The study of development of new simulation system for corrective surgeries for spinal defurmity

各种脊柱内固定手术已用于治疗脊柱侧弯。然而，由于脊柱侧弯是一种三维畸形，通常很难为特定的患者选择最佳的手术方式。本研究的目的是使用具有椎间盘、椎体和肋骨的力学特性的三维数学模型来模拟脊柱侧弯的手术矫正。术前采用双平面X线摄影测量法进行脊柱形态三维测量。在轴位牵引下拍摄X线片，估算材料代偿系数。利用该模型，我们模拟了23例脊柱侧弯矫正手术，平均Cobb角为52°。术后常规X线片平均Cobb角为28.5°，模拟片平均为28.3°。两者的平均相差为6.0度。对于后凸，常规X线片为14.2度，模拟为19.2度。两种测量方法的平均差异为7.4度。轴向旋转时，CT测量的旋转角度为12.3°，模拟测量的旋转角度为9.7°。两种方法之间的平均差异为3.6度。使用我们的模拟模型可以三维地预测内固定手术的矫正效果。该模型在器械手术中得到了实际应用。

Various spinal instrumentation surgery for scoliosis have been carried out. However, since scoliosis is a three-dimensional deformity, it is frequently difficult to select an optimum surgery for a particular patient. The purpose of this study is to simulate surgical correction of scoliotic spine using a three-dimensional mathematical model having mechanical properties of the disc, the vertebral body, and the rib cage. Preoperative spinal shape was measured using bi-plane X-ray photogrammetry three-dimensionally. Material compensational coefficient of each patient was estimated by X-ray film taken under axial traction. Using this model, we simulated 23 corrective surgeries for scoliosis with average Cobb angle 52 degrees. Postoperative average Cobb angle was 28.5 degrees on conventional X-ray and 28.3 degrees by the simulation. The average difference of the two was 6.0 degrees. For kyphosis, 14.2 degrees on conventional X-ray and 19.2 degrees by the simulation. The average difference of two methods of measurement was 7.4 degrees. In axial rotation, postoperative rotation angle was 12.3 degrees using computed tomography and 9.7 degrees by the simulation. The average difference between two methods was 3.6 degrees. The corrective effect of the instrumentation surgery could be predicted three-dimensionally using our simulation model. The model was put to practical use for the instrumentation surgery.