ASTM F2694-16(R2020) pdf free download

ASTM F2694-16(R2020) pdf free download.Standard Practice for Functional and Wear Evaluation of Motion-Preserving Lumbar Total Facet Prostheses
1. Scope
1.1 This practice provides guidance for the functional, kinematic, and wear testing of motion-preserving total facet prostheses for the lumbar spine. These implants are intended to allow motion and lend support to the functional spinal unit(s) through replacement of the natural facets. 1.2 This practice is not intended to address the bone implant interface or the static characteristics of the prosthesis compo- nents. Fatigue characteristics are included, but only as a by-product of cyclic wear testing under facet load and thus are not addressed in the typical process of generating a Stress-Life (S-N) characterization. 1.3 Biocompatibility of the materials used in a total facet prosthesis are not addressed in this practice. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4.1 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. 1.5 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 All functional and kinematic testing terminology is consistent with the referenced standards, unless otherwise stated. 3.2 Definitions ofTerms: 3.2.1 mechanical failure, n—failure associated with a defect in the material (for example, fatigue crack) or the bonding between materials that may or may not produce functional failure. [F2423] 3.2.2 runout (cycles), n—maximum number of cycles that a test needs to be carried to if functional failure has not yet occurred. [F2423] 3.3 Definitions ofTerms Specific to This Standard: 3.3.1 coordinate systems/axes, n—global XYZ orthogonal axes are defined following a right-handed Cartesian coordinate system in which the XY plane is parallel to and co-planar with the superior endplate of the inferior vertebral body. The global axes are fixed relative to the inferior vertebral body, which in this practice is also considered to be stationary with respect to the test machine’s frame. Lower case letters, xyz, denote a local moving orthogonal coordinate system attached to the superior vertebral body with directions initially coincident with those of the global XYZ axes, respectively. The 3D motion of the superior relative to the inferior vertebra is specified and is to be measured in terms of sequential Eulerian angular rotations about the xyz axes, respectively (z axial rotation, x lateral bend, and y flexion-extension). See Figs. 1 and 2. 3.3.1.1 origin, n—center of the global coordinate system that is located at the posterior medial position on the superior endplate of the inferior vertebral body. 3.3.1.2 X-axis, n—the positive X-axis is directed anteriorly relative to the specimen’s initial unloaded position. See Figs. 1 and 2. 3.3.1.3 Y-axis, n—the positive Y-axis is directed laterally (toward the left) relative to the specimen’s initial unloaded position. See Figs. 1 and 2. 3.3.1.4 Z-axis, n—the positive Z-axis is directed superiorly relative to the specimen’s initial unloaded position. See Figs. 1 and 2. 3.3.2 fluid absorption, n—fluid absorbed by the device material during testing or while implanted in vivo. 3.3.3 functional failure, n—permanent deformation or wear that renders the total facet prosthesis assembly ineffective or unable to perform its intended function.