ASTM F3631-24

Standard Test Method for Assessment of Intra-operative Durability of Intervertebral Body Fusion Devices

SIGNIFICANCE AND USE
5.1 IBFDs can be single-piece or multicomponent designs and can be 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 Intra-operative IBFD assembly failures can result in significant clinical consequences.4 This test method outlines materials and methods for the comparative characterization and evaluation of the intra-operative impact performance of IBFD assemblies.  
5.3 The impact forces applied during a surgical procedure may be highly variable and, therefore, the results from these tests may not directly predict in vivo performance. The results, however, can be used to compare mechanical performance of different IBFD assemblies. The tests may also identify the weakest, most likely to fail points in particular IBFD-inserter combinations, thus enabling design improvements.  
5.4 Intra-operative clinical failures may be due to several factors, some of which may not be simulated in the current method. For example, off-axis impact loads applied to the IBFD assembly are not simulated in the current method yet may contribute to intra-operative clinical failures in some designs. The user of this standard should consider incorporating such factors into their evaluations.
SCOPE
1.1 This test method covers the materials and methods for impact testing of lumbar intervertebral body fusion devices (IBFD).  
1.2 This test method is intended to provide a basis for the mechanical comparison among nonbiologic IBFD assemblies (the IBFD and associated inserter tool). This test method is intended to enable the user to compare these IBFD assemblies under impact loads to simulate the intra-operative surgical technique used to insert the IBFD.  
1.3 The test method describes the impact test by specifying impact energies and specific methods for applying these energies. The tests are designed to allow for the comparative evaluation of IBFD assemblies.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard, with the exception of angular measurements, which may be reported in terms of either degrees or radians.  
1.5 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.  
1.6 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: Published
• Publication Date: 14-Mar-2024
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.25 - Spinal Devices

Relations

• Refers: ASTM F2267-24 - Standard Test Method for Measuring Load-Induced Subsidence of Intervertebral Body Fusion Device Under Static Axial Compression
• Effective Date: 15-Apr-2024
• Refers: ASTM F2267-22 - Standard Test Method for Measuring Load-Induced Subsidence of Intervertebral Body Fusion Device Under Static Axial Compression
• Effective Date: 01-Sep-2022

Overview

ASTM F3631-24: Standard Test Method for Assessment of Intra-operative Durability of Intervertebral Body Fusion Devices establishes internationally recognized procedures for evaluating the impact performance of lumbar intervertebral body fusion devices (IBFDs) during surgical implantation. Developed by ASTM International, this standard supports the comparative assessment of IBFD mechanical durability under simulated intra-operative conditions. Adhering to this method is vital for manufacturers, researchers, and regulatory bodies aiming to ensure device reliability, facilitate product improvements, and protect patient safety.

Key Topics

• Scope of ASTM F3631-24: This standard specifies materials and test methods for impact testing of nonbiologic lumbar IBFD assemblies and their associated insertion tools. It is designed to simulate the impact loads applied during the surgical technique used for device placement.

• Comparative Evaluation: The method enables users to compare the mechanical performance and intra-operative durability of different IBFD assemblies, using standardized impact energies and procedures.

• Test Apparatus and Approaches: Two primary testing options are outlined:

  • Insertion Between Foam Blocks: Simulates insertion into bone-like polyurethane foam to assess impact resistance throughout the placement phase.
  • Static Rigid Block: Evaluates device durability against a rigid steel block, representing worst-case load transfer scenarios.

• Measurement and Reporting: Impact resistance is measured by the number of impacts sustained before device failure. Standardized reporting requirements improve the repeatability and comparability of test results.

• Limitations and Safety: While the method provides valuable comparative data, it may not fully reproduce all clinical failure modes, such as off-axis loading scenarios. Users are responsible for safety precautions and for considering additional clinically relevant testing factors.

Applications

• Device Development and Quality Control: Manufacturers utilize ASTM F3631-24 to verify the intra-operative robustness of new intervertebral body fusion device designs. Early identification of failure points helps drive iterative improvements.

• Regulatory Submissions: Compliance with this test method supports regulatory documentation, demonstrating that a device has been subjected to rigorous, standardized impact testing simulating surgical conditions.

• Comparative Effectiveness Studies: The standard provides a scientifically valid basis for third-party evaluations of competing IBFD systems, aiding surgeon and hospital product selections.

• Post-market Surveillance: Analysis of device failures reported in clinical databases can be compared against in vitro results from ASTM F3631-24, supporting root cause analysis and corrective actions.

• Design Validation: Device engineers employ these protocols to benchmark device performance against existing products, validate new inserter tools, or assess changes in material or geometry.

