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Updated: Jul 11, 2026
09:07
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
Construct-construct "rail technique" decreases screw strain during spinal deformity corrective maneuvers: a
Alekos A Theologis1, Jason DePhillips2, Nathaniel A Myers3
1Department of Orthopaedic Surgery, University of California - San Francisco (UCSF), 500 Parnassus Ave, MUW 3rd Floor, San Francisco, CA, 94143, USA. alekos.theologis@ucsf.edu.
Spine Deformity
|March 28, 2025
Summary
The "rail" technique significantly reduces screw strain during spinal deformity correction, lowering the risk of screw pull-out and plow. This method distributes strain more evenly across pedicle screws near the osteotomy.
Area of Science:
- Spinal surgery biomechanics
- Orthopedic implant research
Background:
- Spinal osteotomies are crucial for correcting deformities.
- Pedicle screw fixation is a common method for stabilizing the spine.
- High screw strain can lead to construct failure, such as screw pull-out or plow.
Purpose of the Study:
- To compare screw strains adjacent to a simulated spinal osteotomy.
- To evaluate strains under segmental compression (SC) and cantilever bending (CB).
- To assess strains with traditional constructs versus a construct-to-construct lateral accessory rod ('rail').
Main Methods:
- 10 PCF foam blocks instrumented with 6 pedicle screws each.
- Strain gauges measured real-time screw strains.
- SC and CB performed over traditional midline rods or the 'rail' construct.
Main Results:
- The 'rail' technique significantly reduced screw strains near the osteotomy compared to traditional SC.
- Maximum screw strains were significantly lower with 'rail' SC and CB.
- Screw strain was more evenly distributed across all screws with the 'rail' technique.
Conclusions:
- The 'rail' accessory rod significantly lowers pedicle screw strain adjacent to spinal osteotomies.
- This technique may reduce the risk of screw pull-out and plow during deformity correction.
- Further cadaveric studies are recommended to validate these findings in clinical scenarios.
Keywords:
3-Column osteotomyCantilever bendingCorrection techniquesSegmental compressionSpinal deformityMore Related Videos
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