Utility of a Synthetic Hybrid-Scale Fiber Matrix in Surgical Soft Tissue Reconstruction

Large wounds resulting from surgery, trauma, and other etiologies, such as infectious disease or cancerous resections, can be difficult to heal, especially in circumstances in which underlying structures are exposed.¹ The current technique for the treatment of large wounds is debridement, maintenance of a moist wound bed, infection control, and application of appropriate wound dressings.² However, the avascular nature of underlying structures creates an additional challenge for achieving wound closure.¹ In the instance of exposure of underlying structures, standard wound management often fails.³ 

In these instances, advanced treatment methods can and should be considered. Interventions such as negative pressure wound therapy (NPWT) and biologic treatments such as split-thickness skin grafts (STSGs) can be utilized to treat large, deep wounds. However, NPWT alone often cannot encourage granulation tissue to form over exposed structures.¹ This is problematic when preparing a wound bed for definitive closure via methods such as a STSG, which needs healthy, vascularized tissue to successfully take.⁴ Delayed wound healing due to inability to successfully re-granulate wound beds or failure of a STSG poses significant risk to the patient. Large open wounds are susceptible to infectious disease,⁴ and STSG failure such as dehiscence or infection may lead to a need for additional surgery.⁴

Given the challenges with achieving closure in these wounds, new treatment options should be explored. A synthetic hybrid-scale fiber matrix (Restrata, Acera Surgical Inc) is showing promise in the treatment of complex, challenging wounds.^5-11 The synthetic hybrid-scale fiber matrix is electrospun and engineered to mimic native human extracellular matrix in both size and structure.¹² This engineered design supports cellular ingrowth, retention, and tissue formation.¹² The matrix is composed of resorbable polymers, which are designed to resorb over a period of 1 to 4 weeks at a rate that matches cellular ingrowth and proliferation.¹² As the matrix resorbs at this engineered rate, it provides a controlled transition from the synthetic matrix to the newly formed tissue at the wound site.¹² The primary objective for patients treated with the synthetic hybrid-scale fiber matrix in this retrospective case series was 1) to achieve wound closure utilizing the synthetic hybrid-scale fiber matrix to fully re-epithelialize the wound bed and 2) to utilize the synthetic hybrid-scale fiber matrix to encourage granulation tissue to form over exposed structures to successfully stage to a STSG or flap closure.

A retrospective case series review assessing the use of a synthetic hybrid-scale fiber matrix for the treatment of large complex wounds in the plastic reconstructive setting was conducted. Data was collected via a retrospective review of patient charts. 

Patients who received at least one application of the synthetic hybrid-scale fiber matrix were included in this review. The synthetic hybrid-scale fiber matrix was cut to size, applied to the wound bed, and secured with staples. The wound was then dressed utilizing NPWT. Wound healing was monitored at follow-up visits, and the synthetic hybrid-scale fiber matrix was reapplied as clinically indicated. The wounds were either treated with the synthetic hybrid-scale fiber matrix until complete re-epithelialization or until the wound was sufficiently granulated to stage to a STSG or flap.

A total of 22 patients with 22 wounds were included in this retrospective case series. Wound etiologies included surgical wounds, trauma, infectious disease, and cancerous resections. The average patient age was 59.3 years old, and the average initial wound size was 210.3 cm². The patient population was 55% male and 45% female. Patients also had various comorbidities, including hypertension, diabetes, peripheral vascular disease, chronic obstructive pulmonary disease (COPD), hyperlipidemia, and others (Table 1).  

All 22 wounds achieved complete healing and wound closure (Figures 1-4). The average time to closure was 41.4 days, and on average each wound received 1.7 applications of the synthetic hybrid-scale fiber matrix. For wounds staged to a STSG or flap closure, the wounds were deemed ready for grafting on an average of 38 days, and the skin grafts and flaps were fully adherent to the wound bed on an average of 5.6 days. The wounds were located on various parts of the body including the lower and upper extremities, trunk, and head. All wounds had exposed structures that included muscle, fat, fascia, or tendon. Wounds were closed utilizing healing by secondary intent (23%), bridging to a STSG (63%), or bridging to a flap closure (14%) (Table 2). No complications were reported.

