Negative pressure wound therapy using gauze and foam: histological, immunohistochemical and ultrasonography morphological analysis of the granulation tissue and scar tissue. Preliminary report of a clinical study.

Negative pressure wound therapy (NPWT) is becoming routine for the preparation of wounds prior to grafting for wound closure. We have been using both foam- and gauze-based NPWT to prepare wounds for closure prior to skin grafting and have obtained similar proportions of closed wounds; 7/7 for wounds treated with gauze-based NPWT and 11/11 for wounds treated with foam-based NPWT. In our follow-up consultations we observed that skin grafts on the foam-treated patients were less pliable than those on the gauze-treated patients. To assess what the mechanism of this effect might be, we compared the specific details of the treatments of both 11 foam and 7 gauze patients, including depth, location, patients' age and co-morbidity; biopsies of granulation and scar tissue were taken and stained with haematoxylin-eosin and by Masson's trichrome staining and conducted ultrasound analysis of the closed wounds, to see if there were features which explained those effects. All foam patients were treated at -125 mm Hg for an average of 25·9 days before skin grafts were applied. All gauze patients were treated at -80 mm Hg for an average of 24·7 days before skin grafts were applied. Biopsies of granulation tissue prior to skin grafting from five foam and four gauze-based NPWT patients did not reveal any obvious histological differences between the treatments. Ultrasound analysis of the skin-grafted wounds showed an average depth of scar tissue of 18 mm in the wound beds of the foam-treated wounds and 7 mm in the gauze-treated ones. Biopsies taken on the scar tissue after treatment with the gauze showed a minor tissue thickness and disorganisation and less sclerotic components. The findings of this preliminary analysis suggest that foam-based NPWT may induce a thicker layer of scar tissue beneath skin grafts than gauze-based NPWT which might explain a reduced pliability of the reconstructed bed. At present it is unclear which mechanism might be responsible for the difference in pressure (-125 versus -80 mm Hg), either the length of the time taken to reconstruct the wound bed or the intrinsic nature of the foam or gauze on the tissue surface. Prospective studies are necessary to investigate whether these preliminary observations are confirmed and to investigate what the mechanism might be.

Surgical debridement with VERSAJET: an analysis of bacteria load of the wound bed pre- and post-treatment and skin graft taken. A preliminary pilot study.

Surgical debridement, which is used for the removal of necrotic tissue from a wound, is becoming more and more important in the treatment of skin injuries. VERSAJET (VERSAJET™, Versajet Hydrosurgery System, Smith and Nephew, Hull, UK) is one of the techniques used for wound debridement. Medical literature does not present either analytical or comparative data correlating the bacterial load with the VERSAJET treatment. For this reason, we have decided to carry out a study to evaluate the level of bacterial contamination before and after the surgical debridement treatment with VERSAJET and, in connection with this, the correlation between the bacterial load and the successful healing of the skin graft. We took a total of 100 bacteriological swabs, 50 before and 50 from 27 selected patients after the treatment with VERSAJET, with which the wound bed was prepared to receive the skin graft or Integra graft in order to acquire data about the level of bacterial contamination. After analysing all those data we can assume that reducing the bacterial load is not the only variable which the successful healing of the skin graft depends on. In conclusion, there is still many data to analyse and study in order to better understand the qualitative and quantitative presence of bacteria and the success of this future surgical procedure. We remind that the performance of this study was not sponsored by any company.