Use of disposable negative pressure wound therapy on split‐thickness skin graft recipient sites for peripheral arterial disease foot wounds: A case report

Abstract

Split‐thickness skin graft (STSG) helps to promote healing of wounds by providing a viable soft tissue cover. However, the success of which is influenced by how well it takes to the recipient site. Studies have demonstrated that negative pressure wound therapy (NPWT) is an excellent modality to promote graft survival. Technological advancements have made possible the invention of disposable, ultraportable, and mechanically operated versions for improved user experience. Alas, little has been discussed about their benefits on STSG. Therefore, the purpose of this case report is to highlight the effective use of disposable NPWT on freshly applied STSG. We report here a novel use of the disposable NPWT (SNAP therapy system) for STSG recipient sites in two patients with peripheral arterial disease (PAD) foot wounds. In both patients, there was 100% STSG uptake, and the lightweight disposable NPWT system makes for a more cost‐effective and comfortable experience for patients. Disposable NPWT may be a feasible alternative to conventional NPWT to aid with STSG uptake for PAD foot wound recipient sites.

1. INTRODUCTION

Peripheral arterial disease (PAD) referring to the narrowing of arteries in the body can lead to ischaemic ulcers. There are multiple risk factors1 for PAD and diabetes mellitus (DM) is one of the commonest. It is said that the lifetime risk2 of developing a foot ulcer is 15% with lower extremity amputation as a feared but necessary “evil” when the leg becomes unsalvageable. Split‐thickness skin graft (STSG) has been demonstrated in the literature to improve healing of PAD/DM foot wounds by providing a viable soft tissue closure in “appropriately primed” subjects.3, 4 Of course, the success of soft tissue coverage with STSG is dependent on how well the graft integrates to the recipient site. Typical causes of failure5 of STSG include poor adherence and accumulation of fluids between graft and recipient. To date, two randomised control trials6, 7 comparing different modalities of graft affixation have shown that the use of negative pressure wound therapy (NPWT) has led to a comparable if not superior graft uptake when compared with more traditional methods. NPWT though useful, it is bulky and electrically powered, compromising its portability and ease of usage for patients. However, technological advancements have made possible the invention of a new generation of NPWTs, which are ultraportable, disposable, and mechanically operated. These NPWTs (SNAP therapy system, Acelity, Texas) designed to treat smaller wounds with low‐to‐moderate exudates have been described in the literature8 to be useful in treating different types of wound, alas, only a single case report9 reporting the benefits of using SNAP therapy for STSG has ever been published. Therefore, the purpose of this case report is to generate greater interest and insight into the use of disposable NPWT on STSG. We describe, here, the use of SNAP therapy on STSG recipient sites for peripheral arterial foot wounds in two case presentations.

2. METHODS

A methodic search was performed on PubMed and Google Scholar to identify relevant articles appraising the application of disposable NPWT therapy to STSG.

Animal, in vivo, and review articles were excluded. Search terms were used and combined with Boolean operators were disposable NPWT OR SNAP therapy OR mechanically powered negative pressure wound device AND STSG.

3. RESULTS

3.1. Literature review

So far, three relevant case series documenting the use and benefits of disposable NPWT on STSG have been published in the literature.

Two of the case series reported the use of a disposable and portable but battery operated NWPT: PICO system. In the first case series by Payne et al,10 21 patients with diverse wound types were recruited and treated with PICO therapy. Out of the 21 patients, 7 received STSGs that were treated with PICO therapy. However, only 1 out of the 7 was written up as a case study. In this case study, a saphenous vein graft site that had broken down was covered with STSG and treated with 2 weeks of PICO therapy. It was reported that by the second month after STSG, there was complete wound healing.

Hudson et al11 proposed that there was more than 80% uptake of STSG at recipient site with the use of PICO therapy in 2 out of 20 recruited patients.

In a case series by Sposato et al,12 the use of a portable and battery‐operated negative pressure dressing MiniVAC directly over freshly applied STSGs in 7 patients with different wound types boasted at least an 80% graft take.

Interestingly, only 12 014 case reports chronicling the use of SNAP therapy on STSG has been published in the literature so far. Isaac et al9 described the use of SNAP therapy as a post‐STSG bolster for an 83‐year‐old woman with a diabetic leg ulcer. This dressing was discontinued 4 days after the operation. It was noted that there was a good uptake of graft at recipient site and by 12 weeks post‐operation, the wound was completely healed. User satisfaction and comfort were not discussed.

3.2. Case report

Here, we present two case studies of patients at our local institution with peripheral arterial wounds that were covered with STSGs and bolstered with SNAP therapy.

3.3. Case 1

A 26‐year‐old woman who presented with severe community acquired pneumonia complicated by respiratory failure required extra‐corporeal membrane oxygenation (ECMO), which subsequently led to the inadvertent complication of acute ischaemia of her right lower limb. Prolonged hospitalisation and immobility resulted in the development of a fixed plantarflex contracture of her right foot. She underwent a right forefoot amputation and Achilles tendon lengthening and was discharged with 1‐month duration of conventional NPWT. Her stump was eventually covered with an STSG (0.018 in.), which was harvested from the ipsilateral thigh.

