Effect of Different Fixation Techniques on Segmental Kinematics and Load Sharing of Lumbar Spine: A FEM Study

Fusion has been the gold standard for treatment of various disorders associated with the spine especially at intervertebral disc level. The surgical procedure for fusion often requires fixation of the anterior column of the defected segment with interbody fixation devices such as cages. Anterior (ALIF), transforaminal (TLIF) and lateral (LIF) lumbar interbody fusion are some of the most common techniques for segmental fixation. The unacceptably low fusion rate with the interbody cages, when used as standalone, has led to the practice of combining these devices with posterior instrumentation. The segmental kinematics, the load distribution on the vertebral endplate and on the components of the posterior instrumentation are the key biomechanical parameters which can help to evaluate the performance of interbody fixation techniques with posterior instrumentation. We conducted a finite element (FE) study to compare biomechanics of these fixation methods.