Finite element analysis shows minimal stability difference between individualized mini-hemilaminectomy-corpectomy and...

Area of Science:

• Veterinary Surgery
• Biomechanical Engineering
• Comparative Orthopedics

Background:

• Spinal decompression surgeries are common in veterinary medicine.
• Evaluating the biomechanical stability of different surgical techniques is crucial for patient outcomes.
• Finite element analysis offers a powerful tool for simulating surgical impacts on spinal units.

Purpose of the Study:

• To compare the biomechanical effects of four spinal decompression techniques in Beagle dogs using finite element analysis.
• To determine which technique minimizes functional spinal unit instability.
• To provide data guiding surgical choices for spinal decompression.

Main Methods:

• A 3D finite element model of a canine L1-L2 functional spinal unit was created from CT data.
• Simulated surgical decompressions included individualized mini-hemilaminectomy-corpectomy (iMHC), mini-hemilaminectomy, partial lateral corpectomy (PLC), and hemilaminectomy.
• Loads were applied in six directions (flexion, extension, lateral bending, axial rotation) to assess L1 spinous process tip displacement.

Main Results:

• Mini-hemilaminectomy demonstrated the lowest displacement angles across all tested loading directions, indicating minimal instability.
• Hemilaminectomy resulted in the largest displacement angles, signifying the greatest instability, especially in extension, flexion, and rotation.
• Individualized mini-hemilaminectomy-corpectomy and partial lateral corpectomy showed comparable or slightly greater instability than hemilaminectomy in lateral bending at higher loads.

Conclusions:

• Mini-hemilaminectomy is the most effective technique for minimizing functional spinal unit instability.
• Hemilaminectomy leads to significant instability compared to iMHC and PLC, particularly in sagittal plane motion and rotation.
• While iMHC may offer better visualization than PLC in ventral compression cases, both can lead to instability; careful postoperative assessment is vital, especially after extensive vertebral body resection.