Effectiveness and Safety of the PEGT/PBT Copolymer Scaffold as Dermal Substitute in Scar Reconstruction Wounds (Feasibility Trial)

Skin defects left after excision of hypertrophic scars were treated with a dermal substitute and split-thickness skin grafts transplanted after vascularisation of the substitute. The used substitute was a synthetic porous scaffold made from the biodegradable copolymer polyethyleneglycol-terephtalate and polybuthylene-terephtalate. The study was designed to assess the rate of granulation tissue formation, graft take, and after 3 and 12 months the quality of life (pain, comfort of treatment, cosmetic or functional nuisance), scar formation and wound contraction. In addition, scaffold biodegradation and scar tissue formation were evaluated histologically.Seven patients with different causes of burn injury were enrolled, of which 5 completed the study. In the first 4 patients the time between scaffold application and split-thickness skin overgrafting was in between 17 and 24 days. The time point of overgrafting was significantly reduced to 10-12 days by meshing of the dermal scaffold as evidenced in the last 3 patients. Histological evaluation at 3 months revealed normal generation of dermal tissue, however, the collagen bundles were parallel organized like in scar tissue. In the deeper layers of the neodermis, fragments of the dermal substitute were present, causing a mild inflammatory response. One year post-treatment, some fragments of the copolymer were still observed. The extent of wound contraction after successful overgrafting ranged from 30% to 57% after 1 year. All 5 patients showed an improvement in the total Vancouver Scar Score compared to the value before scar removal being similar to what can be expected when treated with split-thickness skin grafts alone. No unanticipated adverse effects due to application of the substitute were observed.We conclude that although this synthetic dermal substitute can be safely used in humans, the presence of 3D dermal template in a full-thickness skin defect will not automatically improve the skin tissue regeneration process or inhibit wound contraction.