Use of gentamicin-collagen sponges in closure of sternal wounds in cardiothoracic surgery to reduce wound infections

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: Are antibiotic implants like gentamicin-collagen implants useful in preventing sternal wound infections (SWIs)? Altogether, more than 484 papers were found using the reported search; of these, 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that most randomized controlled trials (RCTs) have been performed with gentamicin-collagen sponges for sternal closure. Two out of four RCTs showed a significant benefit of the implant in a reduction in superficial and deep SWIs in routine and emergency cardiac surgery. One RCT showed a significant reduction in superficial infections in 2005, a follow-up trial by the same group in 2009 showed a reduction in deep infections as well. Another group has shown a reduction in deep and superficial SWI with gentamicin implant, in an RCT on 800 patients, however have not published details of the complete trial. The third trial on 542 patients showed no benefit of the implant, but was not adequately powered. However, the most recent multicentre RCT conducted on 1052 patients showed no benefit of gentamicin-collagen sponges in elective surgery (coronary artery bypass grafting and/or valve surgery) in high-risk patients with diabetes, obesity or both. Concerns were raised that gentamicin sponges dipped in saline 1-2 s prior to application may have lost the gentamicin into the saline, thereby reducing their efficacy and that some surgeons may have been unfamiliar with wound closure with sponges. However, these were robustly refuted by the authors. One RCT showed that gentamicin sponges may cause increased sternal rebleeding if used in double layers. Coagulase-negative staphylococci were predominantly isolated from infected wounds in all the trials except the one from USA, where infections were polymicrobial. Gentamicin resistance among common pathogens causing SWIs can vary from 15 to 80%. Gentamicin-collagen is unlikely to reduce SWIs in high-risk patients and polymicrobial infections.