基于角膜生物力学对小切口角膜基质透镜取出手术优化及联合角膜胶原交联手术的效果分析  

Parameter Optimization of Small Incision Lenticule Extraction and Analysis on Surgical Effect of Corneal Cross-Linking Based on Corneal Biomechanical Properties

作　　者：肖策文 肖厦子 文丹[2,3] 夏晓波 尹叶薇[2,3] XIAO Cewen;XIAO Xiazi;WEN Dan;XIA Xiaobo;YIN Yewei(Department of Mechanics,School of Civil Engineering,Central South University,Changsha 410075,China;Eye Center of Xiangya Hospital,Central South University,Changsha 410008,China;Hunan Key Laboratory of Ophthalmology,Changsha 410008,China)

机构地区：[1]中南大学土木工程学院,力学系,长沙410075 [2]中南大学湘雅医院眼科中心,长沙410008 [3]眼科学湖南省重点实验室,长沙410008

出　　处：《医用生物力学》2022年第6期1032-1038,共7页Journal of Medical Biomechanics

基　　金：国家自然科学基金项目(11802344);湖南省优秀青年基金项目(2022JJ20051)。

摘　　要：目的 建立小切口角膜基质透镜取出(small incision lenticule extraction, SMILE)手术的有限元模拟体系,模拟术后角膜生物力学性能变化,为SMILE手术的优化设计提供依据,并探讨角膜胶原交联(corneal collagen cross-linking, CXL)手术对SMILE术后角膜生物力学性能的影响。方法 采用交联强度梯度分布的超弹性本构关系描述角膜的生物力学性能,建立SMILE手术的压痕有限元模型,设置不同的切口位置、切口弧度、侧切口角度和角膜帽厚度,分析SMILE术后角膜生物力学性能的变化;对SMILE术后角膜进行CXL手术的有限元模拟,分析不同辐射能量对角膜生物力学性能的影响。结果 随着切口位置角度变小、切口弧度增加、侧切口角度从90°增大到135°或减小到45°、角膜帽厚度减小,SMILE术后角膜最大von Mises应力不断增大;随着辐射能量增加,CXL术后最大von Mises应力不断增加。结论 构建的有限元模型可有效表征SMILE术后角膜的生物力学响应,为SMILE手术的优化设计提供模拟依据;CXL手术有助于提高SMILE术后角膜的生物力学强度。Objective To establish a finite element simulation system for the surgery of small incision lenticule extraction(SMILE) and provide foundation for the optimization of SMILE based on simulation results of corneal biomechanical properties, and to study the effect of corneal collagen cross-linking(CXL) on biomechanical properties of the cornea after SMILE. Methods The mechanical behaviors of the cornea were characterized by hyperelastic constitutive relations with the consideration of gradient distributions of cross-linking strength. The indentation finite element model of SMILE was established. By setting up different surgical parameters such as incision position, incision length, side-cut angle and thickness of corneal cap, the corneal biomechanical behaviors after SMILE were simulated and analyzed. The finite element simulation under different irradiation doses was conducted to analyze the effect of CXL on the cornea after SMILE. Results The maximum von Mises stress increased as the angle of incision position decreased, the incision length increased, the side-cut angle changed from 90° to 135° or 45°, and the thickness of corneal cap decreased. Moreover, the maximum von Mises stress after CXL increased with the radiation dose increasing. Conclusions The finite element model of SMILE constructed in this study can effectively be used to characterize corneal biomechanical responses and provide simulation references for the optimization of SMILE. In addition, the reduced corneal biomechanical strength after SMILE can be effectively improved by CXL.

关 键 词：小切口角膜基质透镜取出 角膜胶原交联 角膜 生物力学性能 

分 类 号：R318.01[医药卫生—生物医学工程]