ASTM F1717-2009 Standard Test Methods for Spinal Implant Constructs in a Vertebrectomy Model.pdf

1、Designation: F 1717 09Standard Test Methods forSpinal Implant Constructs in a Vertebrectomy Model1This standard is issued under the fixed designation F 1717; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision

2、. 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 These test methods cover the materials and methods forthe static and fatigue testing of spinal implant assemblies in avertebrectomy

3、 model.The test materials for most combinationsof spinal implant components can be specific depending on theintended spinal location and intended method of application tothe spine.1.2 These test methods are intended to provide a basis forthe mechanical comparison among past, present, and futurespina

4、l implant assemblies. They allow comparison of spinalimplant constructs with different intended spinal locations andmethods of application to the spine. These test methods are notintended to define levels of performance, since sufficientknowledge is not available to predict the consequences of theus

5、e of a particular device.1.3 These test methods set out guidelines for load types andmethods of applying loads. Methods for three static load typesand one fatigue test are defined for the comparative evaluationof spinal implant assemblies.1.4 These test methods establish guidelines for measuringdisp

6、lacements, determining the yield load, and evaluating thestiffness and strength of the spinal implant assembly.1.5 Some spinal constructs may not be testable in all testconfigurations.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thiss

7、tandard.1.7 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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Refe

8、renced Documents2.1 ASTM Standards:2D 638 Test Method for Tensile Properties of PlasticsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 691 Practice for Conduct

9、ing an Interlaboratory Study toDetermine the Precision of a Test MethodE 739 Practice for Statistical Analysis of Linear or Linear-ized Stress-Life ( S-N) and Strain-Life (e-N) Fatigue DataE 1150 Definitions of Terms Relating to FatigueF 1582 Terminology Relating to Spinal ImplantsF 2077 Test Method

10、s For Intervertebral Body Fusion De-vices3. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to these test methods,see Terminology E6, Terminology F 1582, and DefinitionsE 1150.3.2 Definitions of Terms Specific to This Standard:3.2.1 active length of the longitudinal elementthe str

11、aightline distance between the center of attachment of the superioranchor and the center of attachment of the inferior anchor.3.2.2 angular displacement at 2 % offset yield (degrees)the angular displacement of a construct measured via theactuator that produces a permanent angular displacement in the

12、X-Y plane equal to 0.020 times the torsional aspect ratio (seePoint A in Fig. 1).3.2.3 block moment armthe perpendicular to the appliedload between the insertion point of an anchor and the axis ofthe hinge pin.3.2.4 compressive or tensile bending stiffness (N/mm)thecompressive or tensile bending yie

13、ld force divided by elasticdisplacement (see the initial slope of line BC in Fig. 1).3.2.5 compressive or tensile bending ultimate load (N)themaximum compressive or tensile force in X-Z plane applied toa spinal implant assembly (see the force at Point E in Fig. 1).The ultimate load should be a funct

14、ion of the device and not ofthe load cell or testing machine.3.2.6 compressive or tensile bending yield load (N)thecompressive or tensile bending force in X-Z plane necessary toproduce a permanent deformation equal to 0.020 times theactive length of the longitudinal element (see the force at PointDi

15、nFig. 1).1These test methods are under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and are the direct responsibility ofSubcommittee F04.25 on Spinal Devices.Current edition approved Sept. 15, 2009. Published October 2009. Originallyapproved in 1996. Last previ

16、ous edition approved in 2004 as F 1717 04.2For 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 website.1Copyright. ASTM In

17、ternational, 100 Barr Harbour Dr., P.O. box C-700 West Conshohocken, Pennsylvania 19428-2959, United StatesCopyright by ASTM Intl (all rights reserved); Wed Nov 4 23:20:22 EST 2009Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.3.2.7 coordinat

18、e system/axesthree orthogonal axes aredefined in Fig. 2 and Fig. 3. The anterior-posterior axis is Xwith positive being anterior. The medial-lateral axis is Y withleft being positive when viewed posteriorly. The superior-inferior axis is Z with superior being positive.3.2.8 displacement at 2 % offse

19、t yield (mm)the displace-ment of a construct measured via the actuator that produces apermanent deformation equal to 0.020 times the active lengthof the longitudinal element (see Point A in Fig. 1).3.2.9 elastic angular displacement (degrees)the angulardisplacement at 2 % offset yield (see Point A i

