• Eur Spine J · Jun 2012

    Comparative Study

    An in vitro biomechanical comparison of Cadisc™-L with natural lumbar discs in axial compression and sagittal flexion.

    • Donal McNally, Jason Naylor, and Scott Johnson.
    • Institute of Biomechanics, School of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham NG7 2RD, UK. donal.mcnally@nottingham.ac.uk
    • Eur Spine J. 2012 Jun 1;21 Suppl 5:S612-7.

    IntroductionThe elastomeric, monobloc disc prosthesis (Cadisc™-L, Ranier Technology, Cambridge, UK) aims to preserve biomechanics of an implanted spinal motion segment.Study DesignThis study presents the findings of an in vitro investigation on the effect of implantation of Cadisc™-L. Compressive stiffness, flexion stiffness at 10, 20, 30 and 40 Nm and the instant-axis-of-rotation (IAR) loci are compared before and after implantation of a MC-10 mm-6° Cadisc™-L.MethodsFresh frozen human monosegmental lumbar spines (n = 8) were prepared, potted and tested in an environmentally controlled chamber to simulate in vivo conditions. Specimens were preconditioned by loading to 500 N for 30 min. Compressive stiffness of the specimen was determined by applying pure compression of 1 kN at 250 N/s via a loading roller positioned at the central loading axis (CLA). The roller was then offset 12.5 mm anterior of the CLA and the loading regime repeated to test specimens in flexion. Bending moments were calculated from the applied load and corresponding flexion angle. The IAR locus was tracked by a motion-tracking camera.ResultsCompressive stiffness was reduced by 50 % (p = 0.0005), flexion stiffness was not statistically significantly reduced (40 % reduction, p > 0.05). IAR locus maintained a 'horizontal figure of eight' characteristic. Change in the locus width in the AP plane of 6.4 mm (p = 0.06) and height in the SI plane of 1.3 mm (p = 0.44) were not significant. The centroid was displaced 4.44 mm (p = 0.0019) and 5.44 mm (p = 0.025) at 3° and 6° flexion, respectively.ConclusionsImplantation of Cadisc™-L caused a reduction in axial stiffness, but maintained disc height and flexion stiffness. IAR loci remained mobile without large displacement of the centroid from the intact spine position.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…