Early Clinical Performance of an Adaptive Self-Assembling Barrier Scaffold in Nonhealing Chronic Wounds

A Review of Six Cases

Daniel Kapp, MD, PA; Laura Pfendler, PT, DPT, CWS; Lou D'Oro, MD; Randall Wolcott, MD

Disclosures

Wounds. 2022;34(1):20-30. 

In This Article

Results

The cases detailed herein represent a broad spectrum of challenging, nonhealing wounds of varying chronicity ranging from 8 weeks to more than 20 years in duration prior to presentation for treatment with aSABS. Additionally, treatment challenges were compounded by associated complexities and etiopathologies, including high bioburden levels in a chronic pressure ulcer and secondary burn; surgical complications, such as below-knee surgeries and amputations; systemic comorbidities (diabetes, peripheral vascular disease, scleroderma, Raynaud's phenomenon, chronic deep vein thrombosis); and patient nonadherence. The ability of aSABS to reinitiate and promote normal healing in a wound in which the healing process had been stalled due to inflammation and infection is reflected in the clinical outcomes described.

A summary of the patient histories provided in the Table is followed by individual case reports detailing the background, aSABS treatment regimen, and healing progression as demonstrated by graphical representation and/or images. Qualitative descriptors of the outcomes observed by the clinicians and the effect on quality-of-life–related parameters reported by patients are also presented.

Case 1

A 47-year-old male presented with a history of paraplegia and an ischial decubitus ulcer that had not healed during the prior decade of standard wound care.[16] The wound was subjected to repetitive trauma from the patient's routine use of heavy farm equipment, which exacerbated the need for wound management. Previous treatment regimens included offloading and topical antimicrobial agents and dressings to address the wound microbiota. Approximately 5 years prior to the start of treatment with aSABS, topical agents and dressings (such as iodoform, antibacterial foam dressing, and silicone absorbent foam dressing) targeting Staphylococcus were used. As the wound aged, the microbiota changed to Pseudomonas and Candida.

After aSABS became commercially available, the clinic treatment protocol transitioned to aggressive surgical debridement (until a bleeding wound bed was visible) with concomitant application of aSABS. The post-debridement wound was packed with iodinated foam and covered with a standard dressing, which was changed 3 times per week at home. Subsequent evaluation of the wound by polymerase chain reaction assays demonstrated reduced Pseudomonas levels and the absence of Candida. During the course of treatment, it was observed that combining aSABS with debridement consistently allowed for a more aggressive debridement procedure while offering bleeding control in the low-acuity clinic setting and without the need for thrombin or sutures. In addition, the nanofiber network appeared to provide a cohesive seal on the wound bed surface after debridement, likely contributing to less biofilm and senescent host cells in the wound microenvironment.

After 3 debridements with concomitant aSABS application performed every 2 weeks, nearly 50% reduction in wound volume was reported (Figure 2); prior to aSABS, in this wound had been refractory to treatment and stalled for more than a decade. The patient self-reported that each dressing change required less packing and that a substantial reduction in drainage and bleeding resulted in more manageable at-home wound care and fewer routine clinic visits. The wound decreased in size and demonstrated decreased exudate, decreased slough, and improved periwound skin appearance with less maceration even though the patient continued to operate heavy farm equipment. This milestone encouraged the patient to adhere to scheduled clinic visits, thus allowing for continued care and healing.

Figure 2.

Wound healing progression as demonstrated by 50% reduction in wound size after 3 applications of the adaptive self-assembling barrier scaffold (aSABS).

Case 2

A 49-year-old male presented with a chronic open friable wound resulting from the breakdown of severe scarring.[17] The initial injury was an extensive burn across the chest and flank that occurred more than 20 years previously. The wound persisted despite years of management with repeat surgical debridement and use of various products, including an antibiofilm gel, nonadherent foams, and dressings. The extreme friability of the wound, coupled with its presence in areas prone to continued friction from clothing, resulted in frequent and extensive bleeding. Laboratory analysis confirmed the suspicion that the friable tissue resulted from the wound microbiota; the tests also confirmed the presence of polymicrobial biofilm with strong fungal (Aspergillus) and bacterial (Enterococcus faecalis and Corynebacterium jeikeium) components.

