基于剔除拟合的股骨头修复建模

Reparative modeling for femoral head based on eliminative fitting

提出了一种可以获得目标病例健康时股骨头模型的新建模方法.通过CT扫描获得髋骨部位的序列断层图像,利用一种精确的自动分割方法提取图像中的髋臼轮廓.针对髋臼的特殊结构,使用辐条式采样法得到髋臼凹面的空间坐标点集.剔除坐标点集中的误差采样点.采用闭合形式解的最小二乘法拟合原始股骨头球面模型.通过对2例不同坏死程度的男性患者进行修复实验,证明此方法可以良好地还原坏死的股骨头模型,既为骨科临床中的精确手术定位提供了理论模型,又为针对个体化制造的人工假体生产提供了新的实践方法.

The quality of fit between femoral head and acetabulum plays an important role in the operative treatment with femoral head repairing or total hip replacement. For the sake of getting the quondam femoral head model of the aiming sufferer in health, a novel modeling method is proposed. It can restore the state of the sinking femoral head owing to ischemic necrosis. By getting the serial tomograms of hip bone part from CT scan; the contour of acetabulum is extracted through an accurate and automatic method. Then contraposing the special structure of acetabulum, a new sampling method named ‘spoke＇ is devised to gather the fiducial marks in the concave of acetabulum. After removing the lumping error sampling points from the fiducial mark muster, a least square method with closed form is used to fit the sphere model of femoral head. Two male sufferers with different necrosis extent were chosen as experimental subject. The restored model produced through above process resembled the primary shape precisely. This new method affords a theoretical model for accurate operation position fixing in orthopaedics clinic, and it also provides an innovative practical means for the individually manufacturing of artificial femoral head.