ASTM F2267-04(2018)

Standard Test Method for Measuring Load Induced Subsidence of Intervertebral Body Fusion Device Under Static Axial Compression

SIGNIFICANCE AND USE
5.1 Intervertebral body fusion devices are generally simple geometric shaped devices, which are often porous or hollow in nature. Their function is to support the anterior column of the spine to facilitate arthrodesis of the motion segment.  
5.2 This test method is designed to quantify the subsidence characteristics of different designs of intervertebral body fusion devices since this is a potential clinical failure mode. These tests are conducted in vitro in order to simplify the comparison of simulated vertebral body subsidence induced by the intervertebral body fusion devices.  
5.3 The static axial compressive loads that will be applied to the intervertebral body fusion devices and test blocks will differ from the complex loading seen in vivo, and therefore, the results from this test method may not be used to directly predict in vivo performance. The results, however, can be used to compare the varying degrees of subsidence between different intervertebral body fusion device designs for a given density of simulated bone.  
5.4 The location within the simulated vertebral bodies and position of the intervertebral body fusion device with respect to the loading axis will be dependent upon the design and manufacturer's recommendation for implant placement.
SCOPE
1.1 This test method specifies the materials and methods for the axial compressive subsidence testing of non-biologic intervertebral body fusion devices, spinal implants designed to promote arthrodesis at a given spinal motion segment.  
1.2 This test method is intended to provide a basis for the mechanical comparison among past, present, and future non-biologic intervertebral body fusion devices. This test method is intended to enable the user to mechanically compare intervertebral body fusion devices and does not purport to provide performance standards for intervertebral body fusion devices.  
1.3 This test method describes a static test method by specifying a load type and a specific method of applying this load. This test method is designed to allow for the comparative evaluation of intervertebral body fusion devices.  
1.4 Guidelines are established for measuring test block deformation and determining the subsidence of intervertebral body fusion devices.  
1.5 Since some intervertebral body fusion devices require the use of additional implants for stabilization, the testing of these types of implants may not be in accordance with the manufacturer's recommended usage.  
1.6 Units—The values stated in SI units are to be regarded as the standard with the exception of angular measurements, which may be reported in terms of either degrees or radians.  
1.7 The use of this standard may involve the operation of potentially hazardous equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-Jan-2018
• 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: F2267 − 04 (Reapproved 2018)
Standard Test Method for
Measuring Load Induced Subsidence of Intervertebral Body
Fusion Device Under Static Axial Compression
This standard is issued under the fixed designation F2267; 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 ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This test method specifies the materials and methods for
mendations issued by the World Trade Organization Technical
the axial compressive subsidence testing of non-biologic in-
Barriers to Trade (TBT) Committee.
tervertebral body fusion devices, spinal implants designed to
promote arthrodesis at a given spinal motion segment.
2. Referenced Documents
1.2 This test method is intended to provide a basis for the 2
2.1 ASTM Standards:
mechanical comparison among past, present, and future non-
E4 Practices for Force Verification of Testing Machines
biologic intervertebral body fusion devices.This test method is
F1582 Terminology Relating to Spinal Implants
intended to enable the user to mechanically compare interver-
F1839 Specification for Rigid Polyurethane Foam for Use as
tebral body fusion devices and does not purport to provide
a Standard Material for Testing Orthopaedic Devices and
performance standards for intervertebral body fusion devices.
Instruments
1.3 This test method describes a static test method by F2077 Test Methods for Intervertebral Body Fusion Devices
specifying a load type and a specific method of applying this
3. Terminology
load. This test method is designed to allow for the comparative
evaluation of intervertebral body fusion devices. 3.1 Allsubsidencetestingterminologyisconsistentwiththe
referenced standards above, unless otherwise stated.
1.4 Guidelines are established for measuring test block
deformation and determining the subsidence of intervertebral 3.2 Definitions:
body fusion devices.
3.2.1 coordinate system/axes—three orthogonal axes are
defined by Terminology F1582 as seen in Fig. 4. The center of
1.5 Since some intervertebral body fusion devices require
the coordinate system is located at the geometric center of the
the use of additional implants for stabilization, the testing of
intervertebralbodyfusiondeviceassembly.The X-axisisalong
these types of implants may not be in accordance with the
the longitudinal axis of the implant, with positive X in the
manufacturer’s recommended usage.
anterior direction, Y is lateral, and Z is cephalic.
1.6 Units—The values stated in SI units are to be regarded
3.2.2 ideal insertion location—the implant location with
as the standard with the exception of angular measurements,
respect to the simulated inferior and superior vertebral bodies
which may be reported in terms of either degrees or radians.
