1、Designation: F2706 08 (Reapproved 2014)Standard Test Methods forOccipital-Cervical and Occipital-Cervical-Thoracic SpinalImplant Constructs in a Vertebrectomy Model1This standard is issued under the fixed designation F2706; the number immediately following the designation indicates the year oforigin
2、al adoption or, in the case of revision, 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 These test methods cover the materials and methods forthe static
3、and fatigue testing of occipital-cervical and occipital-cervical-thoracic spinal implant assemblies in a vertebrectomymodel. The test materials for most combinations of occipital-cervical and occipital-cervical-thoracic spinal implant compo-nents can be specific depending on the intended location an
4、dintended method of attachment.1.2 These test methods are intended to provide a basis forthe mechanical comparison among past, present, and futureoccipital-cervical and occipital-cervical-thoracic spinal im-plant assemblies. They allow comparison of occipital-cervicaland occipital-cervical-thoracic
5、spinal implant constructs withdifferent methods of application to the spine. These testmethods are not intended to define levels of performance, sincesufficient knowledge is not available to predict the conse-quences of the use of a particular device.1.3 These test methods set out guidelines for loa
6、d types andmethods of applying loads. Methods for three static load typesand two fatigue tests for the comparative evaluation ofoccipital-cervical and occipital-cervical-thoracic spinal im-plant assemblies are defined.1.4 These test methods establish guidelines for measuringdisplacements, determinin
7、g the yield load, and evaluating thestiffness and strength of occipital-cervical or occipital-cervical-thoracic spinal implant assemblies.1.5 It may not be possible to test some occipital-cervical andsome occipital-cervical-thoracic spinal constructs in all testconfigurations.1.6 The values stated i
8、n SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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 hea
9、lth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE739 Practice for StatisticalAnalysis of Linear or Linearize
10、dStress-Life (S-N) and Strain-Life (-N) Fatigue DataE1823 Terminology Relating to Fatigue and Fracture TestingF1582 Terminology Relating to Spinal ImplantsF1717 Test Methods for Spinal Implant Constructs in aVertebrectomy ModelF2077 Test Methods For Intervertebral Body Fusion Devices3. Terminology3.
11、1 DefinitionsFor definitions of terms relating to thesetest methods, see Terminologies E6, F1582, and E1823.3.2 Definitions of Terms Specific to This Standard:3.2.1 active length of the longitudinal element, nthestraight line distance between the centers of rotation of the testblocks.3.2.2 block mom
12、ent arm, nthe perpendicular to the ap-plied load between the insertion point of an anchor and the axisof the hinge pin.3.2.3 compressive or tensile bending stiffness (N/mm),nthe compressive or tensile bending yield force divided byelastic displacement (see the initial slope of line BC in Fig. 1).3.2
13、.4 compressive or tensile bending ultimate load (N),nthe maximum compressive or tensile force in the X-Z planeapplied to an occipital-cervical or occipital-cervical-thoracicspinal implant assembly (see the force at Point E in Fig. 1). Theultimate load should be a function of the device and not of th
14、eload cell or testing machine.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 Oct. 1, 2014. Published November 2014. Originallyapproved
15、 in 2008. Last previous edition approved in 2008 as F2706-08. DOI:10.1520/F2706-08R14.2For 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
16、 page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.5 compressive or tensile bending yield load (N), nthecompressive or tensile bending force in the X-Z plane neces-sary to produce a permanent deformation equa
17、l to 0.020 timesthe active length of the longitudinal element (see the force atPoint D in Fig. 1).3.2.6 coordinate system/axes, nthree orthogonal axes aredefined in Figs. 2 and 3. The anterior-posterior axis is X withpositive being anterior. The medial-lateral axis is Y with leftbeing positive when
18、viewed posteriorly. The superior-inferioraxis is Z with superior being positive.3.2.7 displacement at 2 % offset yield (mm), nthe dis-placement of a construct measured via the actuator thatproduces a permanent deformation equal to 0.020 times theactive length of the longitudinal element (distance OA
19、 in Fig.1).3.2.8 elastic angular displacement (degrees), nthe angulardisplacement at 2 % offset yield (see Point A in Fig. 1) minusthe 2 % offset angular displacement (see Point B in Fig. 1) (thatis, the distance between Point A and Point B in Fig. 1).3.2.9 elastic displacement (mm), nthe displaceme
