Ex vivo biomechanical testing of a three-dimensional printed titanium plate and spacer construct and 4.5 mm locking compression plate for ventral cervical fusion of C4-C5 in the horse.
Authors: Zedler Steven, Jukic Chantelle, van Eps Andrew, Stefanovski Darko, Genton Martin, Rossignol Fabrice
Journal: Veterinary surgery : VS
Summary
Cervical vertebral fusion at C4-C5 represents a challenging surgical problem in equine practice, and the choice of fixation construct significantly influences clinical outcomes. Researchers compared the biomechanical performance of a custom 3D-printed titanium plate-and-spacer system against the conventional 4.5 mm locking compression plate using cadaveric equine cervical spines subjected to four-point bending tests in both flexion and extension until failure. Both constructs demonstrated equivalent yield strength, failure moments, and stiffness across loading directions, suggesting comparable load-bearing capacity; however, the locking compression plate showed a notably higher incidence of screw pullout and displaced vertebral fractures when loaded in extension (p = .03), whilst the 3D-printed construct failed more consistently through less catastrophic mechanisms. Although the small sample size (n = 6 per group per direction) limited the detection of smaller biomechanical differences, these findings suggest that patient-specific titanium constructs may offer superior resistance to extension-related failure modes, a clinically relevant advantage given the dynamic loading environments of the equine cervical spine. Further investigation in clinical cases is warranted before widespread adoption, but these results provide promising preliminary evidence that custom additive manufacturing could improve long-term fusion stability and reduce the revision surgery rates associated with plate or screw failure.
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Practical Takeaways
- •The 3D-printed titanium plate and spacer offers comparable mechanical stability to traditional locking compression plates for cervical fusion, with potential advantages in resisting extension-related failure modes.
- •Locking compression plate constructs appear more prone to screw pullout and vertebral fractures under extension loads, which may influence implant selection in cases with expected high extension loads.
- •These cadaveric results are promising but require in vivo validation before clinical adoption; practitioners should await further clinical evidence before changing current surgical protocols.
Key Findings
- •3D-printed titanium plate and spacer (3DM) construct demonstrated similar yield, failure moment, and stiffness to 4.5 mm locking compression plates (LCP) in both flexion and extension testing.
- •LCP constructs failed more commonly by screw pullout (p = 0.09) and displaced vertebral fractures (p = 0.03) under extension loading compared to 3DM constructs.
- •In extension, the 3DM construct showed lower risk of displaced fracture failure mode, suggesting potential biomechanical advantage in this loading direction.