Abstract and Introduction
Abstract
Introduction: NPWT is a surgical dressing that combines polyurethane foam with the subsequent application of continuous or intermittent negative pressure. NPWT facilitates granulation tissue production by macrostrain, microstrain and, if desired, fluid instillation. Sealing the polyurethane foam over the wound bed is achieved using acrylic drapes; however, this can be difficult to use in some anatomic sites. Failure to achieve an effective seal can necessitate additional supplies, which has led to increased innovation in developing a more effective NPWT seal over the target wound bed. Obtaining an effective pressure seal on the feet or hands can be difficult because these anatomic sites have distinct curvature for each digit, with multiple interdigital web spaces and independent mobility. In this case report, the authors propose a technique to apply either an acrylic drape or combination acrylic and soft silicone drape utilizing the "sandwich technique" to seal NPWT foam quickly and efficiently to the feet or hands.
Introduction
NPWT has been widely used for more than 25 years, after Louis C. Argenta and Michael J. Morkywas invented the first NPWT device known as VAC in the mid-1990s.[1] The use of negative vacuum therapy can be traced back to the Roman era, when wounds sustained in battle were sucked directly by mouth to remove toxins. The use of 'cupping' is another technique developed in the 19th century to draw out fluid from a wound.[2] Since its creation, the NPWT device has been used on millions of patients globally and has been a major advancement in managing wounds of varying size and depth.[1–3]
The literature supports the use of NPWT in the treatment of pressure injuries, traumatic wounds, partial-thickness burn wounds, and diabetic foot wounds, and as a bolster dressing for split-thickness skin grafts.[3,4] Advantages of NPWT include visible contraction of wound edges (macrostrain), decreased wound edema, removal of bacterial load and proinflammatory mediators, angiogenesis, and improved tissue perfusion.[3–6]
Macrostrain promotes healing by stimulating myofibroblast differentiation, which enhances the healing process through myofibroblast involvement in the inflammatory response to injury, reduces edema by compressive force, and draws the wound edges together.[4–6]
Microstrain occurs when negative pressure is initiated and the cells on the wound surface are physically pulled into the foam. This mechanical force at a cellular level stimulates the release of TGF-β1 from platelets. Fibroblasts then form collagen, which supports the cellular matrix.[2] The effect of the mechanical force alters the wound environment, creating perfusion changes at the wound surface (hyperperfusion in deep vessels and hypoperfusion on superficial vessels).[4–6] Microstrain also increases cellular energy, which aids in local cellular proliferation.[7,8] These effects enhance the development of granulation tissue and angiogenesis, thus hastening the healing process and eventual wound closure. NPWT may or may not include the use of instillation therapy, which has been shown to decrease the patient's length of stay, number of operations, and time to wound closure.[9,10] Contraindications to NPWT placement include vascular insufficiency, exposed neurovascular structures, infection such as untreated osteomyelitis, and malignancy.[10]
Although NPWT is considered effective for a wide range of wounds,[11] there are complications that can arise during its use, including NPWT device failure, infection, skin necrosis, peri-wound maceration, and pain.[3,12] The NPWT device can have a loss of adequate seal using the acrylic drape, which causes extravasation of serous fluid, peri-wound maceration, and introduces new prokaryotic organisms into the otherwise recently debrided wound bed. Assuring an adequate seal is critical for NPWT to allow for macro- and microstrain to efficiently heal the wound bed.
The complex topography of the foot and hand, wound depth/configuration, digital conformation, digital circumference/size, and interdigital space present a technical challenge in obtaining a proper seal while using NPWT. Adjuncts to create a more effective seal may include the use of liquid medical adhesive (Mastisol, Eloquest Healthcare) or hydrocolloid dressings (DuoDERM Dressings, ConvaTec Group plc) between each digit or around the wound. Obtaining a consistent, reliable, and effortless seal with an occlusive drape is vital to efficient wound healing. In the current report, the authors provide a novel technique to assist clinicians in obtaining an adequate, stable NPWT seal on the foot.
Written informed consent was obtained for the publication of this case and photos. The IRB at ValleyWise Health Medical Center (formerly known as Maricopa Integrated Health System) has determined that this case report (CR2021-018) is exempt from IRB review based on Code or Federal Regulations Title 25, Part 46 – Protection of Human Subjects.
Wounds. 2023;35(1):E17-E21. © 2023 HMP Communications, LLC
