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An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
In vivo accuracy of thoracic pedicle screws
P J Belmont1, W R Klemme, A Dhawan
1Orthopaedic Surgery Service, Department of Surgery, Walter Reed Army Medical Center, Washington, DC 20307, USA.
Spine
|October 27, 2001
Summary
This study assessed the accuracy of thoracic pedicle screws using CT scans. Most screws were accurately placed, with few causing significant canal intrusion, though lateral perforations were common.
Area of Science:
- Spinal surgery
- Orthopedic surgery
- Radiology
Background:
- Proper placement of transpedicular thoracic screws is crucial for spinal fusion.
- In vivo accuracy of pedicle screw placement in the thoracic spine via CT has not been previously established.
Purpose of the Study:
- To determine the accuracy of transpedicular thoracic screw placement.
- To assess screw placement within the pedicle and vertebral body.
- To evaluate the transverse screw angle (TSA) and cortical perforations.
Main Methods:
- Retrospective observational study of 279 transpedicular thoracic screws in 40 patients.
- Postoperative computed tomography (CT) was used to assess screw accuracy.
- Screws were analyzed for placement within the pedicle and vertebral body, cortical perforations, and TSA, with regional grouping.
Main Results:
- 57% of screws were fully contained within the pedicle; 14% had medial perforation (<1% with >2mm canal intrusion).
- Lateral pedicular perforation (68%) was more common than medial perforation.
- Anterior vertebral cortex penetration occurred in 17 screws, associated with smaller TSA and lateral perforation; no neurologic complications were reported.
Conclusions:
- 99% of screws were fully contained or had acceptable medial/lateral perforations using the "in-out-in" technique.
- Anterior vertebral penetration correlated with lateral pedicle perforation and smaller TSA.
- Screw containment varied by thoracic spine region, with higher rates in the T9-T12 region.
