OBJECTIVETo create a stable and reliable model of skin avulsion in rats.

METHODS30 male, SD rats were randomly divided into axial pattern skin flap (9 cm x 3 cm) group and random pattern skin flap group (6 cm x 4 cm), each having the control groups and avulsion groups. Flaps were subjected to avulsion force of 6 kg in axial pattern skin flaps or 8 kg in random pattern skin flaps, and the lasting time was 8 s or 12 s, respectively. Retraction of wounds and necrosis of skin flaps were observed.

RESULTSThere was more significant wound retraction in avulsion groups than that in control groups on post-operation day 7 (P < 0.05). The proportion of the wound retraction increased by 1 fold in avulsion groups on post-operation day 14 as compared to post-operation day 7 (P < 0.01). Interestingly, necrosis of partial or most of skin flaps was observed in all animals of avulsion groups, while slight necrosis happened in one of six in control animals. The necrosis area of flaps was 38% - 77% when avulsed for 8 s, and was 40% - 80% when avulsed for 12 s in axial pattern skin flaps. However, the necrosis area in random pattern skin flaps was smaller than that in axial pattern skin flaps, from 17% - 40% when avulsed for 8 s to 24% - 43% when avulsed for 12 s.

CONCLUSIONSIt might be possible to create animal model of skin avulsion injuries with rats.