Related Standards

• ASTM F1582 – Terminology Relating to Spinal Implants
• ASTM F1839 – Specification for Rigid Polyurethane Foam for Use as a Standard Material for Testing Orthopaedic Devices and Instruments
• ASTM F2077 – Test Methods for Intervertebral Body Fusion Devices
• ASTM F2267 – Test Method for Measuring Load-Induced Subsidence of Intervertebral Body Fusion Device Under Static Axial Compression
• ASTM F3292 – Practice for Inspection of Spinal Implants Undergoing Testing
• ASTM E4 – Practices for Force Calibration and Verification of Testing Machines
• ASTM E177 & E691 – Practices for Precision, Bias, and Interlaboratory Studies

Practical Value

ASTM F3631-24 provides a standardized, reproducible framework for assessing the intra-operative durability of spinal fusion devices. It enhances patient safety, streamlines regulatory pathways, and aids in technological innovation by establishing a level playing field for mechanical comparison of IBFDs. Adhering to this standard helps ensure that spinal cages and similar devices meet the mechanical demands encountered during surgical implantation, reducing the risk of intra-operative failure and improving clinical outcomes.

Keywords: ASTM F3631-24, intervertebral body fusion device, IBFD, impact test, spinal implants, intra-operative durability, mechanical performance, spine surgery, orthopedic device testing, spinal cage fracture

Standards Content (Sample)

