Finite element analysis of Isobar TTL techniques and universal spinal system for lumbar spine: A comparison
10.3724/SP.J.1008.2013.00416
- Author:
Jian-Hang LIU
1
Author Information
1. Centre of Orthopaedics, Zhujiang Hospital, Southern Medical University
- Publication Type:Journal Article
- Keywords:
Dynamic internal fixation;
Finite element analysis;
Spinal fusion;
Spine
- From:
Academic Journal of Second Military Medical University
2013;34(4):416-420
- CountryChina
- Language:Chinese
-
Abstract:
Objective To establish finite element models of universal spinal system (USS) and Isobar TTL on L3-S1 with fine anatomical structures and to compare the characteristics of stress distribution of the two models, so as to explore the influence of dynamic internal fixation system (DIFS) on the lumbar biomechanics, providing a theoretical basis for clinical application of DIFS. Methods The lumbar spine geometries were determined using the CT images of a 26-year-old healthy man. The finite element models of USS and Isobar TTL were constructed by using package Mimics 11. 1, Geomagic studio 10. 0, HyperMesh 10. 0 and Abaqus 6. 8. The ranges of motion, intervertebral disc stress of adjacent segments, and stress distribution and peak of internal fixation were recorded when the models were subjected to 150 N preload and 10 Nm moment of forces under different conditions: flexion, extension, lateral bending and axial rotation. Results We have successfully constructed the definite element model of L3-S1 with fine anatomical structures and the postoperation models of Isobar TTL and USS. The stress of Isobar TTL and USS model was mainly distributed on the screws, with the maximal stress on USS model being higher than that on the Isobar TTL model. The screws had high stress at the middle part, with the maximal stress being all less than 100 MPa under different conditions. The intervertebral stability of Isobar TTL model was not greatly different from that of normal model; however, the overall motion of USS model was obviously deceased, especially when at flexion and extension condition. For Isobar TTL model, the increases of intervertebral disc stress of adjacent segments of L3/L4 for forward bending, backward extension, lateral bending and rotation were 6. 2%, 9. 7%, 3. 6%, and 3. 8%, respectively, and the numbers for USS model were 8. 5%, 13. 5%, 4. 3% and 4. 8%, respectively. Conclusion The maximal stress of Isobar TTL system can effectively maintain the range of motion of the lumbar spine, reduce the resistance of stress, and delay adjacent segment degeneration in theory.
