计算机3D建模在个体化寰枢椎椎弓根钉最佳进钉方式的研究

Computer simulation of the 3D modeling to study the best screw channel in Atlantoaxial pedicle

目的利用3D建模技术设计寰、枢椎椎弓根钉手术模拟系统,为迅速模拟置钉安全区、置钉方案及统一术前设计操作标准。方法从本院PACS系统14例健康成人（男7例,女7例;年龄30~68岁,平均45岁）的寰枢椎CT连续断层扫描数据导入Mimics 10.01软件,三维重建后利用.dwg文件导入3dmax2009。确定三维参照坐标和原点,导入标尺确定进钉点,导入原创设计阵列模型,寰椎以3.5 mm直径,长度为22 mm螺钉,枢椎以3.5 mm直径,长度为24 mm螺钉为研究对象,模拟安全区置钉区间内最佳置钉方案,记录最佳置钉数据,最后输入最佳置钉数据指导计算机模拟置钉,并在透视图中观察置钉效果。结果 185个元素符合寰椎进钉要求,枢椎395个元素符合进钉要求。通过透视图检查,其中寰椎27枚,枢椎25枚共53枚最佳角度模拟螺钉均准确位于椎弓根内。对双侧椎体左、右侧直径3.5 mm椎弓根螺钉最远距离进行比较,差异不具有显著差异（P〉0.05）。结论利用数字3D建模技术能建立标准、简化、精确地术前设计。

Objective To study the regular patterns of atlantoaxial pedicle channel, screw safety zone, and the best screw channel by means of 3D-array model;To establish standards and simplify preoperative design for axis pedicle screws operation. Methods CT scan of axis data of 14 healthy adult from PACS system were collected and imported into Mimics10.01software to reconstruct three-dimensional （3D） models. Then, the 3D reconstruction models were imported into 3Dmax 2009 as .dwg format for analysis of the pedicle screw channels. The three-dimensional coordinates and the origin were determined, then the array model was imported.as for the atlas , the screw with a diameter of 3.5 mm and a length of 22 mm was used as an object of study. As for the axis, the screw with a diameter of 3.5 mm and a length of 24 mm was used as an object of study the screw placement in the safety zone was simulated and the optimal placement scheme was explored. the best placement data was recorded and was then used for guidance of computer simulation of pedicle screws. Results There are 185 elements that meet the demand to place the screws in the atlas, and there are 395 elements that meet the demand to place the screws in the axis. In the transparent mode, 53 nails, 27 nails in the atlas and 25 nails in the axis, all precisely gained entrance to the vertebral body through the vertebral arch pedicle. Therewas no significant difference between the left side and the right side （P〉0.05）. Conclusions The digital 3D modeling technology is a standard, simple, accurate way in the preoperative design and measurement for axis pedicle surgery.