1、Designation: F2706 08 (Reapproved 2014)F2706 17Standard 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
2、oforiginal 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 for th
3、e static and fatigue testing of occipital-cervical andoccipital-cervical-thoracic spinal implant assemblies in a vertebrectomy model. The test materials for most combinations ofoccipital-cervical and occipital-cervical-thoracic spinal implant components can be specific depending on the intended loca
4、tion andintended method of attachment.1.2 These test methods are intended to provide a basis for the mechanical comparison among past, present, and futureoccipital-cervical and occipital-cervical-thoracic spinal implant assemblies. They allow comparison of occipital-cervical andoccipital-cervical-th
5、oracic spinal implant constructs with different methods of application to the spine. These test methods are notintended to define levels of performance, since sufficient knowledge is not available to predict the consequences of the use of aparticular device.1.3 These test methods set out guidelines
6、for load types and methods of applying loads. Methods for three static load types andtwo fatigue tests for the comparative evaluation of occipital-cervical and occipital-cervical-thoracic spinal implant assemblies aredefined.1.4 These test methods establish guidelines for measuring displacements, de
7、termining the yield load, and evaluating the stiffnessand strength of occipital-cervical or occipital-cervical-thoracic spinal implant assemblies.1.5 It may not be possible to test some occipital-cervical and some occipital-cervical-thoracic spinal constructs in all testconfigurations.1.6 The values
8、 stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate saf
9、ety and health practices and determine the applicability of regulatorylimitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Stand
10、ards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE739 Practice for Statistical A
11、nalysis of Linear or Linearized Stress-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 a Vertebrectomy ModelF2077 Test Methods For Intervertebral Bod
12、y Fusion Devices1 These test methods are under the jurisdiction ofASTM Committee F04 on Medical and Surgical Materials and Devices and are the direct responsibility of SubcommitteeF04.25 on Spinal Devices.Current edition approved Oct. 1, 2014March 1, 2017. Published November 2014April 2017. Original
13、ly approved in 2008. Last previous edition approved in 20082014as F2706-08. DOI: 10.1520/F2706-08R14. 08 (2014). DOI: 10.1520/F2706-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume info
14、rmation, refer to the standardsstandards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to ade
15、quately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoho
16、cken, PA 19428-2959. United States13. Terminology3.1 DefinitionsFor definitions of terms relating to these test 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, nthe straight line distance between the
17、centers of rotation of the test blocks.3.2.2 block moment arm, nthe perpendicular to the applied load between the insertion point of an anchor and the axis of thehinge pin.3.2.3 compressive or tensile bending stiffness (N/mm), nthe compressive or tensile bending yield force divided by elasticdisplac
18、ement (see the initial slope of line BC in Fig. 1).3.2.4 compressive or tensile bending ultimate load (N), nthe maximum compressive or tensile force in the X-Z plane appliedto an occipital-cervical or occipital-cervical-thoracic spinal implant assembly (see the force at Point E in Fig. 1). The ultim
19、ate loadshould be a function of the device and not of the load cell or testing machine.3.2.5 compressive or tensile bending yield load (N), nthe compressive or tensile bending force in the X-Z plane necessary toproduce a permanent deformation equal to 0.020 times the active length of the longitudina
20、l element (see the force at Point D inFig. 1).3.2.6 coordinate system/axes, nthree orthogonal axes are defined in Figs. 2 and 3.The anterior-posterior axis is X with positivebeing anterior. The medial-lateral axis is Y with left being positive when viewed posteriorly. The superior-inferior axis is Z
21、 withsuperior being positive.3.2.7 displacement at 2 % offset yield (mm), nthe displacement of a construct measured via the actuator that produces apermanent deformation equal to 0.020 times the active length of the longitudinal element (distance OA in Fig. 1).3.2.8 elastic angular displacement (deg
