Effect of bone biopsy in guiding antimicrobial therapy for osteomyelitis complicating open wounds

Background: Osteomyelitis associated with infected overlying wounds represe nts a difficult diagnostic and therapeutic problem; bone biopsies can be do ne during debridement of the overlying wounds, but it is unclear how often the results of these bone cultures actually affect subsequent antibiotic de cisions. The present study was undertaken to evaluate the usefulness of bon e biopsies in guiding antibiotic therapy for this type of osteomyelitis. Me thods: Culture results of 44 bone biopsies taken during surgical debridemen t in 41 patients over the period from lune 1994 to August 1998 were compare d with those from the overlying wounds to determine whether the data affect ed the subsequent choice of antibiotics. The study design was that of a ret rospective chart review in which the standard operative and microbiological procedures in place at the Milwaukee Veterans Affairs Medical Center were used. Results: Sixty-one wound and 55 bone isolates were obtained during th is study. Thirty-one isolates were found in bone, but not the overlying wou nd; diphtheroids were the most common organism obtained in this fashion. Co rrelation between wound and bone isolates was generally poor. Antibiotics w ere subsequently changed in 20 of the 44 cases after results of the bone bi opsy became known, with the bone isolates already being covered in 10 cases and the bone biopsy results ignored in 14 cases. Conclusion: Because bone biopsy results seem to aid in tailoring antibiotic therapy in almost half t he cases when bone is sampled during wound debridement surgery, this techni que may be very helpful in certain cases and should be regularly undertaken when these procedures are carried out.