A Research into the Development of the Device for Correcting and Fixating Infantile and Juvenile Scoliosis

本研究旨在开发一种矫正婴幼儿及青少年脊柱侧凸的延长棒系统。该系统是在千叶脊柱内固定系统（CSS）的基础上，为了满足儿童生长发育的需要，在器械中心增加了一个移动的系统。根据移动的系统的形状，研制了三种不同的测量仪器。A型由一个直径为13 mm的外圆柱体组成，一个双结构齿轮固定在圆柱体中，以允许向两端延伸。类型B具有与类型A类似的直径为12 mm的移动的系统。类型C由手动操作的移动的系统组成，直径为10 mm，以允许伸长。采用Rigolac材料制作的30 °和50 °弯曲脊柱模型进行生物力学研究，结果表明，CSS双棒稳定性弱于CSS双棒，但与单棒相当，其中B型效果最好。使用Beagle犬的动物实验表明，尽管软组织的张力增加，但在将该系统安装到犬体内后3周、6周和12周，杆可以伸长。但在12周龄时，需要松解软组织以延长棒。结果使我们确信，即使在安装该系统12周后，也可以通过小的皮肤切口手动延长杆。我们相信，通过在弯曲的凸面上增加一个压缩杆，可以获得更好的稳定性。我们还希望在A型和B型中安装一个电机，以允许齿轮自动旋转通过本研究，开发了一种新设计的移动的系统，该系统固定在棒的中心，以允许延长用于矫正和固定婴儿和青少年脊柱侧凸弯曲。

The study is aimed to develop a elongating rod system for correcting infantile and juvenile scoliosis. This new system is based on the Chiba Spinal System (CSS), in order to meet the requirement of the growth of the children, a mobile system is added to the center of the instrument. According to the shape of the mobile system, three kinds of instrumentation are thus developed. Type A consists of a outer cylinder with 13 mm in diameter, and a double structural gear is fixed into the cylinder to allow the elongation toward both ends. Type B is with a 12 mm in diameter mobile system similaly to type A.Type C consists of a manually operated mobile system measured 10 mm in diameter to allow the elongation. Biomechanical study using spinal model made by Rigolac materials of 30 and 50 degree of curvature reveals that it is weaker than the stability of CSS dual rods but is equivalent to that of single rod, the type B shows the best result among all. Animal experiments using Beagle dog shows that the rod can be elongated in 3 weeks, 6 weeks, and 12 weeks after installation of the system into dogs, despite that the tension of the soft tissue is increased. But it is necessary to release soft tissue to elongate the rod in 12 weeks dogs. The result convinces us that even after 12 weeks after installation of this system, the rod can be elongated manually with a small skin incision.To avoid instrumentation failure in clinical usage, we are convinced that better stability can be achieved by adding a compression rod into the convex side of the curvature.We are also looking foward to a motor can be installed into type A and B to allow automatic rotation of the gear and elongation without further surgical invasion.Through this study, a newly designed mobile system fixed into the center of the rod to allow elongation for correcting and fixating infantile and juvenile scoliotic curvature is developed.