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Anatomic consideration of C2 pedicle screw placement
N Ebraheim1, J R Rollins, R Xu
1Department of Orthopaedic Surgery, Medical College of Ohio, Toledo, USA.
Spine
|March 15, 1996
Summary
A new anatomic study found that guiding C2 pedicle screws directly along the C2 pedicle (Method B) is safer than using a predetermined entry point (Method A). Method B minimized cortical violations, unlike Method A which risked vertebral artery injury.
Area of Science:
- Neurosurgery
- Orthopedic Surgery
- Anatomy
Background:
- Transpedicular screw fixation is used for traumatic spondylolisthesis of the axis and other cervical spine injuries.
- Previous studies have described anatomic and clinical applications of transpedicular screw fixation in the cervical spine.
- No prior studies have specifically assessed the safety of C2 pedicle screw placement.
Purpose of the Study:
- To compare the safety of two surgical techniques for transpedicular screw placement in the axis (C2).
- To evaluate the risk of neurovascular injury and cortical violation associated with each technique.
Main Methods:
- Anatomic study using sixteen embalmed cadaveric specimens.
- Method A: Predetermined entry point and screw trajectory.
- Method B: Drill bit guided by the C2 pedicle's medial and superior aspects; followed by gross dissection and imaging.
Main Results:
- Method A resulted in four instances of lateral violations, impacting the vertebral artery.
- Method B showed only two cases of minimal pedicle cortex penetration.
- No medial, superior, or inferior pedicle cortex violations were observed with Method B.
Conclusions:
- Transpedicular screw fixation in the C2 pedicle can be safely performed using the technique of guiding the drill bit directly along the pedicle (Method B).
- The predetermined entry point technique (Method A) is associated with significant risks and is not considered safe for C2 pedicle screw placement.