Ex vivo biomechanical comparison of pedicle screw and rod constructs with and without interbody fusion devices for equine cervical vertebral stabilization.
Authors: Pezzanite Lynn M, Nelson Brad B, Downey Amy C, Gadomski Ben, McGilvray Kirk, Baer Kenzie, Kappel Sarah M, Nout-Lomas Yvette, Seim Howard B, Easley Jeremiah T
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Pedicle Screw-Rod Constructs for Equine Cervical Stabilization Cervical vertebral malformation and associated instability remain challenging surgical problems in equine practice, necessitating robust fixation methods to prevent progressive neurological deterioration. Researchers compared the biomechanical performance of two surgical approaches using cadaveric cervical vertebral columns: pedicle screw-rod (PSR) constructs alone versus PSR combined with an interbody fusion device (PSRIFD), alongside unaltered controls. Both stabilisation methods significantly reduced range of motion, compliance, and neutral zone during flexion-extension movements compared to untreated spines, with PSR constructs additionally showing superior control during axial rotation; however, the two surgical approaches demonstrated equivalent stiffness, moment-to-failure, and overall biomechanical properties. A notable difference emerged in failure patterns: whilst all constructs failed through articular process joint dislocation, the PSRIFD group uniquely experienced ventral interbody device migration, potentially indicating higher risk of catastrophic complications. These findings suggest PSR fixation alone provides comparable stability to more complex PSRIFD constructs, offering practitioners a simplified surgical option that reduces operative time and eliminates complications associated with interbody device placement—a meaningful consideration for surgeons managing equine cervical instability cases where long-term stability must be balanced against surgical invasiveness.
Read the full abstract on PubMed
Practical Takeaways
- •PSR alone provides equivalent biomechanical stability to more complex PSRIFD constructs for cervical vertebral stabilization, potentially reducing surgical time and technical complexity
- •PSR constructs may be preferred over PSRIFD due to comparable stabilization without the additional complication risk of interbody device migration
- •Both constructs fail via articular process joint dislocation, suggesting similar ultimate failure mechanisms despite different construction approaches
Key Findings
- •PSR and PSRIFD constructs both significantly reduced range of motion, compliance, and neutral zone in flexion-extension compared to controls (p < 0.05)
- •In axial rotation, PSR provided lower neutral zone than PSRIFD (p = 0.013), though both were significantly lower than controls
- •Stiffness and moment failure were not significantly different between PSR and PSRIFD groups
- •PSRIFD constructs showed higher catastrophic injury potential with ventral interbody fusion device migration in addition to articular process joint dislocation