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.