Comparative study between Negative Pressure Wound Therapy (NPWT) and Standard Moist Wound Dressing (SMWD) in management of diabetic non ischemic foot ulcers

Abstract

Background and Aims: Diabetes is rapidly increasing in prevalence worldwide and surgery in patients with diabetic foot is becoming more common. Foot complications are a major cause of admissions in diabetic patients, and comprise a disproportionately high number of hospital days because of multiple surgical procedures and prolonged length of stay in hospital. Diabetic foot is an umbrella term for foot problems in patients with diabetes mellitus. Foot disorders such as ulceration, infection and gangrene are the most common, complex and costly sequelae of diabetes mellitus. The optimal therapy for diabetic foot ulcers remains ill-defined. Saline-moistened gauze has been the standard method; however, it has been difficult to continuously maintain a moist wound environment with these dressings. This has led to the development of various hydrocolloid wound gels, which provided more consistent moisture retention. Refinements in topical ointments have resulted in the addition of various pharmacological agents including growth factors and enzymatic debridement compounds. Hyperbaric oxygen therapy and culture skin substitutes are other wound therapies that have been advocated. All these therapies are associated with significant expense and are being utilized in some situations without sufficient scientific evidence demonstrating their efficacy. Therefore, the search for an efficacious, convenient and cost-effective therapy continues. Negative Pressure Wound Therapy (NPWT) is a newer noninvasive adjunctive therapy system that uses controlled negative pressure using Vacuum-Assisted Closure device (VAC) to help promote wound healing by removing fluid from open wounds through a sealed dressing and tubing which is connected to a collection container. The use of sub-atmospheric pressure dressings, available commercially as a VAC device, has been shown to be an effective way to accelerate healing of various wounds. This was aimed to compare wound outcome, limb salvage, and cost effectiveness between Negative pressure wound therapy (NPWT) and Standard moist wound therapy (SMWT) in management of diabetic non ischemic foot ulcers. Methods: we performed a cohort study involving 30 patients with active diabetic foot ulcers, in a high volume tertiary referral vascular center. They were divided into 2 groups: 15 patients (group A) were prescribed NPWT and the other 15 patients (group B) received SMWD. During follow up visits, progress of healing was evaluated and documented in the form of change in wound diameter, depth, up or down scaling along UTWC, wound status at 2, 4, 8, and 12 weeks and 4 weekly thereafter till complete epithelialization. Results: As regard to ulcer depth there were statistically significant difference between the 2 groups during follow up duration of the study after 4 weeks with group A showing faster decrease in ulcer depth than group B denoting faster formation of granulation tissue. As regard to complete granulation of ulcer there were statistically significant difference between the 2 groups during follow up duration of the study markedly shown after 6 weeks with group A showing complete ulcer granulation faster than group B, with statistically significant difference as regard to number of days on dressing and follow up duration in weeks between the 2 groups with group A showing lesser number of days on dressing and shorter follow up duration in weeks than group B. Conclusion: NPWT has a definitive role in promotion of proliferation of granulation tissue, reduction in the wound size, by and rapid clearing of bacterial load. Our data demonstrates that negative pressure wound dressings decrease the wound size more effectively than saline gauze dressings over the first 4 weeks of therapy. It is suggested that NPWT is a cost-effective, easy to use and patient-friendly method of treating diabetic foot ulcers which helps in early closure of wounds, preventing complications and hence promising a better outcome.