20、n Fig. 1) minusthe 2 % offset angular displacement (see Point B in Fig. 1).(The distance between Point A and Point B in Fig. 1.)3.2.10 elastic displacement (mm)the displacement at 2 %offset yield (see Point A in Fig. 1) minus the 2 % offsetdisplacement (see Point B in Fig. 1). (The distance betweenP

21、oint A and Point B in Fig. 1.)3.2.11 failurepermanent deformation resulting from frac-ture, plastic deformation, or loosening beyond the ultimatedisplacement or loosening that renders the spinal implantassembly ineffective or unable to adequately resist load.3.2.12 fatigue lifethe number of loading

22、cycles, N,ofaspecified character that the spinal implant assembly sustainsbefore failure of a specified nature occurs (see DefinitionsE 1150).3.2.13 insertion point of an anchorthe location where theanchor is attached to the test block. The insertion points shownin Figs. 2-15 are to be adhered to if

23、 possible. In situationswhere the design of the spinal implant assembly or themanufacturers surgical instructions for installation dictateotherwise, the attachment points may deviate from thesedimensions.FIG. 1 Typical Load Displacement Curve or Torque AngulationCurveFIG. 2 A Standard Bilateral Cons

24、truct Containing Screw, Rod andScrewFIG. 3 A Bilateral Hook, Rod, Screw, and Transverse ElementConstructF1717092Copyright by ASTM Intl (all rights reserved); Wed Nov 4 23:20:22 EST 2009Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.3.2.14 int

25、ended method of applicationspinal implant as-semblies contain different types of anchors. Each type ofanchor has an intended method of application to the spine.3.2.15 intended spinal locationthe anatomic region of thespine intended for the application of the spinal implantassembly. Spinal implant as

26、semblies are developed for specificspinal locations such as the anterior cervical spine or theposterior thoracolumbar, lumbar, and lumbosacral spine.3.2.16 hinge pinthe cylindrical rod connecting a testblock to a side support. A cervical construct is secured with a9.6 mm diameter pin and the thoraco

27、lumbar, lumbar, andlumbosacral construct uses a 12.7 mm diameter pin.3.2.17 longitudinal directionthe initial spatial orientationparallel to the longitudinal element of the spinal implantassembly. The longitudinal direction is generally in thesuperior-inferior direction and therefore, generally para

28、llel tothe z axis.3.2.18 maximum run out loadthe maximum load that canbe applied to a spinal implant assembly where all of the testedconstructs have withstood 5 000 000 cycles without a failure.3.2.19 permanent deformationthe displacement (mm) orangular displacement (degree) of the spinal implant co

29、nstructrelative to the initial unloaded condition as measured via theactuator after the applied load, moment, or torque has beenremoved.3.2.20 spinal implant assemblya complete spinal implantconfiguration as intended for surgical use. A spinal implantassembly will contain anchors, interconnections,

30、and longitu-dinal elements and may contain transverse elements (see Fig. 4,Fig. 6, Fig. 8, Fig. 10, Fig. 12, and Fig. 14).3.2.21 spinal implant constructa complete spinal implantassembly attached to the appropriate test blocks.3.2.22 test blockthe component of the test apparatus formounting the spin

31、al implant assembly.Aspecific design of testblock is required for each intended spinal location and intendedmethod of application. Fig. 5, Fig. 7, Fig. 9, Fig. 11, Fig. 13,and Fig. 15 describe the recommended designs for the testblocks; however, alternate designs can be used as long asequivalent per

32、formance is demonstrated.3.2.23 test block load pointthe location on the test blockat which the resultant load is transmitted from the testapparatus.3.2.24 tightening torquethe specified torque that is ap-plied to the various threaded fasteners of the spinal implantassembly.3.2.25 torsional aspect r

33、atiothe active length of thelongitudinal element divided by the distance from the center ofrotation to the insertion point of an anchor (for example: in Fig.2 1.70 for a 76-mm active length, X =40mmandY = 40/2mm).FIG. 4 Cervical Unilateral Construct Test Setup for Screws or BoltsF1717093Copyright by

34、 ASTM Intl (all rights reserved); Wed Nov 4 23:20:22 EST 2009Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.A 5LD5Lx21 y2!1/2(1)where:L = active length of longitudinal element,D = distance to insertion point,x = x distance to insertion point,

35、 andy = y distance to insertion point.3.2.26 torsional stiffness (N-m/degree)the yield torque(N-m) divided by elastic angular displacement (degrees) (theinitial slope of line BC in Fig. 1).3.2.27 torsional ultimate load (N-m)the maximum torquein X-Yplane applied to a spinal implant assembly (the tor

