Negative pressure wound therapy reduces the effectiveness of traditional local antibiotic depot in a large complex musculoskeletal wound animal model

OBJECTIVES: Negative pressure wound therapy (NPWT) has been used to help manage open wounds. Surgeons also often use local antibiotic depot as adjunctive therapy in an effort to reduce infection rates. These 2 techniques have been reported to be used in conjunction, but there are little data to support this practice. We sought to compare the contamination levels of wounds treated with the commonly used antibiotic bead pouch technique to wounds that received both antibiotic beads and NWPT. METHODS: The effectiveness of a bead pouch was compared with antibiotic beads with NPWT. The anterior compartment and proximal tibia of goats were injured and inoculated with Staphylococcus aureus. Six hours later, the wounds were debrided and the animals were assigned to a group; the bacteria level was quantified immediately before and after initial debridement and 2 days after treatment. RESULTS: The wounds in the antibiotic bead pouch group had 6-fold less bacteria than the augmented NPWT group, 11 ± 2% versus 67 ± 11% of baseline values, respectively (P = 0.01). As expected, high levels of the antibiotic were consistently recovered from the augmented NPWT effluent samples at all time points. CONCLUSIONS: NPWT reduces the effectiveness of local antibiotic depot. These results can provide surgeons with the information to personalize the adjunctive therapies to individual patients, with the degree of difficulty in managing the wound and concern for infection being the 2 variables dictating treatment.