Currently, rigid fixation systems are the gold standard for degenerative disk disease treatment. Dynamic fixation systems have been proposed as alternatives for the treatment of a variety of spinal disorders. These systems address the main drawbacks of traditional rigid fixation systems, such as adjacent segment degeneration and instrumentation failure. Pedicle-screw-based dynamic stabilization (PDS) is one type of these alternative systems. The aim of this study was to simulate the biomechanical effect of a novel posterior dynamic stabilization system, which is comprised of dynamic (hinged) screws interconnected with a coiled, spring-based dynamic rod (DSDR), and compare it to semirigid (DSRR and RSRR) and rigid stabilization (RSRR) systems. A validated finite element (FE) model of L1-S1 was used to quantify the biomechanical parameters of the spine, such as range of motion, intradiskal pressure, stresses and facet loads after single-level instrumentation with different posterior stabilization systems. The results obtained from in vitro experimental intact and instrumented spines were used to validate the FE model, and the validated model was then used to compare the biomechanical effects of different fixation and stabilization constructs with intact under a hybrid loading protocol. The segmental motion at L4–L5 increased by 9.5% and 16.3% in flexion and left rotation, respectively, in DSDR with respect to the intact spine, whereas it was reduced by 6.4% and 10.9% in extension and left-bending loads, respectively. After instrumentation-induced intradiskal pressure at adjacent segments, L3-L4 and L5-S1 became less than the intact in dynamic rod constructs (DSDR and RSDR) except in the RSDR model in extension where the motion was higher than intact by 9.7% at L3-L4 and 11.3% at L5-S1. The facet loads were insignificant, not exceeding 12N in any of the instrumented cases in flexion. In extension, the facet load in DSDR case was similar to that in intact spine. The dynamic rod constructions (DSDR and RSDR) led to a lesser peak stress at screws compared with rigid rod constructions (DSRR and RSRR) in all loading cases. A dynamic construct consisting of a dynamic rod and a dynamic screw did protect the adjacent level from excessive motion.
Skip Nav Destination
e-mail: tuncoktenoglu@gmail.com
Article navigation
Research-Article
A Computational Biomechanical Investigation of Posterior Dynamic Instrumentation: Combination of Dynamic Rod and Hinged (Dynamic) Screw
Deniz U. Erbulut,
Deniz U. Erbulut
Department of Mechanical
Engineering and Neurosurgery,
e-mail: erbulutdeniz@gmail.com and
derbulut@ku.edu.tr
Engineering and Neurosurgery,
Koc University
, Sariyer,Istanbul 34450
, Turkey
e-mail: erbulutdeniz@gmail.com and
derbulut@ku.edu.tr
Search for other works by this author on:
Ali Kiapour,
Ali Kiapour
Departments of Bioengineering
and Orthopedic Surgery,
e-mail: Kiapour@asme.org
and Orthopedic Surgery,
E-CORE, University of Toledo
,Toledo, OH 43606
e-mail: Kiapour@asme.org
Search for other works by this author on:
Tunc Oktenoglu,
e-mail: tuncoktenoglu@gmail.com
Tunc Oktenoglu
Vehbi Koc Foundation American Hospital
,Nisantasi, Istanbul 34365
, Turkey
e-mail: tuncoktenoglu@gmail.com
Search for other works by this author on:
Ali F. Ozer,
Ali F. Ozer
Department of Neurosurgery,
e-mail: alifahirozer@gmail.com
Koc University
, Sariyer,Istanbul 34450
, Turkey
e-mail: alifahirozer@gmail.com
Search for other works by this author on:
Vijay K. Goel
Vijay K. Goel
Departments of Bioengineering
and Orthopedic Surgery,
e-mail: vijay.goel@utoledo.edu
and Orthopedic Surgery,
E-CORE, University of Toledo
,Toledo, OH 43606
e-mail: vijay.goel@utoledo.edu
Search for other works by this author on:
Deniz U. Erbulut
Department of Mechanical
Engineering and Neurosurgery,
e-mail: erbulutdeniz@gmail.com and
derbulut@ku.edu.tr
Engineering and Neurosurgery,
Koc University
, Sariyer,Istanbul 34450
, Turkey
e-mail: erbulutdeniz@gmail.com and
derbulut@ku.edu.tr
Ali Kiapour
Departments of Bioengineering
and Orthopedic Surgery,
e-mail: Kiapour@asme.org
and Orthopedic Surgery,
E-CORE, University of Toledo
,Toledo, OH 43606
e-mail: Kiapour@asme.org
Tunc Oktenoglu
Vehbi Koc Foundation American Hospital
,Nisantasi, Istanbul 34365
, Turkey
e-mail: tuncoktenoglu@gmail.com
Ali F. Ozer
Department of Neurosurgery,
e-mail: alifahirozer@gmail.com
Koc University
, Sariyer,Istanbul 34450
, Turkey
e-mail: alifahirozer@gmail.com
Vijay K. Goel
Departments of Bioengineering
and Orthopedic Surgery,
e-mail: vijay.goel@utoledo.edu
and Orthopedic Surgery,
E-CORE, University of Toledo
,Toledo, OH 43606
e-mail: vijay.goel@utoledo.edu
Contributed by the Bioengineering Division of ASME for publication in the Journal of Biomechanical Engineering. Manuscript received October 9, 2013; final manuscript received February 26, 2014; accepted manuscript posted March 6, 2014; published online April 10, 2014. Assoc. Editor: James C. Iatridis.
J Biomech Eng. May 2014, 136(5): 051007 (7 pages)
Published Online: April 10, 2014
Article history
Received:
October 9, 2013
Revision Received:
February 26, 2014
Accepted:
March 6, 2014
Citation
Erbulut, D. U., Kiapour, A., Oktenoglu, T., Ozer, A. F., and Goel, V. K. (April 10, 2014). "A Computational Biomechanical Investigation of Posterior Dynamic Instrumentation: Combination of Dynamic Rod and Hinged (Dynamic) Screw." ASME. J Biomech Eng. May 2014; 136(5): 051007. https://doi.org/10.1115/1.4027060
Download citation file:
Get Email Alerts
Effect of Internal Mechanical Environment of Porous Scaffolds on Mechano-driven Bone Ingrowth: A Numerical Study
J Biomech Eng (September 2023)
In Silico Mechanical Effort Analysis of the All-On-4 Design Performed With Platform-Switching Distal Short Dental Implants
J Biomech Eng (September 2023)
Related Articles
Biomechanical Analysis of a Long-Segment Fusion in a Lumbar Spine—A Finite Element Model Study
J Biomech Eng (September,2018)
Application of the Finite Element Technique in the Design and Evaluation of the Artificial Facets for the Lumbar Spine
J. Med. Devices (June,2007)
Related Proceedings Papers
Related Chapters
Fatigue Analysis in the Connecting Rod of MF285 Tractor by Finite Element Method
International Conference on Advanced Computer Theory and Engineering, 4th (ICACTE 2011)
Vibration Analysis of the Seated Human Body in Vertical Direction
International Conference on Computer Technology and Development, 3rd (ICCTD 2011)
Load Transfer in Single Rivet-Row Lap Joints (Conventional and Countersunk)
Structural Shear Joints: Analyses, Properties and Design for Repeat Loading