ISO 12189 standard for the preclinical evaluation of posterior spinal stabilization devices

Abstract

The International Standardization Organization (ISO) 12189 standard was recently introduced to preclinically evaluate and compare the mechanical properties of posterior stabilization devices. This scenario presents some new significant steps ahead over the vertebrectomy model recommended by American Society for Testing and Materials (ASTM) F1717 standard: the modular anterior support allows for describing a closer scenario to the effective clinical use as well as to test very flexible and dynamic posterior stabilization devices. Despite these significant advantages, ISO 12189 received little attention in the literature. Anatomical parameters depending on the spinal level were compared to the published data or original measurements on biplanar stereoradiography on 13 patients. Other mechanical variables, describing the test set-up design, were considered and all parameters were investigated using a numerical parametric finite element model. Stress values were calculated by also considering their worst-case combination. The standard set-up represents quite well the anatomy of an instrumented average thoracolumbar segment. The parametric comparative analysis demonstrates a significant (even beyond +350%) maximum increase in the stress on the device, compared to the standard currently in use. The anterior support stiffness plays the most detrimental effect (maximum stress increases up to 396%). The initial precompression step has an important role in determining the final stress values achieved at peak load (up to +76%). Moreover, when combining these two contributions, an even higher stress increase may be achieved (up to 473%). Despite the other anatomical parameters playing a secondary role, their worst-case combination demonstrates that a device could potentially undergo higher stresses than those reached according to standard suggestions (maximum increase of 22.4% at L1). Any user/designer should be aware of these effects when using ISO 12189 standard for the preclinical evaluation of posterior spinal stabilization devices.

Keywords

ISO 12189 ASTM F1717 ISO 10243 standard fatigue preclinical evaluation pedicle screw spine stabilization finite element parametric study finite element model

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References

ISO 12189:2008. Implants for surgery – mechanical testing of implantable spinal devices: fatigue test method for spinal implant assemblies using an anterior support.

ASTM F1717:2015. Standard test methods for spinal implant constructs in a vertebrectomy model.

ISO 10243:2010. Tools for pressing – compression springs with rectangular section: housing dimensions and colour coding.

Jahng

Kim

Moon

Comparison of the biomechanical effect of pedicle-based dynamic stabilization: a study using finite element analysis. Spine J 2013; 13: 85–94.

Gornet

Chan

Coleman

. Biomechanical assessment of a PEEK rod system for semi-rigid fixation of lumbar fusion constructs. J Biomech Eng 2011; 133(8): 081009.

Ponnappan

Serhan

Zarda

. Biomechanical evaluation and comparison of polyetheretherketone rod system to traditional titanium rod fixation. Spine J 2009; 9(3): 263–267.

Schmidt

Heuer

Wilke

Which axial and bending stiffnesses of posterior implants are required to design a flexible lumbar stabilization system?

J Biomech 2009; 42(1): 48–54.

Zhang

. Comparative effectiveness of PEEK rods versus titanium alloy rods in lumbar fusion: a preliminary report. Acta Neurochir 2013; 155: 1187–1193.

Campbell

Imsdahl

Ching

. Evaluation of a synthetic L2-L5 spine model for biomechanical testing. In: Proceedings of the 17th meeting of the Canadian society for biomechanics/Société Canadienne de Biomécanique (CSB/SCB), Vancouver, BC, 6–9 June 2012. Available at: http://ocs.sfu.ca/csb-scb/index.php/csb-scb/2012/paper/viewFile/306/222

10.

Gioia

Scotti

Mandelli

. Posterior spinal instrumentation: biomechanical study on the role of rods on hardware response to axial load. Eur Spine J 2011; 20(Suppl. 1): S3–S7.

11.

Braithwaite

McCormack

. Towards an artificial functional spinal unit for long-term in vitro testing. In: Proceedings of the 56th annual meeting of the orthopaedic research society, New Orleans, LA, 6–9 March 2010, paper no. 1538. Available at: http://www.ors.org/Transactions/56/1538.pdf

12.

Quaglini

Villa

. Biomechanical evaluation of spinal fixators. In: Proceedings of the 19th European conference on biomaterials, Sorrento, Italy, IT, 11–15 September 2005.

13.

Haher

Yeung

Ottaviano

. The inverse effects of load transfer and load sharing on axial compressive stiffness. Spine J 2001; 1(5): 324–329.

