Managing Wound Dehiscence With Mechanical Negative Pressure Wound Therapy: A Case Report

With the aging population and the rising incidence of diabetes, the prevalence of wounds being managed in the inpatient and outpatient settings is increasing. In 2014, almost 15% of Medicare beneficiaries experienced a wound or infection (not pneumonia).¹ According to data published in that study analyzing Medicare spending in the calendar year 2014 for all wound types (eg, diabetic foot ulcerations, chronic ulcerations, surgical wounds, wound dehiscence, venous ulcerations, traumatic wounds), the estimated cost of treatment for these wounds ranged from $28.1 billion to $96.8 billion.¹ With the higher costs compared with the low-range estimate, mid-range estimate, and upper-bound estimate to manage these wounds, clinicians’ support of the use of advanced wound care modalities and wound care therapies is subject to increased scrutiny and review within value-based reimbursement models.² The use of disposable mechanical negative pressure wound therapy (mNPWT) can be used to manage wounds in the outpatient setting and has been shown to be an effective wound care option when transitioning patients from an inpatient to outpatient setting and continuing NPWT for wound care, and adds value to the patient and the health care system.³ Mechanical NPWT helps promote wound healing by decreasing edema and via removal of tissue debris and exudate.^4,5 Traditional NPWT is bulky, is often noisy, and requires a power source. A mechanically powered, disposable, easily applied, off-the-shelf mNPWT device is available for patients with small- to medium-sized wounds with mild to moderate exudate.⁵

Disposable mNPWT can be used in the outpatient setting for small- to medium-sized wounds with mild to moderate exudate.^5,6 These single-use devices provide NPWT and help with the removal of tissue debris and exudate.^5,6

In this case report, the author uses a disposable mNPWT system (SNAP Therapy System; 3M) that is easy to use and comes prepackaged with a cartridge and dressing with integrated tubing. A key is used to activate and reset this system. When properly applied, this mNPWT system delivers pressure of −125 mm Hg. The dressing consists of a hydrocolloid layer that protects the periwound; blue reticulated open-cell foam is cut to the size of the wound and placed within the wound bed. The author places a ring-shaped hydrocolloid dressing around the periwound at a distance of 1 cm from the periwound to help maintain the seal. The cartridge and tubing are attached to a strap that can be worn on the affected extremity and concealed underneath the patient’s clothing. The mNPWT device is portable and does not require a power source; in addition, the patient can check the visual indicator on the device to determine whether the system is providing negative pressure. Dressing changes are typically performed twice weekly by the wound care center nursing staff, home health agency, and/or the provider, although this varies based on the setting where dressing changes have been scheduled and arranged. Patients are instructed that they may shower with the mNPWT device but are cautioned not to immerse the dressing in water; rather, they are to take a quick shower and protect the dressing with an over-the-counter cast guard that can be purchased at a pharmacy or ordered online. Patients are typically seen every 1 to 2 weeks for follow-up to assess the wound and wound healing. The author discontinues mNPWT when healthy granulation tissue is noted and is observed to be close to the periwound skin level. Typically, the author then transitions the patient to an advanced wound care dressing (oxidized regenerated cellulose [ORC]/collagen/silver-ORC; [Promogran Prisma Matrix; 3M]) that remains in place until wound closure is achieved.

A 67-year-old female was referred to the author with chronic diabetic foot ulcerations of the medial first metatarsal head and dorsal proximal interphalangeal joints of the second and third toes of the left foot, which had not been successfully managed with conservative care and had been present for more than 1 year. The patient’s past medical history was significant for diabetes mellitus, hypertension, anemia of chronic disease, diabetic peripheral neuropathy, chronic obstructive pulmonary disease, morbid obesity, anxiety disorder, degenerative joint disease, heart disease, and fatty liver disease. The patient had previously undergone amputation of the fifth ray and fourth toes of the left foot due to diabetic foot infection. In addition to the ulcerations, hallux valgus and hammertoe deformities were noted (Figure 1). The patient thought she had exhausted all conservative care options. A transmetatarsal amputation was recommended, which the patient declined. Ultimately, the patient consented to amputation of the first, second, and third rays of the left foot. The patient was referred to the primary care provider for preoperative medical clearance. Preoperative work-up included plain radiographs, which were negative for osteomyelitis. Noninvasive vascular studies revealed normal pedal waveforms and an ankle-brachial index of 1.1.

