基于皮肤生物力学的推进皮瓣三维有限元模型与模拟分析

目的 探讨建立局部推进皮瓣的三维有限元模型,用以观测计算推进皮瓣手术后手术区域皮肤变形及应力分布情况,以供临床皮瓣设计参考.方法 通过人体额部离体头皮的生物力学实验研究获取皮肤的生物力学参数,再利用三维有限元软件MSC Marc/Mentat 2005建立局部推进皮瓣的三维有限元模型,设计同一皮瓣修复不同面积的创面,模拟出皮瓣在不同的抻长比例下,观测手术区域术后皮肤组织的变形情况、相应的应力-应变分布情况.结果 皮瓣推进后的抻长比例越大,术后手术区域的应力最大值也随之越大,但不符合线性规律.在不顾及皮瓣血运的条件下,理论上皮瓣抻长比例的最大限度可达到40%,若＞40%,皮肤应力将超过屈服极限.结论 利用三维有限元方法及人体皮肤生物力学参数模拟分析推进皮瓣具有可行性,但其抻长比例应控制在40%范围内,以确保安全.

Three-dimensional finite element models of advancement skin flap and simulation analysis based on skin biomechanical features

Objective To build three-dimensional (3-D) finite element models for local advancement skin flap, by which the post-operative local strain and local stress of skin were figured out to assist in the design of skin flap in clinic. Methods The biomechanical parameters of human forehead skin were obtained in vitro from biomechanical experiments. The 3-D finite element model of local advancement skin flap was set up by MSC Marc/Mentat 2005 (3-D finite element software). Six models were built with the same flap but different skin defects, to simulate post-operative local strain of skin and local stress of skin in different models. Results Post-operative local stress of skin increased with the skin flaps stretching, but the relationship between increase and stretching did not meet the linear rule. Skin flap was able to stretch to 40 % of its initial length in theory if we did not consider blood supply of it. When the skin flap stretched over 40 % of its initial length, the maximal stress could exceed the yield limit. Conclusion It is an effective and workable way to simulate local advancement skin flap using 3-Dfinite element model and biomechanical parameters of human skin. The stretch ratio of local advancement skin flap should be not over 40% for safety.