Alternative Pedicle Screw Design via Biomechanical Evaluation

Jiwoon Kwon,Myung Heon Ha,Moon Gu Lee

doi:10.3390/app10144746

Abstract

With the recent increase in the elderly population, many people suffer from spinal diseases, and, accordingly, spinal fusion surgery using pedicle screws has been widely applied to treat them. However, most research on pedicle screw design has been focused on the test results rather than the behavior of the screws and vertebrae. In this study, a design platform with a series of biomechanical tests and analyses were presented for pedicle screw improvement and evaluation. The platform was then applied to an alternative hybrid screw design with quadruple and double threads. An experimental apparatus was developed to investigate the bending strength of the screw, and several tests were performed based on the ASTM F1717 standard. In the experiments, it was confirmed that the alternative pedicle screw has the highest bending strength. To examine the stress distribution of pedicle screws, finite element models were established, through which it was found that the proposed pedicle screw has sufficient mechanical safety to make it acceptable for spinal fusion treatment. Finally, we conclude that the platform has good potential for the design and evaluation of pedicle screws, and the alternative dual screw design is one of the best options for spinal fusion surgery.

Highlights

Spinal disease is a problem that can lower the quality of peoples’ lives, and various attempts have been made to solve it
Degenerative lumbar diseases cause instability of the spine due to aging and degeneration of facet joints and intervertebral discs [3]. These are generally caused by osteophytes in the vertebral body and facet joints or spinal stenosis due to herniated intervertebral discs
Three types of pedicle screws were used in the analysis, the results of which were compared with each other (Figures 8–10 and Table 5)

Summary

Introduction

Spinal disease is a problem that can lower the quality of peoples’ lives, and various attempts have been made to solve it. Frequent and long-lasting activities can cause degenerative spinal disorders, such as lumbar spinal stenosis, herniation of intervertebral discs, and degenerative lumbar diseases [1,2,3]. Spinal problems occur in young people with high activity or poor posture. Degenerative lumbar diseases cause instability of the spine due to aging and degeneration of facet joints and intervertebral discs [3]. These are generally caused by osteophytes in the vertebral body and facet joints or spinal stenosis due to herniated intervertebral discs. The instability of the spine can compress the spinal nerves and result in sharp pain from the hips to the legs

Methods

Results

Conclusion