Abstract
Introduction
Freehand techniques for thoracic pedicle screw placement have gained popularity as they reduce intraoperative radiation exposure and overall operative time. The goal of this work is to present our technique as well as systematically and comprehensively review the published literature on this topic.
Material and Methods
A PubMed search from 2001 to 2014 was performed, focusing on clinical studies that describe technical aspects of freehand thoracic pedicle screw placement. Cadaveric studies were excluded.
Results
The search yielded 15 studies and, of those, only 5 described technical aspects of thoracic screw placement. Definitive entry points were represented in four studies, and in one study entry point varied by a thoracic level. There were no definitive guidelines for sagittal or an axial trajectory with an exception of a one study in which sagittal trajectory was based on suboptimally visualized endplate. In our technique, we identified a uniform entry point for each thoracic level that is 3 mm caudal to the junction of the transverse process and the lateral margin of the superior articulating process. The sagittal trajectory is orthogonal to the dorsal curvature of the corresponding spine.
Conclusion
Freehand thoracic pedicle screw placement is safe and effective based on published reports in the literature. Few studies, however, detail the technique and provide meaningful instructions for trainees. We are hopeful that precise parameters that rely on less variability in entry point and trajectories will facilitate trainee education.