|Year : 2020 | Volume
| Issue : 2 | Page : 77-82
Harvesting human skin allografts for burn care in a developing country
AO Iyun1, SA Ademola2, OA Olawoye2, AI Michael2, RO Aderibige1, OM Oluwatosin2
1 Department of Plastic Reconstructive and Aesthetic Surgery, University College Hospital, Ibadan, Oyo State, Nigeria
2 Department of Plastic Reconstructive and Aesthetic Surgery, University College Hospital, Ibadan, Oyo State; Department of Surgery, College of Medicine, University of Ibadan, Oyo State, Nigeria
|Date of Submission||22-Jul-2020|
|Date of Acceptance||23-Oct-2020|
|Date of Web Publication||18-Dec-2020|
Dr. A O Iyun
Department of Plastic Reconstructive and Aesthetic Surgery, University College Hospital, Ibadan, Oyo State, Pincode: 200212
Source of Support: None, Conflict of Interest: None
The usage of fresh and glycerolized preserved human skin allograft in burn care is a challenge in a developing countries despites it’s benefits in improving morbidity and mortalities in burn patients. We present two case reports to demonstrates it’s usage. In our first case report, the skin harvested allograft was from a consented patient who was undergoing abdominoplasty. It was harvested as a full thickness skin graft from the panniculus. The harvested skin allograft underwent process of glycerolisation and was stored in 85% glycerol in a fridge at 4°C. The skin allografts were used on the donor site of a patient with 51 percent burns undergoing burn wound excision and skin grafting.
The skin was secured with sutures and adherence of the skin allograft on the donor site was noted on the wound review on the third day. Evidence of rejection of some parts of the skin allograft (sloughing off of the skin) was noted by the 7th day post-surgery.
The second case report, a two-year-old girl who presented with 37% total burn surface area predominantly deep dermal flame burn injury with suspected inhalation injury. She had tangential wound excision and split thickness skin grafting with both autograft and living donor allograft (donor was the mother). The donor was screened for human immunodeficiency virus (HIV) I and II, hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV). The autografts were meshed 6:1. Allografts were previously harvested from the thigh of the mother on the same day using a power dermatome and meshed 3:1.
By the 12th day, there was a 60% loss of the allograft on the left thigh while there was 5% graft loss for the autograft. On the right thigh, there was a 50% graft loss for the allograft while there was a 2% graft loss for the autograft.
Human Skin allograft can be used as an option for wound coverage in patients who have sustained burns.
Keywords: Fresh allografts, glycerolised, human skin allografts
|How to cite this article:|
Iyun A O, Ademola S A, Olawoye O A, Michael A I, Aderibige R O, Oluwatosin O M. Harvesting human skin allografts for burn care in a developing country. Nigerian J Plast Surg 2020;16:77-82
|How to cite this URL:|
Iyun A O, Ademola S A, Olawoye O A, Michael A I, Aderibige R O, Oluwatosin O M. Harvesting human skin allografts for burn care in a developing country. Nigerian J Plast Surg [serial online] 2020 [cited 2021 Nov 28];16:77-82. Available from: https://www.njps.org/text.asp?2020/16/2/77/303834
| Introduction|| |
Glycerolized-preserved skin allografts (GPA) has been reported to have the advantage of being superior to cryopreserved allograft in the sandwich grafting technique in major full thickness burns. There is more reliable take and outgrowth of the autograft due to moderate rejection of the allograft skin and moderate inflammatory reaction in the wound bed. This is due to reduced immunogenicity of GPA. GPA is also reported to be as good as cryopreserved allograft in the treatment of partial thickness burns.
Beverwijk Burn Centre uses the sandwich grafting procedure as the treatment of choice for patients with extensive burns. GPA is used on the excised burn wounds and granulating burn wounds, which have been widely meshed autografted. The GPA firmly attaches to the wound bed on vascular contact, however, there is slow rejection of the allograft and limited inflammation of the wound. This mitigation of the immunogenic reaction in the wound allows the meshed autograft to close the wounds. It has been reported that the sandwich technique results in better take of the meshed autograft than when using meshed autograft without allograft coverage. The Meek technique is however reported to be more efficient for enlargement of skin graft and was preferable for patients with very extensive burns, elderly patients and those in a poor general clinical condition. GPA was also used for partial thickness burns as a biological dressing.
Glycerol preservation was chosen as a preferred method for skin allograft compared to cryopreservation. This is because reports from low and middle income countries (LMIC) like India who started skin banking on April 24, 2000 with cryopreservation as a modality for skin allograft preservation changed to glycerol preservation in 2007 because of difficulty in sustaining the cost of preservation. Cai et al. in Nepal, which is a LMIC in South Asia also reported glycerol preservation of skin allograft for similar reasons.
