Cryopreserved cadaveric allografts for treatment of unexcised partial thickness flame burns: clinical experience with 12 patients

Partial thickness burns (PTB) usually heal within 3 weeks. Prevention of infection and desiccation of the wounds are crucial for optimal healing. Early tangential excision of the burn eschar and allografting prevent deepening of the burns, and are therefore advocated for treatment with the best functional and aesthetic results. For superficial partial thickness burns (SPTB) conservative use of topical antimicrobial agents with frequent dressing changes are implemented. We compared the conservarive treatment for PTBs and SPTBs to grafting cryopreserved cadaveric allografts with no prior excision.

Twelve patients with flame PTB areas were allografted after mechanical debridement without excision of the burn wounds. The allografts were cadaveric skin cryopreserved by programmed freezing and stored at −180°C for 30–48 months. Matching burns for depth and area were treated with silver sulfadiazine (SSD) one to two times daily until healing or debridement and grafting were required.

It was found that 80 per cent of the cryopreserved allografts adhered well and 76 per cent of the treated areas healed within 21 days, whereas only 40 per cent of the SSD-treated burns healed within 21 days.

Partial thickness burns can be treated successfully with viable human allografts (cryopreserved cadaveric skin) with no prior surgical excision. The burn wounds heal well within 3 weeks. For deep partial thickness burns (DPTB) treatment with allografts has no advantage if they have not been previously excised.     

Efficacy of hydrosurgical excision combined with skin grafting in the treatment of deep partial-thickness and full-thickness burns: A two-year retrospective study

IntroductionDeep partial-thickness and full-thickness burn wounds often undergo tangential excision or escharectomy to expose healthy tissue, combined with skin grafting to promote wound healing. However, conventional tangential excision with the humby knife leads to inevitable damage to the dermis while excising burn tissue due to the lack of precision. Indeed, the preservation of dermal tissue is a key factor in determining wound healing and scar quality. The precision and tissue selectivity of the Versajet Hydrosurgical System has been established for excising burn tissue while preserving dermal tissue. In this study, we retrospectively compared the efficacy of "Hydrosurgical excision combined with skin grafting" and "Conventional tangential excision combined with skin grafting" in treating deep partial-thickness and full-thickness burn wounds to demonstrate that hydrosurgery improved the treatment of deep partial-thickness and full-thickness burns.MethodsA total of 86 patients with deep partial-thickness and/or full-thickness burns with a total burn surface area (TBSA) ≤ 25% from July 2018 to July 2020 were included in this study and were divided into experimental (hydrosurgical excision combined with skin grafting, n = 43) and control (conventional tangential excision combined with skin grafting, n = 43) groups. Parameters were analyzed, including the intraoperative blood loss volume per unit area of grafted skin, surgery duration, wound healing time, skin graft survival, and the treatment costs per unit of burned area. Scar assessment was performed at 1 year with the modified Vancouver Scar Scale linked with TBSA (mVSS-TBSA).ResultNo significant difference was found in male to female ratio, age, weight, TBSA, burn depth, skin grafting area (SKA), skin grafting methods, cases treated with carbon dioxide fractional laser or incidence of inhalation injury, and the incidence of hypovolemic shock between two groups(p > 0.05). Compared with the control group, patients treated with hydrosurgical excision combined with skin grafting experienced less intraoperative blood loss volume per unit area of grafted skin (p < 0.05). The mVSS-TBSA of patients that underwent hydrosurgical excision combined with skin grafting was significantly improved in comparison to the control group (p < 0.01). No significant difference was found in surgery duration, wound healing time, skin graft survival and treatment costs per unit of burned area between the two groups (p > 0.05).ConclusionHydrosurgical excision combined with skin grafting reduced intraoperative blood loss volume per unit area of grafted skin, improved scarring 1-year after injury, and did not increase the treatment costs per unit of burned area. This technique provides a novel alternative for managing deep partial-thickness and full-thickness burn wounds.     