At the center in which the patient was treated, effective and aggressive debridement is the first step in the biofilm-focused wound care treatment regimen. Aggressive debridement in this patient's wound was accompanied by application of aSABS once weekly for 4 weeks. The adaptive self-assembling barrier scaffold formed a clear conforming seal on the wound and remained affixed to the surface of the irregular wound bed, even in the presence of copious bleeding (Figure 3A). At the time of the second debridement, the wound bed surface was found to be much less friable and, therefore, produced far less bleeding.

Figure 3.

(A) First application of the adaptive self-assembling barrier scaffold (aSABS), showing its coverage of the wound bed. (B) Wound healing progression 3 weeks after the first aSABS application.

After 2 interventions, the wound bed quality improved, exhibiting a healthier tissue appearance, less exudate, less accumulation of slough on the wound surface, and new granulation buds (Figure 3B). More important for the patient was the cessation of intermittent bleeding episodes, which alleviated the burden of at-home wound care. Because the wound was embedded in a significant scar, wound contracture was not expected; thus, reduction in wound size could not be followed as a metric for healing.

The aggressive debridement made possible by the application of the aSABS facilitated the removal of the infected granulation tissue. This reduction in the wound bioburden likely helped address a major stimuli contributing to the chronicity and severity of this type of wound. Subsequently, aSABS appeared to have enabled healing of this stalled refractory burn wound, thus improving the patient's quality of life.

Case 3

A 66-year-old female who underwent emergency vascular bypass surgery for a limb-threatening posterior tibial ischemia developed a nonhealing surgical site wound as the result of local infection and wound dehiscence.[9] The patient was treated with wet-to-dry dressings for 6 weeks, with no change in the wound. She was subsequently treated with a collagenase ointment for 2 weeks, followed by an unsuccessful skin graft. The surgeon decided to perform excisional debridement and concomitant application of aSABS once weekly for 3 weeks. Because of the peripheral arterial disease, the patient was not a candidate for compression dressings.

Surgical excisional debridement was performed to prepare the wound bed, followed by application of aSABS. A nonadherent, petrolatum-based fine mesh gauze dressing containing 3% bismuth tribromophenate was then applied, followed by sterile gauze and Kerlix dressing (Cardinal Health). The surgeon observed that using aSABS promoted the formation of healthy granulation tissue, thus allowing the patient to resume at-home wound care. The development of a stable granular wound bed and wound closure were achieved without the need for additional skin grafts. The progression of wound healing is illustrated in Figure 4.

Figure 4.

Wound appearance (A) before initial, (B) 2 months after, and (C) 3 months after treatment with the adaptive self-assembling barrier scaffold.

In this case study of a complex surgical wound, aSABS restarted the previously stalled healing process. The results indicate that aSABS may obviate the need for continued costly treatments and procedures, thus reducing the costs of lower extremity wound care while improving the patient's quality of life.

Case 4

A 64-year-old male with diabetes and a history of nonadherence to medical therapy and prior transmetatarsal amputation (TMA) of the right foot presented with severe sepsis and gas gangrene of the left foot. The patient required fluid resuscitation, sepsis treatment per protocol guidelines, and emergent guillotine TMA of the left foot, which resulted in an open wound measuring 8 cm2 × 7 cm2. Despite approximately 50 weeks of treatment, frequent debridement, 5 applications of a placental-based product containing human amnion and chorion membrane, and applications of other products, the wound did not heal. It stalled at 3 cm2 × 2 cm2 in size, and hypertrophic peripheral soft tissue with a fibrotic base occurred.

