颈椎骨铣削表面温度变化规律与预测研究

发布时间：2018-06-29 06:08

本文选题：骨骼 + 逆向工程　；参考：《山东科技大学》2017年硕士论文

【摘要】：目前,颈椎手术中颈椎骨铣削的好坏大多依赖于医生的操作技巧和实践经验,手术具有较高的风险性。颈椎骨铣削同金属铣削有诸多不同,尤其是铣削过程产生大量的热量,会导致骨组织坏死和邻近神经组织的热损伤。研究表明,骨组织的活性与温度及高温持续时间有很大关系,高温导致酶的活性急剧降低,同时,高温会造成骨细胞脱水,进而死亡。由于骨组织及其他周围组织对温度较为敏感;颈椎骨模型复杂,铣削温度变化情况复杂;颈椎骨组织材料属于非匀质材料,较难找出其传热规律等,对颈椎骨铣削的机理进行基础性研究,从而使医生对颈椎骨手术过程中的热损伤有直观的量化感知是颈椎骨手术研究的重点。针对颈椎骨铣削生热的问题,首先,本文对颈椎骨医学扫描CT数据进行可视化处理,通过Mimics、Geomagic等多软件间的结合,对颈椎骨模型进细节优化以适应有限元分析的要求,通过UG将骨骼的三维模型实体化,导出可用的三维模型。其次,本文通过对铣削传热理论的深入研究,借鉴移动热源理论,将单刃铣削的情况等效为移动的持续发热热源,建立了适合骨骼铣削的传热模型。然后,基于骨骼铣削的传热模型,通过对骨骼材料模型的定义,利用DEFORM对骨骼的铣削过程进行有限元分析,得出了颈椎骨铣削温度、铣削力与铣削深度、铣削速度之间的关系,同时,对铣削后铣削温度在骨骼纵深上的分布做了研究,使颈椎骨表面温度变化规律有了直观的呈现。最后,基于颈椎骨铣削温度与各铣削参数之间的关系,利用MATLAB神经网络工具箱对影响铣削温度的各因素进行训练,建立了复杂的铣削温度变化规律同各铣削参数之间可预测的神经元网络模型,基于该模型实现了对颈椎骨铣削温度的较精确预测。本研究对于防止颈椎骨铣削温度过高而造成的严重的组织热损伤,提高铣削表面质量均具有重要意义;并通过仿真分析各铣削参数与铣削温度的关系,为医生实施高效低热损铣削提供合理的方案;也为脊椎骨骼手术诊断、治疗、评价和治疗方案的优化提供理论依据。
[Abstract]:At present, the quality of cervical vertebrae bone milling in cervical spine surgery mostly depends on doctor's operation skill and practical experience, so the operation has high risk. There are many differences between the milling of cervical vertebrae and metal milling, especially the large amount of heat produced during milling, which will lead to the necrosis of bone tissue and the thermal damage of adjacent nerve tissue. The results showed that the activity of bone tissue was closely related to temperature and duration of hyperthermia. High temperature resulted in a sharp decrease of enzyme activity, while high temperature resulted in dehydration of bone cells and death. Because bone tissue and other surrounding tissues are sensitive to temperature, the model of cervical vertebrae is complex, the change of milling temperature is complicated, and the material of cervical vertebrae bone is non-homogeneous, so it is difficult to find out the heat transfer law, etc. The basic research on the mechanism of cervical vertebrae milling is carried out, so that the doctors have a direct and quantitative perception of the thermal injury in the process of cervical vertebrae surgery is the focus of cervical spine bone surgery. Aiming at the problem of hot milling of cervical vertebrae, firstly, the CT data of cervical vertebrae medical scanning are visualized, and by the combination of Mimicsl Geomagic and other software, the model of cervical vertebrae is optimized in detail to meet the requirement of finite element analysis. The three-dimensional model of bone is materialized by UG, and the available three-dimensional model is derived. Secondly, by studying the theory of heat transfer in milling and using the theory of moving heat source for reference, the case of single-edge milling is equivalent to that of moving heat source, and a heat transfer model suitable for bone milling is established. Then, based on the heat transfer model of bone milling, through the definition of bone material model and finite element analysis of bone milling process by deform, the relationship between milling temperature, milling force and milling depth and milling speed of cervical spine is obtained. At the same time, the distribution of milling temperature in the depth of bone is studied, which makes the rule of surface temperature of cervical vertebrae appear intuitively. Finally, based on the relationship between milling temperature and milling parameters of cervical spine, MATLAB neural network toolbox is used to train the factors that affect milling temperature. A neural network model of complex milling temperature variation law and various milling parameters is established. Based on the model, a more accurate prediction of the milling temperature of cervical vertebrae is realized. This study is of great significance to prevent serious tissue thermal damage caused by excessive temperature of cervical spine milling and to improve milling surface quality, and the relationship between milling parameters and milling temperature is analyzed by simulation. It provides a reasonable scheme for doctors to carry out high-efficiency low-heat loss milling, and also provides a theoretical basis for the diagnosis, treatment, evaluation and optimization of surgical treatment of spinal skeleton.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R608

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