(polyurethane)dictatedbythetype,design,andmanufacturer’s
1.7 The use of this standard may involve the operation of
surgical installation instructions.
potentially hazardous equipment. This standard does not pur-
3.2.3 intended method of application—intervertebral body
port to address all of the safety concerns, if any, associated
fusion devices may contain different types of stabilizing
with its use. It is the responsibility of the user of this standard
features such as threads, spikes, and knurled surfaces. Each
to establish appropriate safety, health, and environmental
type of feature has an intended method of application or
practices and determine the applicability of regulatory limita-
attachment to the spine.
tions prior to use.
3.2.4 intended spinal location—the anatomic region of the
1.8 This international standard was developed in accor-
spine intended for the intervertebral body fusion device.
dance with internationally recognized principles on standard-
Intervertebral body fusion devices may be designed and
developed for specific regions of the spine such as the lumbar,
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devicesand is the direct responsibility of Subcommittee
F04.25 on Spinal Devices. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2018. Published April 2018. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2003. Last previous edition approved in 2011 as F2267 – 04(2011). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/F2267-04R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2267 − 04 (2018)
FIG. 1 Intradiscal Height Diagram
FIG. 2 Typical Load-Displacement Curve with 1.5 mm (Thoracic Device) Offset for Polyurethane Foam Test Blocks
thoracic, and cervical spine. Also, there potentially exist 3.2.5 intervertebral subsidence—the process of a vertebral
different anatomical surgical approaches, which will result in body cavitating or sinking around an implanted intervertebral
different implant orientation at different levels of the spine. body fusion device resulting in the loss of intradiscal height.
F2267 − 04 (2018)
FIG. 3 Typical Load-Displacement Plot Comparison for Test Specimens in Metallic and Polyurethane Test Blocks
3.2.6 intradiscal height—the straight-line distance along the 3.2.12 yield load—the applied load, F, transmitted by the
Z-axis between the unaltered simulated vertebral bodies. See pushrod (assumed equal to force component parallel to and
Fig. 1. indicated by load cell), required to produce a permanent
deformation equal to the offset displacement found by plotting
3.2.7 load point—the point through which the resultant
line BC with stiffness, K, originating at point B (see Point D in
force on the intervertebral device passes (that is, the geometric
Fig. 2).
center of the superior fixture’s sphere) (Fig. 4).
3.2.8 offset displacement—offset on the displacement axis
4. Summary of Test Method
equal to 1 mm for cervical disc devices, 1.5 mm for thoracic
4.1 To measure load induced subsidence, a test method is
devices, and 2 mm for lumbar devices (see distanceAB in Fig.
proposed for the axial compression of intervertebral body
2)
fusion devices specific to the lumbar, thoracic, and cervical
3.2.9 simulated vertebral bodies—the component of the test
spine.
apparatus for mounting the intervertebral body fusion device.
4.2 The axial compressive subsidence testing of the in-
3.2.10 stiffness, (N/mm)—the slope of the initial linear
tervertebral body fusion device will be conducted in a simu-
portion of the load-displacement curve (see the slope of line
lated motion segment via a gap between two polyurethane
AE in Fig. 2).
foam blocks.
3.2.11 test block height—thelineardistancealongthe Z-axis
4.3 Grade 15 foam shall be employed conforming to Speci-
fromthetopsurfaceofthesuperiorsimulatedvertebralbodyto
fication F1839.
thebottomsurfaceoftheinferiorsimulatedvertebralbodywith
the intervertebral body fusion device in position. The block
5. Significance and Use
heights shall be 70 mm, 60 mm, and 40 mm for lumbar,
thoracic, and cervical intervertebral disc devices respectively. 5.1 Intervertebral body fusion devices are generally simple
See Fig. 4. geometric shaped devices, which are often porous or hollow in
F2267 − 04 (2018)
FIG. 4 Subsidence Test Fixture
nature. Their function is to support the anterior column of the 6.3 Axial Compressive Testing Apparatus—An example
spine to facilitate arthrodesis of the motion segment. axial compressive test fixture can be referenced in Figs. 4 and
5. Two pieces of polyurethane foam or rigid metal are rigidly
5.2 This test method is designed to quantify the subsidence
mounted inside the test fixture. The actuator of the testing
characteristicsofdifferentdesignsofintervertebralbodyfusion
machine is connected to the pushrod by a minimal friction ball
devices since this is a potential clinical failure mode. These
and socket joint or universal joint (that is, unconstrained in
tests are conducted in vitro in order to simplify the comparison
bending). The pushrod is connected to the superior fixture by a
of simulated vertebral body subsidence induced by the in-
minimal friction sphere joint (that is, unconstrained in bending
tervertebral body fusion devices.
