应用三维建模有限元方法定位分析腕舟骨肿物及切除后的生物力学分析

Three-dimensional model and finite element analysis of scaphoid bone tumor and biomechanical analysis after resection

目的:通过三维建模有限元方法对腕舟骨肿物的精确定位及肿物切除后的生物力学改变,探讨三维建模及有限元分析对腕舟骨肿物切除的指导作用。方法:选择2005-07/08吉林大学中日联谊医院手外科收治的腕舟骨肿物患者1例,女,46岁。腕部疼痛3年余,查体:鼻咽窝部有压痛,腕过屈时加重。X射线片及CT片示舟骨内有一高密度肿物,周围有低密度区。利用螺旋CT获取腕舟骨肿物患者的腕骨DICOM格式文件,利用3D-Doctor1.2建立腕骨三维数字模型及虚拟切除肿物前后舟骨三维模型,导入Ansys9.0,建立实体模型,施加载荷后进行分析。结果:①三维数字模型:所有69层CT文件构建的三维数字模型,可从任意角度观察腕舟骨轮廓构建的三维数字模型,发现肿物位于腕舟骨腰部靠近远极位置,离背侧皮质距离近,于是可确定手术入路为腕背侧鼻咽窝入路。②有限元分析:从VonMises应力分布图可见肿物未切除时腕舟骨应力分布均匀,肿物切除后腕舟骨应力分布不均,提示肿物切除后存在桡舟关节创伤性关节炎或骨折的风险,有必要行植骨术。结论:三维建模及有限元分析能够术前精确定位肿物,并对切除部位是否需要植骨具有指导意义。

AIM： To investigate the guidance of three-dimensional model and finite element analysis on the resection of scaphoid bone tumor by precise localization of tumor and biomechanical changes after resection. METHODS： One female patient with scaphoid bone lumor and 3- year history of wrist pain previously, aged 46 years, was treated in the Hand Surgery Department, China-Japan Union Hospital, Jilin University from July to August 2005. Physical examination： Tenderness was present in nasopharyngeal fossa and became severe at hyperflexion. X ray and CT results showed there was a tumor of high density in scaphoid bone, with circumference of low density. DICOM files of wrist bone were obtained in the female patients with scaphoid bone tumor by spiral CT, and 3D-Doctor 1.2 software was used to establish the three-dimensional digital model of wrist bone and the virtual three-dimensional models of scaphoid bone before and after tumor resection. Then the models were introduced into Ansys9.0 to construct finite element models, and analyze their biomechanical characteristics after loading. RESULTS： ①Three-dimensional digital model： The three-dimensional digital model of scaphoid bone could be observed at every angle with three-dimensional digital model constructed by CT files of 69 layers. The tumor was found to localize in near distal pole of scaphoid bone and in short distance from cortex of back, thus the operative route was determined to be nasopharyngeal fossa of wrist back. ②Finite element analysis： The result of Von Mises stress distribution diagram indicated, the stress of scaphoid bone was well-proportioned before tumor resection while uneven after resection, which implied there was the risk of traumatic arthritis or fracture in radioscaphoid joint after tumor resection, so a bone graft was need to perform. CONCLUSION： The three dimensional model and finite element analysis can precisely localize the tumor before operation and supervise the necessary of bone graft in resected locus.