1、Designation: F2077 18Test Methods ForIntervertebral Body Fusion Devices1This standard is issued under the fixed designation F2077; 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 parentheses i
2、ndicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the materials and methods forthe static and dynamic testing of intervertebral body fusiondevice assemblies, spinal implants designed t
3、o promote arthro-desis at a given spinal motion segment.1.2 This test method is intended to provide a basis for themechanical comparison among past, present, and future non-biologic intervertebral body fusion device assemblies. This testmethod allows comparison of intervertebral body fusion deviceas
4、semblies with different intended spinal locations and meth-ods of application to the intradiscal spaces. This test method isintended to enable the user to compare intervertebral bodyfusion device assemblies mechanically and does not purport toprovide performance standards for intervertebral body fus
5、iondevice assemblies.1.3 The test method describes static and dynamic tests byspecifying force types and specific methods of applying theseforces. These tests are designed to allow for the comparativeevaluation of intervertebral body fusion device assemblies.1.4 These tests are designed to character
6、ize the structuralintegrity of the device and are not intended to test thebone-implant interface.1.5 This test method does not address expulsion testing ofintervertebral body fusion device assemblies (see 1.4).1.6 Guidelines are established for measuring displacements,determining the yield force or
7、moment, evaluating the stiffness,and strength of the intervertebral body fusion device assem-blies.1.7 Some intervertebral body fusion device assemblies maynot be testable in all test configurations.1.8 The values stated in SI units are to be regarded asstandard. No other units of measurement are in
8、cluded in thisstandard, with the exception of angular measurements, whichmay be reported in terms of either degrees or radians.1.9 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish a
9、ppro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.10 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for t
10、heDevelopment 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 Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical T
11、estingE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1823 Terminology Relating to Fatigue and Fracture TestingE2309 Practices for Verification of Displacement MeasuringSystems a
12、nd Devices Used in Material Testing MachinesF1582 Terminology Relating to Spinal Implants3. Terminology3.1 For definition of terms refer to Terminology E6, E1823,and F1582.3.2 Definitions of Terms Specific to This Standard:3.2.1 coordinate system/axes, nThree orthogonal axes aredefined by Terminolog
13、y F1582. The center of the coordinatesystem is located at the geometric center of the intervertebralbody fusion device assembly. The XY plane is to bisect thesagittal plane angle between superior and inferior lines (sur-faces) that are intended to simulate the adjacent vertebral endplates. The posit
14、ive Z axis is to be directed superiorly. Forcecomponents parallel to the XY plane are shear components ofloading. The compressive axial force is defined to be the1This test method is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibi
15、lity of SubcommitteeF04.25 .Current edition approved June 1, 2018. Published August 2018. Originallypublished in 2000. Last previous edition approved in 2017 as F2077 17. DOI:10.1520/F2077-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
16、viceastm.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
17、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.1component in the negative Z direction.
