Split-Thickness Skin and Dermal Pixel Grafts Can Be Expanded up to 500 Times to Re-Epithelialize a Full-Thickness Burn Wound.

Objective: Autologous skin transplantation is limited by donor site availability for patients with extensive burns. The objective of this study was to demonstrate the feasibility and efficacy of split-thickness skin (STS) and dermal pixel grafts (PG) in the treatment of burns. Approach: The study was divided into three arms of validation, expansion, and combination that all followed the same study design. Sixteen deep partial-thickness burns were created on the dorsum of anesthetized pigs. Three days postinjury the burns were debrided and grafted with STS and dermal PGs. The PGs were prepared by harvesting two skin grafts (split-thickness skin graft [STSG] and dermal graft) from the same donor site going down in depth. The grafts were minced to 0.3 × 0.3 × 0.3 mm PGs and suspended in a small volume of hydrogel. Healing was monitored for 6, 10, 14, or 28 days. In the validation study the PGs at 1:2 expansion ratio were transplanted and compared with STSG and untreated controls. The expansion study investigated the maximum expansion potential of the PGs and the combination of the benefits of transplanting STS and dermal PGs together. Results: The validation study showed that when STS and dermal PGs were transplanted in a 1:2 ratio they fully re-epithelialized the wounds in 14 days. The expansion study demonstrated that using expansion ratios up to 1:500 the wounds were re-epithelialized by day 28. The combination study showed that there was no additional benefit to use STS and dermal PGs together. Innovation: Pixel grafting provides expansion ratios greater than conventional STSG. The possibility to harvest both STS and dermal PGs from the same donor area further reduces the need for healthy skin. Conclusion: STSG and dermal grafts can be minced to PGs with preserved viability and expanded up to 500 times to re-epithelialize a wound.

No statistically significant difference in long term scarring outcomes of pediatric burns patients treated surgically vs. those treated conservatively.

Introduction: Paediatric burns are a common clinical presentation. The long-term scar outcomes in paediatric burns patients are relatively unknown as most are discharged after 6 weeks follow up, apart from the small number that are followed up by scar services depending on geographical availability. We aimed to determine whether the long-term scarring outcomes are significantly different in those who had surgical treatment with Versajet® debridement and Biobrane®, vs. those treated conservatively with non-adherent Mepitel® and Acticoat® dressings, in a cohort of paediatric burns patients. Methods: The parents of all paediatric burns patients admitted to Stoke Mandeville Hospital from October 2014 to September 2017 were contacted by telephone to fill in the paediatric Brisbane Burn Scar Impact Profile (BBSIP), the only patient reported outcome measure (PROM) specifically aimed at children. The results from the questionnaires underwent statistical analysis to see if there was a significant difference in questionnaire scores between children treated surgically vs. those treated conservatively. Results: A total of 107 children were admitted in the timeframe, responses were received from 34 patients with 13 having been treated surgically and 21 having been treated conservatively. In all 58 questions that make up the BBSIP, there was no statistically significant difference observed in the scores of those treated surgically vs. those treated conservatively. For 31 questions on the BBSIP, the lowest score indicating the best outcome was observed in all patients in both groups. Discussion: Surgical management for burns is always the last resort. Our results could be interpreted to suggest clinicians need not fear the longer-term impact a scar may have when deciding whether to treat a paediatric burns patient surgically or conservatively. This study is the first to assess longer-term scar outcomes using the BBSIP. A larger data set and comparison with other burn units in the UK may help to provide more information on scar outcomes between different methods of surgical and conservative treatment. We found no statistically significant difference in the long-term scar outcomes as assessed by the BBSIP in paediatric burn patients treated with Versajet® debridement and Biobrane®, vs. those treated conservatively with non-adherent Mepitel® and Acticoat® dressings.

A Systematic Review Comparing Animal and Human Scarring Models.

Introduction: A reproducible, standardised model for cutaneous scar tissue to assess therapeutics is crucial to the progress of the field. A systematic review was performed to critically evaluate scarring models in both animal and human research. Method: All studies in which cutaneous scars are modelling in animals or humans were included. Models that were focused on the wound healing process or those in humans with scars from an existing injury were excluded. Ovid Medline® was searched on 25 February 2019 to perform two near identical searches; one aimed at animals and the other aimed at humans. Two reviewers independently screened the titles and abstracts for study selection. Full texts of potentially suitable studies were then obtained for analysis. Results: The animal kingdom search yielded 818 results, of which 71 were included in the review. Animals utilised included rabbits, mice, pigs, dogs and primates. Methods used for creating scar tissue included sharp excision, dermatome injury, thermal injury and injection of fibrotic substances. The search for scar assessment in humans yielded 287 results, of which 9 met the inclusion criteria. In all human studies, sharp incision was used to create scar tissue. Some studies focused on patients before or after elective surgery, including bilateral breast reduction, knee replacement or midline sternotomy. Discussion: The rabbit ear scar model was the most popular tool for scar research, although pigs produce scar tissue which most closely resembles that of humans. Immunodeficient mouse models allow for in vivo engraftment and study of human scar tissue, however, there are limitations relating to the systemic response to these xenografts. Factors that determine the use of animals include cost of housing requirements, genetic traceability, and ethical concerns. In humans, surgical patients are often studied for scarring responses and outcomes, but reproducibility and patient factors that impact healing can limit interpretation. Human tissue use in vitro may serve as a good basis to rapidly screen and assess treatments prior to clinical use, with the advantage of reduced cost and setup requirements.

Negative Pressure Wound Therapy for Burns.

Negative pressure wound therapy (NPWT) has become a widely used treatment for acute and chronic wounds. NPWT is indicated for a variety of complex wounds, and some studies validate its use for certain aspects of burn care. Although further research is needed to explore the benefits for burns, NPWT has proven beneficial in its use as a dressing that bolsters skin grafts, promotes integration of bilaminate dermal substitutes, promotes re-epithelialization of skin graft donor sites, and potentially reduces the zone of stasis. This article reviews the literature on NPWT in burns, based on indication/application, and describes our experience with the use of modified NPWT for large burns.

A review of negative-pressure wound therapy in the management of burn wounds.

OBJECTIVE: Negative pressure has been employed in various aspects of burn care and the aim of this study was to evaluate the evidence for each of those uses. METHODS: The PubMed and Cochrane CENTRAL databases were queried for articles in the following areas: negative pressure as a dressing for acute burns, intermediate treatment prior to skin grafting, bolster for skin autografts, dressing for integration of dermal substitutes, dressing for skin graft donor sites, and integrated dressing in large burns. RESULTS: Fifteen studies met our inclusion criteria. One study showed negative pressure wound therapy improved perfusion in acute partial-thickness burns, 8 out of 9 studies showed benefits when used as a skin graft bolster dressing, 1 out of 2 studies showed improved rate of revascularization when used over dermal substitutes, and 1 study showed increased rate of re-epithelialization when used over skin graft donor sites. CONCLUSIONS: Negative pressure can improve autograft take when used as a bolster dressing. There is limited data to suggest that it may also improve the rate of revascularization of dermal substitutes and promote re-epithelialization of skin graft donor sites. Other uses suggested by studies that did not meet our inclusion criteria include improving vascularity in acute partial-thickness burns and as an integrated dressing for the management of large burns. Further studies are warranted for most clinical applications to establish negative pressure as an effective adjunct in burn wound care.