Annals of Burns and Fire Disasters - vol. X - n. 1 - March 1997

INTERNATIONAL ABSTRACTS

SPEARHEAD PROCEDURE FOR REPAIR OF WEB SPACE BURN SEQUELAE
Despite early surgery, appropriate physical therapy and active cooperation on the part of the patient, burns of the web space often leave aesthetic and functional sequelae. Two types of deformity are involved: interdigital contracture, which hinders abduction, and webbing, i.e. superfluous interdigital scar tissue joining adjacent fingers. These deformities may be present in varying degree - the most extreme clinical and anatomical form is true syndactyly, where separation between the fingers is nonexistent. A procedure is proposed to obviate these sequelae. This makes use of a local flap drawn on the dorsal aspect of the hand, the shape of which resembles that of the blade of a spear - hence the name "spearhead" procedure. The advantages are that this flap is well vascularized and allows better distribution of the redundant skin of the web, so that the lateral digital regions can be closed directly. Because of the broken suture line recurrence is unlikely, and a very natural appearance is achieved.

I-YOPHILIZED KERATINOCYTE CELL LYSATES CONTAIN MULTIPLE MITOGENIC ACTIVITIES AND STIMULATE CLOSURE OF MESHED SKIN AUTOGRAFT-COVERED BURN WOUNDS WITH EFFICIENCY SIMILAR TO THAT OF FRESH ALLOGENEIC KERATINOCYTE CULTURES
Grafting with allogeneic keratinocyte cultures has long been used as a wound-healing therapy. Their post-graft survival time is however limited, and their effect is generally attributed to the production of wound repair- stimulating factors promoting the proliferation and migration of resident cells. This study shows that lysates of cultured keratinocytes contain mitogerric activity for keratinocytes, endothelial cells, and fibroblasts. The lysates also inhibit the contraction of collagen gels by human skin fibroblasts. In the light of these observations and in vivo data specifically obtained for this research, the effect was evaluated of total keratinocyte lysates on the healing of meshed skin autograft-covered burn wounds. A number of burn wounds (20) were tangentially excised and autografted with meshed conventional skin grafts. An area treated with a gel containing lysated keratinocyte cultures was compared in terms of epithelializa-tion on day 5 with an area treated with placebo-gel. An additional fresh keratinocyte alloculture was used as a positive control in six patients. It was found that the newly formed epithelium on day 5 was 31.1% in the treated area compared with 16.5% in the placebo area, a result comparable with that obtained by treatment with fresh keratinocyte cultures, i.e. 33.8%. These figures indicate a twofold stimulation of epithelialization.

CONTROLLED CLINICAL STUDY OF SKIN DONOR SITES AND DEEP PARTIAL-THICKNESS BURNS TREATED WITH CULTURED EPIDERMAL AUTOGRAFTS
This report describes the results of banked cultured human epidermal autografts in two clinical studies in donor sites and in deep partialthickness burns. Donor split-thickriess skin harvesting was performed in ten burn patients. Banked cultured epidermal autografts (CEAs) promoted more rapid epithelialization of the wounds: 6.9 days compared with 11.1 days in controls (healing reduction time, 37.8%; p < 0.01). Allografted sites were less erythematous than controls (p < 0.01), with a greater tendency towards normal pigmentation. In the deep partial-thickness burns study ten patients with 18 wounds were treated. The wounds treated with cultured allografts presented complete re-epithelialization after 3-6 days. The two studies indicate that banked CEAs promote significantly faster epithelialization of donor sites and deep partial-thickness wounds. It is therefore recommended that cultured allografts should be used routinely in the treatment of burn patients.

