Biomechanical Analysis of Stand-alone Lateral Lumbar Interbody Fusion for Lumbar Adjacent Segment Disease.

Michael Chioffe,Avinash Patwardhan,Joseph P Maslak,Peter R Swiatek,Alpesh A Patel,Muturi Muriuki,Robert M Havey,Michael Mccarthy,Leonard I Voronov

doi:10.7759/cureus.6208

Abstract

Study designBiomechanical cadaveric study ObjectiveTo compare biomechanical properties of a single stand-alone interbody fusion and a single-level pedicle screw construct above a previous lumbar pedicle fusion.Summary of background dataAdjacent segment disease (ASD) is spondylosis of adjacent vertebral segments after previous spinal fusion. Despite the consensus that ASD is clinically significant, the surgical treatment of ASD is controversial.MethodsLateral lumbar interbody fusion (LLIF) and posterior spinal fusion (PSF) with pedicle screws were analyzed within a validated cadaveric lumbar fusion model. L3-4 vertebral segment motion was analyzed within the following simulations: without implants (intact), L3-4 LLIF-only, L3-4 LLIF with previous L4-S1 PSF, L3-4 PSF with previous L4-S1 PSF, and L4-S1 PSF alone. L3-4 motion values were measured during flexion/extension with and without axial load, side bending, and axial rotation.ResultsL3-4 motion in the intact model was found to be 4.7 ± 1.2 degrees. L3-4 LLIF-only decreased motion to 1.9 ± 1.1 degrees. L3-4 LLIF with previous L4-S1 fusion demonstrated less motion in all planes with and without loading (p < 0.05) compared to an intact spine. However, L3-4 motion with flexion/extension and lateral bending was noted to be greater compared to the L3-S1 construct (p < 0.5). The L3-S1 PSF construct decreased motion to less than 1° in all planes of motion with or without loading (p < 0.05). The L3-4 PSF with previous L4-S1 PSF constructs decreased the flexion/extension motion by 92.4% compared to the intact spine, whereas the L3-4 LLIF with previous L4-S1 PSF constructs decreased motion by 61.2%.ConclusionsStand-alone LLIF above a previous posterolateral fusion significantly decreases motion at the adjacent segment, demonstrating its utility in treating ASD without necessitating revision. The stand-alone LLIF is a biomechanically sound option in the treatment of ASD and is advantageous in patient populations who may benefit from less invasive surgical options.

Highlights

Adjacent segment disease (ASD) is a postoperative diagnosis in patients with prior histories of spinal fusion
Lateral lumbar interbody fusion (LLIF) and posterior spinal fusion (PSF) with pedicle screws were analyzed within a validated cadaveric lumbar fusion model
The L3-4 PSF with previous L4-S1 PSF constructs decreased the flexion/extension motion by 92.4% compared to the intact spine, whereas the L3-4 LLIF with previous L4-S1 PSF constructs decreased motion by 61.2%

Summary

Introduction

Adjacent segment disease (ASD) is a postoperative diagnosis in patients with prior histories of spinal fusion. A diagnosis of ASD is predicated on both adjacent segment radiographic degeneration and the development of clinical symptoms. Multiple longitudinal studies have demonstrated that radiographic evidence of adjacent segment degeneration is not directly correlated with ASD, as some radiographic findings can be nonspecific and not clinically relevant [1,2,3]. How to cite this article Chioffe M, Mccarthy M, Swiatek P R, et al (November 20, 2019) Biomechanical Analysis of Stand-alone Lateral Lumbar Interbody Fusion for Lumbar Adjacent Segment Disease.

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