Vacuum-assisted closure has become a new technique in the challenging management of contaminated, acute, and chronic
wounds. Although promising clinical results have been described, scientific proof to substantiate the mechanism of action of this
therapy is scarce. In the present study, we examined whether the positive effect on wound healing found in
vacuum-assisted closure-treated
wounds could be explained by an effect on the bacterial load. Fifty-four patients who needed open
wound management before surgical closure were included in this study.
Wounds were randomized to either
vacuum-assisted closure therapy (n= 29) or treatment by conventional moist gauze
therapy (n= 25). Healing was characterized by development of a clean granulating
wound bed ("ready for surgical
therapy") and reduction of
wound surface area. To quantify bacterial load, biopsies were collected. No significant difference was found in time needed to reach "ready for surgical
therapy" comparing both
therapies.
Wound surface area reduction was significantly larger in
vacuum-assisted closure-treated
wounds: 3.8 +/- 0.5 percent/day (mean +/- SEM) compared to conventional-treated
wounds (1.7 +/- 0.6 percent/day; p < 0.05). The total quantitative bacterial load was generally stable in both
therapies. However, nonfermentative gram negative bacilli showed a significant decrease in
vacuum-assisted closure-treated
wounds (p < 0.05), whereas Staphylococcus aureus showed a significant increase in
vacuum-assisted closure-treated
wounds (p < 0.05). In conclusion, this study shows a positive effect of
vacuum-assisted closure therapy on wound healing, expressed as a significant reduction of
wound surface area. However, this could not be explained by a significant quantitative reduction of the bacterial load.