ASTM International

Standard Guide for Functional, Kinematic, and Wear Assessment of Total Disc Prostheses
 N F2423

Annotation

This guide provides guidance for wear and/or fatigue testing of total disc prostheses under functional and kinematic conditions and, to this end, describes test methods for assessment of the wear or functional characteristics, or both, of total disc prostheses.

Both lumbar and cervical prostheses are addressed.

Load and kinematic profiles for lumbar and cervical devices are not identical and, therefore, are addressed separately in the guide.

Partial disc replacements, such as nucleus replacements or facet joint replacements, are not intended to be addressed.

Wear is assessed using a weight loss method in a testing medium as defined in this guide.

This guide does not address any potential failure mode as it relates to the fixation of the implant to its bony interfaces.

It is the intent of this guide to enable comparison of intervertebral disc (IVD) prostheses with regard to wear and fatigue characteristics when tested under the specified conditions. It must be recognized, however, that there are many possible variations in the in vivo conditions. A single laboratory simulation with a fixed set of parameters might not be universally representative.

Most IVD prostheses primarily fall into two classifications: articulating ball-in-socket type prostheses, and elastomeric or compliant type prostheses. For the former, this guide primarily addresses Mode 1 wear (defined herein); whereas for the latter, this guide addresses potential failure of the prosthesis when the implant is subjected to a range of motion and/or loads that fall within the full range of possible physiologic motions and loads.