Depth of the graft bed influences split-skin graft contraction

Contraction of a split-thickness skin graft used for coverage of large defects remains a great problem in plastic, burn and reconstructive surgery. In this study we evaluated healing of split-thickness skin grafts transplanted in wounds on the subcutaneous fat and muscle fascia in pigs. Four young domestic female pigs were included in the study, and the contraction was measured planimetrically during a 3-months' follow-up. At the end of the study the scar tissue was histologically assessed. From day 42 till the end of the study grafts transplanted on the muscle fascia were significantly more contracted than grafts on the subcutaneous fat without (p < 0.001) and with (p < 0.005, unpaired t-test) correction for the growth of the animal. The histological assessment showed that after 3 months the regenerated dermal tissue in the muscle fascia wounds was thicker, and less remodeled (higher tissue cellularity and thinner collagen bundles). In conclusion, in pigs, split-thickness skin grafts transplanted into deeper wounds contract more, and scar tissue maturation seems to last longer.