大鼠深Ⅱ度烧伤创面保留变性真皮并覆盖自体皮疗效观察

目的为探讨自体皮覆盖变性真皮修复深Ⅱ度烧伤创面的可行性提供实验依据。方法在大鼠背部造成直径3.5cm深Ⅱ度烧伤创面。伤后2—5d行创面浅层削痂保留变性真皮,同时在局部移植大张自体断层皮片。移植前和移植后不同时相点分别切取植皮区全层皮肤,光镜下观察其形态学及胶原纤维变化,并检测其生物力学改变。取移植大鼠同体背部正常皮肤作为对照指标。结果(1)保留的变性真皮为玻璃样变性。(2)大鼠自体皮移植术后7d,皮片与创面融合无法分离,光镜下可见真皮乳头及网状层。术后21d移植部位皮肤厚度、结构、形态与正常组织相似,有萎缩毛囊,胶原纤维条索密度逐渐增大接近融合。(3)鼠皮抗拉强度、最大应变值在术后逐渐增大,至60d时接近正常。结论将自体皮覆盖于变性真皮上用以修复深Ⅱ度烧伤创面,变性真皮能够逐渐复苏,使其结构、形态接近正常。     

Topical acidification promotes healing of experimental deep partial thickness skin burns: a randomized double-blind preliminary study

The effects of three buffered solutions with pH values of 3.5, 7.42 and 8.5, respectively, on the healing rate of deep partial skin thickness burns, was followed for 21 days in 16 guinea-pigs. Two symmetrical burns were inflicted on the back of each animal and then each individual wound was dressed with an irrigation disc dressing; solutions were coded (no. 1 to no. 3) and the animals were randomly divided and blindly treated as follows: Group A, solution no. 1 v. solution no. 2 (n = 4); Group B, solution no. 2 v. solution no. 3(n = 4); Group C, solution no. 1 v. solution no. 3(n = 4); Group D, non-irrigated disc dressings (n = 4). The solutions were applied to the surface of the burn wounds at a rate of 0.15 ml/cm2. Dressings were changed every 7 days to assess contraction and epithelialization by a sonic digitizer. On post-burn day 21 the newly formed scar tissue was measured in all wounds. After computation of the healing rate at the end of the study, the data were then related to the coded treating agent. Contraction did not differ in all test groups during the study. Epithelialization was significantly faster in the pH 3.5-treated burns than in the other treated wounds (P less than 0.001). The present study indicates that topical acidification of experimental deep partial skin thickness burns promoted healing. The precise mechanism should be elucidated.     

Evaluation of hyperspectral imaging as a modern aid in clinical assessment of burn wounds of the upper extremity

The most common burn wound assessment continues to be the clinical inspection and the tactile examination, which are subjective and remain challenging even for experienced burn surgeons. Recently, hyperspectral imaging camera systems have been increasingly used to support the evaluation of burn wounds. The aim of our study was to determine if hyperspectral imaging analysis differentiates and objectifies the assessment of burn wounds in burns of the upper extremities.We included 97 superficial partial, deep partial dermal burns, and full thickness burns. Hyperspectral imaging analysis was performed for all burns using proprietary software. The software recorded parameters for tissue oxygenation (StO2), tissue hemoglobin index, and near-infrared perfusion. These values were compared with the recordings for healthy, non-burned skin.We found that hyperspectral imaging analysis effectively differentiates burn wounds and shows the ability to distinguish even superficial partial burns from deep partial burns in the near-infrared perfusion analysis feature. Although, it was not possible to differentiate burn wounds in all features.Currently, it is important to optimize the respective reference values of the individual burn degrees for an objectified assessment.     

Healing of partial thickness porcine skin wounds in a liquid environment.

This study employs a liquid-tight vinyl chamber for the topical fluid-phase treatment of experimental wounds in pigs. Continuous treatment with normal saline significantly reduced the early progression of tissue destruction in partial thickness burns. Uncovered burns formed a deep layer of necrosis (0.49 +/- 0.004 mm, mean +/- SD) although burn wounds covered with empty chambers demonstrated less necrosis (0.14 +/- 0.01 mm), fluid-treated wounds formed no eschar, and little tissue necrosis could be detected (less than 0.005 mm). Topical treatment with hypertonic dextran increased water flux across burn wounds by 0.24 ml/cm2/24 hr (mean, n = 95) over saline-treated wounds during the first 5 days after wounding. When partial thickness burn and excisional wounds were immersed in isotonic saline until healed, the daily efflux of water, protein, electrolytes, and glucose across the wound surface declined during healing to baseline values found in controls (saline-covered unwounded skin). The declining protein permeability was used as a reproducible, noninvasive, endogenous marker for the return of epithelial barrier function. Saline-treated excisional wounds healed within 8.6 +/- 0.6 days (mean +/- SD, n = 27) and burn wounds within 12.1 +/- 1.4 days (mean +/- SD, n = 15). Healing of fluid-treated wounds occurred without tissue maceration and showed less inflammation and less scar formation than healing of air exposed wounds (no attempt was made to compare rates of healing between air- and fluid-exposed wounds). We consider the fluid-filled chamber a potentially very useful diagnostic, monitoring, and delivery system for wound-healing research and for human wound therapy.     

