Complex Wound Management With an Artificial Dermal Regeneration Template

Abstract: The following case reports on the successful use of Integra® (Integra LifeSciences, Plainsboro, NJ) as an alternative for coverage of exposed tibia in a patient with necrotizing fasciitis and significant comorbidities. Necrotizing fasciitis is a generalized term that is used to describe soft tissue infections in which necrosis of the fascia and subcutaneous tissue occurs. Necrotizing fasciitis will often begin with disproportionate pain, localized erythema, and skin discoloration with vesicle formation. As the disease progresses along fascial planes, an area of deep necrosis develops with eventual signs of systemic toxicity and sepsis. Diagnosis of this condition can be quite challenging, and the diagnostic value of laboratory tests is limited. Aggressive treatment of necrotizing fasciitis is extremely important; the infection develops rapidly and can quickly lead to systemic toxicity and death. Traditionally, management of necrotizing fasciitis consists of resuscitation and stabilization of the patient, aggressive surgical debridement of all nonviable tissue, and the administration of broad-spectrum antibiotics. Reconstructive surgery is indicated for many patients who have recovered from necrotizing fasciitis. Integra, an artificial dermal regeneration template (DRT), has emerged as an adjunct to split-thickness grafts or tissue transfers. This case exemplifies the potential for DRT to provide another, more direct alternative for coverage of a complex, exposed wound.

Address correspondence to:
Milton B. Armstrong, MD, FACS
University of Miami
Division of Plastic Surgery
Miller School of Medicine
1611 NW 12th Ave., ET 3019
Miami, FL 33136
E-mail: marmstro@med.miami.edu

Case Report

     A 62-year-old man with insulin-dependent diabetes was transferred to the authors’ institution from an affiliated hospital for management of a chronic lower extremity wound. At initial presentation to the affiliated hospital, the patient demonstrated signs and symptoms consistent with a necrotizing soft tissue infection of the right lower extremity. According to the patient, his initial symptoms commenced several days prior, after sustaining a puncture wound to his distal calf.      Within 24 hours, his right lower leg, extending from the knee to the medial malleolus, became swollen, painful, and erythematous with associated hemorrhagic blisters (Figure 1).      The patient’s presumptive admitting diagnosis was necrotizing fasciitis. Initially, management at the other institution included broad-spectrum IV antibiotics and multiple surgical debridements (Figure 2). Two days following his last operative debridement, the patient was transferred to our institution for definitive wound closure. The patient was a nonsmoker. Significant past medical history included insulin dependent diabetes mellitus and hypertension. In consultation with the patient, it was decided to further debride and attempt wound coverage. At completion of debridement, there was extensive full-thickness skin loss extending circumferentially from the distal knee to proximal ankle with areas of subcutaneous tissue that appeared necrotic. The tibia was exposed along the majority of its length. Sharp debridement and a burr were utilized to establish a clean base for promotion of granulation tissue. The wound was then covered with a vacuum-assisted closure (V.A.C.®, KCI, San Antonio, TX) dressing at 75 mmHg for the entire treatment. Eight days later, the patient was taken back to the OR for dermal regeneration template (DRT) placement over the exposed tibia (Figure 3). Before placing the DRT, the bone was again burred until we achieved punctate bleeding. The DRT was then placed, covering the extent of exposed areas with 2- to 3-cm of surrounding soft tissue. Mepitel® (Mölnlycke, Göteberg, Sweden) soft silicone contact dressings were placed on top of the DRT graft. Upon completion, the vacuum-assisted closure dressing was replaced over the extent of the wound. The outer silicone layer was removed 3 weeks later revealing a bed of robust vascularized neodermis. It appeared that the DRT had fully adhered to the bone. Split-thickness skin grafts were harvested from the ipsilateral thigh for definitive soft tissue coverage over the entire surface of the wound. The soft silicon dressing was placed on top of the skin graft. Once again, a vacuum-assisted closure dressing was placed over the wound. Upon removal of the dressing 5 days after grafting, there was nearly 100% viability of the skin graft (Figure 4). The patient was eventually discharged home in satisfactory condition and was fully ambulating. At 6 months, the patient demonstrates a stable, closed, wound.

