Time to surgery and skin preparation as prevention techniques to control microbial infections in patients with proximal humeral fracture surgically treated.

Objectives. Proximal humeral fractures (PHF) are common, particularly in the elderly. Non-displaced PHF can be treated conservatively; displaced ones are often treated surgically. Surgical site infections (SSI) following surgery treatment are a devastating complication for patients and a costly one for patients, surgeons and hospitals. To reduce the incidence of post-operative infection in PHF patients is essential to know the risk factors for the occurrence of such complication. Since the delay of surgery and pre-operative skin preparation are potentially important risk factors in deep microbial infection development after PHF, the effect of these variables on skin microbial flora at the level of the surgical site was evaluated. Methods. After the fracture was diagnosed, the first skin culture swab (day 0 swab) was taken from the area of the deltopectoral approach of each PHF patients. To determine the role of the delay to surgery on bacterial type and load at the level of the surgical site, a group of 19 patients were subjected to the second swab collection the day after the fracture (day 1 swab) and to the third swab collection at the planned day of surgery (day 5 swab). To figure out if pre-operative washing with a single (povidone-iodine) or double (chlorhexidine-gluconate solution and povidone-iodine) skin preparation could significantly reduce the bacterial load at the surgical site, for another group of 20 patients at the planned day of surgery a second skin swab was taken (surgery day swab) before starting the skin preparation. After the skin preparation was performed, a third culture swab was taken from single disinfection area and from double disinfection area. The swabs were processed for qualitative and quantitative microbiological analysis by cultural techniques to define aerobic/anaerobic bacteria presence at surgical site. The results were analyzed by descriptive statistics and tested by paired T-Student. Results. The delay of surgery influences the skin microbial colonization in the deltopectoral approach: an exponential raise of the bacterial load was observed after 5 days from trauma for all isolates, including Staphylococcus aureus, coagulase negative staphylococci and Propionibacterium acnes, bacteria usually involved in orthopaedic SSI (Figure 1A). Furthermore, either single or double skin preparation is efficacious in reducing the bacterial load (Figure 1B), with a marked significant effect exerted by the double skin preparation (chlorhexidine-gluconate solution plus povidone-iodine). Conclusions. Since prevention of SSI may substantially decrease morbidity and mortality, improve patient outcomes and reduce the economic burden to the health care system, it is mandatory to control the pathogen source represented by the native flora of the PHF patient skin. We suggested that newer infection prevention techniques, such as reduced delay time to surgery and skin preparation combining chlorhexidine-gluconate solution and povidone-iodine, may help to reduce the infection rate.