Cultured epithelium as a skin substitute

Twenty-five burn patients with full or partial thickness skin loss received cultured epithelium (CE), allografts or autografts as part of their treatment. Overall, a 30 per cent graft 'take' was achieved irrespective of whether the CE was autograft or allograft, fresh or frozen. In the case of deep dermal burns this figure improved to 50 per cent. The surviving grafts merged with split thickness skin grafts (SSG) and advancing wound edges. When full thickness skin loss was grafted, only a patchy take could be achieved and the surviving islands of CE tended not to spread across the wound. No rejection of CE allograft was recorded either clinically or histologically up to 6 months. The technical problems and clinical implications are discussed.     

Use of cultured human epidermal keratinocytes for allografting burns and conditions for temporary banking of the cultured allografts

Five children who suffered burns clinically regarded as full skin thickness loss were grafted with cultured allogeneic skin from newborn prepuce. The wounds had remained open and infected without healing for about 20 days before the patients were received in the burn unit. To avoid losing surviving deep epidermal cells the wounds were débrided but not deeply excised and, a few days before allografting, they were washed with isodine solution and sterile water, and treated with silvadene cream application. All children received 76 cultured allografts of about 60 cm2 each. After allografting, the wounds were epithelized in 7-10 days and the allogeneic grafted skin began desquamation suggesting that the allograft did not 'take' permanently but was replaced by the newly formed skin. On the other hand, since allografting is an adequate therapy to provide early temporary coverage in extensively burned patients, we developed conditions for banking cultured skin to make it available for immediate use. The conditions described allow banking of the cultured grafts for 15-20 days with retention of clonal growth ability similar to that of unstored epithelia. The results show that cultured epidermal cells obtained from human newborn foreskin, when used as allografts for coverage of full skin or deep partial skin thickness burns, allow rapid epithelization of the burn wounds.     

Tangential excision of eschar for deep burns of the hand: analysis of 156 patients collected over 10 years

Deep burns affecting the dorsum of the hand have been treated by tangential excision of the eschar in 156 patients involving 208 hands. From our 10-year experience we have concluded that: If the patient's general condition permits it all hands with deep partial and full thickness skin loss burns are suitable for early tangential excision of the eschar. The best time for the operation is within the first week after injury. If the burn is of limited extent and the requirement for autograft skin is small the operation may be carried out under nerve block anaesthesia. When the burn is more extensive (i.e. involving both hands) intravenous ketamine anaesthesia is recommended. During tangential excision sequential layers of tissue must be removed until the base of the burn appears porcelain white in colour, has a lustrous appearance with many small bleeding points and is firm in consistency. If there are deep burns of the finger webs they are incised or excised and then grafted. Postoperatively an absence of fever, pain or exudation from the wound indicates that inspection of the wound can be delayed for about 2 weeks. By this time the wound is usually healed and functional rehabilitation and physiotherapy can commence.     

复合皮混合移植治疗深Ⅱ度烧伤患者创面疗效观察

目的观察深Ⅱ度烧伤患者创面削痂术后应用复合皮混合移植治疗的效果。方法对23例烧伤患者的30个深Ⅱ度烧伤肢体在伤后3d内分次行削痂术,削至浅筋膜后移植大张异体脱细胞真皮基质,然后切取大张自体刃厚皮(0.10～0.25mm)覆盖于其上。术后10—12d计算移植皮片的存活率,记录创面愈合时间。观察随访3—6个月时患者的肢体外观及功能恢复情况。取1例患者随访3个月时的愈合创面皮肤标本,行病理学观察。结果本组患者复合皮片成活率为93%,7%的皮片因术中固定较差,移植后自体刃厚皮与异体脱细胞真皮基质分离致皮片坏死,或因感染致皮片溶解。随访3—6个月,移植部位皮肤外观、弹性及功能恢复良好。病理学观察显示,成活皮片表皮、真皮结构正常。结论烧伤后早期削痂立即移植复合皮是治疗深Ⅱ度创面的有效方法。     

