ASTM_F_1798_-_13.pdf

Designation:F179813Standard Test Method forEvaluating the Static and Fatigue Properties ofInterconnection Mechanisms and Subassemblies Used inSpinal Arthrodesis Implants1This standard is issued under the fixed designation F1798;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 indicates 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 measurement of uniaxialstatic and fatigue strength,and resistance to loosening of thecomponent interconnection mechanisms of spinal arthrodesisimplants.1.2 The purpose of this test method is to provide a means ofmechanically characterizing different designs of spinal implantinterconnections.Ultimately,the various components and in-terconnections should be combined for static and fatiguetesting of the spinal implant construct.It is not the intention ofthis test method to address the analysis of spinal implantconstructs or subconstructs or to define levels of performanceof spinal implants as insufficient knowledge is available topredict the consequences of the use of particular spinal implantdesigns.1.3 This test method sets out definitions for use in measur-ing the strength of component interconnections of spinalimplants,possible test methods themselves,and the reportingof test results.1.4 The values stated in SI units are to be regarded asstandard,with the exception of angular measurements,whichmay be reported in terms of either degrees or radians.1.5 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.Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesF383 Practice for Static Bend and Torsion Testing of In-tramedullary Rods(Withdrawn 1996)3F1582 Terminology Relating to Spinal Implants3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 active length of longitudinal elementthe span be-tween rigid supports(for example,50 mm is the active lengthin Fig.1,Fig.2,Fig.3(a),Fig.3(b),and Fig.4.3.1.2 global coordinate systemspinal column motion hassix degrees of freedom,having translational motion along,androtational motion about three axes.The axes are labeledanterior-posterior or a-p(X),medial-lateral or transverse(Y),and caudal-cranial or axial(Z).This coordinate system is righthanded with+X in the anterior direction,+Y towards the leftside of the body,and+Z in the cranial direction.Positiverotations are defined by the right hand rule(see Fig.5(a).3.1.3 gripping capacitythe maximum applied load ormoment across an interconnection mechanism within the first1.5 mm of permanent displacement or 5 of permanent rotationbetween the connected components.3.1.4 local coordinate systemthe spines global coordinatesystem shall be applied locally at the position of the intercon-nection.The local direction,z,shall be centered through thelongitudinal element of the x-y plane.The local direction,x,shall be defined as parallel to the axis of a screw or back of ahook.The local transverse axis,y,shall be parallel to atransverse element(See Fig.5(b)and Fig.5(c).3.1.5 loosening torquethe torque required to disconnectthe various threaded fasteners that might comprise the im-plants interconnection mechanism.3.1.6 major directions of loadingdirections of the pre-dominant forces and moments(relative to the local axes)towhich vertebral connection elements are subjected,(that is,axial load,Fz;A-P load,Fx;axial torsion,Mz;and flexion-extension moment,My).1This test method is under the jurisdiction of ASTM Committee F04 onMedicaland Surgical Materials and Devices.Current edition approved Dec.1,2013.Published February 2014.Originallyapproved in 1997.Last previous edition approved in 2008 as F1798 97(2008).DOI:10.1520/F1798-13.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.7 maximum run out load/momentthe maximum loador moment that can be applied to a subassembly where all thetested constructs have withstood 2.5 106 cycles without afailure.3.1.8 relevant directions of loadingthose directions ofloading in which a particular component interconnection isdesigned to provide resistance to loading.For example,aparticular spinal hook may be designed to withstand a positiveaxial load,A-P load,and flexion-extension moment,but not anegative axial