Use of Artificial Dermis and Cultured Epithelial Autograft for Extensive Deep Dermal Burns —A Case Report

In the treatment of extensive burns, cultured epithelial autograph (CEA) became available commercially in Japan from 2009. Based on the 6 years multicenter surveillance data on using CEA for extensive burns, it is reported that using 6:1 split thickness skin graft together with CEA is successful after wound bed preparation for extensive deep dermal burn or patients with deep burn [1].


Case Presentation
A 21-year-old man was driving his car on a mountain road at 600 m height above sea level at midnight. After finishing smoking, he threw the cigarette butt out through the car window, however, the wind blew the cigarette butt back into the car. The cigarette butt fell on the blanket in the back seat and caught fire.
The fire spread so rapidly that he could hardly escape from the car. He suffered flame burns to his face, back, trunk and limbs. He was unable to call for emergency service and had to walk down the mountain on his own strength before he reached the fire station. He was immediately transferred to our hospital for treatment, ten hours after sustaining burn injury.
Initial physical findings: The patient was alert and oriented. His vital signs showed that the heart rate was 120 beats/min, blood pressure 140/100 mmHg, body temperature 36.6˚C, and respiratory rate 14 breaths/min. Contusion on the back of the head and physical injury. And his clothes were burned extensively.
The burn wounds were found on his face, neck, back trunk, and limbs. Back trunk and left limb were assessed as deep dermal burn (DDB), and others as superficial dermal burn (SDB) (Figure 1(a)). The total burn area (TBSA) was estimated at 37%. Sociodemographic and physical characteristics of the patient were summarized in Table 1.
The medical history of the patient was unremarkable. The laboratory blood data were as follows: WBC 25.28 × 10 3 /μL, Hb14.7 g/dL, platelet 25.6 × 10 3 /μL, total protein 6.0 g/dL, BUN 23 mg/dL, Creatinine 0.72 mg/dL, AST 132 IU/L, ALT 42 IU/L, Na 137 mEq/L, K 3.9 mEq/L, Prothrombin time 14.6 sec, APTT 28.6 sec, Antithrombin 97%. Arterial blood gas analysis (at room air) was as follows; pH 7.35, PaCO 2 33.4 mmHg, PaO 2 126.7 mmHg, Lactate 2.5 mmol/L (22.5 mg/dL). Chest X-ray and brain CT scan investigation did not show any abnormal findings. The characteristics of the patient's laboratory data were summarized  However, the wound on his back trunk, which had been diagnosed as DDB, deteriorated into full thickness burn with necrotic tissue on the 9th day of admission ( Figure 1(b)). We performed surgical debridement on this wound on the 10 th day of admission. All necrotic tissues were removed with tangential excision by hand dermatome until we could find blood circulation. After the surgery, we  (Figure 2(b)). On 10 th day after grafting, the wound was evaluated as good condition and epithelized very well (Figure 3(a)).
The patient needed no skin-harvesting for split thickness auto-graft. No remarkable complications were observed during admission. The patient was discharged from the hospital, 54 days after admission.

Discussion
Since early 1980s, CEA has been used clinically for patients with extensive burns.
CEA "JACE ® " has been recognized as a treatment for extensive burns. JACE ® has been certified by the public health insurance since 2009 in Japan. Prior to the certification, we employed the procedure using JACE ® combined with 6:1 split thickness skin graft, for the first time in Japan in 2006. It was very hard to make treatment plans for extensive burns using CEA, because we had few clinical evidences on the merits of using CEA. During this time, the treatment methodology for wounds of full thickness burn, was to implant with artificial dermis to reconstruct the dermis like normal tissue after debridement, followed by CEA implant combined with 6:1 split thickness skin graft. Matsumura [1]  was available including 31 randomized controlled trials and case studies, but these reviews did not show the use of CEA for DDB [4].
In our case, we used artificial dermis to reconstruct dermis and implanted CEA onto the mixed full thickness burn (deep burn; DB) and DDB wounds.
Since the patient was very young in age, the wound bed preparation with artificial dermis appears to have grown like normal tissue. This prevented the complications of graft donor sites and avoided the combination of split-thickness skin graft with CEA implantation [5]. The probable reason why independent CEA is useful for epithelization of the mixed DB and DDB wounds is that artificial dermis may well stimulate the survived dermis cells in the wounds to regenerate.
We implanted Integra ® artificial dermis onto the wound after debridement which is composed of bi-layered dermal substitute. The first layer is a matrix of bovine collagen and shark chondroitin 6-sulfate, cross linked with glutaraldehyde. The second layer is silicone membrane made of thin polysiloxane, which control fluid and heat loss and acts as a temporary epidermis. Integra ® contains 70 -200 µm pores, water and wound leachate can easily discharge from it. The cross-link structure of collagen layer makes horizontal cell movement easier and prompt soaking of dermis cell smoothly and quickly to form dermis tissue [6] [7]. One report evaluated the use of Integra ® in the treatment of extensive burns and showed that wound healing would improve enouch with good epithelization if there is no sepsis [8]. It suggests that the implantation of CEA does not always need split thickness skin graft if the recipient site has been well reconstructed as dermis like tissue.

T. Ueda et al. Open Journal of Emergency Medicine
Based on this report, implanting independent CEA on the well reconstructed dermis would be effective for successful epithelization. Pathological studies on the use of Integra ® , was originally targeted for damaged foot skin due to ulcer and was not about treatment of burn injury. This study showed vascularization and syncytial fibroblast movement into wound that replaced Integra ® hence contributing to the formation of epidermis in microscopic examination [9]. Our treatment strategy was based on this rationale.
Immunohistochemical analysis for our case is shown in Figure 4, comparing the use of artificial dermis and without artificial dermis, stained by anti-laminin and anti-collagen IV. The result shows that wound replaced with artificial dermis had greater amount of basement membrane and basal cell compared to slide without artificial dermis. This suggests that artificial dermis grew natural dermal tissue. Some reports such as Guofeng [10] et al. and Van der Wal [11] et al. seem to support our discussion.
Basement membrane (basal cell layer) consist of collagen IV and laminin produced from basal cell. Basal cell is the stem cell of keratinocytes that forms basal cell, and basement membrane support the development of epidermal cells.
This implies that implanting independent CEA can progress to epithelization of mixed DB and DDB wounds after reconstruction with artificial dermis. Therefore, good wound bed preparation with artificial dermis will produce successful healing process. The independent CEA applied on the burned wound can In cases of patients with extensive skin burns with very limited donor sites, our strategy using CEA without autograft appears to be successful way to treat skin burns and could be considered as an alternative option. We would like to investigate further. Based on this experience, we propose the present strategy instead of split skin graft for clinical treatment of skin burned patients.

Conclusion
We report and suggest an additional strategy for deep dermal burns; the independent CEA (only) implantation can result in good epithelization after wound bed preparation with artificial dermis.