Apoptotic death in deep partial thickness burns vs. normal skin of burned patients

BACKGROUND: Deep partial thickness burns have an ambiguous behavior evolving either into spontaneous healing or full thickness burns. The aim of this study was to investigate these lesions for the presence of apoptosis thereby giving a possible cellular explanation to their peculiar clinical progression. METHODS: We used colocalization of DNA fragments (terminal deoxynucleotidyl transferase mediated dUTP nick end labeling) and Fas ligand CD95 antibodies to calculate the apoptotic rate of deep partial thickness burns and normal skin in 21 patients after acute thermal injuries (significant difference considered: P < 0.05). RESULTS: Deep partial thickness burns were associated with a higher apoptotic rate than normal skin (48.15% +/- 17.22% versus 18.6% +/- 7.2%; P = 0.0002). There were no apparent significant correlations of apoptotic rate with age, days from injury, total burn surface area or deep burn area except for a slight correlation with sex (r = 0.484; P = 0.02). CONCLUSIONS: A higher apoptotic rate was present in dermal cells of deep partial thickness burns if compared to that of the unburned skin. These data would suggest that deep partial thickness progression derive from apoptosis. Specific studies are required to confirm this hypothesis and to investigate its clinical and therapeutic significance.     

Non-thermic skin affections

The Centre for Burns can help by its means (material, technical and personal) in the treatment of burns with extensive and deep losses of the skin cover and other tissue structures and in some affections with a different etiology (non-thermic affections). Indicated for admission are, in particular, extensive exfoliative affections--Stevens-Johnson's syndrome (SJS), Lyell's syndrome--toxic epidermal necrolysis (TEN) and staphylococcal scalded skin syndrome (SSSS), deep skin and tissue affections associated with fulminant purpura (PF), possibly other affections (epidermolysis bullosa, posttraumatic avulsions etc.). The similarity with burn injuries with loss of the skin cover grade II is typical, in particular in exfoliative affections with a need for adequate fluid replacement in the acute stage and aseptic surgical treatment of the affected area from the onset of the disease. In conditions leading to full thickness skin loss, in addition to general treatment rapid plastic surgical interventions dominate.     

Hautersatzverfahren in der Verbrennungschirurgie

Patients with extensive deep partial or full thickness burns require early excision of necrotic tissue, however, in many of these cases simultaneous autografting is not possible due to the general condition of the patient. In this instance temporary dressings like allogeneic or xenogeneic skin or foam dressings can be applied to minimize fluid and protein loss. In Europe glycerolized preserved allogeneic skin remains the treatment standard. Dermal replacements are considered to optimize the long-term outcome of split thickness skin grafting. Reduced contracture rates and increased pliability have been reported after additional dermal enhancement with either collagen-glycosaminoglycan matrix, acellular allogeneic dermis or collagen/elastin matrix. True regeneration of the dermis has not yet been observed. However, these materials are suitable for improvement of the wound bed and also the final result after split thickness skin transplantation.     

Full-thickness skin columns: A method to reduce healing time and donor site morbidity in deep partial-thickness burns

The current standard of care for the coverage of large wounds often involves split thickness skin grafts (STSGs) which have numerous limitations. One promising technique that has gained traction is fractional autologous skin grafting using full-thickness skin columns (FTSC). Harvesting occurs orthogonally by taking numerous individual skin columns containing the epidermis down through the dermis and transferring them to the wound bed. The purpose of this porcine study was to investigate the efficacy of implanting FTSCs directly into deep partial-thickness burn wounds, as well as examining donor site healing at the maximal harvest density. It was hypothesised that by utilising FTSCs, the rate of healing in deep partial thickness burns can be improved without incurring the donor morbidity seen in other methods of skin grafting. Deep partial-thickness burns were created on the dorsum of female red duroc swine, debrided 3 days later and FTSCs were implanted at varying expansion ratios directly into the burn wounds. At day 14, 1:50 expansion ratio showed significantly faster re-epithelialisation compared to the debrided burn control and 1:200. Donor sites (at 7%–10% harvest density) were 100% re-epithelialised by day 7. Additionally, the maximal harvest density was determined to be 28% in an ex vivo model, which then five donor sites were harvested at 28% density on a red duroc swine and compared to five STSG donor sites. At maximal harvest density, FTSC donor sites were significantly less hypopigmented compared to STSGs, but no significant differences were observed in re-epithelialisation, contraction, blood flow or dermal thickness. In conclusion, implantation directly into deep partial-thickness burns is a viable option for the application of FTSCs, favouring lower expansion ratios like 1:50 or lower. Little difference in donor site morbidity was observed between FTSC at a maximal harvest density of 28% and STSGs, exceeding the optimal harvest density.     

