数字化仿真技术确定最佳骶髂螺钉通道的研究

Digital virtual technique in determining the optimal sacroiliac screw channel

目的:探索一种基于数字化仿真技术的最佳骶髂螺钉通道测量方法,用于指导计算机导航下的进钉。方法:将8例成人无病变骨盆CT数据集导入Mimics 10.01进行三维重建,利用数字化仿真技术建立骶椎阴模,利用透视阴模内表面的方法确定最佳骶髂螺钉通道,利用计算机辅助作图结合空间解析几何计算测量相关参数。结果:8例16侧的S1最佳骶髂螺钉通道均可用此方法确定。最佳骶髂螺钉通道参数值:半径,均>7.3mm,其中男8.75±0.72mm,女8.38±0.67mm;进钉深度,男78.44±3.43mm,女74.07±6.04mm;与矢状面夹角,男72.62°±5.01°,女79.65°±7.59°;与横截面夹角,男13.28°±6.33°,女9.60°±4.17°;与冠状面夹角,男9.99°±7.67°,女2.01°±1.58°;与S1椎体上表面夹角,男14.91°±6.48°,女7.62°±5.88°;S1最佳进钉终点位于导航出口位透视图像上上下方向最大径的2∶5处,左右方向最大径1∶1处及入口位上下方向最大径3∶1处;S1最佳进钉点位于导航出口位透视图像上上下方向最大径的3∶5处,左右方向最大径2∶5处及入口位上下方向最大径5∶2处;S1最佳进钉终点约在S1椎体中轴线上下2∶3及前后径3∶5处。与矢状面夹角、与冠状面夹角、与S1椎体上表面夹角男女比较有统计学差异(P<0.05),余无统计学差异(P>0.05)。结论:利用数字化仿真技术可以在几何学上精确确定并测量最佳骶髂螺钉通道,用以指导计算机导航下进钉。双侧S1最佳骶髂螺钉通道具有对称性。S1椎弓根可以置入2枚直径7.3mm的骶髂螺钉。

Objectives： To explore digital virtual teehnique（DVT） to determine the optimal sacroiliac screw ehannel（OSSC）, and to provide a method for instrumentation under navigation. Methods The pelvic CT scan data of 8 healthy adults were processed into Mimics 10.01 for 3D reconstruction. DVT was used to establish the model of sacral cavity die, which was used to determine the OSSC, and the associated parameters were measured by using computer aided design（CAD） and Space Analytical Geometry＇s（SAG） method. Results： The OSSC of 16 S1 pedieles in 8 cases was determined by this way. The radius of the OSSC was greater than 7.3ram in both side of all the cases, which the radius of the OSSC was 8.75±0.72mm for male, and 8.38± 0.67mm for female. The depth was 78.44°±3.43mm for male, and 74.07±6.04mm for female. The introversion angle in sagittal plane was 72.62°±5.01° for male, and 79.65°±7.59° for female. The angle in cross-sectional plane was 13.28°±6.33° for male, and 9.60°±4.17° for female. The angle in coronal plane was 9.99°±7.67° for male, and 2.01°±1.58° for female. The angle in upper face of S1 vertebral was 14.91°±6.48° for male, and 7.62°±5.88° for female. On fluoro-navigation images, the starting point of S10SSC was 3：5 in up-down direction and 2：5 in left-right direction on out-let view, while 5：2 in up-down direction on in-let view. The end-ponit of S10SSC was 2：5 at the max length of pelvis in up-down direction and midpoint in left-right direction on out-let view, while 3：1 in up-down direction on in-let view. The end-point of OSSC was also 2：3 at the axis wire of S1 vertebra and 3：5 at the max length of SI vertebra in anterior-posterior direction. The angles in sagittal plane, coronal plane, and upper surface showed sex-related statistical differences （P〈 0.05）, while the others showed no statistical difference（P〉0.05）. Conclusions： DVT is guided to measure and determine the OSSC. The bilateral OSSC of S1 is symmetrical, and can hold 2 sacroiliac screws.