The Effect of External Beam Irradiation Timing on Skin Graft Survival

Background: The purpose of this study was to evaluate skin graft integrity after external beam irradiation in a rat model. Methods: Forty-eight male Wistar rats were randomly assigned to 8 groups (A, B, C, D, Ac, Bc, Cc and Dc). A rectangular full-thickness skin graft was raised and reapplied to its original bed on the dorsum of each rat. Groups Ac, Bc, Cc and Dc were the control groups and were not given postoperative irradiation. After grafting, 25 Gy unfractioned cobalt60 irradiation was administered to groups A, B, C and D on postoperative days 10, 20, 30 and 40, respectively. Histological samples were obtained 8 weeks after grafting. Dermal and epidermal thickness were measured by the KS-400 image analysis program. Results: The difference in the epidermal and/or dermal thickness between the irradiated groups was not found to be significant. Furthermore, when histological features and the image analysis of the irradiated groups were compared with each other, there were no significant differences between the groups. Conclusions: Although we are aware that experimental results may not directly translate to the clinical setting, the present study indicates that external radiotherapy can be performed to skin-grafted areas as early as 10 days postoperatively.