1、Designation: F2423 11 (Reapproved 2016)Standard Guide forFunctional, Kinematic, and Wear Assessment of Total DiscProstheses1This standard is issued under the fixed designation F2423; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides guidance for wear and/or fatiguetesting of total disc prostheses under functional and
3、kinematicconditions and, to this end, describes test methods for assess-ment of the wear or functional characteristics, or both, of totaldisc prostheses.1.2 Both lumbar and cervical prostheses are addressed.1.3 Load and kinematic profiles for lumbar and cervicaldevices are not identical and, therefo
4、re, are addressed sepa-rately in the guide.1.4 Partial disc replacements, such as nucleus replacementsor facet joint replacements, are not intended to be addressed.1.5 Wear is assessed using a weight loss method in a testingmedium as defined in this guide.1.6 This guide does not address any potentia
5、l failure modeas it relates to the fixation of the implant to its bony interfaces.1.7 It is the intent of this guide to enable comparison ofintervertebral disc (IVD) prostheses with regard to wear andfatigue characteristics when tested under the specified condi-tions. It must be recognized, however,
6、 that there are manypossible variations in in vivo conditions. A single laboratorysimulation with a fixed set of parameters might not beuniversally representative.1.8 Most IVD prostheses primarily fall into two classifica-tions: articulating ball-in-socket type prostheses, and elasto-meric or compli
7、ant type prostheses. For the former, this guideprimarily addresses Mode 1 wear (defined herein); whereas forthe latter, this guide addresses potential failure of the prosthesiswhen the implant is subjected to a range of motion and/or loadsthat fall within the full range of possible physiologic motio
8、nsand loads.1.9 For articulating components, this guide predominantlydescribes a Mode 1 test. The user is cautioned that other modesof wear may occur and may have significant influence on thefunctionality and performance of an articulating IVDprosthesis, and therefore the user should consider the ef
9、fects ofother wear modes on the performance of the prosthesis.1.10 In order that the data be reproducible and comparablewithin and between laboratories, it is essential that uniformprocedures are established. This guide is intended to facilitateuniform methods for testing and reporting of data for t
10、otal discreplacement prostheses.1.11 Without a substantial clinical retrieval history of IVDprostheses, actual loading profiles and patterns cannot bedelineated at the time of the writing of this guide. It thereforefollows that the load and motion conditions specified by thisguide do not necessarily
11、 accurately reproduce those occurringin vivo. Rather, this guide provides useful boundary/endpointconditions for evaluating prosthesis designs in a functionalmanner.1.12 The values stated in SI units are to be regarded as thestandard with the exception of angular measurements, whichmay be reported i
12、n either degrees or radians.1.13 This guide is not intended to be a performance stan-dard. It is the responsibility of the user of this guide tocharacterize the safety and effectiveness of the prosthesis underevaluation.1.14 This standard does not purport to address all of thesafety concerns, if any
13、, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F561 Practice for Retrieval and Analysis of Medical
14、Devices, and Associated Tissues and FluidsF1582 Terminology Relating to Spinal ImplantsF1714 Guide for Gravimetric WearAssessment of Prosthetic1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.
