On every rabbit, bi-axial flap is verified along the back based on thoraco-dorsal artery and the deep iliac artery, flap has the average size 21 cm length, 7 cm width, 2/3 distance delay flap (tail side) is released and elevated by U-shape incision, to isolate artery supply from below and two sides to flap, put a silicone sheet which made hole under flap then close flap, control flap is symmetric flap on the back of every rabbit.