18、 Torsional force isdefined to be the component of moment parallel to the Z axis.3.2.2 crack, nan externally visible physical discontinuityin the form of a narrow opening that arises from mechanicalforces.3.2.3 fatigue life, nthe number of cycles, N, that theintervertebral body fusion device assembly
19、 can sustain at aparticular force or moment before mechanical or functionalfailure occurs.3.2.4 functional failure, npermanent deformation that ren-ders the intervertebral body fusion device assembly ineffectiveor unable to resist force and/or maintain attachment adequately.3.2.5 ideal insertion loc
20、ation, nthe implant location withrespect to the simulated inferior and superior vertebral bodies(polyacetal or metal blocks) dictated by the type, design, andmanufacturers surgical installation instructions.3.2.6 intended method of application, nintervertebralbody fusion device assemblies may contai
21、n different types ofstabilizing anchors such as threads, spikes, and knurled sur-faces. Each type of anchor has an intended method of appli-cation or attachment to the spine.3.2.7 intended spinal location, nthe anatomic region ofthe spine intended for the intervertebral body fusion deviceassembly. I
22、ntervertebral body fusion device assemblies may bedesigned and developed for specific regions of the spine suchas the lumbar, thoracic, and cervical spine. Also, there existsdifferent anatomical potential surgical approaches, which willresult in different implant orientation at different levels of t
23、hespine.3.2.8 intervertebral body fusion device, na structure (bio-logic or synthetic) that is placed in the disc space between twoadjacent vertebral bodies to provide support for eventualarthrodesis of the two adjacent vertebral bodies.3.2.9 intradiscal height, nthe straight-line distance alongthe
24、Z axis between the unaltered simulated vertebral bodiesminimum height of 4 mm and a maximum height of 18 mm.See Fig. 1.3.2.10 force point, nthe point through which the resultantforce on the intervertebral device passes (that is, the geometriccenter of the superior fixtures sphere) (Figs. 2-5).3.2.11
25、 maximum run out force or moment, nthe maximumforce or moment for a given test that can be applied to anintervertebral body fusion device assembly in which all of thetested constructs have withstood 5 000 000 cycles withoutfunctional or mechanical failure.3.2.12 mechanical failure, nthat associated
26、with the onsetof a new defect in the material (that is, initiation of fatiguecrack).3.2.13 offset angular displacement, n(Distance OBFig.6)offset on the angular displacement axis equal to 10 % ofthe intradiscal height, H, divided by the outside diameter orheight of the implant (maximum dimension of
27、implant in XZplane if not cylindrical) (for example, for a 10-mm intradiscalheight and 16-mm intervertebral body fusion device assembly,distance OB = 10 mm/16 mm (0.10)(180)/ = 3.6).3.2.14 offset displacement, n(Distance OBFig. 6)offset on the displacement axis equal to 2 % of the intradiscalheight
28、(that is, 0.2 mm for a 10-mm intradiscal height).3.2.15 permanent deformation, nthe remaining displace-ment (mm or degrees or radians) relative to the initial unloadedcondition of the intervertebral body fusion device assemblyafter the applied force has been removed.3.2.16 stiffness (N/mm or N*mm/De
29、gree (Radian) (TheSlope of Line OGFig. 6), nthe slope of the initial linearportion of the force-displacement curve or the slope of theinitial linear portion of the momentangular displacementcurve.3.2.17 test block, nthe component of the test apparatus formounting the intervertebral body fusion devic
30、e assembly forthe intended test configuration.3.2.18 ultimate displacement (mm or degrees or radians)(Displacement OFFig. 6), nthe displacement associatedwith the ultimate force or ultimate moment.3.2.19 ultimate force or moment (N or N*mm) (PointEFig. 6), nthe maximum applied force, F, transmitted
31、bythe pushrod (assumed equal to force component parallel to andindicated by load cell), or the applied moment about the Z axisthat can be applied to an intervertebral body fusion deviceassembly.FIG. 1 Intradiscal Height DiagramF2077 1823.2.20 yield displacement (Distance OAFig. 6), nthedisplacement
32、(mm) or angular displacement (deg) when anFIG. 2 Compression Testing ConfigurationFIG. 3 Compression-Shear Testing ConfigurationF2077 183interbody fusion device asembly has a permanent deformationequal to the offset displacement or the offset angular displace-ment.3.2.21 yield force or moment (Point
33、 DFig. 6), ntheapplied force, F, transmitted by the pushrod (assumed equal toforce component parallel to and indicated by load cell), or theapplied moment about the Z axis required to produce apermanent deformation equal to the offset displacement or theoffset angular displacement.4. Summary of Test