15、25 on Spinal Devices.Current edition approved Dec. 1, 2016. Published December 2016. Originallyapproved in 2005. Last previous edition approved in 2011 as F2423 11. DOI:10.1520/F2423-11R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
16、eastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance wit
17、h internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Hip Designs in Simulator DevicesF1877 Pra
18、ctice for Characterization of ParticlesF2077 Test Methods For Intervertebral Body Fusion Devices2.2 ISO Standard:3ISO 181921 Implants for SurgeryWear of Total Interver-tebral Spinal Disc ProsthesesPart 1: Loading and Dis-placement Parameters for Wear Testing and Correspond-ing Environmental Conditio
19、ns for Test3. Terminology3.1 All functional and kinematic testing terminology isconsistent with the referenced standards (for example, TestMethods F2077, Terminology F1582, and so forth), unlessotherwise stated.3.2 Definitions:3.2.1 axial load, nthe resultant force Faxialapplied to thesuperior or in
20、ferior fixture-end plate that simulates the in vivoload that an IVD prosthesis (original healthy disc) must resist.3.2.1.1 DiscussionBased on a healthy disc, the primarycomponent would be an axial compressive force FZin thedirection of the negative global Z axis, and it would passthrough the origin
21、of the IVD prosthesis. Shear components inthe XY plane would be FXand FY. Lateral bending moment MXand flexion/extension moment MYcomponents would be cre-ated about the origin when the axial load does not pass throughit.3.2.2 coordinate system/axes, nglobal XYZ orthogonalaxes are defined following a
22、 right-handed Cartesian coordinatesystem in which the XY plane is to bisect the sagittal planeangle between the superior and inferior surfaces that areintended to simulate the adjacent vertebral end plates. Theglobal axes are stationary relative to the IVD prosthesissinferior end plate fixture, whic
23、h, in this guide, is also consid-ered to be stationary with respect to the test machines frame.Lower case letters, xyz, denote a local, moving orthogonalcoordinate system attached to the superior end plate fixturewith directions initially coincident with those of the global XYZaxes, respectively. Th
24、e 3-D motion of the superior relative tothe inferior end plate fixture is specified and is to be measuredin terms of sequential Eulerian angular rotations about the xyzaxes, respectively (z, axial rotation; x, lateral bending; and y,flexion-extension).3.2.2.1 origin, ncenter of the global coordinate
25、 systemwhich is located at the initial position of the total discreplacements instantaneous center of rotation (COR).3.2.2.1 DiscussionSome articulating devices do not havea single center of rotation, but instead have either a mobilecenter of rotation or multiple distinct centers of rotation,dependi
26、ng on the direction of movement. In this case, theorigin should be explicitly defined by the user with a rationalefor that definition.3.2.2.2 X-axis, npositive X-axis is a global fixed axisrelative to the test machines stationary base, and is to bedirected anteriorly relative to the specimens initia
27、l unloadedposition.3.2.2.3 Y-axis, npositive Y-axis is a global fixed axisrelative to the test machines stationary base, and is directedlaterally relative to the specimens initial unloaded position.3.2.2.4 Z-axis, npositive Z-axis is a global fixed axisrelative to the test machines stationary base,
28、and is to bedirected superiorly relative to the specimens initial unloadedposition.3.2.2.5 x-axis, npositive x-axis is a fixed axis relative tothe IVD prosthesis and a moving axis relative to the globalcoordinate system, and is directed anteriorly relative to theprosthesis.3.2.2.6 y-axis, npositive
29、y-axis is a fixed axis relative tothe IVD prosthesis and a moving axis relative to the globalcoordinate system, and is directed laterally relative to theprosthesis.3.2.2.7 z-axis, npositive z-axis is a fixed axis relative tothe IVD prosthesis and a moving axis relative to the globalcoordinate system
30、, and is directed superiorly relative to theprosthesis.3.2.3 degradation, nloss of material or function or mate-rial properties as a result of causes other than that associatedwith wear.3.2.4 fluid absorption, nfluid absorbed by the devicematerial during testing.3.2.5 functional failure, npermanent
31、deformation or wearthat renders the IVD prosthesis assembly ineffective or unableto resist load/motion or any secondary effects that result in areduction of clinically relevant motions or the motions in-tended by the design of the device.3.2.6 interval net volumetric wear rate VRiduring cycleinterva
32、l i (mm3/million cycles), nVRi= WRi/, where =mass density (for example, units of g/mm3) of the wearmaterial.3.2.7 interval net wear rate WRiduring cycle interval i(g/million cycles), nWRi=(NWi NWi-1)/(number of cyclesin interval i)106.3.2.7.1 DiscussionFor i =1,NWi-1=0.3.2.8 intervertebral disc (IVD
33、) prosthesis, nnonbiologicstructure intended to restore the support and motion or aportion thereof between adjacent vertebral bodies.3.2.9 kinematic profile, nrelative motion between adjacentvertebral bodies that the IVD prosthesis is subjected to whilebeing tested.3.2.10 limit, na significant chang
