1.1 This guide is intended to provide guidance for evaluating lumbar total disc prostheses under simulated impingement loading. 1.2 Most IVD prostheses primarily fall into three classifications: mobile bearing ball-in-socket type, fixed bearing ball-in-socket prostheses and elastomeric or compliant type prostheses. For the first two ball-in-socket type devices, this guide primarily addresses impingement wear (defined herein); whereas for the third type, this guide may or may not be applicable. 1.3 For articulating components, this guide predominantly describes an impingement test. The user is cautioned that this method is intended to produced a clinically worst-case loading scenario and the resulting wear and fatigue imparted on the devices under test will likely have a significant influence on the functionality and performance of an articulating IVD prosthesis, and therefore the user should understand the Mode 1 wear of the device first using a protocol like those suggested in ASTM F2423. 1.4 This guide covers a procedure for measuring the range of motion and impingement of mobile and fixed bearing lumbar total disc replacements. 1.5 This guide covers the procedure for static and cyclic fatigue tests. 1.6 This guide should be used to evaluate fixed or mobile bearing prostheses manufactured from polymeric, metallic, or ceramic materials. 1.7 Load and kinematic profiles for lumbar and cervical devices are not identical and therefore this guide presently only addresses lumbar devices. 1.8 Partial disc replacements, such as nucleus replacements or facet joint replacements, are not intended to be addressed. 1.9 Wear is assessed using a weight loss method in a testing medium as defined in this guide. 1.10 This guide is not intended to address any potential failure mode as it relates to the fixation of the implant to its bony interfaces. 1.11 It is the intent of this guide to enable comparison of intervertebral disc (IVD) prostheses with regard to kinematic, functional, and wear 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 may not be universally representative. 1.12 In order that the data be reproducible and comparable within and between laboratories, it is essential that uniform procedures are established. This guide is intended to facilitate uniform methods for testing and reporting of data for total disc replacement prostheses. 1.13 Without a substantial clinical retrieval history of IVD prostheses, actual loading profiles and patterns cannot be delineated at the time of the writing of this guide. It therefore follows that the load and motion conditions specified by this guide do not necessarily accurately reproduce those occurring in vivo. Rather, this guide provides useful boundary/endpoint conditions for evaluating prosthesis designs in a functional manner. 1.14 The values stated in SI units are to be regarded as the standard with the exception of angular measurements, which may be reported in either degrees or radians. 1.15 This guide is not intended to be a performance standard. It is the responsibility of the user of this guide to characterize the safety and effectiveness of the prosthesis under evaluation. 1.16 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Presently no standards for total disc impingement.
KeywordsImpingement:Lumbar Total Disc Replacement:Wear
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top