Treatment of an Open Fracture Wound With Skin Graft Dressings (PELNAC): A Case Report

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Treatment of an Open Fracture Wound With Skin Graft Dressings (PELNAC): A Case Report

August 2011

Index: WOUNDS 2011;23(8):E21–E26.

Abstract: Various methods have been developed to treat wounds produced from a number of causes. Unavoidable limitations associated with each treatment have encouraged researchers to explore new ways to close wounds rapidly and effectively, while simultaneously obtaining satisfactory outcomes. Produced through interdisciplinary research, dermal substitutes provide a potential solution for solving this problem. Here, we report the case of an open fracture wound accompanied by a skin defect caused by a crush injury of the left foot in which satisfactory results were ultimately achieved. This case is of special interest due to the rarity of the treatment. This case demonstrates that satisfactory results can be obtained in the treatment of a skin defect wound caused by contusion or crush injury associated with fracture using a PELNAC dermal substitute. Traumatic injuries are fairly common occurrences that affect patients not only physically, but also psychologically. Rapid and effective closure of traumatic wounds is critically important to prevent infection and facilitate speedy rehabilitation.¹ Autologous split-thickness grafts have been a useful part of the armamentarium for the closure of such wounds.² However, historically, such graphs have resulted in problems, such as severe scarring and a relatively unsatisfactory donor site. Such drawbacks have encouraged the development of skin replacement materials.^3,4 Dermal substitutes represent a successful outcome of interdisciplinary research being applied to reconstructive surgery.⁵ Their discovery has aroused great interest and received good cosmetic and functional results.⁶ Despite abundant literature on wound closure with dermal substitutes, there is a dearth of information regarding the treatment of skin defects complicated by multiple fractures that are treated with dermal substitutes. The following reports an interesting case of successful reconstruction of a skin defect of the foot with multiple fractures using a PELNAC dermal substitute and conventional autografts.

Case Report

On October 16, 2009, a 24-year-old woman was transferred from a regional hospital (Dehui Peoples Hospital, Jilin Province, China) for management of a severe and complicated injury. The woman sustained a crush injury to her left foot from a tractor wheel when she was helping her family harvest corn. After the injury occurred, the woman was rescued immediately by her family and transported to the hospital where she was examined and an x-ray of her left foot was obtained. Multiple fractures of the left foot were observed, and the patient was transferred to the authors’ hospital for definitive treatment. A careful physical examination was performed, which revealed that the wound was spindled and transverse across the dorsum of the left foot. The examination further revealed extensive contamination of soft tissues and exposed bone fragments. In addition, major vessels and nerves were severely contused, though still in continuity. The patient reported a significant amount of pain in response to palpation of the second and third metatarsal bones, as well as the fifth toe. The patient’s foot was cool, and the skin on the foot was dark, as a result of the contusion and avulsion (Figure 1). The x-ray from the regional hospital showed transverse fractures, displacement of the second and third metatarsal bones, and comminuted fractures of the distal phalanx of the fifth toe (Figure 2). Surgical technique. Due to the unclear status of the blood circulation of the contused and lacerated skin on the dorsal aspect of the patient’s left foot, the authors only performed debridement and internal fixation with Kirschner wires; grafting was not considered. After the surgery, the skin exhibited progressive necrosis. Local heat was applied, the patient’s blood volume was increased by supplementing with intravenous 5% glucose, and microcirculation was improved by means of intramuscular anisodamine injection. Exudates were removed, and topical Vaseline gauze dressings were applied to the surgical wound. Exudate removal and re-dressing of the wound was repeated every 2 days until debridement and grafting (PELNAC, Gunze Ltd., Kyoto, Japan) were carried out 10 days later (Figures 5–7). After the operation, Vaseline gauze was applied to the wound together with iodine ointment dressings, which were inspected and changed with suitable pressure every 2 days to avoid local infection and hematomas. At postoperative day 18 the PELNAC neodermis was well vascularized, the silicone layer of the PELNAC was carefully removed, and a thin skin autograft from the left thigh was applied to the wound.

Results

There was no postoperative infection or hematoma and the skin graft survived completely. The donor site showed good healing 10 days after the procedure. Five weeks after the first operation, the authors performed an x-ray review of the patient’s left foot. The x-rays showed that the fractures of the third metatarsal bone and the fifth toe had healed, whereas the second metatarsal bone had not yet healed. Therefore, the two Kirschner wires on the third metatarsal were removed and the single Kirschner wire on the second metatarsal bone was retained. Plaster auxiliary external fixation was applied, as done previously, until 9 weeks after the first operation, at which point another x-ray was reviewed. At this second review, the fracture of the second metatarsal bone had healed, prompting removal of the remaining Kirschner wire and initiation of a rehabilitation program. The patient’s left foot wound healed completely with an acceptable cosmetic outcome (Figure 11).

