Radiographic verification of pedicle screw pilot hole placement in thoracic spine using Kirschner wires versus spiral wires

Objective: To evaluate the feasibility of the pedicle screw pilot holes placement in thoracic spine using the spiral wires as the guide pin. Methods: The pedicle screw pilot holes were drilled within the center of the pedicle and the lateral and medial pedicle walls were violated in 9 human dried thoracic vertebrae. Kirschner wires or spiral wires were separately placed in the holes, and then the posteroanterior and lateral radiographs were taken. The radiographs were evaluated by 3 experienced spine surgeons and 3 young orthopedists. After radiographs were shown to these observers, they combined the posteroanterior and lateral radiographs in each place and determined whether the pedicle screw pilot hole violated the pedicle cortex or not. The results were analyzed by a statistical software. Results: Sensitivity, specificity and accuracy of the method using spiral wires to detect pedicle pilot hole placement were significantly higher than those of using Kirschner wires. With a true posteroanterior radiograph, the sensitivity, specificity and accuracy of the method using spiral wires approximated or attained 100%. Conclusions: The method of intrapedicular pilot hole placement verification using spiral wires is effective for guiding the accurate placement of pedicle screws.