34、 Method4.1 These test methods are proposed for the mechanicaltesting of intervertebral body fusion device assemblies specificto the lumbar, thoracic, and cervical spine.FIG. 4 Torsion Testing Configuration With Pin-Slot GimbalFIG. 5 Spherical Gimbal (Cross Section) for Torsion Testing ApparatusF2077
35、 1844.2 Fatigue testing of the intervertebral body fusion deviceassemblies will simulate a motion segment via a gap betweentwo polyacetal test blocks. The polyacetal will eliminate theeffects of the variability of bone properties and morphology forthe fatigue tests. The minimum ultimate tensile stre
36、ngth of thepolyacetal blocks shall be no less than 61 MPa.4.3 Static testing of the intervertebral body fusion deviceassemblies will simulate a motion segment via a gap betweentwo stainless steel blocks. The minimum ultimate tensilestrength of the blocks shall be no less than 1310 MPa.4.4 The pushro
37、d shall also be manufactured from stainlesssteel, which shall also have a minimum ultimate tensilestrength no less than 1310 MPa.4.5 Static and dynamic tests will evaluate the intervertebralbody fusion device assembly. The user of this test method mustdecide which series of tests are applicable to t
38、he intervertebralbody fusion device assembly in question. The user of this testmethod may choose to use all or a selection of the testsdescribed in this test method for testing a particular interver-tebral body fusion device assembly.5. Significance and Use5.1 Intervertebral body fusion device assem
39、blies are gener-ally simple geometric-shaped devices which are often porousor hollow in nature. Their function is to support the anteriorcolumn of the spine to facilitate arthrodesis of the motionsegment. This test method outlines materials and methods forthe characterization and evaluation of the m
40、echanical perfor-mance of different intervertebral body fusion device assembliesso that comparisons can be made between different designs.5.2 This test method is designed to quantify the static anddynamic characteristics of different designs of intervertebralbody fusion device assemblies. These test
41、s are conducted invitro to allow for analysis and comparison of the mechanicalperformance of intervertebral body fusion device assemblies tospecific force modalities.5.3 The forces applied to the intervertebral body fusionassemblies may differ from the complex loading seen in vivo,and therefore, the
42、 results from these tests may not directlypredict in vivo performance. The results, however, can be usedto compare mechanical performance of different intervertebralbody fusion device assemblies.5.4 Since the environment may affect the dynamic perfor-mance of intervertebral body fusion device assemb
43、lies, dy-namic testing in a saline environment may be considered.Fatigue tests should first be conducted in air (at ambienttemperature) for comparison purposes since the environmentaleffects could be significant. If a simulated in vivo environmentis desired, the investigator should consider testing
44、in a salineenvironmental bath at 37C (for example, 0.9-g NaCl per100-mLwater) at a rate of 1 Hz or less.Asimulated body fluid,FIG. 6 Typical Force Displacement CurveF2077 185a saline drip or mist, distilled water, or other type of lubricationat 37C could also be used with adequate justification.5.5
45、If the devices are known to be temperature and envi-ronment dependent, testing should be conducted in physiologicsolution as described in 5.4. Devices that require physiologicsolution for testing should be tested in the same type solutionfor comparison purposes.5.6 The location within the simulated
46、vertebral bodies andposition of the intervertebral body fusion device assembly withrespect to the loading axis will be dependent upon the design,the manufacturers recommendation, or the surgeons preferredmethod for implant placement.5.7 It is well known that the failure of materials is depen-dent up
47、on stress, test frequency, surface treatments, and envi-ronmental factors. Therefore, when determining the effect ofchanging one of these parameters (for example, frequency,material, or environment), all others must be kept constant tofacilitate interpretation of the results.6. Apparatus6.1 Test mac
48、hines will conform to the requirements ofPractices E4.6.2 The intradiscal height, H, shall be determined fromvertebral body and disc morphometric data at the intendedlevel of application. Suggested heights are as follows: 10 mmfor the lumbar spine, 6 mm for the thoracic spine, and 4 mm forthe cervic
49、al spine. The intradiscal height should not reach zerobefore the onset of functional or mechanical failure. If thisoccurs, the test is considered a failure. The user of the testmethod should select the intradiscal height that is appropriatefor the device being tested.6.3 Axial Compression Test ApparatusThe actuator of thetesting machine is connected to the pushrod by a minimalfriction ball and socket joint or universal joint (that is,unconstrained in bending). The pushrod is connected to thesuperior fixture by a minimal friction spher
