Vacuum-Assisted Closure Therapy for the Treatment of Skin and Soft-Tissue Infections. Are Wound Specimens of Use in Planning Secondary Wound Closure?

Aim: Vacuum-assisted closure is used frequently for the treatment of skin and soft-tissue infections (SSTI) of the extremities. After debridement and repeated VAC dressing changes, the wounds are closed by secondary suture, split-thickness skin grafts or local flaps. However, no objective parameters describe the time point for secondary wound closure. Our thesis was that negative microbiological results from wound specimens can indicate the time for secondary wound closure. Patients and Methods: 24 patients with SSTI of the extremities were treated by serial debridements and VAC therapy and analysed prospectively. Debridements were repeated until the wounds were macroscopically free from signs of infection (good granulation/no necrosis). During each revision specimens were taken for microbiological analysis. Moreover, number of revisions, bacterial cultures, type of wound closure and wound status after 3 years and 5 months on average after the last surgery were analysed. Results: 6.3 revisions on average were performed until secondary wound closure was possible. In spite of the absence of macroscopic infection, bacteria were still found in tissue samples from 14 of 24 wounds. 6 wounds were free of bacteria for the first time right before wound closure, 3 wounds had become negative during the treatment. After 3.4 years on average, the wounds of all 18 patients available for examination had healed well and were free from signs of infection. Conclusion: Vacuum-assisted closure resulted in clean, good granulating wounds without necrosis. However, in more than half of the wounds bacteria persisted. This bacterial load had no correlation to wound healing and outcome after over 3 years. In conclusion, microbiological tissue samples are not suitable as indicator for the time point of secondary wound closure in SSTI.