Biomechanical evaluation of three surgical scenarios of posterior lumbar interbody fusion by finite element analysis

Abstract

BackgroundFor the treatment of low back pain, the following three scenarios of posterior lumbar interbody fusion (PLIF) were usually used, i.e., PLIF procedure with autogenous iliac bone (PAIB model), PLIF with cages made of PEEK (PCP model) or titanium (Ti) (PCT model) materiel. But the benefits or adverse effects among the three surgical scenarios were still not fully understood.MethodFinite element analysis (FEA), as an efficient tool for the analysis of lumbar diseases, was used to establish a three-dimensional nonlinear L1-S1 FE model (intact model) with the ligaments of solid elements. Then it was modified to simulate the three scenarios of PLIF. 10 Nm moments with 400 N preload were applied to the upper L1 vertebral body under the loading conditions of extension, flexion, lateral bending and torsion, respectively.ResultsDifferent mechanical parameters were calculated to evaluate the differences among the three surgical models. The lowest stresses on the bone grafts and the greatest stresses on endplate were found in the PCT model. The PCP model obtained considerable stresses on the bone grafts and less stresses on ligaments. But the changes of stresses on the adjacent discs and endplate were minimal in the PAIB model.ConclusionsThe PCT model was inferior to the other two models. Both the PCP and PAIB models had their own relative merits. The findings provide theoretical basis for the choice of a suitable surgical scenario for different patients.

Preserving Posterior Complex Can Prevent Adjacent Segment Disease following Posterior Lumbar Interbody Fusion Surgeries: A Finite Element Analysis

“…Our results suggest that the patients who underwent posterior lumbar interbody fusion surgery with total laminectomy operation are likely to experience a higher incidence of ASD than those who underwent posterior lumbar interbody fusion with hemi-laminectomy operations, which were in accordance with the previous clinical studies [3, 11]. Biomechanically, the SSL and ISL act as a tension band in an intact spine, especially during flexion [23, 24]. In the PLIF-LAM model, the removal of the whole L4 spinous process would damage the SSL, ISL or the anchoring point of the neighboring unfused segments, jeopardize the effect of the tension band, and thus causing the accelerated development of ASD.…”

“…Oppositely, the removal of the posterior complex eliminated the tension band effect in the flexion motion [4, 7], which may thus produce larger forces on the PLL, ITL and CL to resist to flexion loading. Several authors reported that the changes in load sharing among ligaments would alter the normal physiological and mechanical environments of ligaments, leading to ligament failure and hypertrophy [24, 25]. Moreover, the increase in ligaments forces were likely relevant to the invocation of pain and prone to cause chronic soft tissue injury, facet joint degeneration as well as hypertrophy of the LF, and thereby cause the ASD [5, 23, 24, 26].…”

“…Compared with previous PLIF FE models [16, 17, 24], the current PLIF FE model focused on the important role of posterior complex. Biomechanically, posterior complex acts as the posterior tension band in flexion.…”

Effects of resting modes on human lumbar spines with different levels of degenerated intervertebral discs: a finite element investigation

“…The Interaction Property "TIE" in ABAQUS was used to define all the surface to surface contacts in the FE models [35].…”

Use of Nonlinear Finite Element Analysis of Bone Density to Investigate the Biomechanical Effect in the Bone around Intervertebral Cages in Posterior Lumbar Interbody Fusion

“…Finite element analysis (FEA) is one technique that can be used for in vitro biomechanical and biomaterial studies. FEA is an indispensable biomechanical evaluation tool for supplementing in vitro biomechanical studies of the spine [9][10][11][12][13]. Most previous studies of PLIF using FEA have not taken into account the strength of osteoporotic bone in the elderly, and FEA analysis of PLIF in a model simulating vertebral bodies of normal bone strength for young people found almost no fractures [14], with the damage elements localized at the part of the bone around the cage.…”