The objective of this presentation is to demonstrate the usage of fresh and glycerolized preserved human skin allograft in burn care in a developing country. We present two patients who had skin allografts used in their care. The first patient had GPA, whereas the second patient had fresh skin allografts.
Case presentation 1
The first skin allograft in our institution was harvested on February 14, 2018 from a consenting patient who was undergoing abdominoplasty. It was harvested as a full thickness skin graft from the panniculus [Figure 1]. After harvesting the skin, it was placed in a container with 50% glycerol, 1 g salbactam and ampicillin, and 80 mg of gentamycin. The glycerol that was available had a concentration of 99.5% [Figure 2]. Plastic containers (800 milliliters capacity) was bought from the local market and sterilized with Perasafe® (peracetyl ions at pH 8 equivalent to 0.26% peracetic acid). This was washed off with normal saline after it was soaked in it for at least 10 minutes. The glycerol was diluted with distilled water to make concentrations of 50, 70, and 85% in separate containers to a volume of 500 mLs. Antibiotics were then added to the content.
The harvested skin allograft placed in 50% glycerol was placed in an incubator at 33°C for 3 hours, then the allograft was transferred to a container of 70% glycerol, and placed in an incubator for another 3 hours after which it was transferred to the container of 85% glycerol. The skin allograft in 85% glycerol was kept at room temperature for a month. After a month, it was stored in a fridge at 4°C.
The skin allograft was used on the donor site of a patient who had flame burns involving both lower limbs and upper limbs and anterior trunk following a road traffic accident. The patient had mainly full thickness burns involving 51% of the total body surface area. Her first surgery on April 11, 2018 involved excision of the burn wounds on the right lower limb and right forearm. The skin graft was harvested from normal skin on the right thigh and the right upper arm. This was meshed 1:3 and grafted on the excised burn wounds. Because the donor site and recipient sites were on the same thigh, the skin allograft was laid on some parts of the donor site [Figure 3].
The skin allograft was washed thoroughly with normal saline then soaked for 1 hour. It was washed again with normal saline to remove the glycerol from the skin. It was observed however that the skin was stiff and was not elastic enough to attain the original dimension, hence only half of the stored allograft was used at surgery.
The skin was secured with sutures and adherence of the skin allograft on the donor site was noted on the wound review on the third day. Evidence of failure of some parts of the skin allograft (sloughing off of the skin) was noted by the seventh day postsurgery.
Case presentation 2
A 2-year-old girl is presented with 37% total burn surface area predominantly deep dermal flame burn injury with suspected inhalation injury [Figure 4]. She had tangential wound excision and split thickness skin grafting with both autograft and living donor allograft (donor was the mother). The donor was screened for human immunodeficiency virus (HIV) I and II, hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV). The autografts were meshed 6:1 [Figure 5]. Allografts were previously harvested from the thigh of the mother on the same day using a power dermatome and meshed 3:1.
At the first review on the fifth postoperative day the areas cover with autograft had a 98% graft take, whereas the areas covered by the allografts had a 100% graft take.
By the 12th day, there was a 60% loss of the allograft on the left thigh, whereas there was 5% graft loss for the autograft. On the right thigh, there was a 50% graft loss for the allograft, whereas there was a 2% graft loss for the autograft.
Patient was discharged to the surgical outpatient clinic to continue wound care 3 weeks postsurgery. At the last clinic visit at 3 months postoperation patient’s wounds had completely healed.
| Discussion|| |
Since skin allografts are not being widely practiced done in any hospital in Nigeria, there was inertia to be overcome in order to start procurement of skin allografts. This required collaboration with and education of other health professionals on the process and benefits of skin allografts. Funding was also another challenge. For example, cost of screening the skin donors and cost of the materials needed for harvest such as glycerol. The concentration of glycerol available was 99.5%. In order to achieve the concentrations of 50, 70, and 85% the glycerol was diluted with distilled water. Dilution with 0.9% saline has also been described in literature if there are challenges with getting distilled water.
There were challenges in achieving uninterrupted power supply, which was overcome by using alternate power supply such as solar fridges. Finally, there were series of interruption of hospital services due to industrial actions involving health workers agitating over unpaid salaries, poor conditions of service, salary increase, and allowances. This disruption in health services lasted for weeks and months. This had a negative impact on the yield of skin harvest since the site and team for skin harvest are hospital-dependent.
The process of revascularization or “take” occurs once the skin allograft adheres to the burn wound bed. This process occurs at the level of the dermal collagenous matrix.
