颅颌面外科手术术前预测模拟相关技术研究

With the development of techniques in computer-assisted orthognathic surgery, the research on craniofacial morphology and modeling of bone and soft tissue has been an important part in maxilla-craniofacial therapy. 3D reconstruction of hard and soft tissues models, quantitative measurement and virtual surgical simulation results provide a significant reference to optimize surgical programs and enhance communication between surgeon and his patient. Especially, the prediction of new facial outlook is particularly important. This proposal intends to study the key technologies on prediction of the deformation of the facial soft tissues due to bone movement and build a pre-operatively maxillofacial soft tissue prediction system. Firstly, an ideal three-dimensional data model of bone and soft tissue will be built with well anatomical structure and high mesh quality, and the contact of bone and soft tissue will also be considered, so that it can be well applied in building physical models for soft tissue deformation. Moreover, the physiological characteristics of craniofacial soft tissue and existing physically-based deformation algorithms will be researched, in order to build a multi-layered soft tissue model for accurately and real-time displaying the new facial changes due to bone movement. And morever, the proposed model will be applied in clinical applications, to validate its accuracy for further improvement of the simulation results of predicting. Once the research purposes could be successfully achieved, it will have a huge application perspective in the field of computer assisted design and prediction of post-operative facial outcome for maxillofacial surgery.

随着计算机辅助正颌外科技术的发展，研究分析颅頜面软硬组织模型及形态，已经成为颅頜面外科手术治疗的重要组成部分。软硬组织的三维建模、测量分析及手术效果仿真，为优化手术方案、增进医患交流提供了重要的参考依据。其中软组织容貌的预测尤为重要。本项目将重点研究如何实时、准确地反映骨骼移位、缺失、填充造成的软组织形变模拟的相关关键技术问题，并建立一个完整的颅頜面术前辅助模拟预测平台。重点研究建立一种理想的软硬组织三维数据模型，既能真实体现頜面软硬组织的解剖结构，软硬组织附着关系，又能直接应用于建立面部软组织模型。重点研究颅頜面生理特性，分析现有的物理形变算法，建立多层软组织物理形变模型，以实时精确地显示骨组织重置导致的颅頜面容貌变化。并进一步在临床实际应用中，验证预测模型的准确性，对形变模拟加以改进完善。若研究目标能够顺利实现，将在计算机辅助颌面外科术前设计与术后评估方面都具有重要的应用价值。

本项目研究和分析了颅頜面软硬组织模型及形态，包括软硬组织的三维建模、测量分析及手术效果仿真，为优化手术方案、增进医患交流提供参考依据。本项目详细研究了如何实时、准确地反映骨骼移位、缺失、填充造成的软组织形变模拟的相关关键技术问题，并建立了一个颅頜面术前辅助模拟预测平台。首先，本项目研究了软硬组织三维模型生成技术，针对面部皮肤的特殊结构，提出了一种基于3D扫描数据生成体网格的方法(简称为ST算法)，该算法保证了面部软组织的结构特性，并且生成的模型可以直接作为后续形变的几何模型应用于建立软组织形变模型。其次，在形变模型方面，本项目分析了传统的质点弹簧算法和有限元算法，质点弹簧模型虽然易于实现但是算法精度不高，而有限元方法虽然计算量大但算法精度高，本项目通过设计实验分析了两种方法模拟皮肤组织的效果，在模拟预测平台中采用有限元方法作为形变建模方法。最后，本项目基于C++语言，OpenGL图形开发包和QT用户界面应用程序开发框架设计搭建了颅頜面术前辅助模拟预测平台，并通过真实数据的实验验证了颅颌面外科手术术前辅助模拟预测系统。