生物安全性的下颈椎后路经椎弓根固定的个性化导航模板研究

Biological-safe patient-specific navigation template of posterior transpedicular fixation of lower cervical vertebrae: in vitro study

目的设计制作生物安全性的下颈椎个性化导航模板,并评价其精度。方法选取4具下颈椎防腐标本,CT扫描后,利用三维重建及快速成型技术设计制作生物安全性的后路经椎弓根个性化导航模板,在标本上辅助克氏针置入。再次CT扫描并三维重建,计算实际克氏针与虚拟克氏针的位置参数,通过配对样本T检验检测两者之间的差异;并计算虚拟克氏针与实际克氏针的位置偏差。结果虚拟和实际克氏针在X、Y、Z轴的位移和旋转均无统计学差异(P>0.05);实际克氏针与虚拟克氏针之间的偏差,X、Y、Z轴的位移偏差分别为(1.58±0.66)、(1.96±0.84)、(2.33±1.15)mm;X、Y、Z轴的旋转偏差分别为(1.43±1.18)°、(2.43±1.67)°、(1.14±0.50)°。结论本研究提出了一种可行的新型生物安全的导航模板的制作方法,其造型及精度尚需进一步改进。

Objective To develop a biological-safe patient-specific navigation template of posterior transpedicular fixation of lower cervical vertebrae and evaluate its accuracy in assisting screw inserting. Methods 4 formalin-fixed lower cervical spine specimens （C3-C7） were harvested and CT scanned. With the technologies of 3D reconstruction, rapid prototyping and molding, biological-safe patient-specific navigation templates of posterior transpedicular fixation of lower cervical vertebrae were developed. With the assist of the navigation template, Kirschner wires were inserted into the pedicles of cervical vertebrae. After second CT scan and 3D reconstruction, the positions of virtual and actual Kirschner wires were calculated and statistically analyzed by paired-sample T test to evaluate its feasibility. The position deviations were also calculated to evaluate its accuracy. Results There were no significant difference between the position of virtual and actual Kirschner wires in all displacement and rotation directions （P〉0.05）. The X, Y and Z axis displacement deviations were （1.58±0.66） mm, （1.96±0.84） mm and （2.33±1.15） mm, respectively. The X, Y and Z axis rotation deviations were （1.43±1.18）°, （2.43±1.67）° and （1.14±0.50）°, respectively. Conclusions The developed navigation template is feasible for posterior transpedicular fixation of lower cervical vertebrae, however, it＇s model shape and accuracy need further improvement.