ALLOGENEIC FIBROBLASTS USED TO GROW EPIDERMAL AUTOGRAFTS PERSIST IN VIVO AND SENSITIZE THE GRAFT RECIPIENT FOR ACCELERATED SECONDSET REJECTION
Cultured epidermal autografts (CEAs) are widely used for wound coverage in severely burned patients. These grafts are particularly attractive because they permit a 10,000-fold expansion of donor keratinucytes, but they also have their disadvantages. Apart from the long period required for their growth (3 weeks), the unpredictability of take, the lack of a dermal component, and high costs, there is also the phenomenon of late graft loss. The purpose of this study was twofold: to determine whether foreign fibroblasts used to cultivate CEAs persist in vivo after grafting and whether these fibroblasts sensitize the host to foreign histocompatibility antigens. Experiments involving mice showed that immunogenic fibroblasts used to grow CEAs survive in vivo and sensitize the graft recipient for accelerated second-set rejection. These persistent cells may initiate an inflammatory response capable of leading to late graft breakdown, thus limiting the utility of CEAs cultivated with a foreign fibroblast feeder layer.

PRODUCTION OF CYTOKINES AND PROSTAGLANDIN E2 BY SUBPOPULATIONS OF GUINEA PIG ENTEROCYTES: EFFECT OF ENDOTOXIN AND THERMAL INJURY
The purpose of this research was to determine whether distinct subpopulations of enterocytes located in various areas of the intestinal villi differ from each other in the production of cytokines and other mediators, whether these cells respond differently to stimulation with lipopolysaccharides, and whether thermal injury affects the production of the mediators by these cells. The production of the inflammatory cytokines tumour necrosis factor (TNF), interleukin- I (IL- 1), and interleukin-6 (IL-6), and the production of prostaglandin E, an immunosuppressive agent and a regulator of the the production of inflammatory cytokines, were evaluated for enterocytes from unburned guinea pigs and from guinea pigs 24 hours after thermal injury. Three subpopulations of enterocytes were obtained by sequential incubations of the small intestine, from the villus tip towards the crypt, with buffer containing ethylenediaminetenaacetic acid. The cells were cultured in the presence of endotoxin, and the supernatants were assayed for the mediators. It was found that thermal injury prompted all three enterocyte subpopulations to produce larger quantities of TNF and IL-6 compared with cells from unburned animals, and that enterocytes nearer the crypt produced the largest quantities of the cytokines. These results are of clinical relevance since gut integrity is compromised after thermal injury and enterocytes that may previously have been unexposed or less exposed to endotoxin can become a significant source of inflammatory cytokines.

Ogle C.K., Mao J.X., Hasselgen P.O., Ogle J.D., Alexander J.W.
J. Trauma, 41: 298-305, 1996.

EARLY USE OF PRESSURE MASKS TO AVOID FACIAL CONTRACTURE DURING THE PREGRAFTING PERIOD
This paper considers the concept of the use of pressure therapy on facial burns before definitive debridement and split-thickness skin grafting are performed, in order to reduce the formation of contracture and deformity in the healing burn wound. This concept is based on the knowledge that the granulating wound bed is extremely prone to contraction, with most wound bed contracture occurring within the first four weeks post-burn as a result of the high myofibroblast content. If definitive treatment is delayed, considerable wound contraction and deformity will occur during this pre-graft period and be present at the time of debridement. The application of pressure masks may prevent these complications. A case history in which good results were obtained is presented, regarding a 15-year-old patient with 40% BSA flame burns and deep partial-thickness facial burns. The patient ultimately refused to wear his pressure mask following discharge and contracture occurred, with reconstruction proving necessary.

PRE-EXPANSION OF FREE FLAP DONOR SITES USED IN RECONSTRUCTION AFTER BURN INJURY
It is usually possible to manage burn wounds without using free tissue transfers. One reason for this is that tissue expansion techniques for the creation of local flaps are now very versatile and represent a simple alternative when it is necessary to have vascularized tissues. There are however some exceptional circumstances when the two concepts can be combined to enhance burn injury reconstruction even further. Pre-transfer expansion of free flap donor sites also has a number of advantages compared with post-transfer expansion as it is possible to achieve immediate primary donor site closure, and the fabrication of flaps of appropriate size and thickness can be specifically manipulated simultaneously. Three illustrative case histories are presented.

Hallock G.G.
J. Burn Care Rehabil., 16: 641-5, 1995.