14.

Polly

Klemme

Cunningham

. The biomechanical significance of anterior column support in a simulated single-level spinal fusion. J Spinal Disord 2002; 13(1): 58–62.

15.

Wilke

Russo

Schmitt

. A mechanical model of human spinal motion segments. Biomed Tech 1997; 42(11): 327–331.

16.

La Barbera

Ottardi

Villa

. Comparative analysis of international standards for the fatigue testing of posterior spinal fixation systems: the importance of preload in ISO 12189. Spine J 2015; 15(10): 2290–2296.

17.

Villa

La Barbera

Galbusera

Comparative analysis of international standards for the fatigue testing of posterior spinal fixation systems. Spine J 2014; 14(4): 695–704.

18.

Hocquard

Évaluation clinique, caractérisation mécanique et modélisation pour l’évolution de la conception d’un implant rachidien dynamique. PhD Thesis, Department of Sciences and Technologies, Université Bordeaux 1, Bordeaux, 2012.

19.

Mosnier

Contribution à l’analyse biomécanique et à l’évaluation des implants rachidiens. PhD Thesis, École Nationale Supérieure d’Arts et Métiers, Paris, 2008.

20.

La Barbera

Galbusera

Villa

. ASTM F1717 standard for the preclinical evaluation of posterior spinal fixators: can we improve it? Proc IMechE, Part H: J Engineering in Medicine 2014; 228(10): 1014–1026.

21.

La Barbera

Villa

. ISO 12189 standard for the preclinical evaluation of posterior spinal stabilization devices-I: Assembly procedure and validation. Proc IMechE, Part H: J Engineering in Medicine 2015; 230(2): 122–133.

22.

Han

Biomechanical roles of spinal muscles in stabilizing the lumbar spine via follower load mechanism. PhD Thesis, The University of Iowa, Iowa City, IA, 2008.

23.

Rohlmann

Zander

Rao

. Applying a follower load delivers realistic results for simulating standing. J Biomech 2009; 42(10): 1520–1526.

24.

Schmidt

Heuer

Claes

. The relation between the instantaneous center of rotation and facet joint forces – a finite element analysis. Clin Biomech 2008; 23(3): 270–278.

25.

Rohlmann

Bauer

Zander

. Determination of trunk muscle forces for flexion and extension by using a validated finite element model of the lumbar spine and measured in vivo data. J Biomech 2006; 39(6): 981–989.

26.

Patwardhan

Havey

Meade

. A follower load increases the load-carrying capacity of the lumbar spine in compression. Spine 1999; 24(10): 1003–1009.

27.

Panjabi

Takata

Goel

. Thoracic human vertebrae. Quantitative three-dimensional anatomy. Spine 1991; 16(8): 888–901.

28.

Panjabi

Goel

Oxland

. Human lumbar vertebrae. Quantitative three-dimensional anatomy. Spine 1992; 17(3): 299–306.

29.

Semaan

Skalli

Veron

. Quantitative 3D anatomy of the lumbar spine. Rev Chir Orthop Reparatrice Appar Mot 2001; 87: 340–353.

30.

ASTM F2706:2008. Standard test methods for occipital-cervical and occipital-cervical-thoracic spinal implant constructs in a vertebrectomy model.

31.

Kemper

McNally

Manoogian

. Stiffness properties of human lumbar intervertebral discs in compression and the influence of strain rate. Washington, DC: National Highway Traffic Safety Administration (NHTSA), 2013.

32.

Gardner-Morse

Stokes

Physiological axial compressive preloads increase motion segment stiffness, linearity and hysteresis in all six degrees of freedom for small displacements about the neutral posture. J Orthop Res 2003; 21: 547–552.

33.

Rohlmann

Claes

Graichen

. Comparison of intradiscal pressures and spinal fixator loads for different body positions and exercises. Ergonomics 2001; 44(8): 781–794.

34.

Rohlmann

Graichen

Bergmann

Influence of load carrying on loads in internal spinal fixators. J Biomech 2000; 33(23): 1099–1104.

35.

Rohlmann

Claes

Graichen

. Loads on an internal spinal fixation device during walking. J Biomech 1997; 30(1): 41–47.

ISO 12189 standard for the preclinical evaluation of posterior spinal stabilization devices – II: A parametric comparative study

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