Vancomycin and Tobramycin Powder Use in Acute Open Fractures

Description

Open limb fractures are severe orthopedic injuries and at an increased risk for complications including nonunion and infection. Rates of infection are dependent upon features such as extent of soft tissue trauma, patient characteristics, degree of contamination and modifiable factors such as time to surgical debridement and IV (intravenous) antibiotics. Surgical debridement within 24 hours and IV antibiotics are the current standard of care, but despite advances in care, the infection rates for these injuries has remained stable over the last several decades.

Possible explanations for this stagnation in care may be related to the current standard of care and the pathophysiology of open fractures. There is significant soft-tissue damage in open fractures, which compromises local vasculature leading to devascularized soft tissue and bone. This devitalized tissue serves as a nidus for infection, a base for biofilm production and reduces the level of systemic antibiotics delivered to the zone of injury. Local antibiotic therapy has the potential to overcome these challenges, by allowing a high concentration of antibiotics to be delivered to the devitalized tissue. Additional benefits of local antibiotics are their powdered form, which is stable, easy to transport, and can be applied immediately in austere situations without the need for IV access. A recent randomized control trial found a 4% decrease risk of infection following powdered vancomycin placement at the time of hardware fixation. However, a recent meta-analysis showed nearly a 12% risk reduction in open fractures treated with local antibiotics when compared to the standard of care. However, this meta-analysis was predominantly made up of small retrospective studies, underlying the need for a randomized control trial evaluating the efficacy of local antibiotics in acute open fracture management.

While causative organisms vary with location, cultures from open fractures are positive 83% of the time. Cultures have shown high rates of colonization of both gram-positive organisms (predominantly Staphylococcus aureus and epidermidis) as well as gram-negative organisms (mostly Pseudomonaonas aeruginosa). Given this prevalence the antibiotics vancomycin and tobramycin are likely good candidates given that they have high efficacy against the common colonizing bacteria, are available in standardize powdered formula, reach high local concentrations, and have a minimal cytotoxic effect to local cells6. Using a combination of vancomycin and tobramycin in the acute care of severe open fractures may substantially decrease risks of infection from both gram-positive and gram-negative pathogens.