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.
Designation: F3631 − 24
Standard Test Method for
Assessment of Intra-operative Durability of Intervertebral
Body Fusion Devices
This standard is issued under the fixed designation F3631; 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 E4 Practices for Force Calibration and Verification of Test-
ing Machines
1.1 This test method covers the materials and methods for
E177 Practice for Use of the Terms Precision and Bias in
impact testing of lumbar intervertebral body fusion devices
ASTM Test Methods
(IBFD).
E691 Practice for Conducting an Interlaboratory Study to
1.2 This test method is intended to provide a basis for the
Determine the Precision of a Test Method
mechanical comparison among nonbiologic IBFD assemblies
F1582 Terminology Relating to Spinal Implants
(the IBFD and associated inserter tool). This test method is
F1839 Specification for Rigid Polyurethane Foam for Use as
intended to enable the user to compare these IBFD assemblies
a Standard Material for Testing Orthopaedic Devices and
under impact loads to simulate the intra-operative surgical
Instruments
technique used to insert the IBFD.
F2077 Test Methods for Intervertebral Body Fusion Devices
1.3 The test method describes the impact test by specifying
F2267 Test Method for Measuring Load-Induced Subsid-
impact energies and specific methods for applying these
ence of Intervertebral Body Fusion Device Under Static
energies. The tests are designed to allow for the comparative
Axial Compression
evaluation of IBFD assemblies.
F3292 Practice for Inspection of Spinal Implants Undergo-
ing Testing
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3. Terminology
standard, with the exception of angular measurements, which
may be reported in terms of either degrees or radians.
3.1 For definitions of terms, refer to terminology in Prac-
1.5 This standard does not purport to address all of the
tices E4, Terminology F1582, Specification F1839, and Prac-
safety concerns, if any, associated with its use. It is the
tice F3292.
responsibility of the user of this standard to establish appro-
3.2 Definitions of Terms Specific to This Standard:
priate safety, health, and environmental practices and deter-
3.2.1 coordinate system/axes, n—for the Insertion Between
mine the applicability of regulatory limitations prior to use.
Foam Blocks method (Annex A1), the center of the coordinate
1.6 This international standard was developed in accor-
system is located at the geometric center of the foam block
dance with internationally recognized principles on standard-
assembly. The XY plane is to bisect the sagittal plane angle
ization established in the Decision on Principles for the
across the foam blocks that are intended to simulate the
Development of International Standards, Guides and Recom-
adjacent vertebral end plates. The positive Z-axis is to be
mendations issued by the World Trade Organization Technical
directed superiorly and should be collinear with the long axis
Barriers to Trade (TBT) Committee.
of the inserter instrument and the guide rod. The compressive
intraspinal force is defined to be the component in the positive
2. Referenced Documents
X direction. Impact force is defined to be the force along the
2.1 ASTM Standards:
negative Z-axis, Fig. 1(a). For the Static Rigid Block method
(Annex A2), the XY plane is coplanar with the bottom surface
1 of the pocket that mates with the tip of the IBFD. The positive
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 Z-axis is to be directed superiorly and should be collinear with
F04.25 on Spinal Devices.
the long axis of the inserter instrument and the guide rod, Fig.
Current edition approved March 15, 2024. Published April 2024. DOI: 10.1520/
1(b).
F3631-24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.2 crack, n—an externally visible physical discontinuity
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in the form of a narrow opening that arises from mechanical
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. impact forces.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3631 − 24
FIG. 1 Coordinate System with Lateral (Left) and Frontal (Right) Views for (a) Insertion Between Foam Blocks Method (Annex A1)
Coordinate System; (b) Static Rigid Block Method (Annex A2) Coordinate System
3.2.3 drop weight, n—a 1 kg stainless steel structure (similar vertebral bodies to provide support for eventual arthrodesis of
in weight to a surgical mallet) that is dropped from the the two adjacent vertebral bodies.
appropriate height to simulate an impact hit.
3.2.9 intervertebral body fusion device (IBFD) assembly,
3.2.4 functional failure, n—permanent deformation that ren-
n—the IBFD and associated inserter instrument.
ders the intervertebral body fusion device assembly ineffective
3.2.10 intervertebral body fusion device (IBFD) leading
or unable to resist impact force and/or maintain attachment
portion, n—the distal section of the IBFD that is initially
adequately.
inserted into the disc space during surgery. This section often
3.2.5 impact energy, n—the product of the weight of the
contains an IBFD nose.
drop weight and the vertical distance it travels before touching
the specimen.
3.2.11 intervertebral body fusion device (IBFD) nose, n—a
wedge-shaped feature on the leading portion of certain IBFDs
3.2.6 impact resistance, n—the number of hits, N, and
associated impact energy step level that the intervertebral body that is intended to assist with insertion during surgery.
fusion device assembly can sustain before mechanical or
3.2.12 lip, n—a structure in the foam blocks that is defined
functional failure occurs.
at a distance from top surface of the polyurethane foam blocks
3.2.7 inserter, n—a surgical instrument used to implant the
to act as a hard stop. The hard stop allows for continued impact
IBFD in situ (within the intervertebral disc space) between the
on the device even after insertion is completed to simulate
two adjacent vertebral bodies. This instrument is attached to
impact to failure or reach a relevant number of impact hits.
the IBFD and then impacted with a mallet during the implan-
3.2.13 mechanical failure, n—that associated with the onset
tation procedure.
of a new defect in the material (for example, initiation of crack)
3.2.8 intervertebral body fusion device (IBFD), n—a struc-
or breakage.
ture that is placed in the disc space between two adjacent
