Using Negative Pressure Wound Therapy With Instillation and Dwell Time to Create a Path to Closure for Older Patients With Chronic Wounds: A Retrospective Case Series

Chronic podiatric wounds present a significant burden to the older patient population, increasing the risk of complications the longer the wound remains unhealed. Age affects closure frequency in chronic wounds after age 60,¹ which can lead to amputation and further disability. In a study examining 495 nontraumatic lower-extremity amputations between 2007 and 2013, 84.1% of patients were reported to have had preexisting foot ulcers and 27.8% underwent more than one amputation.² One-year survival rates after lower limb amputation range from 53% to 86%, with lower survival rates associated with increased age, diabetes, and multimorbidity.³ By targeting wound healing in older patients with multiple comorbidities, clinicians can change the trajectory of patients’ health care experiences and improve their quality of life.^4,5

One tool for approaching the goal of wound healing is negative pressure wound therapy (NPWT), a method of active wound management that removes infectious materials, reduces edema, and promotes growth of granulation tissue.⁶ This approach can be combined with instillation and dwell time (NPWTi-d) of topical solutions on the wound bed, allowing for the solubilization of thick slough and wound cleansing.⁷ In contrast to irrigation and lavage, the instilled solution is slowly introduced to the wound surface before negative pressure is applied and repeated in a controlled, automated cycle for up to 3 days before dressing changes. The use of NPWTi-d has been recommended in wounds with high levels of exudate, contaminated wounds, and wounds in which normal healing progression has stalled.^7,8

In this retrospective case series, the author reports on the utility of NPWTi-d in the management of 4 chronic lower extremity wounds in older patients with comorbidities, following each case to complete closure.

Case data of patients who were managed with NPWTi-d between April 2019 and June 2020 at Prisma Health Greenville Memorial Hospital were collected. Informed patient consent to collect de-identified information and photographs was obtained prior to the onset of this study. An institutional review board was consulted for this retrospective collection of case data and waived the need for a full review. Four cases were selected in which chronic wounds (≥ 3 months) were complicated by the presence of nonviable tissue and more than one risk factor for impaired wound healing.⁸ Patients were seen in a wound clinic that was part of a private, nonprofit health care system.

Wounds were covered with slough and thick exudate, present for 90 to 300 days, and undergoing therapies including standard or advanced dressings, enzymatic or incisional debridements, and conventional NPWT. Upon initial presentation, wounds were debrided if there was insoluble, nonviable tissue (including necrotic tissue) obscuring the wound surface and the patient could tolerate sharp debridement. All patients were admitted to the clinic prior to receiving NPWTi-d.

Negative pressure with instillation and dwell time (Veraflo Therapy, 3M) of 10 to 20 mL of normal saline was applied with a 1-minute dwell time, followed by 3-hour cycles of 125 mm Hg negative pressure. Reticulated open cell foam (ROCF) dressings with (ROCF-CC; Veraflo Cleanse Choice Dressing, 3M) and without (ROCF-V; VAC Veraflo Dressing, 3M) through-holes were placed on the wound surface and covered with a clear adhesive drape. Dressings were changed every 2 to 3 days, and antibiotics were administered as needed.

NPWTi-d was discontinued after therapy goals were met. Wound management was transitioned to advanced wound dressings, including silver-embedded cellulose/collagen dressing (Promogran Prisma Matrix, 3M)⁹ and gentian violet/methylene blue antibacterial dressings (Hydrofera Blue, Hydrofera), until closure. The former was chosen because it contains bovine collagen, which acts as a sacrificial substrate for dysregulated metalloproteinases, and silver, which suppresses bacterial growth within the dressing material. The latter was chosen because methylene blue and gentian violet are used to control microbial growth. Dressings were changed every 2 to 3 days. Patient 4 also received coverage with a skin substitute to support reepithelialization.

Reporting the complete history of these chronic wounds was limited by the fact that the patients received previous wound care outside the author’s facility. When possible, the patients’ comorbidities, reasons for previous admissions for medical care, wound features and dimensions, and previous wound care methods are provided. The patients were admitted for wound care with NPWTi-d and then discharged home or to a long-term care facility.

Before presenting to the author’s clinic, the patients were recently diagnosed with infections of bone (patient 1), hardware (patient 2), or soft tissue (patients 3 and 4). Additional signs of infection included erythema, discolored exudate, and unpleasant odor. If necessary, the infectious disease department was consulted for treatment recommendations.

