Biomechanical role of osteoporosis in the vibration characteristics of human spine after lumbar interbody fusion.

Lumbar vertebrae osteoporosis is the most common challenge for lumbar interbody fusion, and this challenge has been widely concerned by scholars for many years. However, under whole-body vibration, osteoporosis how to affect the vibration characteristics of the fusion lumbar spine, complications, and fusion outcomes is urgent to know. The L1-L5 finite element model of lumbar spine was modified to simulate the transforaminal lumbar interbody fusion model with the bilateral pedicle screw fixator at L4-L5 level. A 5 Hz, 40 N sinusoidal vertical load supplemented with a 400 N preload was used to simulate the vertical vibration of human body. The results showed that under whole-body vibration, osteoporosis of fused vertebrae may cause the adjacent segments more unstable and increase the risk of adjacent segment diseases, subsidence, cage failure, rod failure, and lumbar instability. Osteoporosis of the fused vertebrae may cause the vertebral cells an unstable, inhibited growth and lead to poorer fusion outcomes. The findings may assist us in understanding the effect of osteoporosis on the vibration characteristics of lumbar spine fusion and provide references to clinical treatments for lumbar interbody fusion and lumbar vertebrae osteoporosis.