Effects of split-thickness and full-thickness skin grafts on secondary graft contraction in horses.

The research article studied the effects of using split-thickness and full-thickness skin grafts on the amount of contraction that occurs in the wound area of horses. It found that the type of graft used, whether split-thickness or full-thickness, did not significantly affect the contraction rate. However, whether the graft was applied to a fresh or granulating wound did significantly impact the contraction rate, with fresh wounds showing less contraction.

Experiment Set-up

• The study made round full-thickness wounds, measuring 4cm in diameter, on the metacarpus and metatarsus areas of six horses.
• Each horse had one wound treated with a meshed, split-thickness skin graft, and another wound treated with a meshed, full-thickness skin graft. The split-thickness grafts were taken from the horse’s ventrolateral thorax using a pneumatic dermatome, and the full-thickness grafts were taken from the pectoral area.
• Furthermore, sections of both types of skin grafts were refrigerated in a solution made up of McCoy’s 5A medium, 10% equine serum, and 16mg/dl of gentamicin sulfate solution.
• Ten days after initial wounding, each horse also had one granulating wound treated with a refrigerated, meshed, split-thickness graft and another treated with a refrigerated, meshed, full-thickness graft.

Data Collection and Analysis

• The areas of the wounds were measured and calculated from photographs taken on days 1, 5, 10, 15, 20, 25, and 30 after the initial wounding.
• To determine the time course of wound contraction, a first-order mathematical model was used, modelling changes in wound area over time.
• The study compared the rate constants of wound contraction from different types of grafts on either fresh or granulating wounds.

Results and Conclusion

• The study found that the rate constants of contraction in wounds receiving full-thickness grafts were not significantly different from those receiving split-thickness grafts.
• However, the rate constants of contraction were significantly different when comparing fresh and granulating wounds, regardless of the type of graft used. Fresh wounds exhibited less contraction compared to granulating wounds.
• This suggests that the state of the wound at the time of grafting (whether fresh or granulating) impacts the contraction rate more significantly than the type of graft applied.