22、rees), nthe angular displacement at 2 % offset yield (see Point A in Fig. 1) minus the2 % offset angular displacement (see Point B in Fig. 1) (that is, the distance between Point A and Point B in Fig. 1).3.2.9 elastic displacement (mm), nthe displacement at 2 % offset yield (see Point A in Fig. 1) m
23、inus the 2 % offsetdisplacement (see Point B in Fig. 1). (The distance between Point A and Point B in Fig. 1.)3.2.10 failure, npermanent deformation resulting from fracture, plastic deformation, or loosening beyond the ultimatedisplacement or loosening that renders the occipital-cervical or occipita
24、l-cervical-thoracic spinal implant assembly ineffective orunable to adequately resist load.FIG. 1 Typical Load Displacement Curve or Torque Angulation CurveF2706 1723.2.11 fatigue life, nthe number of loading cycles, N, of a specified character that the occipital-cervical or occipital-cervical-thora
25、cic spinal implant assembly sustains before failure of a specified nature occurs (see Terminology E1823).3.2.12 hinge pin, nthe cylindrical rod connecting a test block to a side support. The superior and inferior aspects of the testconstruct are each secured with a single 9.6-mm diameter pin.3.2.13
26、insertion point of an anchor, nthe location where the anchor is attached to the test block. The insertion points shownin Figs. 4-7 are to be adhered to, if possible. In situations where the design of the occipital-cervical or occipital-cervical-thoracicspinal implant assembly or the manufacturers su
27、rgical instructions for installation dictate otherwise, the attachment points maydeviate from these dimensions.3.2.14 intended method of application, noccipital-cervical and occipital-cervical-thoracic spinal implant assemblies containdifferent types of anchors. Each type of anchor has an intended m
28、ethod of application to the spine.3.2.15 intended occipital-cervical spinal location, nthe anatomic region of the spine intended for the application of theoccipital-cervical spinal implant assembly. Spinal implant assemblies are developed for specific spinal locations such as theposterior occipital-
29、cervical spine.3.2.16 intended occipital-cervical-thoracic spinal location, nthe anatomic region of the spine intended for the application ofthe occipital-cervical-thoracic spinal implant assembly. Spinal implant assemblies are developed for specific spinal locations suchas the posterior occipital-c
30、ervical-thoracic spine.FIG. 2 A Standard Bilateral Construct Containing Screw, Rod and ScrewF2706 1733.2.17 longitudinal axis offset (mm), ndistance in the X direction between the centerline of the longitudinal element and theinsertion point of the anchors on the polyacetal test block.3.2.18 longitu
31、dinal direction, nthe initial spatial orientation parallel to the longitudinal element of the occipital-cervical oroccipital-cervical-thoracic spinal implant assembly. The longitudinal direction is generally in the superior-inferior direction andtherefore, generally parallel to the Z-axis.3.2.19 max
32、imum runout load, nthe maximum load that can be applied to an occipital-cervical or occipital-cervical-thoracicspinal implant assembly where all of the tested constructs have withstood 5 000 000 cycles without a failure.3.2.20 occipital-cervical spinal implant assembly, na complete occipital-cervica
33、l spinal implant configuration as intended forsurgical use. An occipital-cervical spinal implant assembly will contain anchors, interconnections, and longitudinal elements andmay contain transverse elements (see Figs. 2-7).3.2.21 occipital-cervical spinal implant construct, na complete occipital-cer
34、vical spinal implant assembly attached to theappropriate test blocks.3.2.22 occipital-cervical-thoracic spinal implant assembly, na complete occipital-cervical-thoracic spinal implant configu-ration as intended for surgical use. An occipital-cervical-thoracic spinal implant assembly will contain anc
35、hors, interconnections,and longitudinal elements and may contain transverse elements (see Figs. 2-7).3.2.23 occipital-cervical-thoracic spinal implant construct, na complete occipital-cervical-thoracic spinal implant assemblyattached to the appropriate test blocks.3.2.24 offset angular displacement
