A novel computer-assisted drill guide template for thoracic pedicle screw placement: a cadaveric study

Introduction The objective of this study was to develop a novel, patient-specific, navigational template for thoracic pedicle screw placement. Methods Twenty thoracic cadaver specimens were randomly divided into two groups of 10: the navigational template group and the free-hand group. A volumetric CT scan was performed on each thoracic vertebra, and a three-dimensional reconstruction model was generated. A drill template was designed with a surface that was the inverse of the posterior vertebral surface. Each drill template and its corresponding vertebra were manufactured using a rapid prototyping technique and tested for violation. Two hundred and forty screws were implanted into the thoracic spines and the positions of the screws were evaluated. Results Two hundred and forty thoracic screws were inserted using either the navigational template method or the free-hand method. The accuracy rate and incidence of risk for setting thoracic pedicle screws differed statistically between the two methods (P < 0.05): The navigational template method had a higher accuracy rate and a lower incidence of risk than the free-hand method. Moreover, the free-hand method had a significant learning curve, whereas a learning curve for the navigational template method was not obvious. Conclusion We have developed a novel, patient-specific, navigational template for thoracic pedicle screw placement with good applicability and high accuracy.