ASTM F2624-12

Standard Test Method for Static, Dynamic, and Wear Assessment of Extra-Discal Single Level Spinal Constructs

ABSTRACT
This test method deals with static, dynamic, and wear testing of extra-discal motion preserving implants. These implants are intended to augment spinal stability without significant tissue removal while allowing motion of the functional spinal unit(s). Wear is assessed using a weight loss method and a dimensional analysis for determining wear of components used in extra-discal spinal motion preserving procedures, using testing medium as defined in this test method. This test method is not intended to address facet arthroplasty devices and any potential failure mode as it relates to the fixation of the device to its bony interfaces; and does not prescribe methods for assessing the mechanical characteristics of the device in translation. The static test includes the static flexion test, static extension test, static torsion test, static lateral bending test, and fatigue tests. Wear test includes flexion/extension wear assessment, rotational wear assessment, and bending wear assessment. The apparatus which shall be used includes implant components and spinal testing apparatus. The calculation and interpretation of wear results are also elaborated.
SIGNIFICANCE AND USE
This test method is designed to quantify the static and dynamic characteristics of different designs of single level spinal constructs. Wear may also be assessed for implants that allow motion using testing medium (see 6.1) for simulating the physiologic environment at 37°C. Wear is assessed using a weight loss method in addition to dimensional analyses. Weight loss is determined after subjecting the implants to dynamic profiles specified in this test method. This information will allow the manufacturer or end user of the product to understand how the specific device in question performs under the test conditions prescribed in this test method.
This test method is intended to be applicable for single level extra-discal spinal constructs. Three different types of fixtures are specified for testing single level extra-discal spinal constructs (See Fig. 2, Fig. 4, and Fig. 5). See also Table 1.
Implants may be designed using a variety of materials (for example, ceramics, metals, polymers, or combinations thereof), and it is the goal of this test method to enable a comparison of the static, dynamic, and wear properties generated by these devices, regardless of material and type of device.
TABLE 1 Loading Modes and Associated Apparatus Listing Possible Tests That May Be Conducted (see 1.9)
Note 1—For all loading modes, static, dynamic, and wear tests are described in this test method.
Note 2—“Offset” refers to 8 mm of offset induced in the spinal construct (see Fig. 6) before subjecting the construct to rotational flexion/extension moments (see Fig. 2).  Associated
ApparatusAssociated
FigureLoading Mode RotationalFig. 2Flexion Extension Lateral Bending Axial Rotation  Fig. 2 and Fig. 6Offset Flexion and Offset Extension  ShearFig. 4Anterior/Posterior Shear  Compression BendingFig. 5Compression Bending
FIG. 4 Schematic of Anterior/Posterior Shear Testing Apparatus
FIG. 5 Schematic of Single Level Compression Bending Test
SCOPE
1.1 This test method describes methods to assess the static and dynamic properties of single level spinal constructs.
1.2 An option for assessing wear using a weight loss method and a dimensional analysis is given. This method, described herein, is used for the analysis of devices intended for motion preservation, using testing medium as defined in this standard (6.1).
1.3 This test method is not intended to address any potential failure mode as it relates to the fixation of the device to its bony interfaces.
1.4 It is the intent of this test method to enable single level extra-discal spinal constructs with regard to kinematic, functional, and wear characteristics when tested under the specified conditions.
1.5 This test method is not intended to address facet arthroplasty devices.
1.6 In or...

General Information

• Status: Historical
• Publication Date: 30-Nov-2012
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.25 - Spinal Devices

