Negative Pressure Wound Therapy (NPWT) became popular for use in wound healing over a decade ago.^1,2 Theoretically, NPWT assists in development of granulation tissue, leads to wound contracture and neo-epithelization, removes interstitial fluid and infectious materials when applied to wound edges, and provides a closed, moist wound-healing environment.³ Negative pressure wound therapy assists in preparing wounds to heal by secondary intention or to be closed through simple reconstructive means but can also provide an ideal dressing to help increase the chances of skin graft incorporation.³ It has been indicated for use in diabetic foot wounds, pressure ulcers, chronic wounds, acute or traumatic wounds, dehisced surgical wounds, partial-thickness burns, and flaps or grafts.

Modifications to traditional NPWT devices now allow the use of fluid instillation therapy in combination with NPWT. Instillation therapy was designed to reduce the bioburden within the wound and promote healing and has been shown in select cases to help in pain control.^7–9

Insulin has long been recognized as an important contributor to wound healing,¹¹ and many studies have demonstrated the positive effects of insulin on wound healing.^11–18 Insulin-like growth factor (IGF), which has a high sequence similarity to the hormone insulin, has been shown through in vivo studies to stimulate the proliferation, migration, and extracellular matrix excretion by keratinocytes, endothelial cells, and fibroblasts, and even promote the reformation of granulation tissue.^18–20 Topical formulations of insulin was utilized in the 20th century in an attempt to control local hyperglycemia of peripheral tissue. However, later investigations have focused on topical insulin applications as it relates to insulin growth factors.

A 71-year-old male patient with a past medical history of hypertension, diabetes mellitus, and peripheral vascular disease received an emergency amputation at the midfoot level. Following this urgent procedure, the wound was treated with traditional NPWT and subsequently with a split-thickness skin graft (STSG) application to the dorsal lateral aspect of his right foot. After the STSG failed, several weeks of subsequent traditional NPWT was initiated, but also proved unsuccessful. The patient was referred to our clinic with a four-month history of ulceration (Figure 1) at the site of the STSG to his right foot. After intraoperative debridement and reapplication of traditional NPWT, the wound continued to show peri-wound maceration and clinically apparent colonization. We discontinued traditional NPWT, favoring a device along with insulin infusion (Sved; Figure 2) using the dosing defined by Wilson and associates.²⁶ We ran the infusion drip into the NPWT foam at 40 ml/h for 48 h.

The epidemiology and morbidity of diabetic foot wounds is, in many ways, not dissimilar to cancer.²⁸ This comparison has, over the years, made us rethink how we treat patients—in terms of counseling, a team approach to care, as well as with technology. Additionally, we believe that “infusion” of various modalities over a wound using a proven method of matrix stimulation (such as NPWT) might be a promising way forward. We have called this “wound chemotherapy.”¹⁰ We have been very active in modifying many of the techniques first described by Wim Fleischmann and others to both provide active matrix management (NPWT) with other chemotherapeutic tools to manipulate the wound environment (e.g., antimicrobials/antiseptics and analgesics).