Objective Animal study is to investigate the biomechanics properties of using the botulinum toxin A to accelerate the expansion in forehead. Methods The bilateral chest and abdomen of every guinea pig was marked symmetrically in grid by tattoo. The botulinum toxin A was injected in cutaneous muscle of one side as the experimental group, the saline in other side as the control group. Implanted a 200ml expander beneath the cutaneous muscle on the bilateral chest and abdomen, and it was inflated 20ml each time, twice a week. After finished expansion, the specimens were obtained from the expanded flap and the capsule was resected. The stress-strain relationship, stress relaxation and creep of these specimens were tested by the material testing machine Instron4302. Results The viscoelasticity of the flap in the experimental group was better than the control group and similar to the unexpanded flap. In the same relaxation time.the flap in the experimental group was easy to relax than the control group. Keeping the same stress.the creep strain in the experimental group was less than the control group in the same period. Conclusion The botulinum toxin A can enhance the viscoelasticity of the expanded forehead flap.and make it similar to the unexpanded flap. It also can reduce the inflation resistance, accelerate the expansion,shorten the expansion period and enhance the area of expanded myocutaneous flap in forehead.%目的:通过动物实验探讨A型肉毒毒素注射后额部扩张皮瓣的生物力学性能的变化规律,以期为临床应用提供理论依据.方法:选用白色实验小型猪,在其胸腹部两侧用作网格样标记,一侧注射A型肉毒毒素,对侧注射生理盐水对照,两侧置入200ml扩张器,注水完成后切取全层扩张皮瓣作为试件,在Instron4302万能材料试验机上对皮瓣试件进行应力-应变、应力松弛和蠕变实验.结果:实验组皮瓣的粘弹性比对照组的好,更接近于未扩张皮瓣；在同样的松弛时间内,实验组皮瓣比对照组更容易松弛；在相同的应力作用下,相同的时间内,实验组皮瓣的蠕变量要小于对照组.结论:注射A型肉毒毒素后,可以使扩张皮瓣的粘弹性增强,更接近于未扩张皮瓣,扩张器注水量增加,注水间隔缩短,在相同注水量下扩张面积增加.
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