20、nt at2 % offset yield (see Point A in Fig. 1) minus the 2 % offsetdisplacement (see Point B in Fig. 1). (The distance betweenPoint A and Point B in Fig. 1.)3.2.10 failure, npermanent deformation resulting fromfracture, plastic deformation, or loosening beyond the ultimatedisplacement or loosening th
21、at renders the occipital-cervical oroccipital-cervical-thoracic spinal implant assembly ineffectiveor unable to adequately resist load.3.2.11 fatigue life, nthe number of loading cycles, N,ofaspecified character that the occipital-cervical or occipital-cervical-thoracic spinal implant assembly susta
22、ins before fail-ure of a specified nature occurs (see Terminology E1823).3.2.12 hinge pin, nthe cylindrical rod connecting a testblock to a side support. The superior and inferior aspects of thetest construct are each secured with a single 9.6-mm diameterpin.3.2.13 insertion point of an anchor, nthe
23、 location wherethe anchor is attached to the test block. The insertion pointsshown in Figs. 4-7 are to be adhered to, if possible. Insituations where the design of the occipital-cervical oroccipital-cervical-thoracic spinal implant assembly or themanufacturers surgical instructions for installation
24、dictateotherwise, the attachment points may deviate from thesedimensions.3.2.14 intended method of application, n occipital-cervical and occipital-cervical-thoracic spinal implant assem-blies contain different types of anchors. Each type of anchorhas an intended method of application to the spine.3.
25、2.15 intended occipital-cervical spinal location, ntheanatomic region of the spine intended for the application of theoccipital-cervical spinal implant assembly. Spinal implantFIG. 1 Typical Load Displacement Curve or Torque Angulation CurveF2706 08 (2014)2assemblies are developed for specific spina
26、l locations such asthe posterior occipital-cervical spine.3.2.16 intended occipital-cervical-thoracic spinal location,nthe anatomic region of the spine intended for the applica-tion of the occipital-cervical-thoracic spinal implant assembly.Spinal implant assemblies are developed for specific spinal
27、locations such as the posterior occipital-cervical-thoracicspine.3.2.17 longitudinal axis offset (mm), n distance in the Xdirection between the centerline of the longitudinal elementand the insertion point of the anchors on the polyacetal testblock.3.2.18 longitudinal direction, nthe initial spatial
28、 orienta-tion parallel to the longitudinal element of the occipital-cervical or occipital-cervical-thoracic spinal implant assembly.The longitudinal direction is generally in the superior-inferiordirection and therefore, generally parallel to the Z-axis.3.2.19 maximum runout load, nthe maximum load
29、thatcan be applied to an occipital-cervical or occipital-cervical-thoracic spinal implant assembly where all of the testedconstructs have withstood 5 000 000 cycles without a failure.3.2.20 occipital-cervical spinal implant assembly, nacomplete occipital-cervical spinal implant configuration asinten
30、ded for surgical use. An occipital-cervical spinal implantassembly will contain anchors, interconnections, and longitu-dinal elements and may contain transverse elements (see Figs.2-7).3.2.21 occipital-cervical spinal implant construct, nacomplete occipital-cervical spinal implant assembly attached
31、tothe appropriate test blocks.FIG. 2 A Standard Bilateral Construct Containing Screw, Rod and ScrewF2706 08 (2014)33.2.22 occipital-cervical-thoracic spinal implant assembly,na complete occipital-cervical-thoracic spinal implant con-figuration as intended for surgical use. An occipital-cervical-thor
32、acic spinal implant assembly will contain anchors,interconnections, and longitudinal elements and may containtransverse elements (see Figs. 2-7).3.2.23 occipital-cervical-thoracic spinal implant construct,na complete occipital-cervical-thoracic spinal implant as-sembly attached to the appropriate te
33、st blocks.3.2.24 offset angular displacement at 2 degrees offset, napermanent angular displacement in the X-Y plane measured viathe actuator equal to 0.020 times the torsional aspect ratio (forexample: 1.95 for 1.70 0.02 180/pi) (see Point B in Fig.1).3.2.25 offset displacement (mm), na permanent de
34、forma-tion measured via the actuator equal to 0.020 times the activelength of the longitudinal element (for example: 1.52 mm for a76 mm active length of the longitudinal element) (see Point Bin Fig. 1).3.2.26 permanent deformation, nthe displacement (mm)or angular displacement (degree) of the occipi