34、e in stiffness during agiven motion, indicating the implant has reached its designedendpoint in range of motion.3.2.11 load profile, nloading that the device experienceswhile being tested under an applied kinematic profile or theloading that the IVD prosthesis is subjected to if tested in loadcontro
35、l.3.2.12 mechanical failure, nfailure associated with a de-fect in the material (for example, fatigue crack) or of thebonding between materials that may or may not producefunctional failure.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, ht
36、tp:/www.ansi.org.F2423 11 (2016)23.2.13 Wear modes (1)4for articulating type designs:3.2.13.1 Mode 1 refers to the articulation between twoprimary bearing surfaces only.3.2.13.2 Mode 2 occurs whenever a primary surface articu-lates directly against a secondary, nonbearing surface.3.2.13.3 Mode 3 occ
37、urs when the two primary bearingsurfaces are still articulating together, but third-body particleshave become entrapped between them.3.2.13.4 Mode 4 refers to any contact and motion occurringbetween two secondary, nonbearing surfaces.3.2.14 net wear NWiof wear specimen (g), nNWi5W02Wi!1Si2S0! ; loss
38、 in weight of the wear specimen correctedfor fluid absorption at end of cycle interval i.3.2.15 net volumetric wear NViof wear specimen (mm3),nNVi5NWi/ at end of cycle interval i where = mass density(for example, units of g/mm3) of the wear material.3.2.16 run out (cycles), nmaximum number of cycles
39、 thata test needs to be carried to if functional failure has not yetoccurred.3.2.17 wear, nprogressive loss of material from the de-vice(s) as a result of relative motion at the surfaces as measuredby the change in mass of the IVD prosthesis or components ofthe IVD prosthesis.3.2.17.1 DiscussionIn t
40、he case of a nonarticulating, com-pliant IVD prosthesis, wear is defined simply as the loss ofmaterial from the prosthesis. Note that inferior and superiorbone interface components are excluded from this definition;see 5.2.2.3.2.18 weight Siof soak control specimen (g), nS0initialand Siat end of cyc
41、le interval i.3.2.19 weight Wiof wear specimen (g), nW0initial andWiat end of cycle interval i.4. Significance and Use4.1 This guide can be used to determine the fatigue andwear behavior of IVD prostheses subjected to functional andkinematic cyclic loading/motion for relatively large numbers ofcycle
42、s (for example, various designs of IVD prostheses, as wellas the effects of materials, manufacturing techniques and otherdesign variables on one particular design can be determinedusing this guide).4.2 This guide is intended to be applicable to IVDprostheses, that support load and transmit motion by
43、 means ofan articulating joint or by use of compliant materials.Ceramics, metals, or polymers, or combination thereof, areused in IVD prostheses, and it is the goal of this guide to enablea kinematic wear and/or fatigue comparison of these devices,regardless of material and type of device.5. Apparat
44、us5.1 Total Disc Prosthesis ComponentsThe total disc re-placement may comprise a variety of shapes and configura-tions. Some known forms include ball-and-socket articulatingjoints, biconcave joints having a free-floating or semi-constrained third body, metallic endplates bonded to elastomercores, an
45、d single-axis hinge joints.5.2 Spinal Testing Apparatus:5.2.1 Test ChambersIn case of a multi-specimen machine,each chamber shall be isolated to prevent cross-contaminationof the test specimens. The chamber shall be made entirely ofnoncorrosive components, such as acrylic plastic or stainlesssteel,
46、and shall be easily removable from the machine forthorough cleaning between tests.5.2.2 Component Clamping/FixturingSince the purposeof the test is to characterize the wear and/or fatigue propertiesof the IVD prosthesis under functional and kinematicconditions, the method for mounting components in
47、the testchamber shall not compromise the accuracy of assessment ofthe weight loss or stiffness variation during the test. Forexample, prostheses having complicated superior and inferiorsurfaces for contacting bone (for example, sintered beads,hydroxylapatite (HA) coating, plasma spray) may be specia
48、llymanufactured to modify that surface in a manner that does notaffect the wear simulation.5.2.3 The device should be securely (rigidly) attached at itsbone-implant interface to the mating test fixtures.5.2.4 The motion of the superior test fixture relative to theinferior testing fixture shall be un
49、constrained in three-dimensional space except for the components in the directionof specified test motions/loads.5.2.5 Load and Motion (components in Table 1 and Table2):5.2.5.1 An axial load is to be a compressive load applied inthe direction of the negative Z-axis. Deviations from this as theIVD moves from its initial position are to be reported as shearcomponents FX, FY, and moments MXand MY.5.2.5.2 Flexion load and motion are positive moment, MY,and rotation about the y-axis, respectively.5.2.5.3 Extension load and motion
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