In all cases, therapy goals for NPWTi-d included wound bed preparation, granulation tissue growth, and removal of infectious materials. These goals were achieved in 3 to 33 days, and NPWTi-d was discontinued in all patients.

Case 1. Patient 1 was a 75-year-old male who presented with a 3.2 × 1.8 × 0.3 cm³ Wagner grade 3 diabetic foot ulcer on the right lateral malleolus that had been present for 210 days (Figure 1A). Comorbidities included type 2 diabetes, coronary heart disease, peripheral vascular disease, obesity, previous myocardial infarction, hyperlipidemia, hypertension, hyperkalemia, chronic obstructive pulmonary disease, stage 4 chronic kidney disease, and osteomyelitis. The wound had been previously treated with oral doxycycline, enzymatic debridement (22 days), and silver-embedded collagen dressings. Application of NPWTi-d was initiated using ROCF-CC dressings for 3 days (Figure 1B) and then transitioned to NPWTi-d with ROCF-V for 13 days. After conclusion of NPWTi-d, the wound exhibited reduced slough and increased granulation, and measured 2.3 × 1.2 × 0.1 cm³ (Figure 1C). The patient was then discharged to a long-term assisted care facility. There, the patient received intravenous vancomycin and ceftriaxone, and wound management changed to applications of a silver-embedded cellulose/collagen dressing and gentian violet/methylene blue antibacterial dressings over 30 days until closure was achieved (Figure 1D).

Case 2. Patient 2 was a 65-year-old female with a 9.5 × 2.6 × 0.4 cm³ dehisced wound on the right foot that remained nonhealing after 90 days (Figure 2A). The patient previously received care for an infected arthrodesis, which required washout and hardware removal, and the wound had been treated with enzymatic debridement for 8 days. Medical history included hypertension, obesity, peripheral vascular disease, fibromyalgia, anemia, hyperthyroidism, chronic lymphedema, chronic venous insufficiency, chronic obstructive pulmonary disease, and current tobacco use. Application of NPWTi-d was initiated with ROCF-CC dressings, and oral ciprofloxacin was prescribed. NPWTi-d continued for 8 days, after which the wound exhibited reduced slough and increased granulation tissue, measuring 7 × 1.5 × 0.3 cm³ (Figure 2B). The patient was then discharged to a long-term assisted care facility. Wound management transitioned to silver-embedded cellulose/collagen dressing and gentian violet/methylene blue antibacterial dressings (Figure 2C) until closure was achieved 42 days later (Figure 2D).

Case 3. Patient 3 was a 78-year-old female with a neuropathic ulcer with undermining and tunneling under the first metatarsal head of the left foot (Figure 3A). The initial wound measured 0.7 × 0.5 × 2.1 cm,³ probed to bone, and had been present for 300 days. Previous treatments at a different wound clinic included oral amoxicillin/clavulanate potassium, debridements, local wound care, and offloading. The patient’s comorbidities included peripheral neuropathy, hypertension, osteoarthritis, and basal cell carcinoma of the face. The patient was admitted for surgical debridement and NPWTi-d with ROCF-V dressings. The patient was prescribed intravenous vancomycin and oral rifampin and amoxicillin/clavulanate potassium. On postoperative day 3, the patient was transferred to a long-term assisted care facility for continued wound management with NPWTi-d.

After 13 days of NPWTi-d, the wound was covered with red granulation tissue and was clear of nonviable tissues, measuring 5 × 2.8 × 1.5 cm³ (Figure 3B). On day 33, the wound measured 3.5 × 1.7 × 0.2 cm³ (Figure 3C), and the patient was discharged home. Wound care transitioned to applications of silver-embedded cellulose/collagen dressings until closure at 90 days (Figure 3D).

Case 4. Patient 4 was a 95-year-old male with a 4.5 × 3.3 × 0.9 cm³ Wagner grade 2 dorsal right diabetic foot ulcer that had been present for 150 days (Figure 4A). He sustained a right ankle fracture and underwent open reduction internal fixation, which was complicated by skin breakdown and extensor tendon exposure 2 weeks after surgery. Previous treatment at a different wound care facility included application of standard NPWT. Comorbidities included type 2 diabetes, hypertension, atrioventricular septal defect, atrial fibrillation, aortic stenosis, pulmonary hypertension, chronic kidney disease stage 3, gastroesophageal reflux disease, and age-related debility. The patient was admitted and prescribed intravenous cefazolin and oral amoxicillin/clavulanate potassium. After an initial debridement, NPWTi-d with ROCF-CC dressing was applied for 3 days, after which slough decreased and there was significant granulation tissue coverage of the wound bed (Figure 4B).

