A FINITE ELEMENT ANALYSIS OF SEMI-RIGID SINGLE AND TWO LEVEL PEDICLE SCREW-ROD FIXATION IN LUMBAR SPINE

Abstract

For the treatment of degenerative disc disease (DDD) and associated back pain and instability in the spinal segments, the success of pedicle screw-based spinal implant system has been found in the literature. Over the last couple of years, various nonfusion implants are made for the treatment of minor DDD. In this study, the biomechanical response of pedicle screw-based implant with semi-rigid rod material on the lumbar spine is evaluated. Computed tomography (CT) scan-based finite element (FE) model is used to evaluate the performance of pedicle screw fixation with flexible rods made of carbon fiber-reinforced polyetheretherketone (CFR PEEK). Typical physiological loadings are applied to the intact and implanted lumbar spine model. It is observed that the pediclescrew with the CFR-PEEK rod can restore the range of motion (ROM) on the surgical segment. The CFR-PEEK RODs carried out more loads and reduced the stress on the vertebral body. Using traditional rigid rods, ROM is generally almost restricted on the fusion zone, which can be improved by CFR-PEEK rod system to a certain degree. After successful experimental validation and clinical trial, the CFR-PEEK rod may be recommended for improved clinical outcomes.