Emerging Insights On Negative Pressure Wound Therapy

Karen Shum, DPM, and Kazu Suzuki, DPM, CWS

   Delayed closure and increased granulation tissue formation. This is the original indication for NPWT, which promotes healthy granulation tissue over the wound bed faster than conventional wound dressings.3 Negative pressure also facilitates granulation tissue formation over tendon, fascia, bone or otherwise hard-to-heal wounds (i.e. previously operated or irradiated tissues). In the operating room, we routinely drill holes in fascia and bones to create microbleeding in order to promote granulation tissue formation. Surgeons may allow the wound to heal via secondary intention or one may opt for delayed primary closure and the use of NPWT.

   Status-post skin graft. This is a newer indication but clinicians routinely use NPWT for this in the hospital setting. It is known that hematoma and seroma formation under the skin graft are the primary causes of graft failure. After the application of the skin graft, cover the graft with non-adherent mesh (i.e. Vaseline gauze or plastic contact layer) and then apply NPWT directly over the graft. This treatment allows effective drainage of wound fluids while bolstering the grafts against the wound bed.

   Conventionally, we prefer to keep NPWT dressings on wounds over a five- to seven-day period in order to minimize the graft disturbance. In addition, some clinicians advocate lowering the suction pressure to 75 or 100 mmHg to minimize the graft disturbance. However, in our experience over the years, we have found that the 125 mmHg setting may work just as effectively.

   Surgical incisions and status-post skin flap. As with skin grafting, clinicians may apply NPWT to any skin flap as well as surgical incisions, assuming that the incision is also protected with a non-adherent mesh dressing. This application is most useful in complex incisions or skin flaps, which benefit from increased blood flow to the skin edges, or if there is a significant “dead space” underneath the flaps that one should fill with granulation tissue. We also prefer to leave the dressing on for five to seven days, although a longer duration may cause the maceration of the skin edges. We recommend placing the sutures farther apart than conventional primary closure to promote drainage. There are currently a few disposable NPWT devices, such as Prevena (KCI) or PICO (Smith and Nephew) that are specifically designed for large surgical incisions. Another relatively new option is the ciSNaP system (Spiracur), which minimizes tension on staples and sutures, and helps reduce the risks of dehiscence and infection.

   Continuous or intermittent irrigation of chronic wounds. Although there are no randomized control trials showing efficacy in wound healing with NPWT and topical wound solution instillation devices (which provide irrigation and decontamination), various case reports have shown anecdotal support for such approaches.18 It has been proposed that instilling a topical antimicrobial solution (i.e, Dakin’s solution) intermittently may help in reducing biofilm in heavily contaminated chronic wounds. VAC Ulta (KCI) allows programmable instillation of irrigation fluid and one may use it for this purpose.

What You Should Know About Reimbursement And NPWT

The application of NPWT dressings and educating your patients about these dressings takes time and expertise, for which you may be reimbursed. Here are some explanations of the relevant codes.

CPT 97605 (Work RVU 0.55,
Non-facility RVU 0.62)
Descriptor: Negative pressure wound therapy, including topical application, wound assessment, and instructions for ongoing care, per session. Total wound surface area less than or equal to 50 cm2.

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