Combining the Benefits of Collagen and Negative Pressure Wound Therapy to Heal a Chronic Diabetic Foot Ulcer: A Case Report

Introduction. Diabetes affects 30 million children and adults in the United States, equivalent to 1 out of every 11 people in the country, and results in costs of $327 billion annually. Interventions that can improve healing rates and/or reduce the size of diabetic ulcers may lower the incidence of infection, rate of amputations, and cost of care. This report is on the use of a collagen wound contact layer in conjunction with negative pressure wound therapy (NPWT) to achieve healing in a chronic diabetic foot ulcer (DFU). Case Report. A known patient with type 1 diabetes presented with a chronic DFU of 6 months’ duration. Previous treatment modalities included offloading regimens and topical therapies (ie, clostridial collagenase, human platelet-derived growth factors, and 6 applications of a human amniotic membrane allograft). A collagen wound contact layer was applied to the debrided wound bed with subsequent debridements performed every other week, weekly NPWT dressing changes, and weekly contact layer changes. A 91% reduction in wound area was seen at day 35, with complete healing at day 63, and no recurrence at 18 months. Conclusions. The combination of a collagen wound contact layer and weekly NPWT had a significantly positive effect on healing in this chronic DFU. The regimen was well-tolerated and simple to administer in this case.

Diabetes affects 30 million children and adults in the United States, equivalent to 1 out of every 11 people in the country, and results in costs of $327 billion annually.¹ The International Diabetes Federation estimates 9.1 to 26.1 million people with diabetes will develop foot ulcers,² accounting for a lifetime incidence of about 19% to 34%.³ In the United States alone, about one-third of the annual cost of diabetes care is related to lower extremity complications.⁴ With the prevalence of diabetic foot ulcers (DFUs) on the rise,¹ the need for new and innovative tools to achieve healing in this class of chronic wounds has never been more pressing.

Collagen, the most common protein in the body and a key component of the wound healing process, is degraded by elevated protease levels within chronic wounds.⁵ An application of a collagen wound contact layer to a wound bed introduces a sacrificial substrate, sparing the newly formed tissues and acting as a scaffold for the generation of new tissue.⁶

Negative pressure wound therapy (NPWT) is an adjunctive system that takes a biophysical approach to wound healing by creating subatmospheric pressure in the wound environment.⁷ Using a vacuum-assisted closure device, negative pressure is induced in a controlled manner to remove excess fluids and increase blood flow to the area. This approach has been shown to be beneficial in the treatment of various wound types, including DFUs.^7-10 Similarly, collagen-based dressings also have been shown to be an effective tool for healing chronic DFUs.^11,12

This case report presents the use of a collagen matrix wound contact layer (Figure 1; ColActive Transfer, Covalon Technologies Ltd, Mississauga, Canada) in conjunction with NPWT (V.A.C. Therapy; 3M+KCI, San Antonio, TX) to treat a chronic DFU nonresponsive to other advanced treatment options.

A 34-year-old man with a history of type 1 diabetes and Charcot neuroarthropathy presented with a chronic DFU of the right plantar medial surface. No sign of infection was present. The ulcer had persisted for 6 months; previous treatment consisted of efforts to offload pressure with a surgical shoe and removable cast boot. The wound also was treated with topical therapies, including clostridial collagenase, human platelet-derived growth factors (PDGFs), and 6 applications of a human amniotic membrane allograft. The initial assessment revealed a hemoglobin A_1c of 9.2, palpable pedal pulses, and no indication of peripheral artery disease. Noninvasive arterial Doppler showed normal ankle-brachial index and normal segmental pressures. At the initial visit, the ulcer measured 3.8 cm x 3.7 cm x 3 mm (Figure 2).

The DFU was debrided of hyperkeratotic margins and NPWT utilizing nondisposable durable medical equipment was commenced at -125 mm Hg continuously. All debridements were sharp debridements using a scalpel blade. Then, an advanced collagen matrix wound contact layer containing alginate and designed with uniform perforations to facilitate removal of exudate was applied to the wound bed (Figure 1). The NPWT sponge and secondary dressings were changed 3 times per week. The patient was instructed to use crutches and keep weight off the affected foot as much as possible. The patient returned to the clinic on day 7 and then every 2 weeks for the remainder of his care. After the first week, debridement was performed every 2 weeks, and the collagen wound contact layer dressing was changed weekly with the application of NPWT. 

Wound healing progressed with the previously described treatment regimen of biweekly debridement and weekly application of collagen wound contact layer with NPWT. On day 35, the total wound area had decreased by 91%, measuring 3.2 mm x 1.2 mm x 1 mm (Figure 3). 

Assessment on day 63 showed full closure of the wound had been achieved (Figure 4). The patient was advised to begin utilizing a Charcot Restraint Orthotic Walker (Scheck & Sirees, Oakbrook Terrace, IL) to prevent reoccurrence. The wound remained healed at his 18-month follow-up visit.

Both collagen dressings and NPWT are commonly used in the management of a wide range of wound types, but little has been documented about their effectiveness when used in combination. A case of combining the benefits of collagen powder and an alternative method mimicking NPWT was reported by Sreelesh and Laxminarayan Bhandari¹³ to have beneficial effects; however, to the best of the author’s knowledge, this is the first report on the use of a collagen matrix wound contact layer in combination with traditional NPWT methods. In the present case, combining the 2 technologies resulted in timely healing of a chronic DFU, on which multiple advanced treatment modalities (ie, human PDGFs and amniotic membrane allograft) had been attempted previously. 

The design of this collagen contact layer makes it particularly well-suited for use on wounds requiring removal of large amounts of exudate, an indication shared with NPWT. The collagen conforms to the wound bed but maintains structural integrity under pressure and over an extended wear time, and the specialized porous design, along with the sodium alginate component, allows for the removal of unwanted fluid from the wound bed into a secondary dressing. When applying NPWT with this collagen contact layer in place, the traditional foam dressing is still able to absorb exudate without coming in direct contact with the wound bed, minimizing any potential for trauma to the newly formed tissues. Furthermore, with its porous design, it is reasonable to surmise this technology may be applicable to a wide range of exuding wounds, such as pressure injuries, leg ulcers, postoperative wounds, and traumatic wounds, which all have indications compatible with the use of collagen dressings. 

The present case highlights the use of this collagen with NPWT; however, compatibility with other commonly used treatment modalities (eg, compression therapy) opens up additional opportunities. Further investigation is needed to determine efficacy and investigate the use on different types of wounds and with other medical technologies, such as with single-use portable NPWT systems as they become more readily available. In this case, the technology proved to be a beneficial addition to the care regimen, which achieved complete healing. 

The case described herein suggests combining the advanced wound healing properties of collagen with NPWT has a beneficial effect on wound healing, indicating this specialized wound contact layer may be a positive addition to the wound care clinician’s tool kit. Considering the limitation of this being a single case study, further research is required to determine definitively the benefit of utilizing a specialized collagen wound contact layer in combination with regular NPWT for the management of chronic wounds. 

Author: Jeffrey D. Lehrman, DPM, FASPS, MAPWCA, CPC

Affiliation: Foot & Ankle Specialists of Delaware County, Springfield, PA

Correspondence: Jeffrey D. Lehrman, DPM, FASPS, MAPWCA, CPC, PO Box 270968, Fort Collins, CO 80527; jdlehrman@hotmail.com

Disclosure: The product was offered in-kind by Covalon Technologies Ltd.