Use of NPWT with and without Soft Port technology in infected foot wounds undergoing partial diabetic foot amputation.

OBJECTIVE: Negative pressure wound therapy (NPWT) has previously been shown to be effective in closing diabetic foot wounds that have undergone amputation over a 16-week period. For patients with plantar foot wounds, NPWT is a key therapy. An alternative NPWT with and without a novel soft, flexible port system needs to be evaluated for its comparable efficacy. Our objective was to show the non-inferiority of an alternative negative pressure system, and in a small subset, a novel foam dressing system. METHOD: We performed a single centre prospective study of patients with diabetes undergoing open bone resection in the foot for acutely infected wounds. Wounds were treated with NPWT/soft port technology (SPT), for 112 days or until primary closure or the wound was deemed ready for delayed primary closure. Rate of closure and quality of life were analysed. A previously published cohort was used as a control. RESULTS: Of the 30 patients initially recruited, 29 met eligibility requirements and had NPWT applied a median of 2 days postoperatively. There were seven patients (24%) who had delayed primary closure (mean=58 days) and 52% had sufficient progress to change in treatment (15/29; mean=62 days). Only one patient reached the 112-day mark without sufficient progress to be closed. The primary method of delayed primary closure was split-thickness skin graft. There was a reduction in wound area 56.3% (initial mean area=17.4cm(2) to final mean area=7.6 cm(2); p=0.001) at the end of treatment (mean=58.7 days) reduced to 4.3cm(2) a 67.2% reduction (p=0.004) at the end of study (112 days). CONCLUSION: The alternative NPWT and the soft port technology was well tolerated and effective in the population in aggregate. There was no inferiority between the two technologies. The aggregate closure or progression to be ready for closure rate of 75% at 69 days compares very favourably with previously published data for NPWT in this population of 56% at 56 days (range: 26-92 days). Both cohorts did significantly better than previously published standard of care closure rates of 39% at 77 days. DECLARATION OF INTEREST: J.C. Lantis is a paid consultant for Smith & Nephew, Acelity, Macrocure and Manukamed. This trial as supported by an institutional grant to St Luke's and Roosevelt Hospital sponsored by Smith & Nephew. The outcome of the trial had no bearing on the condition of the grant. No investigator holds an equity position in Smith & Nephew. C. Gendics is a paid consultant of Acelity.

Surgical debridement alone does not adequately reduce planktonic bioburden in chronic lower extremity wounds.

OBJECTIVE: It is commonly believed that sharp surgical debridement provides adequate bacteria control for local wound beds, despite limited supporting scientific evidence. We undertook a prospective study to evaluate the reduction in planktonic bacteria pre- and post-operative debridement in critically colonised wounds. METHOD: Twelve patients, corresponding to 14 wounds, underwent debridement with either hydrodebridement or sharp steel debridement with pulse irrigation. Wound quantitative tissue cultures were taken pre- and post-debridement. There was no significant difference in wound aetiology or surface area between the two groups. RESULTS: TThe bacterial counts before debridement were 1×107 colony-forming units per gram (CFU/g) in the hydrodebridement group vs 1.4×107 CFU/g in the sharp debridement group; and 2.5×106 CFU/g (hydrodebridement) vs 7.5×105 CFU/g (sharp) after debridement (p=0.41). The total bacteria reduction was 7.5×106 CFU/g after hydrodebridement vs 1.3×107 CFU/g after sharp steel debridement (p=0.37). The mean percentage of bacteria killed from baseline was 75% by hydrodebridement and 93% killed by sharp debridement (p<0.05). CONCLUSION: Extensive operative debridement using either modality does not provide adequate immediate reduction in wound planktonic bioburden. However, all wounds appeared clinically appropriate for closure after debridement and postoperative antibacterial therapy. Postoperative antibacterial therapy may be imperative in cases of critically colonised wounds to achieve good outcomes. DECLARATION OF INTEREST: The senior author receives research grant support from Healthpoint Biotherapeutics; KCI; Manuka Honey; Smith & Nephew; Medline Ind., Macrocure; CODA. In addition the senior author is a consultant for: Smith & Nephew and KCI and medical consultant and reviewer for Macrocure. While the study as presented evaluates in part the efficacy of a commercial product from Smith & Nephew, no industry support for this study was sought or provided.

Negative Pressure Wound Therapy With Instillation (NPWTi) Better Reduces Post-debridement Bioburden in Chronically Infected Lower Extremity Wounds Than NPWT Alone.

OBJECTIVE: An overabundance of bacteria in the chronic wound plays a significant role in the decreased ability for primary closure. One means of decreasing the bioburden in a wound is to operatively debride the wound for wound bed optimization prior to application of other therapy, such as Negative Pressure Wound Therapy (NPWT). We undertook a prospective pilot study to assess the efficacy of wound bed preparation for a standard algorithm (sharp surgical debridement followed by NPWT) versus one employing sharp surgical debridement followed by Negative Pressure Wound Therapy with Instillation (NPWTi). METHODS: Thirteen patients, corresponding to 16 chronic lower leg and foot wounds were taken to the operating room for debridement. The patients were sequentially enrolled in 2 treatment groups: the first receiving treatment with operative debridement followed by 1 week of NPWT with the instillation of quarter strength bleach solution; the other receiving a standard algorithm consisting of operative debridement and 1 week of NPWT. Quantitative cultures were taken pre-operatively after sterile preparation and draping of the wound site (POD # 0, pre-op), post-operatively once debridement was completed (POD # 0, post-op), and on post-operative day 7 after operative debridement (POD # 7, post-op). RESULTS: After operative debridement (post-operative day 0) there was a mean of 3 (±1) types of bacteria per wound. The mean CFU/gram tissue culture was statistically greater - 3.7 × 10(6) (±4 × 10(6)) in the NPWTi group, while in the standard group (NPWT) the mean was 1.8 × 10(6) (±2.36 × 10(6)) CFU/gram tissue culture (p = 0.016); at the end of therapy there was no statistical difference between the two groups (p = 0.44). Wounds treated with NPWTi had a mean of 2.6 × 10(5) (±3 × 10(5)) CFU/gram of tissue culture while wounds treated with NPWT had a mean of 2.79 × 10(6) (±3.18 × 10(6)) CFU/gram of tissue culture (p = 0.43). The mean absolute reduction in bacteria for the NPWTi group was 10.6 × 10(6) bacteria per gram of tissue while there was a mean absolute increase in bacteria for the NPWT group of 28.7 × 10(6) bacteria per gram of tissue, therefore there was a statistically significant reduction in the absolute bioburden in those wounds treated with NPWTi (p = 0.016). CONCLUSION: It has long been realized that NPWT does not make its greatest impact by bioburden reduction. Other work has demonstrated that debridement alone does not reduce wound bioburden by more than 1 Log. Wounds treated with NPWTi (in this case with quarter strength bleach instillation solution) had a statistically significant reduction in bioburden, while wounds treated with NPWT had an increase in bioburden over the 7 days.