Abstract: Objective   To investigate the relationship between the perforating vessels of grade IV perforators and the survival of reticular blood-supplying flap, and to compare the distribution of grade IV perforating vascular network in multi-site skin tissue of the whole human body.    Methods    Eighteen healthy adult SD rats, weighing 200~250 g, were not restricted to males and females. They were divided into a normal skin group (control group), a reticular blood supply flap group on both sides of the abdomen, and a reticular blood supply flap group on both sides of the back. There were 6 flaps in each group. The model was made by using the method of making blood-supply skin flaps with reticular blood vessels. At the same time, the excess skin tissue of the "cat ear" deformity formed during suture of donor site  of patients with skin defects of head and face, inner and outer thighs and the inner and outer leg were collected in our hospital. On the 7th day after operation of the rat, the survival rate of the skin flap was calculated by using Image J software. The skin tissues of each group of rats and the excess skin tissues of the patient′s donor area were taken.  HE and CD31 staining were used to compare the density of IV perforator blood vessels and diameter situation.    Results    On the 7th day after operation, the survival rate of the back reticular blood supply flap was higher than that of the abdominal reticular blood supply flap (P<0.05). The density of grade IV perforator blood vessels in the back skin of the normal group was higher than that in the abdominal skin (P<0.05), but there was no significant difference in diameter (P>0.05). The diameter of the distal grade IV perforating vessels was significantly decreased compared with the proximal end in the abdominal and back flap group (P<0.05), while the density was significantly increased compared with the proximal end (P<0.05). Comparison of the diameters of grade IV perforator vessels: head > inner thigh, outer thigh, inner calf, outer calf > inner calf, the difference was statistically significant (P<0.05), the outer thigh was larger than the inner thigh, the difference was not statistically significant. Comparison of blood vessel density: head > inner and outer thigh, inner and outer calf, outer thigh> inner thigh, outer calf> inner calf, the difference was statistically significant (P<0.05).    Conclusions    The distribution of grade IV perforating vessels is different in different parts of the whole body. The density of grade IV perforating vessels is of great significance for the survival of skin flap. The ratio of length to width of the reticular vascular flap is related to the density of subdermal vascular network and / or the diameter of blood vessels.

Key words: Perforator flap,  ,  , Reticular vascular flap,  ,  , Grade IV perforator