Biomechanical Analysis of Thoracolumbar Interbody Constructs: How Important Is the Endplate?

Hollowell, James P.; Vollmer, Dennis G.; Wilson, Charles R.; Pintar, Frank A.; Yoganandan, Narayan

doi:10.1097/00007632-199605010-00007

Cited by 125 publications

(74 citation statements)

References 6 publications

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“…Removal of the stiffer cortical endplate exposes a host bed of bleeding trabecular bone (potentially osteogenic cells) which is advantageous from a biological point of view allowing bone fusion with the graft material. A number of in vitro investigations of the effect of endplate removal on the vertebral subsidence force have provided conflicting recommendations including: endplate preservation (Lim et al 2001;Oxland et al 2003); partial endplate removal (Steffen et al 2000;Lowe et al 2004); complete endplate removal (Hollowell et al 1996;Closkey et al 1993). Regardless of the endplate preparation technique, the insertion of a stiff metallic IFD will induce significant stress concentrations in the surrounding bone.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental studies on subsidence have predominantly focused on endplate preparation and implant geometry with the maximum failure load being measured to evaluate subsidence resistance (Lim et al 2001;Oxland et al 2003;Steffen et al 2000;Lowe et al 2004;Hollowell et al 1996;Closkey et al 1993). Oxland et al (2003) found a significant decrease in failure load and stiffness for endplate removal.…”

mentioning

confidence: 99%

“…Lim et al (2001) found a reduction in compressive strength with complete endplate removal. According to Hollowell et al (1996), the endplate thickness may not be sufficient to resist subsidence. The current study provides significant insight into trabecular bone plasticity and demonstrates that the pressure dependent crushable foam plasticity formulations provide accurate macroscale continuum simulation of vertebral IFD subsidence.…”

mentioning

confidence: 99%

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An experimental and computational investigation of the post-yield behaviour of trabecular bone during vertebral device subsidence

Kelly

Harrison

McDonnell

et al. 2012

Biomech Model Mechanobiol

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PublisherSpringer-Verlag AbstractInterbody fusion device subsidence has been reported clinically. An enhanced understanding of the mechanical behaviour of the surrounding bone would allow for accurate predictions of vertebral subsidence. The multiaxial inelastic behaviour of trabecular bone is investigated at a microscale and macroscale level. The post-yield behaviour of trabecular bone under hydrostatic and confined compression is investigated using micro-computed tomography derived microstructural models, elucidating a mechanism of pressure dependent yielding at the macroscopic level. Specifically, microstructural trabecular simulations predict a distinctive yield point in the apparent stress-strain curve under uniaxial, confined and hydrostatic compression. Such distinctive apparent stress-strain behaviour results from localised stress concentrations and material yielding in the trabecular microstructure. This phenomenon is shown to be independent of the plasticity formulation employed at a trabecular level. The distinctive response can be accurately captured by a continuum model using a crushable foam plasticity formulation in which pressure dependent yielding occurs.Vertebral device subsidence experiments are also performed, providing measurements of the trabecular plastic zone. It is demonstrated that a pressure dependent plasticity formulation must be used for continuum level macroscale models of trabecular bone in order to replicate the experimental observations, further supporting the microscale investigations. Using a crushable foam plasticity formulation in the simulation of vertebral subsidence, it is shown that the predicted subsidence force and plastic zone size correspond closely with the experimental measurements. In contrast the use of von Mises, Drucker-Prager and Hill plasticity formulations for continuum trabecular bone models lead to over prediction of the subsidence force and plastic zone.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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An experimental and computational investigation of the post-yield behaviour of trabecular bone during vertebral device subsidence

Kelly

Harrison

McDonnell

et al. 2012

Biomech Model Mechanobiol

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“…The literature offers no uniform recommendations for the test conditions in compression trials of this type, and test speeds of 5 mm/min [14,30], 0.4 mm/s [18], 35 mm/ min [38] and 2.54 mm/s [16] are described in the literature. Since no group of authors offers any rationale for their respective test speed, we assumed that the various speeds were determined by the test machine employed in each case.…”

Section: Discussionmentioning

confidence: 99%

“…The following average maximum compression forces were measured with various grafts or implants against the vertebral body end-plate by Hollowell et al [16]: 1473 N ("Harms mesh cage", 17×22 mm), 1165 N (iliac crest bone graft), 1038 N (humerus), 1037 N (3×ribs) and 537 N (1×rib). The deformation (distance covered) measured for the "Harms mesh cage" was 5.9 mm, i.e., almost identical to our own results.…”

Section: Discussionmentioning

confidence: 99%

Biomechanical compression tests with a new implant for thoracolumbar vertebral body replacement

Knop

Lange

Bastian

et al. 2001

European Spine Journal

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Use of postmortem human subjects to describe injury responses and tolerances

et al. 2011

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Traumatic injuries from blunt, penetrating, and blast events expose the human body to unintentional and intentional external mechanical loads. To mitigate trauma and develop safety-engineered devices for clinical and bioengineering applications, it is critical to delineate the structural load-bearing anatomy and biomechanics of the various components of the human body. This article presents advances made in the understanding of the injury responses and tolerances through experiments conducted using intact or segmented tissues from postmortem human subjects (PMHS), and a considerable majority of data for the presentation has been extracted from studies conducted at the Institutions of the authors. The role of the PMHS model for studying traumatic injuries to the head and face, vertebral column (cervical, thoracic and lumbar spines), thorax, abdomen, pelvis, and lower extremities is discussed. Different impact loading scenarios, likely responsible for the initial trauma causation, are considered in the analysis and determination of the human response to injury. Clinical advances made using the PMHS model are discussed. This includes vertebral stabilization system evaluations secondary to traumatic injuries to the spinal column. The critical importance of using data from the PMHS model in developing validated computational models for advancing crashworthiness research, occupant safety in motor vehicle crashes, medical devices, and safety-engineering applications is highlighted.

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Biomechanical Analysis of Thoracolumbar Interbody Constructs: How Important Is the Endplate?

Abstract: Preservation of the vertebral endplate may not offer a significant biomechanical advantage in reconstructing the anterior column. Several alternative constructs are mechanically equivalent.

Cited by 125 publications

References 6 publications

An experimental and computational investigation of the post-yield behaviour of trabecular bone during vertebral device subsidence

An experimental and computational investigation of the post-yield behaviour of trabecular bone during vertebral device subsidence

Biomechanical compression tests with a new implant for thoracolumbar vertebral body replacement

Use of postmortem human subjects to describe injury responses and tolerances

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