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Computer-assisted Patient-specific Prototype Template for Thoracolumbar Cortical Bone Trajectory Screw Placement: A Cadaveric Study

Authors :
Sang Bum Kim
Hee Young Lee
Gi Soo Lee
Yougun Won
Taehyung Kim
John M. Rhee
Source :
Techniques in Orthopaedics (Rockville, Md.)
Publication Year :
2018
Publisher :
Ovid Technologies (Wolters Kluwer Health), 2018.

Abstract

The cortical bone trajectory (CBT) screw technique yields effective mechanical and clinical results, improving the holding screw strength with a less invasive exposure. Accurate and safe screw placement is crucial. A patient-specific drill template with a preplanned trajectory was considered a promising solution; however, it is critical to assess the efficacy and safety of this technique. This study aims to evaluate the accuracy of patient-specific computed tomography (CT)-based rapid prototype drill guide templates for the CBT technique. CT scanning was performed in 7 cadaveric thoracolumbar spines, and a 3-dimensional reconstruction model was generated. By using computer software, we constructed drill templates that fit onto the posterior surface of thoracolumbar vertebrae with drill guides to match the CBT. In total, 80 guide templates from T11 to L5 were created from the computer models by using rapid prototyping. The drill templates were used to guide the drilling of CBT screws without any fluoroscopic control, and CT images were obtained after fixation. The entry point and direction of the planned and inserted screws were measured and compared. In total, 80 screws were inserted from T11 to L5. No misplacement or bony perforation was observed on postoperative CT scan. The patient-specific prototype template system showed the advantage of safe and accurate cortical screw placement in the thoracolumbar spine. This method showed its ability to customize the patient-specific trajectory of the spine, based on the unique morphology of the spine. The potential use of drill templates to place CBT screws is promising.

Details

ISSN :
08859698
Volume :
33
Database :
OpenAIRE
Journal :
Techniques in Orthopaedics
Accession number :
edsair.doi.dedup.....3ef6af83bf5717146b2efa0013304a9c
Full Text :
https://doi.org/10.1097/bto.0000000000000285