1、Designation: F3295 18Standard Guide forImpingement Testing of Total Disc Prostheses1This standard is issued under the fixed designation F3295; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard is intended to provide guidance on theevaluation of wear and fatigue characteristics of total discprostheses under cyclic impingemen
3、t conditions.1.2 This guide describes impingement testing of deviceswith articulating components. The user is cautioned that themethods described herein are intended to produce an impinge-ment condition which may or may not be indicative of clinicalperformance and which may or may not be consistent
4、with theintended use of the device, and that this should be consideredwhen interpreting the data. Clinically, total disc prosthesesshould always be implanted per labeling and the manufactur-ers instructions for use.1.3 Impingement has been observed in retrievals amongseveral total disc prosthesis de
5、signs; however, impingement isnot necessarily associated with device or clinical failure. It isthe intent of this guide to investigate possible impingement-induced wear and mechanical failure modes associated withdevice design, as well as potential mechanical failure modesassociated with clinical ev
6、ents such as subsidence,malpositioning, and improper implant sizing. Note that me-chanical failure may or may not be associated with functionalfailure.1.4 It is recommended that the user define the bearing andnon-bearing features of the intervertebral disc (IVD) prosthesisand evaluate the performanc
7、e of the IVD prosthesis underMode 1 wear by using Guide F2423 or ISO 18192-1 prior touse of this guide. This standard is not intended to provideguidance on Mode I testing.1.5 The goal of this guide is to evaluate impingement inIVD prostheses regardless of the intended region of the spine(cervical or
8、 lumbar), material or material combinations(ceramic, metal, polymer), and bearing type (fixed or mobile).1.6 It is the intent of this guide to enable comparison of IVDprostheses with regard to wear and fatigue characteristics whentested under the specified conditions.1.7 The values stated in SI unit
9、s are to be regarded as thestandard with the exception of angular measurements whichshould be reported in degrees.1.8 The use of this standard may involve the operation ofpotentially hazardous equipment. This standard does not pur-port to address all of the safety concerns, if any, associatedwith it
10、s use. It is the responsibility of the user of this standardto establish appropriate safety, health, and environmentalpractices and determine the applicability of regulatory limita-tions prior to use.1.9 This international standard was developed in accor-dance with internationally recognized princip
11、les on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verificatio
12、n of Testing MachinesE1402 Guide for Sampling DesignE1488 Guide for Statistical Procedures to Use in Developingand Applying Test MethodsF561 Practice for Retrieval and Analysis of MedicalDevices, and Associated Tissues and FluidsF1714 Guide for Gravimetric WearAssessment of ProstheticHip Designs in
13、Simulator DevicesF1877 Practice for Characterization of ParticlesF2423 Guide for Functional, Kinematic, and Wear Assess-ment of Total Disc Prostheses2.2 ISO Standard:3ISO 181921 Implants for surgeryWear of total interver-tebral spinal disc prosthesesPart 1: Loading and dis-placement parameters for w
14、ear testing and correspondingenvironmental3. Terminology3.1 Definitions of Terms Specific to This Standard:1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.25 on Spinal Devices.Current edition
15、 approved July 1, 2018. Published August 2018. DOI: 10.1520/F329518.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM w
16、ebsite.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordan
17、ce with 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.13.1.1 axial force, nthe resultant f
18、orce Faxial forceapplied tothe IVD prosthesis along the Z-axis that simulates the in vivoaxial force. Based on a healthy disc, the primary componentwould be an axial compressive force, FZ, in the direction of thenegative global Z-axis, and it would pass through the center ofrotation of the IVD prost
19、hesis.3.1.2 coordinate system/axes, nglobal XYZ orthogonalaxes are defined following a right-handed Cartesian coordinatesystem in which the XY plane is to bisect the sagittal planeangle between superior and inferior surfaces that are intendedto simulate the adjacent vertebral end plates. The global
