STP1431

    An Evaluation of the Influence of UHMWPE Test Block Design on the Mechanical Performance of Bilateral Lumbar Corpectomy Constructs

    Published: Jan 2003


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    Abstract

    The purpose of this study was to investigate how the design of corpectomy test blocks influences key strength parameters in bilateral lumbar construct testing. Two different test block designs were used with components from DePuy AcroMed's Stainless Steel ISOLA™ Spinal System in the evaluation. Both test block designs were made to approximate the bending moment and pedicle screw angle in the lower lumbar spine. The first block type was fixed to the test frame by a pin that passed through the block as recommended in ASTM Fl717-97. The second block type had a spherical indentation that mated with a spherical ball fixture (ball-socket connection). A battery of static and dynamic compression bending was performed for each block type. Static compression bending tests for the bilateral constructs yielded statistically different values (p<0.05) for the yield strength, stiffness, and ultimate strength for the two test block types. Dynamic compression bending results showed a difference in runout load of 5.27 Nm between the two block types. The failure modes in static and dynamic compression testing were the same for each block type.

    Keywords:

    Spinal implant testing, lumbar, bilateral construct, corpectomy, test blocks


    Author Information:

    Dunbar, WL
    Senior Research Engineer, Research & Technology Group, DePuy AcroMed Inc., Raynham, MA

    Cesarone, D
    Project Engineer, Customs & Specials Group, DePuy AcroMed Inc., Raynham, MA

    Serhan, H
    Director, Research & Technology Group, DePuy AcroMed Inc., Raynham, MA


    Paper ID: STP11145S

    Committee/Subcommittee: F04.25

    DOI: 10.1520/STP11145S


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