A cadaveric study on establishing individualized navigation templates for axis laminar screw insertion by using a three-dimensional printing forming technique

English Keywords:Laminar screw  Individualized navigation templates  Three-dimensional printing  Stereo lithography apparatus  Fused deposition modeling  Polylactic acid

English Abstract:

  【Abstract】 Objectives: To investigate the feasibility of establishing individualized navigation templates for axis laminar screw insertion by using a three-dimensional printing forming technique, and to evaluate the accuracy of template-assisted laminar screw insertion. Methods: Nineteen adult cervical specimens were selected to take CT-scan. After original Dicom data were imported into the Mimics software, the axis model was established to generate the cavity model based on a three-dimensional printing forming technique. After using a free-hand procedure to create a navigation template with a well-established laminar screw path, bilateral laminar screws were inserted assisted by the navigation templates. CT-scan was taken postoperatively to access the position of the screws. Results: Establishing axis and the related cavity models based on CT-scan images proved to be a feasible and precise method. Thirty-eight laminar screws were implanted assisted by 19 navigation templates. CT-scan images indicated all the screws were completely contained within the laminae. No screw perforated laminar walls or transverse foramen. Conclusions: Axis laminar screw insertion assisted by a three-dimensional printing model is highly accurate and simple which can be a new alternative to conventional technique.