36、at 2 degrees 2 % offset, na permanent angular displacement in the X-Y plane measured viathe actuator equal to 0.020 times the torsional aspect ratio (for example: 1.95 for 1.70 0.02 180/pi) (see Point B in Fig. 1).3.2.25 offset displacement (mm), na permanent deformation measured via the actuator eq
37、ual to 0.020 times the active lengthof the longitudinal element (for example: 1.52 mm for a 76 mm active length of the longitudinal element) (see Point B in Fig. 1).3.2.26 permanent deformation, nthe displacement (mm) or angular displacement (degree) of the occipital-cervical oroccipital-cervical-th
38、oracic spinal implant construct relative to the initial unloaded condition as measured via the actuator after theapplied load, moment, or torque has been removed.FIG. 3 A Bilateral Hook, Rod, Screw, and Transverse Element ConstructF2706 1743.2.27 test block, nthe component of the test apparatus for
39、mounting the occipital-cervical or occipital-cervical-thoracic spinalimplant assembly. A specific design of test block is required for each intended spinal location and intended method of application.Figs. 5-7 describe the recommended designs for the test blocks; however, alternate designs can be us
40、ed as long as equivalentperformance is demonstrated.3.2.28 test block load point, nthe location on the test block at which the resultant load is transmitted from the test apparatus.3.2.29 tightening torque, nthe specified torque that is applied to the various threaded fasteners of the occipital-cerv
41、ical oroccipital-cervical-thoracic spinal implant assembly.3.2.30 torsional aspect ratio, nthe active length of the longitudinal element divided by the distance from the center of rotationto the insertion point of an anchor on the cervical block (for example: in Fig. 2, 1.70 for a 76-mm active lengt
42、h, X = 40 mm andY = 40/2 mm).A 5 LD 5 Lx21y2!1/2 (1)where:L = active length of longitudinal element,D = distance to insertion point,x = x distance to insertion point, andy = y distance to insertion point.FIG. 4 Occipital-Cervical Bilateral Construct Test Setup for Occipital Screws or BoltsF2706 1753
43、.2.31 torsional stiffness (N-m/degree), nthe yield torque (N-m) divided by elastic angular displacement (degrees) (the initialslope of line BC in Fig. 1).3.2.32 torsional ultimate load (N-m), nthe maximum torque in the X-Y plane applied to an occipital-cervical oroccipital-cervical-thoracic spinal i
44、mplant assembly (the torque at Point E in Fig. 1). The ultimate torque should be a function ofthe device and not of the load cell or testing machine.3.2.33 ultimate displacement (mm), nthe displacement associated with the ultimate load, ultimate bending load or ultimatetorque (the displacement at Po
45、int F in Fig. 1).3.2.34 yield displacement (distance OAFig. 6), nthe displacement (mm) or angular displacement (deg) when an assemblyhas a permanent deformation equal to the offset displacement or the offset angular displacement.3.2.35 yield torque (N-m), nthe torque in the X-Y plane required to pro
46、duce a permanent displacement of 0.020 times thetorsional aspect ratio (the torque at Point D in Fig. 1).3.2.36 zero displacement intercept (mm), nthe intersection of the straight line section of the load-displacement curve and thezero load axis (the zero displacement reference Point 0 in Fig. 1).4.
47、 Summary of Test Methods4.1 Similar test methods are proposed for the mechanical evaluation of all occipital-cervical and occipital-cervical-thoracicspinal implant assemblies (see Fig. 4).4.2 A vertebrectomy model is used for the evaluation of both occipital-cervical and occipital-cervical-thoracic
48、systems. Thespinal hardware is attached at the superior and inferior aspects to polyacetal homopolymer (polyacetal) test blocks separated bya large gap. The polyacetal homopolymer used to manufacture the test blocks should have a tensile breaking strength no less than61 MPa. The use of polyacetal te
49、st blocks (see Figs. 5-8) eliminates the effects of the variability of bone geometry and materialproperties associated with cadaveric testing. Alternate designs of test blocks may be used as long as equivalent performance isdemonstrated.4.3 Three static mechanical tests and two dynamic tests will evaluate the occipital-cervical or occipital-cervical-thoracic spinalimplant assemblies. The three static mechanical tests are compression bending, tensile bending, and torsion. The dynamic tests arecompression bending fatigue and tors