36、que atPoint E in Fig. 1). The ultimate torque should be a function ofthe device and not of the load cell or testing machine.3.2.28 two percent (2 %) offset angular displacement(degrees)a permanent angular displacement in the X-Y planemeasured via the actuator equal to 0.020 times the torsionalaspect

37、 ratio (for example: 1.95 for 1.70 3 0.02 3 180/pi)(see Point B in Fig. 1).3.2.29 two percent (2 %) offset displacement (mm)a per-manent deformation measured via the actuator equal to 0.020times the active length of the longitudinal element (for ex-ample: 1.52 mm for a 76 mm active length of the lon

38、gitudinalelement or 0.70 mm for 35 mm) (see Point B in Fig. 1).3.2.30 ultimate displacement (mm)the displacement asso-ciated with the ultimate load, ultimate bending load or ultimatetorque (the displacement at Point F in Fig. 1).FIG. 5 Cervical Unilateral UHWMPE Block for Screws or BoltsF1717094Copy

39、right by ASTM Intl (all rights reserved); Wed Nov 4 23:20:22 EST 2009Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.3.2.31 yield torque (N-m)the torque in X-Y plane requiredto produce a permanent displacement of 0.020 times thetorsional aspec

40、t ratio (the torque at Point D in Fig. 1).3.2.32 zero displacement intercept (mm)the intersectionof the straight line section of the load displacement curve andthe zero load axis (the zero displacement reference Point 0 inFig. 1).4. Summary of Test Methods4.1 Similar test methods are proposed for th

41、e mechanicalevaluation of cervical spinal implant assemblies (see Fig. 4,Fig. 6, and Fig. 8) and thoracolumbar, lumbar, and lumbosacralspinal implant assemblies (see Fig. 10, Fig. 12, and Fig. 14).4.2 Testing of the spinal implant assemblies will simulate avertebrectomy model via a large gap between

42、 two Ultra HighMolecular Weight Polyethylene (UHMWPE) test blocks. TheUHMWPE used to manufacture the test blocks should have atensile breaking strength equal to 40 6 3 MPa (see Specifica-tion D 638). The UHMWPE test blocks (see Fig. 5, Fig. 7, Fig.9, Fig. 11, Fig. 13, and Fig. 15) will eliminate the

43、 effects of thevariability of bone properties and morphometry. Alternatedesigns of test blocks may be used as long as equivalentperformance is demonstrated.4.3 Three static mechanical tests and one dynamic test willevaluate the spinal implant assemblies. The three static me-chanical tests are compre

44、ssion bending, tensile bending, andtorsion. The dynamic test is a compression bending fatigue.4.4 A specific clinical indication generally requires a spe-cific spinal implant assembly. Spinal implant assemblies willbe evaluated with test configurations which simulate theclinical requirements for the

45、 intended spinal location. Theintended spinal locations are both anterior (see Fig. 4) andposterior (see Fig. 6 and Fig. 8) surfaces of the cervical spineor both anterior (see Fig. 10) and posterior (see Fig. 12 and Fig.14) surfaces of the thoracolumbar, lumbar, and lumbosacralspine. The block momen

46、t arm (see 6.6) for a test configurationdepends on the intended spinal location. The cervical spineconfiguration (see Fig. 5, Fig. 7, and Fig. 9) specifies one blockmoment arm, while a larger block moment arm (see Fig. 11,Fig. 13, and Fig. 15) is specified for the thoracolumbar, lumbar,and lumbosacr

47、al spine.4.5 The intended method of application of the spinal im-plant assembly may vary for specific anatomic regions andclinical indications. Spinal implant assemblies contain differenttypes of anchors. Each type of anchor has an intended methodof application to the spine. For example, one assembl

48、y mayinclude anterior vertebral body screws and rods (see Fig. 2),while another assembly may contain posterior sacral screws,hooks, rods, and transverse elements (see Fig. 3). The blockmoment arm of a test configuration will be independent of theintended method of application of a spinal implant ass

49、embly;therefore, the test data for different intended methods ofapplication may be compared.5. Significance and Use5.1 Spinal implants are generally composed of severalcomponents which, when connected together, form a spinalimplant assembly. Spinal implant assemblies are designed toFIG. 6 Cervical Bilateral Construct Test Setup for Screws or BoltsF1717095Copyright by ASTM Intl (all rights reserved); Wed Nov 4 23:20:22 EST 2009Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.provide som