After securing the STSG to the recipient site with absorbable sutures, we lined the margins with DuoDERM (Convatec, Oklahoma; Figure 1) hydrocolloid strips. UrgoTul (Urgo Medical, Chenove, France) was placed onto the STSG (Figure 2) and secured with skin staplers. We further lined the wound edges with SNAP SecuRing Hydrocolloid (Acelity, Texas) before cutting the SNAP Advanced Dressing Kit Foam (Acelity, Texas) to shape and applying it to achieve a seal (Figure 3). A continuous sub‐atmospheric pressure of −125 mmHg was delivered to the wound by the SNAP Therapy Cartridge (Acelity, Texas), which was mechanically primed (Figure 4). The disposable NPWT was applied for 5 days and then taken down for wound inspection. Routine wound care was instituted thereafter. Both recipient and donor sites were inspected on post‐operative day 7. Complete graft uptake was noted (Figure 5). Patient was discharged on the same day. No further surgical revisions were required thereafter (Figure 6).

Figure 1.

Duoderm thin lining

Figure 2.

Urgotul sheet secured with skin staplers

Figure 3.

SNAP advanced dressing kit foam

Figure 4.

SNAP therapy cartridge

Figure 5.

Complete graft uptake 1 week after the operation

Figure 6.

Complete wound healing 1 month after the operation

3.4. Case 2

A 48‐year‐old Indian male with DM presented to us with wet gangrene of his left forefoot for which he required a left forefoot amputation. This was followed with appropriate endovascular revascularisation efforts and NPWT. His recovery process was complicated by a dehiscence and infection of the lateral aspect of his stump after he attempted to shave off a callus that had formed. He required multiple surgical debridements and a prolonged course of intravenous antibiotics treatment. Eventually, this defect (Figure 7) was closed with an STSG (0.018 in.) obtained from the ipsilateral thigh. Application of SNAP therapy over STSG is as per case study 1. Similarly, the SNAP therapy was discontinued 5 days after the operation and wound inspection was conducted 2 days later. Complete integration of the STSG to the recipient site was noted (Figure 8). Patient has since returned work in the construction industry without any complications (Figure 9).

Figure 7.

Lateral stump wound

Figure 8.

Complete graft uptake 1 week after the operation

Figure 9.

Complete wound healing 1 month after the operation

4. DISCUSSION

Restoration of an intact skin barrier over an exposed surface is essential for protection against trauma and infections. The human body attempts to reestablish such a balance via innate mechanisms of granulation, wound contraction, and re‐epithelialisation. However, in parts of the body such as the peripheries where skin is a limited commodity, the scar tissue that results is often more delicate and easily damaged.

Medical know‐hows have allowed for a more satisfactory coverage of wounds by means of STSG.

STSG13 comprises the epidermis and a variable portion of the underlying dermis. It can be harvested from any part of the body but most typically from the upper thigh where the donor site can be easily concealed under clothing. STSG is applied to the desired site following which its integration to the host bed is said to occur via the processes that permit the initial exchange of nutrients and subsequent formation of important vascular networks.

One of the characteristics5 of STSG is that it shrinks considerably after it is applied to its recipient site as well as during the process of its integration to the aforementioned, unless the STSG is evenly distributed over it. This in itself may impact negatively on how well the graft integrates to the recipient site. Other common factors that result in graft failure include the formation of fluid collections underneath the STSG as well as infection and poor vascularity.

As studies6, 7, 10, 11, 12, 13 have demonstrated, NPWTs are pragmatic options to fixating STSGs and they help to promote improved graft survival by ensuring uniform graft adherence to wound beds including those with uneven contours, removal of excess fluids, and infectious materials as well as promoting angiogenesis.

In modern medicine where care is increasingly geared towards enhancing patient comfort and convenience, conventional NPWTs seem to fall short as they come with a hard‐to‐conceal bulky unit that is electrically powered and produces alarming sounds following a system error.

The disposable NPWT (SNAP therapy system, Acelity, Texas) had been designed to overcome the aforementioned shortcomings. These contraptions8 come with a pump that uses a spring mechanism to produce a predetermined continuous negative pressure to the wound bed. They are ultraportable and can be easily attached to the body and hidden under clothing. Errors in the system are detected via a visual indicator on the therapy unit as opposed to the loud noises that are generated from the unit in a conventional NPWT. Additionally, the one‐time‐use feature makes them more cost‐effective alternatives for wounds, which are smaller and/or with less exudates not unlike STSGs.

In our case report, two patients who presented to our institutions with unilateral poorly healing foot wounds of differing aetiologies received wound coverage with STSGs that were bolstered with SNAP therapy. In our experience, there was 100% graft uptake in both instances and no post‐operative complications. Patients reported having positive user experience and improved comfort level as was demonstrated in another case report,14 evaluating the efficacy of SNAP therapy.

Much is left to be explored with regard to the efficacy of SNAP therapy on STSGs, given that there is limited discussion in modern literature. We have proven in our case series that SNAP therapy is just as efficacious as conventional NPWT in promoting graft survival while also providing greater user satisfaction.

5. CONCLUSION

SNAP therapy is a safe and feasible alternative to conventional NPWT to aid with STSG uptake at recipient sites.

CONFLICT OF INTEREST

The authors declare no conflicts of interest.

Leong SW, Lo ZJ. Use of disposable negative pressure wound therapy on split‐thickness skin graft recipient sites for peripheral arterial disease foot wounds: A case report. Int Wound J. 2020;17:716–721. 10.1111/iwj.13291