Clinical Application of a Synthetic Hybrid-Scale Fiber Matrix in a Pediatric Trauma Patient

Soft tissue wounds resulting from trauma are often challenging to manage, are susceptible to contamination or functional impairment, and are common amongst the pediatric population, accounting for 20% to 40% of emergency department visits annually.^1,2 MLLs are a rare subset of soft tissue injuries that occur when skin and subcutaneous tissue become separated from the underlying fascia owing to direct, high-impact trauma.³ There are many options for the management of MLLs; however, no standard treatment protocol exists.⁴ Standard management goals include drainage and debridement to eliminate deformity and remove necrotic tissue.⁴ Drainage and debridement of the lesion can result in large soft tissue defects, which may require advanced treatment modalities to achieve closure.^4,5

MLLs have been managed postoperatively with NPWT and STSGs.^4-6 STSGs can provide rapid coverage and a biologic barrier; however, they require additional surgical procedures and are susceptible to enzymatic degradation and donor site morbidity.^6-8 Other biologic allogeneic and xenogeneic skin substitutes can also be considered for wound closure. Decellularized tissues may work well in patients with MLLs by encouraging the natural wound healing process via stimulation of growth factors.⁹ While allograft and xenograft therapies can eliminate challenges associated with donor site morbidity and additional surgery, they have limitations. Biologic skin substitutes introduce the need for decellularization and can require burdensome storage requirements and tissue tracking.¹⁰ Additionally, collagen-based materials are prone to premature degradation and carry the risk of an inflammatory response.^8,10

An autograft may provide adequate coverage of a deep burn wound of limited size. All autografts require the creation of a second dermal wound.¹¹ Ameer et al¹² noted that “three basic types of instruments have been designed for removing a graft of split-thickness skin from its donor site: The knife, the drum-type dermatome and the electrical dermatome.” The author has had experience with all these types and currently uses an air (ie, pneumatic) dermatome. All of these types of instruments use a sharp blade to remove a layer of skin.¹² Skin thickness can be controlled either by a setting on the instrument or by the surgeon directly.¹² Typically, autografts for burns of the extremity and torso are STSGs.^11,12 

Typical donor sites include the thigh, abdomen, and buttocks. The scalp is also a reliable donor site with rapid healing, particularly in children, allowing for multiple or more frequent harvests from the same site.¹¹ STSGs are expanded by meshing to provide coverage to the area of injured skin. Meshed STSGs can stretch to cover large surface areas, but they consequently have a higher risk of contraction compared with FTSGs, which are not meshed. Unmeshed grafts (eg, sheet graft [STSG or FTSG]) can be used for smaller burns of the face and hands.^12,13 Grafting from the epidermis and a superficial portion of the dermis leaves the remaining epidermal appendages intact to regenerate the epidermal layer, allowing re-harvesting later.^12,13 

Given some of the drawbacks of current treatment options for large open wounds and the unwillingness of some patients to undergo multiple surgical procedures, new wound management options should be considered in the management of MLLs. An SHSFM (Restrata; Acera Surgical Inc) designed with a structure and architecture similar to native human extracellular matrix is a recent alternative in the management of these complex wounds.^10,11,14 The synthetic extracellular matrix is electrospun from 2 resorbable polymers: polyglactin 910 and polydioxanone. These synthetic polymers are commonly used in resorbable sutures, dura substitutes, and other clinical orthopedic implants.¹⁰ The electrospun design of the matrix mimics native human extracellular matrix and thus encourages cellular infiltration and revascularization.¹⁰ The matrix is engineered to resorb via hydrolysis at a rate that matches that of cellular infiltration and provides controlled offloading from the matrix to newly formed tissue.^10,11,14 The synthetic nature of the matrix limits inflammatory responses and resists enzymatic degradation.⁸ Prior studies of the SHSFM have demonstrated success in reepithelializing large, complex wounds in instances of STSG failure owing to a volatile wound bed.⁸

In the current case study, a pediatric patient underwent surgical debridement of an MLL resulting from a traumatic injury. The patient’s parents declined an STSG to avoid additional surgical procedures, and an SHSFM was used to achieve total wound closure.

A 12-year-old female with no prior medical history presented to a local trauma center after an all-terrain vehicle accident. The patient underwent a standard trauma workup and was noted to have a thermal contact burn injury and an MLL on the right lower medial thigh (Figure 1). The patient was taken to the operating room, where the wound was surgically debrided. Post-debridement, the patient had a large open wound measuring 14 cm × 12 cm and that involved subcutaneous tissue and muscular fascia (Figure 2). NPWTi-d (VAC Veraflo Cleanse Choice; 3M) with HClO instillation (Vashe Wound Solution; Urgo Medical North America) was initiated for wound management immediately postoperatively to encourage granulation tissue formation and prophylactically address the risk of infection. NPWTi-d consisted of instillation of 80 mL HClO with a 20-minute dwell time, followed by 2 hours of NPWT at −125 mm Hg (Figure 3).

