Finite-element analysis for lumbar interbody fusion under axial loading

Area of Science:

• Biomechanical Engineering
• Spinal Surgery
• Finite Element Analysis

Background:

• Interbody fusion aims to stabilize the lumbar spine.
• Spacer placement is a key surgical consideration.
• Understanding biomechanical effects is crucial for optimizing fusion outcomes.

Purpose of the Study:

• To evaluate the impact of spacer position on axial stiffness, endplate stress, and bulging.
• To assess the mechanical behavior of lumbar interbody fusion with and without fusion bone.
• To analyze the influence of anterior-posterior spacer positioning on spinal stability.

Main Methods:

• Anatomically accurate L2-L3 finite-element model was developed and validated.
• The model was subjected to physiological axial compression.
• Parametric study varied spacer position with/without fusion bone.

Main Results:

• The spacer significantly contributes to initial stability during fusion.
• High compressive forces were predicted at the ventral endplate when spacer and fusion bone were present.
• Varying anterior-posterior spacer position showed no significant changes in axial stiffness, stress, or endplate bulging.

Conclusions:

• Spacer placement is vital for initial stability in lumbar interbody fusion.
• Anterior-posterior spacer positioning does not substantially affect the mechanical behavior post-fusion.
• Surgical adjustments in spacer position may not impact long-term mechanical outcomes.