Discussion

     Necrotizing fasciitis is caused by a wide variety of microorganisms, including (but not limited to) group A streptococcus, group B streptococcus, Staphylococcus aureus, and Clostridium perfringens. Often, necrotizing fasciitis infections are polymicrobial in nature, further complicating definitive management.¹ Diagnosis of necrotizing fasciitis is limited to nonspecific clinical findings and associated diagnostic studies. Symptoms include severe pain, skin discoloration, hemorrhagic bullae, sepsis, and multiorgan failure. Effectiveness of laboratory and imaging studies in the diagnosis of necrotizing fasciitis is extremely limited. ¹ In later stages of necrotizing fasciitis, invasive soft tissue infection often requires extensive, serial debridement with the concurrent administration of systemic, broad-spectrum antibiotics. Aggressive management often results in large complex wounds that present difficult challenges. The biosynthetic DRT skin substitute and vacuum-assisted closure device used in this case demonstrated their efficacy in facilitating early excision and satisfactory coverage for a complex wound.      Integra is a bilaminate dermal regeneration template that may potentially be used in the treatment of partial- and full-thickness wounds. The dermal replacement layer is a matrix of bovine tendon collagen and glycosaminoglycan, which serves as a template for the generation of neodermis. ² The upper layer is a temporary epidermal substitute made of silicone. During neodermis formation, the silicone epidermal layer controls moisture loss from the wound. The silicone epidermal layer is removed once the neodermis has fully developed. A thin epidermal autograft is then applied over the neodermis. In clinical trials, the DRT method has demonstrated excellent take and satisfactory aesthetics. ² An early study on artificial dermis by Heimbach et al³ confirmed its efficacy for the closure of wounds in burn patients. More recent studies have reported successful use of DRT to aid in the closure of other types of soft tissue wounds, including skin cancer excision sites and degloving injuries. ^4,5In one study, the use of a DRT to treat degloving injuries appeared to be a viable alternative to full-thickness skin graft and tissue flaps. ⁴ With respect to full-thickness excisions for basal and squamous cell carcinomas, the DRT’s main advantage is immediate closure of large defects over muscle, fascia, and cartilage. ⁵ However, few studies have demonstrated the successful grafting of a DRT directly onto bone. Engraftment onto bone is often clinically challenging, due to the lack of vascularity and risk of infection. The DRT, unlike skin, is acellular and therefore does not require immediate revascularization for successful incorporation into poorly vascularized tissues, such as bare bone. This has been demonstrated by one study in which DRT was successfully applied to radiated scalp wounds. ⁶ Although vascular ingrowth is significantly delayed in irradiated tissues, DRT has been successful for the treatment of these types of wounds because of the relatively slow vascularization rate of the dermal template. ⁶

Conclusion

     The present case employed a DRT on a large complex leg wound, secondary to necrotizing fasciitis. The grafting of bilaminate DRT has two clinical advantages: 1) Early coverage of the exposed bone making it less prone to infection, ^3,6and 2) a more simple method of obtaining wound coverage, obviating the need for more complicated microsurgical reconstruction of this patient with diabetes. Molnar et al⁷ recently showed that the application of subatmospheric pressure accelerates the incorporation rate and vascularization of DRT in complex wounds. Vacuum-assisted closure dressings are useful because the subatmospheric pressure minimizes fluid accumulation and may have bactericidal properties. Vacuum-assisted closure also stabilizes the wound, protecting the DRT graft from shear forces. ⁷ Vacuum-assisted closure was successfully utilized to improve the take of the DRT in the present case. Bilaminate biosynthetic dermal regeneration templates can be successfully utilized to treat complex leg wounds. Use of a DRT potentially prevented amputation of the affected leg. Despite its initial cost, the DRT method has a relatively low morbidity, and is a potentially viable alternative to other grafting techniques. Furthermore, it may be indicated in cases that will require grafting onto poorly vascularized tissue, and in other situations in which free tissue transfer is not an option.      From the Division of Plastic Surgery, University of Miami, Miller School of Medicine, Miami, FL