[Fixateur interne: a comparative biomechanical study of various systems]

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Spinal Biomechanics

Background:

• Internal fixation devices are crucial for spinal stability.
• Understanding the biomechanical performance of these devices is essential for clinical application.
• In vitro models allow for controlled assessment of spinal stability.

Purpose of the Study:

• To evaluate the three-dimensional stability of three "fixateur interne" spinal fixation devices.
• To compare the performance of different internal fixation systems under physiological loads.
• To assess device efficacy in a simulated severe fracture model.

Main Methods:

• In vitro biomechanical testing of L2-L4 lumbar spine sections.
• Measurement of 3D rotations and translations under physiological loads (flexion/extension, lateral bending, axial rotation).
• Introduction of a dimensionless stability parameter for objective comparison; testing included a vertebrectomy L3 fracture model.

Main Results:

• Instrumented spines exhibited linear structural behavior, unlike the intact spine.
• Significant stabilization was observed in flexion/extension and lateral bending.
• Moderate stabilization was noted in axial rotation, with minimal differences between tested systems.

Conclusions:

• Internal fixation devices significantly enhance lumbar spine stability.
• These devices demonstrate efficiency in stabilizing both intact and fractured spine models.
• The tested "fixateur interne" systems provide reliable spinal stabilization.