and torsion). The inferior sphere portion firmly holds the
5.3 Thestaticaxialcompressiveloadsthatwillbeappliedto
inferior polyurethane block and is rigidly fixed within the base
the intervertebral body fusion devices and test blocks will
socket so that no rotation occurs. The hollow pushrod and
differ from the complex loading seen in vivo, and therefore, the
superior sphere should be of minimal weight so as to be
resultsfromthistestmethodmaynotbeusedtodirectlypredict
considered a “two force” member. It thus applies to the
in vivo performance. The results, however, can be used to
intervertebral device a resultant force directed along the
compare the varying degrees of subsidence between different
pushrod’s axes and located at the center of the superior
intervertebral body fusion device designs for a given density of
fixture’s sphere joint (the geometric center of the device being
simulated bone.
tested). The polyurethane blocks are to have surfaces that mate
5.4 The location within the simulated vertebral bodies and
geometrically with the intervertebral device similar to how the
positionoftheintervertebralbodyfusiondevicewithrespectto
device is intended to mate with vertebral end plates. The test
the loading axis will be dependent upon the design and
apparatus will be assembled such that the Z-axis of the
manufacturer’s recommendation for implant placement.
intervertebral device is initially coincident with the pushrod’s
axis and collinear with the axis of the testing machine’s
6. Apparatus
actuator and load cell. The length of the pushrod between the
6.1 Test machines will conform to the requirements of
center of the ball-and-socket joint to the center of the spherical
Practices E4.
surface is to be a minimum of 38 cm. This is required to
6.2 The intradiscal height, H, (Fig. 1) shall be determined minimize deviation of the pushrod’s axis (direction of applied
force, F) from that of the test machine’s load cell axis. In other
f
...

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: F2267 − 04 (Reapproved 2011) F2267 − 04 (Reapproved 2018)
Standard Test Method for
Measuring Load Induced Subsidence of Intervertebral Body
Fusion Device Under Static Axial Compression
This standard is issued under the fixed designation F2267; 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 specifies the materials and methods for the axial compressive subsidence testing of non-biologic
intervertebral body fusion devices, spinal implants designed to promote arthrodesis at a given spinal motion segment.
1.2 This test method is intended to provide a basis for the mechanical comparison among past, present, and future non-biologic
intervertebral body fusion devices. This test method is intended to enable the user to mechanically compare intervertebral body
fusion devices and does not purport to provide performance standards for intervertebral body fusion devices.
1.3 This test method describes a static test method by specifying a load type and a specific method of applying this load. This
test method is designed to allow for the comparative evaluation of intervertebral body fusion devices.
1.4 Guidelines are established for measuring test block deformation and determining the subsidence of intervertebral body
fusion devices.
1.5 Since some intervertebral body fusion devices require the use of additional implants for stabilization, the testing of these
types of implants may not be in accordance with the manufacturer’s recommended usage.
1.6 Units—The values stated in SI units are to be regarded as the standard with the exception of angular measurements, which
may be reported in terms of either degrees or radians.
1.7 The use of this standard may involve the operation of potentially hazardous equipment. This standard does not purport to
address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish
appropriate safety safety, health, and healthenvironmental practices and determine the applicability of regulatory limitations prior
to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E4 Practices for Force Verification of Testing Machines
F1582 Terminology Relating to Spinal Implants
F1839 Specification for Rigid Polyurethane Foam for Use as a Standard Material for Testing Orthopaedic Devices and
Instruments
F2077 Test Methods for Intervertebral Body Fusion Devices
3. Terminology
3.1 All subsidence testing terminology is consistent with the referenced standards above, unless otherwise stated.
3.2 Definitions:
This test method is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devicesand is the direct responsibility of Subcommittee F04.25
on Spinal Devices.
Current edition approved Dec. 1, 2011Feb. 1, 2018. Published January 2012April 2018. Originally approved in 2003. Last previous edition approved in 20042011 as
F2267 – 04.F2267 – 04(2011). DOI: 10.1520/F2267-04R11.10.1520/F2267-04R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2267 − 04 (2018)
3.2.1 coordinate system/axes—three orthogonal axes are defined by Terminology F1582 as seen in Fig. 4. The center of the
coordinate system is located at the geometric center of the intervertebral body fusion device assembly. The X-axis is along the
longitudinal axis of the implant, with positive X in the anterior direction, Y is lateral, and Z is cephalic.
3.2.2 ideal insertion location—the implant location with respect to the simulated inferior and superior vertebral bodies
(polyurethane) dictated by the type, design, and manufacturer’s surgical installation instructions.
3.2.3 intended method of application—intervertebral body fusion devices may contain different types of stabilizing features such
as threads, spikes, and knurled surfaces. Each type of feature has an intended method of application or attachment to the spine.
3.2.4 intended spinal location—the anatomic region of the spine intended for the intervertebral body fusion device.
Intervertebral body fusion devices may be designed and developed for specific regions of the spine such as the lumbar, thoracic,
and cervical spine. Also, there potentially exist different anatomical surgical approaches, which will result in different implant
orientation at different levels of the spine.