Large, complex wounds with exposed structures are difficult to close, given the avascular nature of the underlying structures.¹ When the treatment of these wounds fails, the patient is put at significant risk of infection, amputation, and mortality, as well as significant increases in cost to the patient and health care system alike.¹ New wound care therapies are needed to address the needs of this patient population by encouraging granulation tissue formation over exposed structures to successfully take the wound to full closure, whether that be by primary or secondary intention. The retrospective case series presented here demonstrates the successful utilization of the synthetic hybrid-scale fiber matrix in the treatment of deep wounds with exposed structures. The matrix’s versatility was utilized in a way that allowed the treating physician to achieve the appropriate clinical goal for the patient. 

Flap reconstruction and STSGs are an effective and rapid method for the reconstruction of large skin defects.⁴ In this retrospective case series, all wounds treated with the synthetic hybrid-scale fiber matrix prior to closure with a STSG achieved closure after an average of 6.5 weeks. A 2-step treatment approach was necessary to encourage granulation over the exposed muscle, tendon, fascia, and fat tissue present in these defects. The synthetic hybrid-scale fiber matrix successfully encouraged regranulation over exposed structure when used in conjunction with NPWT. The average time to achieve sufficient regranulation over exposed structures was 5.2 weeks across all wound etiologies. These results are comparable with results seen using cryopreserved human skin allografts. In a retrospective review conducted by Wilson et al, 15 patients with exposed bone and tendon were treated the cryopreserved human skin allograft. Results showed that the average time to regranulation over exposed structure was 5.16 weeks.¹³

The synthetic hybrid-scale fiber matrix has shown efficacy in treating large wounds of various etiologies in prior case studies as well. In a case study conducted by Martini et al,¹⁴ a patient with an acute crush injury was treated with the synthetic hybrid-scale fiber matrix to granulate the wound bed in preparation for a STSG. After debridement, the synthetic hybrid-scale fiber matrix was fenestrated and applied to the wound bed in conjunction with NPWT. After 3 weeks and 1 application of the matrix, the wound bed was deemed sufficiently granulated and the STSG was applied. Three weeks after the application of the STSG, 100% wound closure was observed.  

In the present retrospective case series, several patients were treated with the synthetic hybrid-scale fiber matrix until re-epithelization of the wound bed via secondary intention. This method of closure was used in a cancer resection case, lower extremity trauma and infectious wounds, and a surgical wound on the trunk of the body. Other authors have used the method as well. McGowan used the synthetic hybrid-scale fiber matrix to re-epithelize post-Mohs surgical wounds on the auricular helix. The patients included in McGowan’s case series had multiple comorbidities, and most of the post-Mohs wounds resulted in exposed cartilage.⁸ All wounds achieved complete re-epithelization after an average of 7.9 weeks and 1.3 applications of the synthetic hybrid-scale fiber matrix.⁸ Fernandez et al also opted to use the synthetic hybrid-scale fiber matrix in the treatment of a dehisced midline abdominal incision in preparation of an ileostomy. The authors originally attempted to close the wound using a STSG; however, the small intestinal succus dissolved the STSG. The synthetic hybrid-scale fiber matrix ultimately assisted in the closure of this wound, as it was resistant to exposure to bile due to its synthetic nature.⁶ This demonstrates the versatility of the matrix to either bridge to a STSG or preclude an STSG in specific situations. In doing so, this provides more options to the patient and treating physician in addition to limiting the number of surgical sites and operations.

This retrospective case series does have its limitations. This was a retrospective study conducted by a single investigator at a single site with no control group. This case series also investigated multiple use cases and closure methods as opposed to one singular focus. As a retrospective study, the series is susceptible to recall and selection bias.¹⁵ Further studies should be conducted to continue to evaluate the results seen in this current review. 

Large soft tissue defects resulting from various etiologies often require advanced treatment options to achieve complete wound closure. This becomes especially relevant in instances in which underlying structures are exposed. Alternative treatment methods are needed to encourage granulation tissue formation over exposed structures and improve the success of STSG and flap closures. In this present study, the synthetic hybrid-scale fiber matrix showed efficacy in encouraging granulation tissue formation over these structures, and in some cases resulted in complete re-epithelialization of the wound bed. All wounds presented in this retrospective case series achieved complete closure without complications. These results suggest that the synthetic hybrid-scale fiber matrix may be a viable treatment option for the management of large, deep wounds.