Abstract:

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.

Key words: Lower cervical spine, Navigation template, Pedicular fixation, Biological safe, Rapid prototyping