Impingement-wear testing of lumbar prostheses - ISO 18192-3

Normative References  

ISO 18192-3: Implants for surgery - Wear of total intervertebral spinal disc prostheses - Part 3: Impingement-wear testing and corresponding environmental conditions for test of lumbar prostheses under adverse kinematic conditions  

This test method covers a procedure to simulate impingement between the inferior and superior endplate in a spinal disc prosthesis; the subsequent assessment of wear; and assessment of contact pattern.

The EndoLab^® spine simulator is used for this type of testing. An axial load and a time-varying angular displacement are applied to the lumbar prostheses. The axial load remains constant during impingement and fluctuates in a sinusoidal waveform during the remaining movement. Thus, a constant moment is applied during impingement.

The specimens are inspected after 125 thousand, 250 thousand, 500 thousand and after 1 million cycles. At each inspection, the wear of the prostheses is determined by gravimetric measurements.

SEM of the bearing surfaces as well as particle analysis can be performed.