Placement of C2 laminar screws using rapid prototyping navigational temple.

Abstract

Objective To observe the placement of C2 laminar screws using rapid protyping naviga-tional template. Methods CT scan of C2 vertebrae was performed. 3-D model of C2 vertebrae was reeon-structured by software amira 3.1 and was preserved in STL format. Then 3-D model was runed in sofeware UG imageware 12.0, the best trajectory of laminar screw was extracted according to the reverse engineering principle. A virtual navigational template was established according to he lamina anatomic trait. The virtual vertebrae and navigational template were manufactured using rapid prototyping. The navigational template was sterilized and used intra operative to assist with the placement of laminar screw. The accuracy of screw placement was confirmed with postoperative X-ray and CT scanning. Results The digital navigational tem-plate had been established and used in the five patients undergoing posterior cervical fusion. Overall, eleven C2 laminar screws were placed. There were no complications in any of the patients. Postoperative computed tomographic (CT) scanning was available allowing evaluation of placement of C2 laminar screws, all of which were in good position with no spinal canal violation. There were not complications of related screw insertion. Conclusion A novel method of C2 laminar screw placement using Reverse Engineering and rapid prototyp-ing has been developed, the navigational template is found to be highly accuracy and has great expectation. Key words: Surgery, computer-assisted; Axis; Stereotaxic techniques