F3631 − 24
3.2.14 test block, n—the component of the test apparatus for materials and methods for the comparative characterization and
mounting the intervertebral body fusion device assembly for evaluation of the intra-operative impact performance of IBFD
the intended test configuration.
assemblies.
5.3 The impact forces applied during a surgical procedure
4. Summary of Test Method
may be highly variable and, therefore, the results from these
4.1 This standard contains two options for impact testing of
tests may not directly predict in vivo performance. The results,
IBFD assemblies. The user of this test method must decide
however, can be used to compare mechanical performance of
which of these two impact tests is most appropriate to evaluate
different IBFD assemblies. The tests may also identify the
the impact resistance of the IBFD assembly in question. The
weakest, most likely to fail points in particular IBFD-inserter
user of this test method may choose to use either or both of the
combinations, thus enabling design improvements.
tests described in this test method for testing a particular
intervertebral body fusion device assembly.
5.4 Intra-operative clinical failures may be due to several
factors, some of which may not be simulated in the current
4.2 Annex A1 describes an impact test method that can be
method. For example, off-axis impact loads applied to the
used to evaluate both the insertion phase and impact resistance
IBFD assembly are not simulated in the current method yet
of the IBFD assembly. Intra-operative insertion is simulated
may contribute to intra-operative clinical failures in some
using two Grade 40 polyurethane foam (per Specification
designs. The user of this standard should consider incorporat-
F1839) test blocks with a simulated preload to represent two
ing such factors into their evaluations.
adjacent vertebral bodies. A hard stop (“lip”) is incorporated
into the polyurethane test blocks to allow for continued impact
6. Apparatus
loading until failure or completion of a 40 impact test regimen.
4.3 Annex A2 describes an impact test method that evalu-
6.1 For apparatus descriptions, see Annex A1 for the Inser-
ates the impact resistance of the IBFD assembly against a
tion Between Foam Blocks Test Method and Annex A2 for the
stainless steel block.
Static Rigid Block Test Method.
4.4 Two options for stair-step loading schemes are provided
7. Procedure
that can each be used for either method described in Annex A1
or Annex A2.
7.1 For procedures, see Annex A1 for the Insertion Between
4.5 Each of these impact test methods should be performed
Foam Blocks Test Method and Annex A2 for the Static Rigid
using an IBFD assembly with acceptable clinical performance Block Test Method.
as a comparator.
8. Report
5. Significance and Use
8.1 For reporting requirements, see Annex A1 for the
5.1 IBFDs can be single-piece or multicomponent designs
Insertion Between Foam Blocks Test Method and Annex A2
and can be porous or hollow in nature. Their function is to
for the Static Rigid Block Test Method.
support the anterior column of the spine to facilitate arthrodesis
of the motion segment.
9. Precision and Bias
5.2 Intra-operative IBFD assembly failures can result in
9.1 For precision and bias statements, see Annex A1 for the
significant clinical consequences. This test method outlines
Insertion Between Foam Blocks Test Method and Annex A2
for the Static Rigid Block Test Method.
Palepu, V., et al., “Development of an In Vitro Test Method to Simulate
Intra-operative Impaction Loading on Lumbar Intervertebral Body Fusion Devices,”
Journal of Biomechanics, Vol 121, 2021, 110412. 10. Keywords
Piple, A. S., et al., “An Analysis of a Decade of Lumbar Interbody Cage
10.1 IBFD; impact; insertion; spinal cage fracture; spinal
Failures in the United States: A MAUDE Database Study,” Spine, Vol 48, No. 23,
2023, pp. 1652–1657. implants
F3631 − 24
ANNEXES
(Mandatory Information)
A1. IMPACT TEST METHOD VIA INSERTION BETWEEN FOAM BLOCKS
A1.1 Scope for Insertion Between Foam Blocks Method attached to the horizontal gimbals. A compression load cell
attached to a digital indicator is housed rigidly in a custom
A1.1.1 The Insertion Between Foam Blocks test method can
fixture at the opposite end of the pneumatic cylinder to monitor
be used to evaluate lumbar IBFDs with parallel endplates.
the preload applied to the polyurethane foam blocks. The mass
A1.2 Apparatus
of the moving parts (horizontal gimbal and the foam block
pocket) of the preload apparatus should be 2.5 kg 6 2 % (see
A1.2.1 The test machines will conform to the requirements
X1.4 for the rationale). Any displacements or rotations of the
of Practices E4.
fixtures in any degree of freedom other than the horizontal axis
A1.2.2 Insertion Between Foam Blocks Test Apparatus—An
(X-axis) should be minimized in order to ensure uniform
example schematic of Insertion Between Foam Blocks test
preload is applied to the IBFD throughout the test. The user of
setup can be referenced in Fig. A1.1. The test apparatus
this standard may choose to use an alternative method to apply
consists of: (1) a preload apparatus which consists of a
preload to the test blocks and IBFD that achieves the same
mechanism for applying a constant axial preload on the foam
result.
test blocks and IBFD throughout testing, (2) a drop weight
A1.2.2.2 Drop Weight Apparatus—A vertical drop weight
apparatus which consists of a drop weight, a guiding rod, an
apparatus is used for applying the impact loads on the
impact platform, and a frame, (3) the test specimen which
IBFD/inserter instrument combination. A stainless steel drop
consists of an IBFD and an inserter instrument, and (4)
weight is used to apply the impact loads. The drop weight shall
polyurethane foam test blocks simulating vertebral body end-
weigh 1 6 0.02 kg and can be entirely spherical but shall at
plates.
least be spherical on the side that contacts the impact platform.
A1.2.2.1 Preload Apparatus—Two custom Grade 40 poly-
The intention behind designing a spherical drop weight is to
urethane foam blocks are rigidly mounted to metal pockets for
facilitate a consistent contact of the drop weight with the
rigid support. A constant preload is required to be transmitted
platform upon impact and minimize any errors related to
and verified across the IBFD/foam block assembly. A pneu-
applying bending moment at the implant-inserter interface
