Application of digital navigation template for cervical pedicle screw placement

English Keywords:Pedicle screw  Cervical vertebra  Individual navigation templates  Computer-aided design  Rapid prototyping

English Abstract:

  【Abstract】 Objectives: To evaluate the accuracy and safety of the application of individulalized navigation template for cervical pedicle screw placement. Methods: From August 2010 to August 2013, twenty-five patients required cervical pedicle screw fixation were studied. Preoperative 64-slice spiral CT scan was applied. by computer, three-dimensional cervical spine models were reconstructed, the optimal trajectory of cervical pedicle screws were designed, and the morphological feature of the posterior cervical spine elements were extracted. The reverse template was designed according to morphological feature. Then, the optimal trajectory and the template were fused into unilateral navigation template. The cervical spine model and the navigation template were created by rapid prototyping and 3D print technique. The length of each pedicle screw channel and the width of pedicle were measured. Cervical pedicle screws were inserted with the assistance of navigation templates. Postoperative CT scan was used to evaluate the screw position. The complications associated with screw placement were recorded. Results: Total 164 screws were inserted with the assistance of individual navigation templates. 152 screws were placed entirely within the pedicle, 4 screws perforated the medial cortex of pedicle, and 8 screws perforated the lateral cortex of pedicle. No screw perforated through the superior and inferior wall of the pedicle. No pedicle screws had placement-related complications, such as the injury of vertebral arteries, nerve roots and spinal cord occurred. Conclusions: The individualized navigation template-assisted internal fixation is a feasible and safe method for cervical pedicle screw placement.