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Biomechanical Evaluation of Cervicothoracic Junction Fusion Constructs
Jakub Godzik1, Jonathan F Dalton2, Eduardo Martinez-Del-Campo3
1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
World Neurosurgery
|December 23, 2018
Summary
Rod diameter does not significantly impact subaxial spinal construct stability. Screw-rod and screw-connector-rod constructs offer superior biomechanical stability compared to hook-rod constructs in spinal fusion procedures.
Area of Science:
- Spine biomechanics
- Orthopedic surgery
- Spinal instrumentation
Background:
- Cervicothoracic spinal instability requires surgical stabilization.
- Various instrumentation techniques exist, including hook-rod, screw-rod, and screw-connector-rod constructs.
- Understanding the biomechanical differences between these constructs is crucial for optimal patient outcomes.
Purpose of the Study:
- To evaluate the in vitro biomechanical stability of different cervicothoracic spinal construct designs.
- To compare the influence of rod diameter and construct type on spinal motion.
Main Methods:
- Six human cadaveric spines (C5-T4) were tested.
- Intact, destabilized, and reconstructed states were analyzed.
- Constructs included hook-rod, screw-rod, and screw-connector-rod designs with varying rod diameters (3.5mm and 4.0mm).
- Global and intervertebral ranges of motion were measured.
Main Results:
- Rod diameter (3.5mm vs 4.0mm) did not significantly affect global stability across construct types.
- Hook-rod constructs showed significantly less stability in lateral bending and axial rotation compared to screw-rod and screw-connector-rod constructs.
- Screw-rod and screw-connector-rod constructs demonstrated comparable stability, with screw-rod showing less axial rotation at C6-C7 with 3.5mm rods.
Conclusions:
- Rod diameter is not a significant factor in subaxial construct biomechanical stability.
- Screw-rod and screw-connector-rod constructs provide superior stability over hook-rod constructs.
- Screw-rod constructs may offer biomechanical advantages over screw-connector-rod constructs in specific spinal segments.
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