3.2.5 intervertebral subsidence—the process of a vertebral body cavitating or sinking around an implanted intervertebral body
fusion device resulting in the loss of intradiscal height.
3.2.6 intradiscal height—the straight-line distance along the Z-axis between the unaltered simulated vertebral bodies. See Fig.
1.
3.2.7 load point—the point through which the resultant force on the intervertebral device passes (that is, the geometric center
of the superior fixture’s sphere) (Fig. 4).
3.2.8 offset displacement—offset on the displacement axis equal to 1 mm for cervical disc devices, 1.5 mm for thoracic devices,
and 2 mm for lumbar devices (see distance AB in Fig. 2)
3.2.9 simulated vertebral bodies—the component of the test apparatus for mounting the intervertebral body fusion device.
3.2.10 stiffness, (N/mm)—the slope of the initial linear portion of the load-displacement curve (see the slope of line AE in Fig.
2).
3.2.11 test block height—the linear distance along the Z-axis from the top surface of the superior simulated vertebral body to
the bottom surface of the inferior simulated vertebral body with the intervertebral body fusion device in position. The block heights
shall be 70 mm, 60 mm, and 40 mm for lumbar, thoracic, and cervical intervertebral disc devices respectively. See Fig. 4.
3.2.12 yield load—the applied load, F, transmitted by the pushrod (assumed equal to force component parallel to and indicated
by load cell), required to produce a permanent deformation equal to the offset displacement found by plotting line BC with
stiffness, K, originating at point B (see Point D in Fig. 2).
4. Summary of Test Method
4.1 To measure load induced subsidence, a test method is proposed for the axial compression of intervertebral body fusion
devices specific to the lumbar, thoracic, and cervical spine.
4.2 The axial compressive subsidence testing of the intervertebral body fusion device will be conducted in a simulated motion
segment via a gap between two polyurethane foam blocks.
4.3 Grade 15 foam shall be employed conforming to Specification F1839.
FIG. 1 Intradiscal Height Diagram
F2267 − 04 (2018)
FIG. 2 Typical Load-Displacement Curve with 1.5 mm (Thoracic Device) Offset for Polyurethane Foam Test Blocks
5. Significance and Use
5.1 Intervertebral body fusion devices are generally simple geometric shaped devices, which are often porous or hollow in
nature. Their function is to support the anterior column of the spine to facilitate arthrodesis of the motion segment.
5.2 This test method is designed to quantify the subsidence characteristics of different designs of intervertebral body fusion
devices since this is a potential clinical failure mode. These tests are conducted in vitro in order to simplify the comparison of
simulated vertebral body subsidence induced by the intervertebral body fusion devices.
5.3 The static axial compressive loads that will be applied to the intervertebral body fusion devices and test blocks will differ
from the complex loading seen in vivo, and therefore, the results from this test method may not be used to directly predict in vivo
performance. The results, however, can be used to compare the varying degrees of subsidence between different intervertebral body
fusion device designs for a given density of simulated bone.
5.4 The location within the simulated vertebral bodies and position of the intervertebral body fusion device with respect to the
loading axis will be dependent upon the design and manufacturer’s recommendation for implant placement.
6. Apparatus
6.1 Test machines will conform to the requirements of Practices E4.
6.2 The intradiscal height, H, (Fig. 1) shall be determined from vertebral body and disc morphometric data at the intended level
of application. Suggested heights are as follows: 10 mm for the lumbar spine, 6 mm for the thoracic spine and 4 mm for the cervical
spine. The user of this test method should select the intradiscal height that is appropriate for the device being tested.
6.3 Axial Compressive Testing Apparatus—An example axial compressive test fixture can be referenced in Figs. 4 and 5. Two
pieces of polyurethane foam or rigid metal are rigidly mounted inside the test fixture. The actuator of the testing machine is
F2267 − 04 (2018)
FIG. 3 Typical Load-Displacement Plot Comparison for Test Specimens in Metallic and Polyurethane Test Blocks
connected to the pushrod by a minimal friction ball and socket joint or universal joint (that is, unconstrained in bending). The
pushrod is connected to the superior fixture by a minimal friction sphere joint (that is, unconstrained in bending and torsion). The
inferior sphere portion firmly holds the inferior polyurethane block and is rigidly fixed within the base socket so that no rotation
occurs. The hollow pushrod and superior sphere should be of minimal weight so as to be considered a “two force” member. It thus
applies to the intervertebral device a resultant force directed along the pushrod’s axes and located at the center of the superior
fixture’s sphere joint (the geometric center of the device being tested). The polyurethane blocks are to have surfaces that mate
geometrically with the intervertebral device similar to how the device is intended to mate with vertebral end plates. The test
apparatus will be assembled such that the Z-axis of the intervertebr
...