The patient was discharged home with oral antibiotics and conventional NPWT to be used for 2 weeks, followed by 4 weekly applications of a bioactive skin substitute (TheraSkin, Misonix) (Figure 4C). This patient received a bioactive skin substitute because his age, wound type, and multiple comorbidities significantly decreased the probability of secondary closure.⁵ Wound care was then changed to applications of silver-embedded cellulose/collagen dressings until closure 56 days later (Figure 4D).

Wound bed preparation is a widely accepted goal of chronic wound management that can be defined as the removal of barriers to the healing process to allow wound healing to progress normally.^10,11 By remedying the dysfunctional wound environment characterized by hyperactive proteolytic enzymes, overexpression of cytokines, prolonged inflammation, and suppressed angiogenesis, wound bed preparation can support the growth of healthy granulated tissue. This results in a wound surface that is well-vascularized, stable, and with little or no exudate. This endpoint can be difficult to achieve in chronic wounds in patients of advanced age and with multiple comorbidities, in whom these wounds have a poor prognosis for reaching closure.¹ Given the increasing risks of complications and disability the longer a wound remains unhealed, podiatrists’ approach to wound management can be the difference between limb salvage and limb loss.¹²

In the current case series, each patient had undergone previous treatment regimens that did not succeed in closing the wound. In addition, all patients had chronic conditions and nonviable tissue on the wound surface that compromised the natural course of healing. In particular, patient 4 was at high risk of amputation due to his advanced age, limited mobility, many comorbidities, and previous failed attempts at wound closure. The treatment focused on cleaning the wound of debris and promoting growth of healthy granulation tissue, allowing the wound to progress to closure. With this goal in mind, NPWTi-d was selected because of its ability to automatically deliver topical cleansing solutions to the wound and apply cyclic negative pressure.⁸ These mechanisms proved beneficial for each patient, with wounds exhibiting granulation and well-defined wound edges at the conclusion of NPWTi-d. The improved wound characteristics allowed for a transition to advanced wound dressings, which could be administered outside the hospital, and ultimately led to a completely healed wound.

Infection control was also an important aspect of wound management in these patients. Wound infection is a well-established predictor of poor wound healing and amputation in patients with lower limb ulcers.¹³ Two patients had prior infections on the affected limb, and all patients were prescribed oral or intravenous antibiotics. Although NPWTi-d does not treat infection, it is safe to use in wounds when an infection is suspected, provided infection management strategies are employed concurrently.⁷ After NPWTi-d was concluded, wound management transitioned to advanced wound dressings, including silver-embedded cellulose/collagen dressings and gentian violet/methylene blue antibacterial dressings, which kept the wounds clean as they decreased in size and ultimately closed.

This study is a limited retrospective case series that describes qualitative clinical outcomes in 4 older patients with multiple contributing factors for nonhealing wounds. It does not contain a comparative control population, and it does not indicate that similar outcomes will be observed across all wound types or patient populations. Furthermore, the full details of previous methods of wound management prior to undergoing care at the author’s clinic are limited in scope.

The author thanks Mikaela Sifuentes, PhD, of the 3M Company, for assistance with manuscript preparation.

This limited retrospective case series reports the utility of NPWTi-d, as part of a treatment regimen including debridement, antibiotics, and advanced wound dressings, to create an environment promoting wound healing and preparing for eventual closure in patients at high risk of lower extremity amputation. Future studies comparing amputation rates among high-risk populations treated with standard of care or NPWTi-d would be highly valuable for clarifying the effectiveness of NPWTi-d in older patients with chronic wounds.

Dr Klein is division chair of wound care, PRISMA Health-Upstate, Greenville, SC. 

Address all correspondence to: Robert Klein, DPM, FACFAS, CWS, VHA Wound Healing and Hyperbaric Oxygen Center, 200 Patewood Drive, Suite C300, Greenville, SC 29615; email: robklein63@gmail.com.

DISCLOSURES: Dr Klein is a consultant for the 3M Company, St. Paul, MN.