Successful homografting in an elderly patient with extensive burns using his identical twin brother as skin donor

A 60-year-old patient with 50 per cent body surface area (BSA) flame burns (of which 46 per cent were full skin thickness loss) was treated successfully with skin grafts taken from his identical twin brother to cover 20 per cent of the wounds. On theoretical grounds, it can be assumed that the period in hospital was reduced by 28 days. Blood for tissue and blood group typing should be taken at an early stage, before the patient is given a blood transfusion.     

脱细胞异体真皮与自体瘢痕薄皮复合移植的临床应用

目的:为大面积深度烧伤后期继发瘢痕挛缩、功能障碍且皮源不足的患者寻求比较理想的治疗手段.方法:切开松解功能区孪缩的瘢痕组织,将脱细胞异体真皮与自体大张瘢痕薄皮复合移植覆盖创面,加压固定包扎.结果:5例患者12个创面中,除一个创面皮片部分坏死外,余均成活.术区平整、柔软,所植皮片挛缩轻,无瘢痕增生,功能恢复良好.结论:脱细胞异体真皮 自体瘢痕薄皮复合移植是目前修复大面积深度烧伤患者功能部位创面,实现功能重建的有效方法.     

The boiled potato peel as a burn wound dressing: a preliminary report

This paper discusses the suitability of potato peel as a burn wound dressing in developing countries. Clinical trials have demonstrated that epithelial growth occurs under the potato peel dressing in superficial partial thickness skin loss burns. In deep partial, full skin thickness burns and in the late granulating burn wound the results are not so favourable. More experience is required.     

Conservative surgical debridement as a burn treatment: Supporting evidence from a porcine burn model

In thermal deep‐dermal burns, surgical debridement is normally used in conjunction with skin grafting or skin substitutes and debridement alone as a burn treatment is not usually practiced. The current study addresses whether or not debridement alone would enhance burn wound healing on small deep‐dermal‐partial thickness burns. This was a prospective and blinded experimental trial using a porcine deep‐dermal‐partial thickness burn model. Four burns, approximately 50 cm² in size, were created on each of eight pigs. Two burns from each pig were immediately surgically debrided and the other two were not debrided as the internal control. Hydrate gel together with paraffin gauze were used to cover the burns for four pigs and silver dressings for the other four. Clinical assessment of wound healing was conducted over a 6‐week period. Skin samples were collected at the end of the experiment and histopathological evaluation was performed. The results show thinner scar formation and lower scar height in the debrided compared with nondebrided wounds in the hydrate gel/paraffin gauze groups. There were no statistically significant differences in wound healing assessment between the debrided and nondebrided wounds dressed with silver dressings. This study provides supporting evidence that immediate debridement with an appropriate dressing and without skin grafting may promote wound healing, suggesting its potential benefit for clinical patients.     

The histology of early necrectomy

The healing of deep dermal burns after tangential excision and full-thickness burns after total excision was examined. The study was carried out in laboratory pigs. The results were compared with results obtained in unexcised burns. It appears that early excision of thermally damaged skin, even if the ensuing defect is left without further treatment, shortens considerably the process of healing both in tangentially excised deep dermal burns and excised full-thickness burns. (In full-thickness burns, the percentage of scar contraction during the process of healing is demonstrated and compared with scar contraction in unexcised full-thickness burns and in mechanical wounds.)     

Biosynthetic compound dressings--management of hand burns

To achieve optimal hand function, wound closure becomes the most important ingredient in hand burns. This study documents the use of a biosynthetic compound dressing (Biobrane) which has been fabricated as a glove for management of hand burns. The glove allowed rapid active motion and minimized the pain of open wounds. Forty-two Biobrane glove applications were evaluated with 50 per cent applied over superficial hand burns and 50 per cent over deep partial thickness or full thickness injuries. In the superficial hand burns, the patients were discharged home after a mean time of 2.8 days. With the deep burns the dressing provided a closed wound after early excision of eschar without the use of an autograft or biological dressing. Based on these studies, we conclude that the biosynthetic compound dressing glove is a useful adjunct to be added to the armamentarium for treatment of the burned hand.