IMAGE-GUIDED INSERTION OF TRANSPEDICULAR SCREWS - A LABORATORY SET-UP

Study Design. A computer-assisted system allowing precise preoperative planning and real-time intraoperative image localization of surgical instruments is tested in a laboratory setup. Objectives. The purpose o f this study is to assess the applicability, functionality, and accura cy of this transpedicular spinal fixation technique. Summary of Backgr ound Data. Most techniques in transpedicular spinal fixation rely on t he identification of predefined targets with the help of anatomic land marks the intraoperative use of image intensifiers. Various studies re port considerable screw mis placement rates which may lead to serious clinical sequelae such as permanent nerve damage. Methods. The propose d system was tested in,an in vitro setup drilling 20 pedicle pilot hol es in lumbar vertebrae. The accuracy was assessed using precision cuts through the pedicles and simulation of a 6-mm pedicle screw insertion . Results. An ideal screw position was found in 70 of 77 cuts, and in no case was an injury to the pedicular cortex observed. Conclusions. T he presented technique provides a safe, accurate, and flexible basis f or transpedicular screw placement in the spine. This approach should b e further evaluated in clinical applications.