【作者】 刘英；

【导师】 胡仕新； 王树新；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 医疗机器人的出现为血管吻合手术带来了新的发展。与传统血管吻合手术相比,机器人辅助血管吻合手术具有精度高、操作稳定等优点,但也存在手眼配合不协调和触感信息缺失等缺点。本文针对血管端端吻合手术,分析其物理过程和操作规程,构建了适合机器人辅助血管吻合手术的质量评价方法,建立了质量参数和手术参数之间的手术优化数学模型,通过数理统计工具,得到了蕴涵在质量参量与缝合参量之间的影响规律。论文主要工作进展与成果如下:(一)、给出了血管端端吻合手术中缝线许用张紧力范围的计算方法。在常规血管吻合手术质量评价体系的基础上,确立了基于机器人操作模式的手术质量评价参数与影响因素,给出了血管端端吻合手术中的力学模型;运用有限元方法,得出了在缝线张紧力变化过程中,血管组织变形状态和组织应力的分布,给出了保证血管吻合手术成功的缝线许用张紧力范围。(二)、分析了缝合变量对血管吻合手术质量的影响规律。建立了以缝点个数、缝合边距、缝线张紧力为设计变量,以增加缝线许用张紧力范围和减小血管轴向组织应力分布差值为优化目标的多目标优化设计模型。以试验设计方法,建立了目标函数与优化变量之间的响应关系,给出优化手术质量的Pareto优化设计结果,并对医生的手术操作提出了相应的建议。(三)、进一步分析了噪声变量对血管吻合手术质量的影响规律,在手术优化设计的基础上,建立了以血管材料特征函数、血管壁厚为噪声变量的稳健设计模型。以试验设计方法,得到了质量特性与变量之间的响应关系。根据稳健设计的数据,分析了设计变量对质量特性均值、标准偏差的影响规律,以及设计变量与噪声变量对质量特性的相关非线性效应,给出了以信噪比为质量功能性评价的Pareto稳健设计结果,并比较了两种设计方法得到的各设计方案的不同。更多还原

【Abstract】 The robot-assisted anastomosis holds great promise for the future in many surgical procedures involving blood vessels. Compared with traditional surgery, high precision and accuracy can be obtained in robot-assisted surgery, especially in microvascular reconstruction. A robotic system can provide quantitative information of tissue dimensions, supply force feedback, and enhance the surgeon’s vision and kinematic capabilities. However, robot-assisted surgery also has some limitations, i.e., the lack of haptic feedback and high eye-hand coordination required of the surgeon. Because of the difference in the operations between traditional surgery and robot assisted surgery, there is a new challenge in ensuring the sucessful completion and quality of surgical procedures. This dissertation develops new quality evaluation criteria based on the physical process and clinical requirements of end-to-end vessel anastomosis. Mathematical models are developed for the optimization of the end-to-end vessel anastomosis. The relationships between surgery quality and process factors are obtained using statistical methods. The contributions of the disseration are as follows:(1). A new method is developed to obtain the allowable limit of the suture tension in order to avoid blood osmosis and keep the tissue free from injury. Based on the classical surgery evaluation system, the new quality evaluation criteria and process factors are presented for the robot-assisted anastomosis. A three-dimensional finite element model of anastomosis is presented to establish the mechanical relationship between the vessel and sutures. The stress distribution of the vessel loaded by the suture is calculated using finite-element simulations and the limit of the suture tension is given to allow successful surgical tasks.(2). A mathematical model, including optimization variables, multi-objective functions and constraint conditions, is established to describe the optimization problem in robot-assisted vessel anastomosis. Simulation experiments are arranged by design of experiment to obtain the allowable tension range of suture and distribution of tissue stress based on finite element model of surgery process. The relationship between the objective functions and process variables is extracted from experimental data. A Pareto optimal solution is presented which aids surgeons in process parameter selection according to applications. (3). A robust design is carried out to consider the influence of the noise variables on the relationship between surgery quality and design variables. The noise variables investigated include the wall thickness of blood vessel and vessel property described using material constitutive equation. Based on such robust design, the effects of design variables on the mean value and standard deviation of the objective function are analyzed, and the influence of noise variables is also discussed. Furthermore, a Pareto optimal solution is also provided with the objective of increasing the S/N ratio, which is defined as the ratio of mean response over standard deviation. Finally, results from traditional optimal design are compared with those obtained by robust design.更多还原