Canine Vertebral Screw and Rod Fixation System: Design and Mechanical Testing

Area of Science:

• Veterinary Orthopedics
• Biomechanical Engineering
• Small Animal Surgery

Background:

• Internal fixation of the canine vertebral column is crucial for stabilization.
• Existing methods like the screw and polymethylmethacrylate (Screw-PMMA) technique have limitations.
• A need exists for advanced fixation systems offering improved biomechanical performance.

Purpose of the Study:

• To develop a novel canine vertebral screw and rod fixation system (CVSRF).
• To compare the biomechanical properties of the CVSRF system against the Screw-PMMA technique.
• To evaluate the suitability of CVSRF for canine spinal stabilization.

Main Methods:

• The CVSRF system was designed with monoaxial screws, rods, and connecting inner screws, prototyped from titanium alloy.
• Simulated canine vertebrectomy models were created using polyethylene blocks.
• Biomechanical testing (compressive bending yield load, stiffness, ultimate load, load displacement) followed ASTM F-1717-04 standards for both CVSRF (n=8) and Screw-PMMA (n=8) groups.

Main Results:

• The CVSRF system exhibited significantly higher mean values for compressive bending yield load, compressive bending stiffness, and compressive ultimate load (p < 0.01) compared to the Screw-PMMA technique.
• Load displacement curves indicated superior rigidity and durability for the CVSRF system.
• Statistical analysis confirmed significant biomechanical advantages of the CVSRF.

Conclusions:

• The developed CVSRF system is a viable option for canine vertebral stabilization.
• The CVSRF system demonstrates superior biomechanical properties, including enhanced rigidity and durability, over the Screw-PMMA technique.
• This study supports the clinical application of CVSRF for improved outcomes in canine spinal surgery.