It was determined that a change in treatment was necessary; aSABS was applied once weekly for 4 weeks with aggressive surgical debridement. The wound responded well, and the previously stalled healing process restarted. After 4 weeks of aSABS treatment, the wound demonstrated excellent wound bed granulation, diminished hypertrophic margins, and approximately 95% wound healing. Photographs of the wound before and after aSABS treatment are shown in Figure 5. Furthermore, aSABS was observed to possess hemostatic properties, which enabled both more aggressive wound debridement and management of bleeding without the need for additional modalities.

Figure 5.

Wound appearance (A) before initial treatment and (B) after 4 weekly applications of the adaptive self-assembling barrier scaffold.

The overall results provided clinical evidence of wound healing and hemostasis in a previously clinically stalled and challenging wound in a patient with diabetes and a history of medication nonadherence.

Case 5

A 59-year-old female presented with a nonhealing trophic ulcer on the left lateral malleolus.[18] The patient had a complex medical history with multiple systemic comorbidities, including lupus, scleroderma with Raynaud's phenomenon, small vessel peripheral vascular disease, and right below-knee amputation secondary to small vessel disease and a prior nonhealing ulcer. The current ulcer had persisted for 4 years despite extensive standard and advanced wound care interventions, including debridement, moist wound treatment, nitropaste, and skin substitutes.

Management of the ulcer with aSABS was initiated following excisional debridement. The wound was then covered with a nonadherent, petrolatum-based fine mesh gauze dressing containing 3% bismuth tribromophenate and a dry secondary dressing. Subsequent applications of aSABS were performed weekly, for a total of 3 applications. Treatment with the first 2 applications of aSABS showed significant healing of the ulcer, with a greater than 90% reduction in wound volume. At the patient's last visit on day 19, the wound was completely epithelialized, with 100% closure. The course of healing progression is shown in Figure 6, as demonstrated by a photograph of the wound after 3 weeks of treatment and a graphical presentation of wound size data.

Figure 6.

(A) Wound healing progression as demonstrated by complete epithelialization by day 19 after beginning treatment with the adaptive self-assembling barrier scaffold (aSABS). (B) Wound healing progression as demonstrated by 100% closure after 3 weekly applications of aSABS.

Complete healing of this previously nonhealing trophic ulcer, which had been unresponsive to multiple wound management regimens during the prior 4 years, was achieved in less than 1 month with 3 weekly applications of aSABS. The outcome can be considered notable due to the patient's multiple concurrent vascular and autoimmune diseases, which are known to hinder wound healing progression and that likely contributed to the failure of previously used wound care regimens.

Case 6

A 51-year-old male presented with a nonhealing surgical wound of the pretibial right lower leg.[19] The patient underwent Mohs surgery for squamous cell carcinoma 9 weeks prior to presenting to the clinic. The patient had a history of hypertension, dyspnea, chronic deep vein thrombosis, chronic right pulmonary artery thrombosis, and idiopathic mediastinal fibrosis. Previous wound care treatment included the use of various topical antibiotics and nonadhesive pads.

On admission, the wound had a moderate amount of slough and measured 2.6 cm2. The following week, treatment with aSABS was initiated immediately after excisional debridement, and then covered with a nonadherent, petrolatum-based fine mesh gauze dressing containing 3% bismuth tribromophenate. Unna boot compression was applied. This regimen was repeated once weekly for a total of 4 applications. During the course of treatment, granulation tissue formation increased, and by the final application, the wound surface area had decreased by 90% (Figure 7). Complete wound healing was achieved by the final follow-up visit at week 6. Use of excisional debridement and treatment with aSABS stimulated healing progression of this stalled wound that had not responded to 2 months of standard therapy.

Figure 7.

(A) Wound healing progression as demonstrated by 90% reduction in wound size after 4 weekly applications of the adaptive self-assembling barrier scaffold (aSABS). (B) Appearance of wound healing after 4 weekly applications of aSABS.

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