Bacteria aerosol spread and wound bacteria reduction with different methods for wound debridement in an animal model.

Debridement is essential in wound treatment to remove necrotic tissue and wound bacteria but may lead to bacteria spread by aerosolization. This study investigated the wound bacterial reduction and bacterial transmission induced by debridement using curette, plasma-mediated bipolar radiofrequency ablation (Coblation®) or hydrodebridement (Versajet®). Full thickness dermal wounds in porcine joint specimens inoculated with S. aureus were debrided with curette, Coblation, Versajet, or were left untreated. During and after debridement, aerosolized bacteria were measured and to assess wound bacterial load, quantitative swab samples were taken from each wound. Only Coblation was able to reduce the bacterial load of the wound significantly. Versajet debridement resulted in a significant bacterial aerosolization, but this was not the case with Coblation and curette debridement. This study shows that Coblation is a promising wound debridement method, which effectively reduces the wound bed bacterial load without the risk of bacterial aerosolization.

Antimicrobial effects of plasma-mediated bipolar radiofrequency ablation on bacteria and fungi relevant for wound infection.

Infection constitutes an important part of wound pathology and impedes wound healing. Plasma-mediated bipolar radiofrequency ablation (Coblation(®)) is a tissue-removal technique suggested for use in wound treatment. The aims of this study were to determine the antimicrobial effect of ablation exposure on bacteria and fungi relevant to wound infection, and how exposure time, temperature and aerobic/anaerobic growth influence the effect. Suspensions of 10(6) colony-forming units/ml of Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli and Candida albicans were exposed to ablation or thermal control for 500, 1000 or 2000 ms, or left untreated, and incubated aerobically. E. coli was also incubated anaerobically. Ablation was significantly (p < 0.0001) microbicidal on all strains compared with untreated and thermal control. The reductions compared with untreated control were 99.87-99.99% for all strains. In conclusion, plasma-mediated bipolar radio-frequency ablation has a general microbicidal effect in vitro on microbes relevant to wound infection independent of aerobic/anaerobic growth and thermal effect.

Bipolar radiofrequency plasma ablation induces proliferation and alters cytokine expression in human articular cartilage chondrocytes.

PURPOSE: The aim of the study was to determine the in vitro effects of plasma-mediated bipolar radiofrequency ablation on human chondrocyte compensatory proliferation and inflammatory mediator expression. METHODS: Human articular cartilage biopsy specimens, from total knee replacement, and human chondrocytes in alginate culture, from patients undergoing autologous chondrocyte implantation, were exposed to plasma ablation with a Paragon T2 probe (ArthroCare, Austin, TX). Instantaneous chondrocyte death was investigated with live/dead assays of biopsy specimens and cell cultures. Chondrocyte proliferation was determined by Hoechst staining of DNA on days 3 and 6. Messenger RNA expression of IL-1ß, IL-6, IL-8, tumor necrosis factor α, high-mobility group protein B1, matrix metalloproteinase 13, type IIA collagen, and versican was determined on days 3 and 6. RESULTS: Live/dead imaging showed a well-defined local margin of cell death ranging from 150 to 200 µm deep, both in the alginate gel and in the biopsy specimens exposed to plasma ablation. The ablation-exposed group showed a significant proliferation increase compared with control on day 3 (P < .043). There were significant increases compared with control in IL-6 expression on day 3 (P < .020) and day 6 (P < .045) and in IL-8 expression on day 3 (P < .048). No differences were seen for IL-1ß, tumor necrosis factor α, high-mobility group protein B1, matrix metalloproteinase 13, type II collagen, or versican. CONCLUSIONS: This study has shown that exposure to plasma-mediated ablation induces a well-defined area of immediate cell death and a short-term increase in proliferation with human articular chondrocytes in vitro. The exposure also alters cytokine expression for the same period, causing upregulation of IL-6 and IL-8. CLINICAL RELEVANCE: The results show the potential of plasma-mediated ablation to cause the onset of a tissue regeneration response with human articular cartilage.