Comparison of the Optimal Design of Spinal Hybrid Elastic Rod for Dynamic Stabilization: A Finite Element Analysis
Source abstract
Abstract
The spinal hybrid elastic (SHE) rod is a semi-rigid pedicle screw-based rod for spinal dynamic stabilization. This study investigated the biomechanical effects of different ratios of SHE rod using finite element analysis (FEA). A three-dimensional nonlinear FEA of an intact lumbar spine model (INT) was constructed. The SHE rod was composed of an inner nitinol stick (NS) and an outer polycarbonate urethane shell (PS). Four groups implanted at L3–L4 had the same outer diameter (5.5 mm) but different NS diameter/PS thickness ratios: Nt45, Nt35, Nt25, and Nt15. The resultant intervertebral range of motion (ROM), disc stress, facet joint contact force, screw stress, NS stress, and PCU stress were analyzed. The results indicated that ROM, disc stress, and facet force decreased moderately in the implanted L3–L4 levels and increased slightly in the adjacent L2–L3 levels. The NS stress and NS diameter trended towards inverse proportionality. Changing the ratio did not markedly influence screw or PS stress. The SHE rod system with elastic NS and insulated PS has a 5.5 mm diameter for universal pedicle screws. The SHE rod system provides sufficient spinal support and increases gentle adjacent segment stress. Considering the durability, the optimal NS diameter/PS thickness ratio of the SHE rod system is 3.5/2.0 mm.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Spine and Intervertebral Disc Pathology · Spinal Fractures and Fixation Techniques · Scoliosis diagnosis and treatment
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Biomedical Engineering, National Taiwan University, Taipei 100, Taiwan
Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei 100, Taiwan
Department of Orthopedic Surgery, National Taiwan University Hospital, Jinshan Branch, New Taipei City 208, Taiwan
Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
Funding
National Taiwan University Hospital and its Jinshan branch
References (28)
Show source-provided references
1. Mid- to long-term outcomes in adolescent idiopathic scoliosis after instrumented posterior spinal fusion: A meta-analysis10.1097/BRS.0b013e31827ae3d0 ↗
2. A systematic review of clinical outcomes in surgical treatment of adult isthmic spondylolisthesis10.1016/j.spinee.2018.04.022 ↗
3. Lumbar interbody fusion: Techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF
4. Posterolateral fusion (PLF) versus transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis: A systematic review and meta-analysis10.1016/j.spinee.2018.01.028 ↗
5. Hu, Y.-H., Niu, C.-C., Hsieh, M.-K., Tsai, T.-T., Chen, W.-J., and Lai, P.-L. (2019). Cage positioning as a risk factor for posterior cage migration following transforaminal lumbar interbody fusion—An analysis of 953 cases. BMC Musculoskelet. Disord., 20.10.1186/s12891-019-2630-0 ↗
6. Adjacent Segment Degeneration Versus Disease After Lumbar Spine Fusion for Degenerative Pathology: A Systematic Review With Meta-Analysis of the Literature10.1097/BSD.0000000000000328 ↗
7. Etiology, Evaluation, and Treatment of Failed Back Surgery Syndrome10.4184/asj.2018.12.3.574 ↗
8. Adjacent segment degeneration after lumbar spinal fusion compared with motion-preservation procedures: A meta-analysis10.1007/s00586-016-4415-6 ↗
9. Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: A clinical and radiological outcomes-based meta-analysis10.3171/2015.10.FOCUS15426 ↗
10. Wu, A.-M., Zhou, Y., Li, Q.-L., Wu, X., Jin, Y.-L., Luo, P., Chi, Y.-L., and Wang, X.-Y. (2014). Interspinous Spacer versus Traditional Decompressive Surgery for Lumbar Spinal Stenosis: A Systematic Review and Meta-Analysis. PLoS ONE, 9.10.1371/journal.pone.0097142 ↗
11. Interspinous process spacers versus traditional decompression for lumbar spinal stenosis: Systematic review and meta-analysis10.21037/jss.2016.01.07 ↗
12. Kok, D., Firkins, P.J., Wapstra, F.H., and Veldhuizen, A.G. (2013). A new lumbar posterior fixation system, the memory metal spinal system: An in-vitro mechanical evaluation. BMC Musculoskelet. Disord., 14.10.1186/1471-2474-14-269 ↗
13. Structure−Mechanical Property Relationships for Poly(carbonate urethane) Elastomers with Novel Soft Segments10.1021/ma901317t ↗
14. Biomechanical comparison between lumbar disc arthroplasty and fusion10.1016/j.medengphy.2008.07.007 ↗
15. Influence of Dynesys System Screw Profile on Adjacent Segment and Screw
16. Load- and displacement-controlled finite element analyses on fusion and non-fusion spinal implants10.1243/09544119JEIM476 ↗
17. Effect of the cord pretension of the Dynesys dynamic stabilization system on the biomechanics of the lumbar spine: A finite element analysis10.1007/s00586-011-1817-3 ↗
18. Water Content in Human Intervertebral Discs10.1097/00007632-198711000-00012 ↗
19. Three-Dimensional Movements of the Whole Lumbar Spine and Lumbosacral Joint10.1097/00007632-198911000-00020 ↗
20. An improved model of 3-dimensional finite element analysis of mechanical behavior of endodontic instruments10.1016/j.tripleo.2009.10.039 ↗
21. Biomechanical Rationale for Using Polyetheretherketone (PEEK) Spacers for Lumbar Interbody Fusion—A Finite Element Study10.1097/01.brs.0000250177.84168.ba ↗
22. Biomechanical Assessment of a PEEK Rod System for Semi-Rigid Fixation of Lumbar Fusion Constructs10.1115/1.4004862 ↗
23. Retrieval analysis of PEEK rods for posterior fusion and motion preservation10.1007/s00586-013-2920-4 ↗
24. Nitinol Memory Rods Versus Titanium Rods: A Biomechanical Comparison of Posterior Spinal Instrumentation in a Synthetic Corpectomy Model10.1177/2192568220902401 ↗
25. Corrosion resistance, surface mechanical properties, and cytocompatibility of plasma immersion ion implantation-treated nickel-titanium shape memory alloys10.1002/jbm.a.30413 ↗
26. Biomechanical analysis of a new lumbar interspinous device with optimized topology10.1007/s11517-017-1767-y ↗
27. Hsieh, J.-Y., Chen, C.-S., Chuang, S.-M., Wang, J.-H., Chen, P.-Q., and Huang, Y.-Y. (2022). Finite element analysis after rod fracture of the spinal hybrid elastic rod system. BMC Musculoskelet. Disord., 23.10.1186/s12891-022-05768-x ↗
28. Effect of spacer diameter of the Dynesys dynamic stabilization system on the biomechanics of the lumbar spine: A finite element analysis