Preoperative laboratory results were unremarkable, and the patient was not on any medications that would have impaired or delayed wound healing. The surgery was uneventful, and the patient was seen on postoperative day 3 for a wound check and dressing change (Figure 2). On postoperative day 17, a small area of wound dehiscence was noted along the medial aspect of the left foot; sutures were removed, and the wound was initially managed with collagen dressing with silver (Figure 3). On postoperative day 31, the area of wound dehiscence was noted to be larger, and mNPWT was recommended at that time (Figure 4). The patient’s insurance company required prior authorization for such treatment, and mNPWT was applied on postoperative day 35 per the manufacturer’s instructions for use. The author does not routinely apply a secondary dressing over the mNPWT device.

The first mNPWT dressing change was performed on postoperative day 38, at which time a decrease in tissue debris was noted and granulation tissue formation was observed (Figure 5). Twice-weekly dressing changes were performed, the patient continued to wear a surgical shoe for offloading, and the wound continued to improve (Figure 6). The patient underwent 34 days of mNPWT. Wound care goals were met, with the wound decreasing in size and depth. Wound care was changed from mNPWT to use of ORC/collagen/silver-ORC per the manufacturer’s instructions for use.

At 82 days postoperatively, wound closure was achieved (Figure 7) and the patient was fitted for diabetic shoes and custom insoles with an amputation fill.

The prevalence of wounds is increasing along with the aging population, and wound care specialists treat patients with significant comorbidities. Providers are regularly challenged to effectively manage wounds that require advanced wound care modalities, including NPWT. With the move toward a more value-based health care model, clinicians need to better understand how best to use advanced wound care therapies. Mechanical NPWT is an exceptional wound care modality for small- to medium-sized wounds with mild to moderate exudate. It is effective in the outpatient setting and can also be used when transitioning patients from an inpatient to outpatient setting for those who require NPWT upon discharge.

This study is limited due to the single case presented. A larger case series using mNPWT for wound dehiscence and other wounds (eg, diabetic foot ulcers, venous leg ulcers, pressure injuries) would be helpful to establish the efficacy of mNPWT and would healing. Additional studies and case reports are needed to demonstrate positive outcomes using mNPWT and to focus on patient satisfaction and cost savings to the health care system. These studies and case reports could serve as a guide for additional applications for mNPWT and aid clinicians regarding best practices for this modality.

The author presents herein a case report in which mNPWT was used to successfully manage wound dehiscence in a patient with diabetes and multiple comorbidities. Providing patients with an off-the-shelf, silent, discrete, mechanically operated NPWT device that keeps patients ambulatory can be a cost-effective way to manage complex wounds and increase patient satisfaction. The mNPWT device evaluated provides −125 mm Hg of pressure, is silent and small, can be worn under clothing, and allows the patient to be fully ambulatory and more mobile than possible with a powered NPWT system. The mNPWT device tubing can be cut to fit, making for safer ambulation than with a powered NPWT system and providing the patient with the ease and convenience of wearing the mNPWT device to work and social activities without a medical device showing.

Author: Robert J Klein, DPM, FACFAS, CWS

Affiliation: Wound Healing and Hyperbaric Oxygen Center, Greenville, SC; PRISMA Health; The University of South Carolina School of Medicine - Greenville, Greenville, SC

Correspondence: Robert J Klein, DPM, FACFAS, CWS, 200 Patewood Drive, Suite C300, Greenville, SC 29615; robklein63@gmail.com

Disclosure: Dr Klein serves as a Consultant for 3M and Consultant for Integra Lifesciences.