Graft take occurs in several phases which are adherence, serum imbibition, the inosculatory phase and revascularization phase. The adherence of the graft occurs in two ways, either through direct chemical bonding between the fibrin in the wound bed and the allograft or by the fibrin entrapped between the surfaces of the wound bed and the graft.
The serum imbibition occurs either to serve as nutrition for the graft or to prevent the graft from drying out and keep the graft patent within the first 24 to 48 hours. The graft tends to be ischemic for an undetermined period of time depending on the wound bed after it has been laid on the recipient wound bed. The graft gains weight due to movement of fluid from the wound bed to the graft.
The inosculation phase which takes place after about 48 hours of grafting involves the establishment of a fine vascular network within the fibrin layer between the graft and the wound bed. Open vascular channels are formed as the capillary buds from the blood vessels in the recipient bed make contact with the vessels in the graft. Hereby, establishing blood flow to the allograft.
Revascularization may be due to one or a combination of processes which include the following:
- The alignment of vessels from the host wound bed and the graft, thereby opening new vascular channels.
- The in-growth of blood vessels from the recipient site wound bed into the endothelial channels of the allograft.
- The random penetration of blood vessels from the recipient wound bed into the dermis of the allograft resulting in the formation of new endothelial channels.
The distension of the established vascular system heralds the rejection of the allograft, a sluggish circulation with clumped elements follows. The blood then completely stops with cessation of vascular supply to graft. This process may take about 7 to 10 days, though it may be prolonged with the use of immunosuppressive agents.
The duration of adherence of GPA to the wound bed has been reported to range from 7 days to 2 weeks. Some report it being 8 days and 8.4 days. Nonadherence or peeling off of the skin allograft is clinically judged as a sign of rejection. This is in addition to the other signs such as dry, sloughy, or necrotic appearance.
Viability and immunogenicity levels have no influence on the clinical performance of allografts hence preservation method should not be the main reason for choice of specific skin allografts. There is no significant difference clinically amongst the various types of allografts either amnion or cadaver skin whether fresh, glycerolized, lyophilized, cryopreserved, or irradiated.11 Factors such as the superior intrinsic antimicrobial properties of glycerol preservation, cheaper storage equipment such as household refrigerator, should be the driver of the choice of allograft.
Use of GPA in sandwich grafting technique of allograft and autograft
It may be used to immediately overlay widely meshed autograft. The autograft may be meshed 1:4 or 1:6, whereas the allograft overlay may be meshed 1:1.5.
The reported complications with use of GPA include occasional wound infection and graft failure.The long-term use of GPA in children with scald showed that it only partly prevented the development of hypertrophic scars and pigmentation changes pattern. The hypertrophic scarring tended to occur on the ventral thorax and upper extremities with predilection to the presternal region.
There are usually strong religious and cultural debate against the harvesting of cadaveric skin, which is a challenge is most LMIC. The option of harvesting from living donors especially when extensive deep burns are being managed may be explored to achieve early wound cover. Glycerol preservation is more cost effective than cryopreservation particularly since the storage facilities are simple and of relatively low cost such as household refrigerators., The estimated cost of 1 cm2 of glycerol preserved skin allograft in a skin bank is $0.55, whereas in the Euro Skin Bank, it is &z.euro;0.91. This makes it a favorable option of preservation in LMIC.
Recommendations to LMIC for human allograft skin procurement and skin banking
- Establishment of a specified health facility to serve as a regional center for skin banking. This health facility should have collaboration with other health facilities within the region.
- A protocol for procurement of skin allografts from living and deceased skin donors should be developed. The protocol should include modality of storage and transportation to the regional skin bank specified.
- Setting up a dedicated skin harvesting team that has the logistics for transportation and administration. The team will include the medical team doing the harvesting and the administrative staff.
- Continued Medical Educational programs should be given to health professionals about the benefits of skin harvest and skin banking.
- Community educational programs using media such as television, radio, and the social media should be employed to educate the community on the benefits of skin harvest especially to those with extensive burns. Community liaison officers are also needed.
- Procurement of human skin allografts may be from both living and cadaveric skin donors.
- Funding for the setting up and maintenance of the skin harvesting process and skin banking should be established. Alternate power supply sources should be available to ensure uninterrupted power supply.
| Conclusion|| |
Human skin allografts can be used as in burn care in low- and middle-income countries. Its use may result in improved survival especially in patients with extensive surface area burns. It can be used fresh or as GPA with favorable outcome. There is, however, the need for a well-structured procurement, storage, and distribution chain in addition to wide public enlightenment programs in order for the benefits of the use of human skin allografts be enjoyed by the populace in a low- and middle-income country.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]