35、tal-cervical oroccipital-cervical-thoracic spinal implant construct relative tothe initial unloaded condition as measured via the actuator afterthe applied load, moment, or torque has been removed.3.2.27 test block, nthe component of the test apparatus formounting the occipital-cervical or occipital
36、-cervical-thoracicspinal implant assembly. A specific design of test block isrequired for each intended spinal location and intended methodof application. Figs. 5-7 describe the recommended designs forthe test blocks; however, alternate designs can be used as longas equivalent performance is demonst
37、rated.3.2.28 test block load point, nthe location on the testblock at which the resultant load is transmitted from the testapparatus.3.2.29 tightening torque, nthe specified torque that isapplied to the various threaded fasteners of the occipital-cervical or occipital-cervical-thoracic spinal implan
38、t assembly.3.2.30 torsional aspect ratio, nthe active length of thelongitudinal element divided by the distance from the center ofrotation to the insertion point of an anchor on the cervical block(for example: in Fig. 2, 1.70 for a 76-mm active length, X =40mm and Y = 40/2 mm).A 5LD5Lx21y2!1/2(1)FIG
39、. 3 A Bilateral Hook, Rod, Screw, and Transverse Element ConstructF2706 08 (2014)4where:L = active length of longitudinal element,D = distance to insertion point,x = x distance to insertion point, andy = y distance to insertion point.3.2.31 torsional stiffness (N-m/degree), n the yield torque(N-m) d
40、ivided by elastic angular displacement (degrees) (theinitial slope of line BC in Fig. 1).3.2.32 torsional ultimate load (N-m), n the maximumtorque in the X-Y plane applied to an occipital-cervical oroccipital-cervical-thoracic spinal implant assembly (the torqueat Point E in Fig. 1). The ultimate to
41、rque should be a functionof the device and not of the load cell or testing machine.3.2.33 ultimate displacement (mm), nthe displacementassociated with the ultimate load, ultimate bending load orultimate torque (the displacement at Point F in Fig. 1).3.2.34 yield displacement (distance OAFig. 6), nth
42、edisplacement (mm) or angular displacement (deg) when anassembly has a permanent deformation equal to the offsetdisplacement or the offset angular displacement.3.2.35 yield torque (N-m), nthe torque in the X-Y planerequired to produce a permanent displacement of 0.020 timesthe torsional aspect ratio
43、 (the torque at Point D in Fig. 1).3.2.36 zero displacement intercept (mm), n the intersec-tion of the straight line section of the load-displacement curveand the zero load axis (the zero displacement reference Point 0in Fig. 1).4. Summary of Test Methods4.1 Similar test methods are proposed for the
44、 mechanicalevaluation of all occipital-cervical and occipital-cervical-thoracic spinal implant assemblies (see Fig. 4).4.2 A vertebrectomy model is used for the evaluation ofboth occipital-cervical and occipital-cervical-thoracic systems.The spinal hardware is attached at the superior and inferioras
45、pects to polyacetal homopolymer (polyacetal) test blocksFIG. 4 Occipital-Cervical Bilateral Construct Test Setup for Occipital Screws or BoltsF2706 08 (2014)5separated by a large gap. The polyacetal homopolymer used tomanufacture the test blocks should have a tensile breakingstrength no less than 61
46、 MPa. The use of polyacetal test blocks(see Figs. 5-8) eliminates the effects of the variability of bonegeometry and material properties associated with cadaverictesting.Alternate designs of test blocks may be used as long asequivalent performance is demonstrated.4.3 Three static mechanical tests an
47、d two dynamic tests willevaluate the occipital-cervical or occipital-cervical-thoracicspinal implant assemblies. The three static mechanical tests arecompression bending, tensile bending, and torsion. The dy-namic tests are compression bending fatigue and torsionfatigue.4.4 A specific clinical indic
48、ation generally requires a spe-cific occipital-cervical or occipital-cervical-thoracic spinal im-plant assembly. Occipital-cervical and occipital-cervical-thoracic spinal implant assemblies will be evaluated with testconfigurations that simulate the clinical requirements for theintended spinal locat
49、ion. The intended spinal location is theposterior surface of the occipital-cervical or occipital-cervical-thoracic spine (see Fig. 4). The block moment arm for a testconfiguration depends on the intended spinal location. Theblock moment arm of the occipital-cervical or occipital-cervical-thoracic spine configuration (see Fig. 4) varies de-pending on the occipital attachment components, but should beno less than the block moment arm specified in the cervicalspine configuration. The cervical spine configuration (see Figs.6 and 7) spec
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