Biomechanical Effects of Oblique Lumbar Interbody Fusion on Adjacent Segment Degeneration After Surgery in Patients with Osteoporosis: A Finite Element Study.

Abstract

Osteoporosis is considered one of the important factors influencing the biomechanics of the lumbar spine. Oblique lumbar interbody fusion (OLIF) is an emerging lumbar interbody fusion technique. Adjacent segment degeneration (ASD) is a common complication after lumbar interbody fusion surgery. This study primarily discusses the impact of OLIF on ASD in patients with osteoporosis. An intact three-dimensional finite element model of the lumbar spine from L1 to S1 was established. An osteoporosis model was established based on the intact model. The OLIF with osteoporosis model was established based on the osteoporosis model, with L4-L5 as the surgical segment. The range of motion, intervertebral disc pressure, intervertebral disc Tresca stress, and endplate stress of the cranial adjacent segment (L3-L4) were compared between the OLIF with osteoporosis model and the osteoporosis model. The range of motion, intervertebral disc pressure, intervertebral disc Tresca stress, and endplate stress at the L3-L4 level in the osteoporosis model were all higher than in the intact model. These biomechanical parameters at the cranial adjacent segment (L3-L4) in the OLIF with osteoporosis model were significantly higher than in the osteoporosis model. Compared to the osteoporosis model, the OLIF with osteoporosis model showed the greatest increase in biomechanical parameters at the cranial adjacent segment during flexion and lateral bending. OLIF carries the risk of accelerating ASD at the cranial level after surgery in patients with osteoporosis.