20、axesare stationary relative to the IVD prosthesess inferior end platefixture, which in this standard guide is also considered to bestationary with respect to the test machines frame. Lower caseletters, xyz, denote a local, moving orthogonal coordinatesystem attached to the superior end plate-fixturi
21、ng with direc-tions initially coincident with those of the global XYZ axes,respectively. The 3D motion of the superior relative to inferiorend plate-fixture is specified and is to be measured in terms ofsequential Eulerian angular rotations about the xyz axes,respectively (z, axial rotation; x, late
22、ral bending; and y,flexion-extension).3.1.2.1 origin, ncenter of the global coordinate system,located at the initial position of the IVDs instantaneous centerof rotation (COR). Note that some articulating devices do nothave a fixed center of rotation, but instead have either a mobilecenter of rotati
23、on or multiple distinct centers of rotation,depending on the direction of movement. In this case the originshould be explicitly defined by the user with a rationale for thatdetermination.3.1.2.2 X-axis, npositive X-axis is a global fixed axisrelative to the testing machines stationary base and is to
24、 bedirected anteriorly relative to the specimens initial unloadedposition.3.1.2.3 Y-axis, npositive Y-axis is a global fixed axisrelative to the testing machines stationary base and is directedlaterally relative to the specimens initial unloaded position.3.1.2.4 Z-axis, npositive Z-axis is a global
25、fixed axisrelative to the testing machines stationary base and is to bedirected superiorly relative to the specimens initial unloadedposition.3.1.2.5 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 anter
26、iorly relative to theprosthesis.3.1.2.6 y-axis, npositive 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.3.1.2.7 z-axis, npositive z-axis is a fixed axis relative tothe IVD prosthesis
27、and a moving axis relative to the globalcoordinate system and is directed superiorly relative to theprosthesis.3.1.2.8 device neutral position, nthe device positionwhere the user considers the local xyz coordinate systeminitially parallel to those of the global XYZ axes coordinatesystem, defined by
28、the user. Device neutral position is often theposition when the device endplates are parallel to one another.3.1.3 device range of motion (ROM), nthe maximumamount of angular displacement that an IVD prosthesis canundergo from the device neutral position to the point at whichinitial impingement occu
29、rs around a defined global axis. Forexample, if a device impinges at 15 from the device neutralposition in flexion and 20 from the device neutral position inextension, the device range of motion can be defined as+15/-20 in flexion-extension.3.1.4 functional failure, npermanent deformation or weartha
30、t renders the IVD prosthesis assembly ineffective or unableto resist force/motion or any secondary effects that result in asubstantial alteration of clinically relevant motions or themotions intended by the design of the device.3.1.5 impingement, ncontact between two components,resulting in a restri
31、ction of motion (Fig. 1).3.1.5.1 impingement conditions, nthe angles determinedto produce impingement in the device in flexion-extension,lateral bending and axial rotation.3.1.5.2 impingement test parameters, nthe test inputs forrotations and forces which create the intended impingementconditions an
32、d are used for impingement testing.3.1.5.3 initial impingement angle (A in Fig. 2),ntheangular displacement in a given plane, with respect to thedevice neutral position, at which impingement initially occurs,usually indicated by a sharp change in moment.3.1.5.4 impingement moment, nthe moment (N-m)
33、mea-sured or applied at the point of impingement (POI). It may bedetermined as the product of the applied axial force andimpingement moment arm.3.1.5.5 maximum impingement angular displacement,nthe greater of the two angular displacement test parameters(farthest from the device neutral position); it
34、 is the ultimateangle plus 2.0.3.1.5.6 minimum impingement angular displacement,nthe lesser of the two angular displacement test parameters(that closer to the device neutral position). It is 2.0 less thanthe initial impingement angle.3.1.5.7 impingement moment arm, mm (Fig. 1b and Fig. 1e),nthe dist
35、ance in the x-y plane from the z-axis of the device tothe POI.3.1.5.8 impingement region (Fig. 1C and Fig. 1F),nphysical area on the device components where the impinge-ment wear scar develops as a result of repeated loading andmotion cycles.3.1.5.9 point of impingement (POI) (Fig. 1C and Fig. 1F),n
