spine surgery with instrumentation, even a small inoculum can become clinically important once foreign material is present. The bundle addressed those vulnerabilities at several points in the perioperative pathway rather than relying on a single defensive step.
The study design also strengthens the case for implementation. Structured observations in the operating room preceded the bundle, suggesting the protocol was not abstract policy but a response to observed practice gaps. Team agreement is important in this setting because infection prevention depends on coordinated behavior across surgeons, anesthesia, nursing, infection control, and operating-room staff. A protocol that is understood and accepted by the whole team is more likely to be applied consistently than a rule that exists only on paper.
Reoperations and costs moved in the same direction
The clinical effect extended beyond infection counts. Reoperations fell from 15 before the bundle to 3 after it, representing a 70% reduction versus expected. In spine surgery, each avoidable reoperation can mean additional anesthesia exposure, prolonged recovery, greater pain, and a harder rehabilitation course. Hardware-associated infection often forces surgeons into a cycle of debridement, repeat hospitalization, and prolonged antimicrobial treatment, so fewer reoperations represent a meaningful operational and patient-level gain.
Economic consequences were equally concrete. The estimated net savings reached €140,815. Those savings likely reflect fewer readmissions, fewer repeat procedures, and less downstream resource use tied to infection management. For hospitals performing instrumented spinal surgery, that kind of reduction is not just an accounting exercise. It can alter bed turnover, operating-room demand, and the strain placed on infection control services.
What the numbers can and cannot prove
The findings are encouraging, but this remains a before-and-after analysis from a tertiary care center, not a randomized trial. Temporal improvements in perioperative practice, changes in case mix, or other unmeasured shifts in care could have contributed to the observed decline. The authors compared pre-bundle and post-bundle periods with interrupted time-series analysis to reduce some of that bias, yet the post-intervention trend still carried uncertainty. The estimate of an immediate benefit is compelling, but the design does not fully isolate the bundle from other real-world changes happening over the same period.
No external funding supported the work, and the program was built entirely within a local hospital system. That makes the intervention more relevant to routine clinical practice, where infection prevention efforts often have to be assembled from existing staff, local audit data, and practical workflow changes rather than expensive technology. It also means the bundle reflects a hospital culture capable of translating surveillance into action, which is often the hardest part of infection prevention.
Instrumented spinal surgery has a narrow margin for error. When infection falls, the entire care pathway feels it: fewer returns to the operating room, fewer rehospitalizations, and less collateral harm from prolonged recovery. The open question is not whether bundled prevention can work in principle, but how reliably similar programs perform across other centers, different case mixes, and longer follow-up periods.
Local surveillance turned into a measurable infection-control gain
The most useful aspect of this study is its operational clarity. The bundle did not introduce a vague quality-improvement slogan; it focused on elements clinicians already recognize as decisive in surgical infection prevention. Hair removal, skin antisepsis, antibiotic timing, and glycaemic control are familiar tools, but the study shows the benefit of treating them as a coordinated sequence rather than isolated tasks.
For spinal teams, the takeaway is straightforward: infection prevention in instrumented cases can be improved when perioperative behavior is standardized and audited. The size of the observed reduction supports clinical relevance, even though the interrupted time-series estimate did not achieve statistical significance. Future multicenter follow-up will need to test whether the same bundle retains its effect when applied beyond a single institution and whether the early drop in infection can be sustained over longer observation windows.