The utility of deep soft-tissue cultures in diagnosing the causative agent of sternal osteomyelitis following median sternotomy

Background: The authors' goal was to determine whether the bacteria cultured from the mediastinal deep soft tissues matched those identified by the sternal bone cultures in cases of mediastinitis with clinically suspected sternal osteomyelitis, in hopes of eliminating the need for sternal bone biopsy. Methods: The authors retrospectively reviewed the charts of 27 Detroit Medical Center patients who underwent median sternotomy and developed mediastinitis with clinical suspicion of osteomyelitis between 1996 and 2004. Results: Although only 18 of 27 of the authors' patients had positive bone cultures, they demonstrate that in 94 percent (17 of 18) of these patients, the organisms cultured from the mediastinal deep soft-tissue cultures matched those cultured from the positive sternal bone cultures. Conclusions: With the results obtained from this study, the authors hope to promote a less-invasive means of investigating osteomyelitis in sternal wounds, to prevent the complications associated with obtaining a bone biopsy specimen in a contaminated soft-tissue setting. Instead, the authors suggest thoracic computed tomographic scanning as a noninvasive means of clinically demonstrating osteomyelitis of the sternum, and culture of the deep soft tissues of the mediastinum at the time of mediastinal debridement to determine the offending organism, if osteomyelitis is suggested by computed tomographic scan.