36、the theoretical location on the IVD prosthesiss x-y planewhere impingement occurs with respect to the origin.3.1.5.10 theoretical ultimate moment (Mtin Fig. 2),nthemathematical product of the axial force to be applied during theimpingement wear test (Table 1) and the distance in the x-yplane from th
37、e z-axis of the device to the POI (mm); forexample, for a cervical IVD prosthesis with a POI 9.0 mm fromthe z-axis, Mt= (100 N) (9.0 mm) / (1000) = 0.9 Nm.F3295 1823.1.5.11 ultimate angle, nthe angular displacement asso-ciated with the theoretical ultimate moment, in degrees (AuinFig. 2).3.1.6 inter
38、vertebral disc (IVD) prosthesis, nnon-biologicstructure intended to restore the support and motion or aportion thereof, to the space between adjacent vertebral bodies.Also referred to as total disc prosthesis.3.1.7 kinematic profile, nrelative motion between adjacentvertebral bodies that the IVD pro
39、sthesis is subjected to whilebeing tested.3.1.8 force profile, nloading that the IVD prosthesis issubject to during testing.3.1.9 mechanical failure, nfailure associated with a defectin the material (for example, fatigue crack) or of the bondingbetween materials that may or may not produce functiona
40、lfailure.3.1.10 wear, nprogressive loss of material from the de-vice(s) or device components as a result of relative motion atthe surface with another body as measured by the change inmass of the IVD prosthesis.3.1.11 fluid absorption, nfluid absorbed by the devicematerial during testing.3.1.12 inte
41、rval net volumetric wear rate VRiduring cycleinterval i (mm3/million cycles), nVRi= WRi/ , where =mass density (for example, units of g/mm3) of the wearmaterial.3.1.13 interval net wear rate WRiduring cycle interval i(g/million cycles), nWRi=(NWi NWi-1/ (number of cyclesin interval i)106.3.1.13.1 Di
42、scussionFor i =1,NWi-1=0.3.1.14 net wear NWiof wear specimen (g), nNWi=(W0Wi)+(SiS0); loss in weight of the wear specimen correctedfor fluid absorption at end of cycle interval i.3.1.15 net volumetric wear NViof wear specimen (mm3),nNVi= NWi/ at end of cycle interval i where = massdensity (for examp
43、le, units of g/mm3) of the wear material.3.1.16 weight Siof soak control specimen (g), nS0initialand Siat end of cycle interval i.3.1.17 weight Wiof wear specimen (g), nW0initial and Wiend of cycle interval i.4. Summary of Guide4.1 This guide provides a generic approach for developingimpingement tes
44、t parameters for total disc or IVD prostheses,summarizing the key steps in the process of developing,conducting, and interpreting results from an impingement test(Fig. 3).5. Background, Significance and Use5.1 This guide can be used to develop test parameters forevaluating fatigue and wear behavior
45、of IVD prostheses underimpingement loading. It must be recognized, however, thatA-C show an example of a mobile bearing disc at its neutral position (A), impinged position (B), and its superior endplate with impingement region indicated (C). D-Fshow an example of a fixed bearing disc at its neutral
46、position (D), impinged position (E), and its superior endplate with impingement region indicated (F). The dashed arcsshow the geometry of the bearing (black) and the endplate (gray). For B and E the point of impingement (POI) and impingement moment arm are indicated. For C andF, the impingement regi
47、on is illustrated as a series of overlapping regions indicating the expected progression of the impingement region over the duration of the test andreinforcing the concept that there is an angular range over which the impingement region develops. The concept for the point of impingement has also bee
48、n indicated inB,C and E,F and is provided as a purely theoretical representation for the purpose of defining the impingement moment arm.FIG. 1 Schematic of Impingement Modes for Two Total Disc ProsthesesF3295 183there are likely many possible impingement conditions for agiven IVD prosthesis.5.2 The
49、user should attempt to determine the clinicallyrelevant and geometrically possible impingement conditionsand dictated by the design and impingement wear test param-eters that may result in wear and fatigue damage for the IVDprosthesis. The user should also attempt to select the devicesize which will represent a worst case for the impingementconditions and parameters selected.5.3 The user should reference and utilize existing sources ofinformation to identify the impingement test parameters thatproduce the clinic
