A Closer Look At Advances With NPWT

Author(s): 
Noah G. Oliver, DPM, Caitlin Garwood, DPM, Paul Kim, DPM, MS, FACFAS, and John S. Steinberg, DPM, FACFAS

Negative pressure wound therapy (NPWT) has been a proven technique for facilitating wound healing and the technology continues to evolve beyond the original negative pressure devices. These authors examine the efficacy of innovations in NPWT delivery, including NPWT with instillation.

Negative-pressure wound therapy (NPWT) has now been in use for decades as an effective adjunctive treatment of acute and chronic wounds. The primary benefits of NPWT are the promotion of wound healing and preparation of the wound bed for closure.    

Clinicians first applied subatmospheric or negative pressure to wounds with soft tissue damage in open fractures.1 Since then, physicians have successfully used the technology to prepare the wound bed for delayed closure, skin grafts or flap closure. Negative pressure has also emerged in many wound healing protocols as an adjunct or bolster for skin grafts, biologic alternative tissue substitutes and as a dressing over high-risk wound closures.2-8    

In 2011, Janis and colleagues described a modification of the reconstructive ladder that incorporated NPWT, stating that NPWT can be an adjunct to any other method of soft tissue reconstruction.9 They noted that NPWT may be especially useful for the common but problematic small wound with poorly vascularized tissue at its base. This includes wounds with exposed bone or tendon, which would have traditionally required a flap for closure.    

Proposed benefits of NPWT include less frequent dressing changes and reducing exposure of the wound to contamination. In addition, NPWT offers possible economic value to the healthcare system through reduced infection rates, fewer hospital stays and fewer trips to the operating room.10-11

How NPWT Can Facilitate Diabetic Limb Salvage

The innovation of NPWT has both revolutionized and simplified the treatment of complex lower extremity wounds, including chronic wounds in patients with diabetes.6,8,12    

In 2013, the Cochrane Review published an analysis of the literature on NPWT for treating foot wounds in people with diabetes mellitus.12 It identified five randomized controlled trials with a total of 605 patients and focused on two studies comparing NPWT with standard moist wound dressings. The authors concluded that there is some evidence that NPWT is more effective than moist wound dressings in patients with diabetes but cautioned that these findings are uncertain due to the possible risk of bias in these studies.    

The first of these notable studies compared NPWT to standard moist wound care after partial foot amputation.6 Seventy-seven wounds received NPWT and 85 received moist dressings until healing or completion of the 112-day treatment phase. Researchers found that more patients healed in the NPWT group (56 percent) in comparison to the control group (39 percent). The rate of wound healing was also faster in the NPWT group than in control patients. Importantly, NPWT patients were approximately 25 percent less likely than control patients to need a second amputation.6    

The second randomized control trial included 342 patients and found that a greater percent of foot ulcers achieved complete closure with NPWT (43 percent) than with advanced moist wound therapy (29 percent) within the 112-day active treatment phase.8 They found a greater decrease in ulcer area with NPWT (-4.32 cm2) versus advanced moist wound therapy (-2.53 cm2) from baseline on day 28. Additionally, Kaplan-Meier median estimates for 76–100 percent granulation tissue formation were 56 days for NPWT and 114 days for advanced moist wound therapy.

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