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F2624 − 12
Standard Test Method for
Static, Dynamic, and Wear Assessment of Extra-Discal
1
Single Level Spinal Constructs
This standard is issued under the fixed designation F2624; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope device design. In most instances, only a subset of the herein
described test methods will be required.
1.1 This test method describes methods to assess the static
and dynamic properties of single level spinal constructs. 1.10 The values stated in SI units are to be regarded as the
standard with the exception of angular measurements, which
1.2 Anoptionforassessingwearusingaweightlossmethod
may be reported in either degrees or radians. No other units of
and a dimensional analysis is given. This method, described
measurement are included in this standard.
herein, is used for the analysis of devices intended for motion
1.11 This test method does not purport to address all of the
preservation, using testing medium as defined in this standard
safety concerns, if any, associated with its use. It is the
(6.1).
responsibility of the user of this test method to establish
1.3 Thistestmethodisnotintendedtoaddressanypotential
appropriate safety and health practices and to determine the
failuremodeasitrelatestothefixationofthedevicetoitsbony
applicability of regulatory limitations prior to use.
interfaces.
1.4 It is the intent of this test method to enable single level
2. Referenced Documents
extra-discal spinal constructs with regard to kinematic,
2
2.1 ASTM Standards:
functional, and wear characteristics when tested under the
E2309Practices forVerification of Displacement Measuring
specified conditions.
Systems and Devices Used in Material Testing Machines
1.5 This test method is not intended to address facet
F561 Practice for Retrieval and Analysis of Medical
arthroplasty devices.
Devices, and Associated Tissues and Fluids
F1714GuideforGravimetricWearAssessmentofProsthetic
1.6 In order that the data be reproducible and comparable
Hip Designs in Simulator Devices
within and between laboratories, it is essential that uniform
F1717Test Methods for Spinal Implant Constructs in a
procedures be established. This test method is intended to
Vertebrectomy Model
facilitate uniform testing methods and data reporting.
F1877Practice for Characterization of Particles
1.7 The motion profiles specified by this test method do not
F2003Practice for Accelerated Aging of Ultra-High Mo-
necessarily accurately reproduce those occurring in vivo.
lecular Weight Polyethylene after Gamma Irradiation in
Rather this method provides useful boundary/endpoint condi-
Air
tions for evaluating implant designs in a functional manner.
F2423Guide for Functional, Kinematic, and Wear Assess-
1.8 This test method is not intended to be a performance
ment of Total Disc Prostheses
standard. It is the responsibility of the user of this test method
to characterize the safety and effectiveness of the device under 3. Terminology
evaluation.
3.1 All terminology is consistent with the referenced
1.9 Multiple test methods are included in this standard. standards, unless otherwise stated.
However, it must be noted that the user is not obligated to test
3.2 Definitions:
using all of the described methods. Instead, the user should
3.2.1 center of rotation (COR)—the point about which the
only select test methods that are appropriate for a particular
simulated vertebral bodies rotate in performing the range of
motion (ROM) specified in this test method.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeF04onMedical
andSurgicalMaterialsandDevicesandisthedirectresponsibilityofSubcommittee
2
F04.25 on Spinal Devices. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2012. Published February 2013. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2007. Last previous edition approved in 2007 as F1587–07. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/F2624-12. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F2624 − 12
FIG. 1 Typical Force Displacement Curve
3.2.2 compressive bending stiffness (N/mm)—the compres- 3.2.5.2 X-Axis—the positive X-Axis is a global fixed axis
sive bending yield force divided by elastic displacement (see
relative to the testing machine’s stationary base and is to be
the initial slope of line BC in Fig. 1). directed a
...

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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F2624 − 07 F2624 − 12
Standard Test Method for
Static, Dynamic, and Wear Assessment of Extra-Discal
Spinal Motion Preserving ImplantsSingle Level Spinal
1
Constructs
This standard is issued under the fixed designation F2624; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method is intended to provide test methods for the static, dynamic, and wear testing of extra-discal motion
preserving implants. These implants are intended to augment spinal stability without significant tissue removal while allowing
motion of the functional spinal unit(s).describes methods to assess the static and dynamic properties of single level spinal
constructs.
1.2 Wear is assessed An option for assessing wear using a weight loss method and a dimensional analysis for determining wear
of components used in extra-discal spinal motion preserving procedures, is given. This method, described herein, is used for the
analysis of devices intended for motion preservation, using testing medium as defined in this test method standard (6.1).
1.3 This test method is not intended to address any potential failure mode as it relates to the fixation of the device to its bony
interfaces.
1.4 It is the intent of this test method to enable comparison of motion preserving, extra-discal implants single level extra-discal
spinal constructs with regard to kinematic, functional, and wear characteristics when tested under the specified conditions. It must
be recognized, however, that there are many possible variations in the in vivo conditions. A single laboratory simulation with a
fixed set of parameters may not be universally representative.
1.5 This test method is not intended to address facet arthroplasty devices.
1.6 This test method prescribes the use of pure angular rotations for assessing the mechanical characteristics of extra-discal
motion preserving implants. This test method does not, however, prescribe methods for assessing the mechanical characteristics
of the device in translation (for example, anterior/posterior translation), though this type of linear motion may be clinically
relevant.
1.6 In order that the data be reproducible and comparable within and between laboratories, it is essential that uniform procedures
arebe established. This test method is intended to facilitate uniform testing methods and data reporting for extra-discal motion
preserving implants. reporting.
1.7 Without a substantial clinical retrieval history of spinal, motion preserving extra-discal implants, actual loading profiles and
patterns cannot be delineated at the time of the writing of this test method. It therefore follows that the motion profiles The motion
profiles specified by this test method do not necessarily accurately reproduce those occurring in vivo. Rather this method provides
useful boundary/endpoint conditions for evaluating implant designs in a functional manner.
1.8 This test method is not intended to be a performance standard. It is the responsibility of the user of this test method to
characterize the safety and effectiveness of the device under evaluation.
1.9 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
Multiple test methods are included in this standard. However, it must be noted that the user is not obligated to test using all of the
described methods. Instead, the user should only select test methods that are appropriate for a particular device design. In most
instances, only a subset of the herein described test methods will be required.
1.10 The values stated in SI units are to be regarded as the standard with the exception of angular measurements, which may
be reported in either degrees or radians. No other units of measurement are included in this standard.
1
This test method is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.25 on Spinal Devices.
Current edition approved Dec. 15, 2007Dec. 1, 2012. Published March 2008February 2013. Originally approved in 2007. Last previous edition approved in 2007 as
F1587 – 07. DOI: 10.1520/F2624-07.10.1520/F2624-12.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unit
...