The patient was transitioned to acute inpatient treatment to manage wound dressing changes. She remained there for 7 days and was ultimately transitioned to follow-up care at the outpatient clinic. An STSG was offered; however, the patient’s parents declined it to avoid additional surgery. The SHSFM was selected for further wound management to encourage granulation tissue formation and subsequent epithelialization. The SHSFM was applied in the outpatient clinic. The matrix was fenestrated and secured to the wound bed with broad adhesive strips (Figure 4A, B). A nonadherent primary dressing was applied over the matrix in conjunction with standard NPWT set at −125 mm Hg, which remained in place between visits (Figure 4C, D). 

The patient returned to the clinic every 1 to 2 weeks for the first 6 weeks of treatment, and eventually transitioned to visits every 1 to 2 months for monitoring of healing progress and for dressing changes (Figure 5A, B). During active treatment, the SHSFM was reapplied once every 2 to 3 weeks based on the resorption rate of the matrix and the healing response. During the first 66 days of treatment, NPWT was applied in conjunction with the SHSFM, after which NPWT was discontinued and treatment with the SHSFM continued in conjunction with standard of care wound dressings. After 4 months of treatment with the SHSFM, complete wound closure was achieved (Figure 5C). The SHSFM was applied a total of 6 times on an outpatient basis at a 2- to 3-week frequency. Upon wound closure, good scar quality was observed. Scar quality was assessed using the POSAS, a scale of 1 to 10 with 1 being “like normal skin” and 10 the “worst scar imaginable,” and the FSS, a pediatric outcome measure that is an objective, rapid, quantitative, and reliable tool to assess functional status in all children from full-term newborns to adolescents. Conceptually, the FSS is based on activities of daily living, which have been used in adult studies to evaluate functioning, disability, and dependency. The FSS has 6 domains of function, each domain receives a score of 1 (normal), 2 (mild dysfunction), 3 (moderate dysfunction), 4 (severe dysfunction), or 5 (very severe dysfunction). Cumulative scores range from 6 to 30. 

It is important to note that the FSS is not designed to predict long-term outcomes. Furthermore, the FSS should not be used to assess or predict outcomes for individual pediatric patients.^14-16 The patient had POSAS score of 3 and an FSS score of 6 (normal). At the 6-month follow-up visit, the wound remained closed, and no complications or infections were observed (Figure 5D). 

In this case study, an SHSFM was successfully used to reepithelialize an MLL in a pediatric patient. Given the large soft tissue defect resulting from surgical debridement of the injury, STSG was recommended to provide rapid coverage. The patient’s parents declined this option in order to avoid additional surgical procedures, and an SHSFM was used instead.

MLLs, while rare, are difficult to treat and can result in chronic and refractory wounds.¹⁷ Chronic, complex wounds often require lengthy hospital stays and have high treatment costs.⁸ Quick closure of large wounds at high risk for complications is vital for improving patient clinical outcomes and reducing health care costs to both the patient and the hospital system. STSGs provide rapid coverage of these wounds and can provide a biologic barrier to limit infection and further wound complications. STSGs have limitations, however, including donor site morbidity and additional surgical time and costs.⁸ This case suggests that the use of the SHSFM in a pediatric population in place of STSGs is a reasonable alternative to STSG, and provides acceptable results.

Given the high rate of contamination observed with MLLs (19%-46% depending on the location of the lesion), biologic skin substitutes may not always be appropriate in these settings because they are subject to enzymatic and bacterial degredation.^8,17,18 The SHSFM has demonstrated resistance to enzymatic degradation in prior case studies.^8,13 In the case of an abdominal fistula reported by Fernández et al,⁸ an STSG was applied to the wound bed but was quickly dissolved by bile. An SHSFM was then applied to the wound, which persisted in the wound bed and encouraged reepithelialization. This not only resulted in an improved healing outcome, but also translated to cost savings by reducing operating room time.⁸ Positive results were also observed in a case study of a complex pressure ulcer with multiple failed flap reconstructions over a 16-year period.¹⁸ The wound tested positive for Staphylococcus aureus, Pseudomonas, Escherichia coli, and Proteus. Multiple (6) applications of the SHSFM resulted in significant wound healing and reduced wound exudate. The number of SHSFM applications used in the pediatric patient described in the current case study is similar to what has been observed in an adult population. Depending on the etiology of the wound, whether the wound is acute or chronic, and the clinical goals, the SHSFM can either be applied serially (2–9 times over a 12-week treatment period) or once to achieve complete closure.^7,8,10,19-21

This study has limitations. It is a single retrospective case report and thus is dependent on the availability and accuracy of medical records. Owing to the retrospective nature of this study, protocols and outcome measures were not normalized. This is a novel clinical approach, and the case serves only as an illustration of the potential use of the SHSFM in the pediatric patient population. Additionally, the SHSFM was used together with NPWTi-d with HClO instillation. Additional work assessing the effectiveness of the SHSFM alone versus in conjunction with NPWT is needed to further elucidate the precise effect of each of these modalities on the healing response when used in combination. The positive outcomes observed in the current case report warrant further evaluation to determine if these results are generalizable to a larger patient population and to study the effects of the SHSFM on wound healing when used either alone or in combination with other advanced treatment modalities. 

The successful clinical application of an SHSFM, as illustrated in the current case study, suggests that its use may be warranted as part of the wound care continuum for the management of complex skin lesions. The SHSFM encourages both regranulation and reepithelialization. This matrix may provide a reasonable alternative to STSGs.