Retrosternal gentamicin-collagen sponge does not reduce the incidence of mediastinitis in cardiac surgery

Objective: The reduction of poststernotomy mediastinitis (PSM) remains a challenge for cardiac surgery. This prospective cohort study was conducted to evaluate the effect of implantable gentamicin – collagen sponge (Genta Coll® resorb) used retrosternal on the incidence of mediastinitis after cardiac surgical procedures via median sternotomy.

Methods: Between September 2011 and June 2012 a total of 1227 consecutive patients (72% male, 28% female) underwent elective cardiac surgery using median sternotomy in Dresden Heart Center. The study group was divided in two cohorts. In treatment cohort (602 patients), a gentamicin – collagen sponge (5 × 20 cm) was implanted retrosternal before closing sternotomy. In control cohort (625 patients) the sponge was not used. Primary endpoint was freedom from mediastinitis according to CDC criteria on the 30^th postoperative day. Secondary endpoint was freedom from surgical site infection (SSI) of any kind.

Results: Both cohorts were matched in baseline characteristics as well as known risk factors. Incidence of PSM was 1.7% in the treatment cohort and 1.9% in the control cohort and was not significantly different. Secondary endpoint was also without significant difference between the cohorts. Most common isolated pathogens as cause of PSM were Gram-positive species – S. aureus and S. epidermidis (7 patients in treatment cohort, 11 patients in control cohort) compared with 3 Gram-negative infections in each cohort. No MRSA was isolated as cause of mediastinitis.

Conclusion: Retrosternal use of gentamicin- collagen sponge Genta Coll® resorb exerts no influence on incidence of mediastinitis in elective adult cardiac surgery with median sternotomy.