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Design and Manufacturing of a Patient-specific Drill Guide Template for Thoracic Pedicle Screw Placement

Mohammadi Moghaddam, Shima | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51311 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Arjmand, Navid
  7. Abstract:
  8. Spinal instrumentation with pedicle screws has become a widespread surgical procedure in the treatment of spinal disease. The traditional way of placing pedicle screws is to use the anatomical landmarks which at many times can be a best guess resulting in breaches of the pedicle and causing neurological injuries. Additional modalities used include the intra-operative fluoroscopy or navigation systems, which results in radiation exposure and more intra-operative time. In order to solve the technical problems, a pedicle screw navigation template that guarantees the correct implantation position and direction of vertebral pedicle screws, can be used. Compared to pedicles in the lumbar spine, thoracic pedicles have smaller diameters, and the inter-individual and inter-segmental variability in pedicle dimensions is higher. The present thesis provides a patient-specific drill guide template for placing screws in 2 thoracic vertebras of a cadaver and a real patient. The production method comprises the following steps of: at first, importing CT serial sectional image data into Mimics 19.0 for three-dimensional model rebuilding by CT scanning; then, designing a guide template in 3matic 11.0; and finally, fabricating the template by PLA material, with a 3D printing technology. During the test, stability of drill guide template on vertebrae checked out by measuring the force, which applied to guide template while drilling. The accuracy of the drill template was confirmed by preoperatively drilling the screw trajectory into the vertebra biomodel. In the cadaveric experiment, 4 pedicle screws were inserted and no pedicle perforation was observed by postoperative CT scan. 3 screws were rated as Grade 0, 1 as Grade 1, and no screws as Grade 2 or 3. Hence, safer screw positioning was accomplished with the drill template technique
  9. Keywords:
  10. Pedicel Screw ; Thoracic Spine ; Patient-Specific Modeling ; Guided Template ; Fusion Surgery ; Screw Placemant Accuracy

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