Discussion

Advances in science and technology in recent decades have increased the number of choices that are available for the treatment of traumatic wounds. Currently, it is hardly disputable that an autograft is still the best replacement for lost skin.² Many alternative methods^7–12 have been developed, including skin graft dressings (ie, PELNAC). Suzuki et al¹³ reported that use of bilayer artificial skin to cover muscle and bone wounds produces satisfactory outcomes, but their cases were not complicated by fracture or tendon exposure.¹⁴ PELNAC is categorized into two types: standard and mesh fortified. The latter was used in the present case. Similar to Integra™ (Integra LifeSciences, Plainsboro, NJ), a widely used collagen/silicone bilayer skin substitute, PELNAC consists of two layers—a superficial silicone film layer to protect wounds from vapor loss and infection and a porcine collagen-based dermal analog which integrates with the patient’s own cells. In addition to both having a bilayer composition, these two materials also have other common features including in vivo primary cellular loading, a heterogeneous synthetic scaffold source, and semi-permanency. In addition, with both interventions, a temporary epidermal silicone sheet is peeled away as the wound heals and a very thin autograft is then grafted onto the neodermis. There are, however, several noteworthy differences between the two materials. First, the PELNAC collagen dermal component is derived from pig tendon (about 3 mm thick with pores that are 60 mm–110 mm in diameter), whereas the porous dermal component of Integra is made of bovine type I collagen. The dermal replacement layer of Integra consists of a porous matrix of fibers of cross-linked bovine collagen and chondroitin-6-sulfate (C6S) manufactured with a controlled porosity and defined degradation. Scaffold cross-linking may result in cytotoxicity or foreign body responses, which still need to be investigated further in order to avoid such problems.³ The synthetic pseudo-epidermis of the mesh fortified PELNAC is fortified with nonadhesive silicone gauze (TREX), which is inserted into a silicone film to provide additional reinforcement of the material’s tensile strength without C6S or cross-linking.¹⁵ Addition of C6S serves to reinforce the mechanical strength of the collagen sponge layer, but also decreases cell proliferation.¹³ The end of the pig tendon is removed from the PELNAC material to reduce its antigenicity, as it has been reported that the telopeptides located on the ends of the tri-helical collagen molecule may provoke an immune response, and that removal of such peptides produces non-immunogenic “atelocollagen.”¹⁶ However, the relevance of collagen immunogenicity and the supposed benefits produced by removal of telopeptides has been questioned.¹⁷ An immune response was not observed in the present case, and whether any relation with the atelocollagen-based structure exists is unclear. PELNAC is indicated for the post-excisional treatment of full-thickness or deep partial-thickness burns and has been shown to have advantages.¹⁸ A one-step wound closure immediately after debridement has been developed in which the dermal substitute is placed on the wound and covered with an autologous split-skin graft to provide more rapid wound healing. However, graft survival may be hampered by the presence of a non-vascularized dermal substitute in the wound.^3,19 A two-step procedure, which is still favored by many surgeons, aims to achieve temporary wound coverage by applying a dermal substitute to which an impermeable cover, usually a silicone layer, is attached. As soon as vascularization has advanced sufficiently into the dermal tissue, the silicone layer can be removed and replaced by an autologous split-skin graft.^3,20–22 This method has obtained satisfactory results in the treatment of avulsion injuries.^23,24 In this case, since the distal skin was contused and mangled, the authors sutured the PELNAC dermal substitute material to the wound without any tension to observe the circulation status. In the authors’ experience, contused skin generally becomes progressively necrotic due to the trauma itself, and impaired microcirculation often necessitates a second surgery. Hence, primary closure of these wounds may not be the best approach. Instead of grafting, dressing changes were combined with anisodamine to improve microcirculation. The advantage of this approach was that we were able to operate on clear wound boundaries, preventing the need for a secondary operation, and the wound conditions were improved with the removal of necrotic tissue and exudates. This process ultimately facilitates healing. A skin graft or flap can be utilized to close the wound as needed. Nonunion or delayed healing of fractures may occur after injury.²⁵ Common causes of these complications include advanced age, poor nutrition status, poor immobilization, inadequate blood supply, infection, and soft tissue incarcerated between the two ends of a fracture. In the present case, despite the distal phalanx of the fifth toe being fractured, only performed plaster external fixation was performed after carefully weighing the pros and cons. From the radiographs, it was concluded that the bone fragments were in good positions, and that the possibility of tissue incarceration could reliably be excluded. All of the fractures eventually healed; the delayed healing observed in this case may be attributed to destruction of the blood supply related to soft tissue contusion and avulsion. A dilemma faced when closing skin defects after a complicated fracture is determining the extent of pressure that should be exerted. As is well known, grafted skin requires pressure to avoid accumulation of blood and liquid in order to facilitate vascularization. For fractures, however, too much pressure may lead to nonunion or malunion, as a result of displacement or angular deformity of the fracture ends. Conversely, partial or total loss of the skin graft may also arise due to accumulation of blood or liquid under the skin or delayed vascularization, which occurs when pressure is inadequate.

Conclusion

In this case, the bone fractures were fixated with Kirschner wire instead of a plate for several reasons. First, the former costs substantially less than the latter and is easier to perform. Second, plating would have been inappropriate due to the anatomical location of the fracture. Lastly, internal fixation with a plate would have stripped much of the surrounding tissue and perturbed the blood supply. Undeniably, internal fixation with a Kirschner wire is not as stable as a plate, and thus may prolong rehabilitation. The optimal fixation technique to be utilized in future cases has yet to be clarified. There was no obvious hypertrophic scarring observed in this case. This non-scarring may be related to the application of PELNAC or perhaps the short follow-up time. Studies with long-term follow up are necessary to further elucidate the potential benefits of PELNAC.