Negative Pressure Wound Therapy Patients Research Articles

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.

Negative Pressure Wound Therapy After Severe Open Fractures: A Prospective Randomized Study

To evaluate the impact of negative pressure wound therapy (NPWT) after severe open fractures on deep infection. Prospective randomized study. Academic level I trauma center. Fifty-nine patients with 63 severe high-energy open fractures were enrolled in this study, with data available on 58 patients with 62 open fractures. Twenty-three patients with 25 fractures randomized to the control group and underwent initial irrigation and debridement followed by standard fine mesh gauze dressing, with repeat irrigation and debridement every 48-72 hours until wound closure. Thirty-five patients randomized to the NPWT group and had identical treatment except that NPWT was applied to the wounds between irrigation and debridement procedures until closure. The presence or absence of deep wound infection or osteomyelitis, wound dehiscence, and fracture union were primary outcome measures. Control patients developed 2 acute infections (8%) and 5 delayed infections (20%), for a total of 7 deep infections (28%), whereas NPWT patients developed 0 acute infections, 2 delayed infections (5.4%), for a total of 2 deep infections (5.4%). There is a significant difference between the groups for total infections (P = 0.024). The relative risk ratio is 0.199 (95% confidence interval: 0.045-0.874), suggesting that patients treated with NPWT were only one-fifth as likely to have an infection compared with patients randomized to the control group. NPWT represents a promising new therapy for severe open fractures after high-energy trauma.

Comparison of Negative Pressure Wound Therapy Using Vacuum-Assisted Closure With Advanced Moist Wound Therapy in the Treatment of Diabetic Foot Ulcers

The purpose of this study was to evaluate safety and clinical efficacy of negative pressure wound therapy (NPWT) compared with advanced moist wound therapy (AMWT) to treat foot ulcers in diabetic patients. This multicenter randomized controlled trial enrolled 342 patients with a mean age of 58 years; 79% were male. Complete ulcer closure was defined as skin closure (100% reepithelization) without drainage or dressing requirements. Patients were randomly assigned to either NPWT (vacuum-assisted closure) or AMWT (predominately hydrogels and alginates) and received standard off-loading therapy as needed. The trial evaluated treatment until day 112 or ulcer closure by any means. Patients whose wounds achieved ulcer closure were followed at 3 and 9 months. Each study visit included closure assessment by wound examination and tracings. A greater proportion of foot ulcers achieved complete ulcer closure with NPWT (73 of 169, 43.2%) than with AMWT (48 of 166, 28.9%) within the 112-day active treatment phase (P = 0.007). The Kaplan-Meier median estimate for 100% ulcer closure was 96 days (95% CI 75.0-114.0) for NPWT and not determinable for AMWT (P = 0.001). NPWT patients experienced significantly (P = 0.035) fewer secondary amputations. The proportion of home care therapy days to total therapy days for NPWT was 9,471 of 10,579 (89.5%) and 12,210 of 12,810 (95.3%) for AMWT. In assessing safety, no significant difference between the groups was observed in treatment-related complications such as infection, cellulitis, and osteomyelitis at 6 months. NPWT appears to be as safe as and more efficacious than AMWT for the treatment of diabetic foot ulcers.