Biomechanical properties of a novel nonfusion artificial vertebral body for anterior lumbar vertebra resection and internal fixation

Jiantao Liu,Yanzheng Gao,Hongbo Wang,Jintao Xiu,Binbin Niu,Yanbiao Wang,Xijing He,Yin Yang

doi:10.1038/s41598-021-82086-7

Abstract

The aim of the study was to evaluate the biomechanical properties of a novel nonfused artificial vertebral body in treating lumbar diseases and to compare with those of the fusion artificial vertebral body. An intact finite element model of the L1–L5 lumbar spine was constructed and validated. Then, the finite element models of the fusion group and nonfusion group were constructed by replacing the L3 vertebral body and adjacent intervertebral discs with prostheses. For all finite element models, an axial preload of 500 N and another 10 N m imposed on the superior surface of L1. The range of motion and stress peaks in the adjacent discs, endplates, and facet joints were compared among the three groups. The ranges of motion of the L1–2 and L4–5 discs in flexion, extension, left lateral bending, right lateral bending, left rotation and right rotation were greater in the fusion group than those in the intact group and nonfusion group. The fusion group induced the greatest stress peaks in the adjacent discs and adjacent facet joints compared to the intact group and nonfusion group. The nonfused artificial vertebral body could better retain mobility of the surgical site after implantation (3.6°–8.7°), avoid increased mobility and stress of the adjacent discs and facet joints.

Highlights

The aim of the study was to evaluate the biomechanical properties of a novel nonfused artificial vertebral body in treating lumbar diseases and to compare with those of the fusion artificial vertebral body
The results of the ROMs were in accordance with the findings of previous cadaveric studies[12,13] (Fig. 1), suggesting that the intact L1–L5 finite element (FE) model in the present study was successfully constructed and could be used for further analysis
Long-term follow-up results showed that the incidence of complications such as adjacent disc degeneration was significantly increased after this procedure[14]

Summary

Introduction

The aim of the study was to evaluate the biomechanical properties of a novel nonfused artificial vertebral body in treating lumbar diseases and to compare with those of the fusion artificial vertebral body. The finite element models of the fusion group and nonfusion group were constructed by replacing the L3 vertebral body and adjacent intervertebral discs with prostheses. The nonfused artificial vertebral body could better retain mobility of the surgical site after implantation (3.6°–8.7°), avoid increased mobility and stress of the adjacent discs and facet joints. The treatment method can achieve complete spinal decompression and restore the height and stability of the lumbar s pine[5,6], the operation often requires the fusion of three or more vertebrae, which inevitably leads to loss of the physiological and motor function of the spine in the surgical area. Some studies have reported that the pressure on the adjacent intervertebral disc and articular process will increase after fusion, accelerating the degeneration of the adjacent s egment[7] In severe cases, another operation is required. Finite element (FE) analysis was used to study the biomechanical properties of this new prosthesis to provide a reference for its long-term biomechanical safety after implantation

Objectives

Methods

Results

Conclusion