matic cylinder rigidly connected to a horizontal gimbal can be
employed for applying intraspinal preload (axial) to the poly- caused by off-axis loading. The drop weight should have a hole
through the center to sleeve onto the guiding rod. The
urethane foam blocks and implant assembly (X, 0, 0). The
metal pockets housing the polyurethane foam blocks are difference between the internal diameter of the drop weight
FIG. A1.1 Schematic of the Example Insertion Between Foam Blocks Test Apparatus
F3631 − 24
center hole and outer diameter of the guiding rod should be worst-case inserter connection should be considered that can be
0.25 mm. The drop weight travels along a guiding rod that is customized to be connected to the impact platform (for
long enough to achieve the drop heights specified and pass example, a threaded connection) or an alternate design for
through the drop weight frame with sufficient overlap. The achieving the same result. The weight of the customized
inferior end of the guiding rod can be rigidly attached to an impactor should be identical to the impactor used clinically or
impact platform made of stainless steel. The impact platform is the difference shall be justified. At the beginning of testing, the
intended to act as a stop for the drop weight and is rigidly fixed IBFD leading portion is placed between the test blocks in the
between the guiding rod and the inserter instrument. The axial preload apparatus, Fig. A1.2.
weight of the impact platform and guiding rod (if connected) A1.2.2.4 Test Blocks—Grade 40 PCF polyurethane foam
shall be recorded and provided in the test report. The impact blocks per Specification F1839 are machined to a rectangular
platform is not mandatory and direct contact with the inserter shape with a flat surface. Grade 40 polyurethane foam is
can also be considered in the apparatus. Furthermore, the guide commonly used to simulate dense bone such as that on the
rod is not required to be rigidly attached to the inserter as long vertebral endplates. The foam blocks are machined to have a
as vertical drop vector (direction and distance) is maintained. lip approximately the depth of the implant from the top of the
The top end of the guiding rod passes through a circular slotted blocks to act as a hard stop for the IBFD. The test blocks are
hole in the impact frame and is unconstrained (0, 0, Z) in the then mounted in the custom metal pocket fixture of the preload
Z-axis to allow vertical movement of the IBFD-inserter com- apparatus. This design allows the IBFD to be inserted a defined
bination upon impact loading. Furthermore, the difference in distance while maintaining a constant axial load on the IBFD.
internal diameter of the circular slotted hole and diameter of The hard stop allows for continued impact loading on the
the guiding rod should be such that sufficient stability is device even after insertion is completed to test the IBFD until
provided to the guiding rod during impact testing and the IBFD failure. Fig. A1.3 describes the foam block design in this
as well as inserter are not pre-stressed when the intraspinal load example test setup. The foam block should have a sufficient
is transmitted across the IBFD. The user of this standard may length of foam underneath the lip (hard stop) to ensure the
use an alternate design that achieves the same result. However, failure of the lip does not occur during the test. The lip
care should be taken to center the impact area of the drop thickness should be sufficient to prohibit the device from
weight with the center of the inserter to avoid off-axis impact advancing further. The user may design the setup so that the
loading. IBFD is centered along the axis of horizontal preload when it
A1.2.2.3 Test Specimen—The test specimen consists of an reaches the final insertion depth. The test setup should be
IBFD and inserter combination. The inserter should be rigidly designed such that the inserter does not interfere with the foam
attached to the inferior side of the impact platform. The inserter blocks at any point during the test. The width of the foam block
can consist of the actual IBFD inserter designed for the is designed to have at least the width of the device plus 10 mm
intended use of the implant. If this final design is not used, a on either side. The minimum thickness of each foam block
FIG. A1.2 Test Configuration
F3631 − 24
FIG. A1.3 Single Polyurethane Foam Block Design Schematic with Lateral And Frontal Views Respectively
shall be 15 mm. It is important to monitor that the two foam blocks at the beginning of the testing such that 5 mm of the
blocks are not touching each other when the intraspinal preload IBFD parallel endplates are inserted (excluding IBFD nose).
is transmitted across the foam/implant assembly, and through- This position shall be constant for all the IBFD test samples.
out the impact testing.
A1.6.3 An intraspinal preload of approximately 200 N shall
be applied to the foam blocks throughout the testing using the
A1.3 Hazards
pneumatic cylinder or other means of static compression. This
A1.3.1 The user(s) should take precautions to protect them-
force of 200 N was selected based on in vivo axial load values
selves from any potential flying debris through the use of items 5
of subjects lying in a relaxed position. The operator should
such as, but not limited to, safety goggles and protective
monitor the consistency of the spikes in intraspinal preload that
shields.
occur during impact loading to ensure that variability does not
affect the repeatability and reproducibility of the test.
A1.3.2 The user(s) should protect themselves from any
injury related to the drop weight and the preload apparatus.
A1.6.4 An inserter is to be connected to the IBFD and then
the inserter must be rigidly connected to the guiding rod on the
A1.4 Sampling
opposite end. Furthermore, the alignment of both inserter and
A1.4.1 Each pair of polyurethane foam blocks shall be used
guiding rod must be vertical with a tolerance of 63° (measured
for one specimen only.
with the angle indicator) so that the load is applied along the
vertical axis. Alternatively, the guiding rod is not required to be
A1.4.2 The test assemblies (that is, IBFD, inserter, and
rigidly attached to the inserter as long as the vertical drop
polyurethane blocks) shall be labeled, inspected (per Practice
vector (direction and distance) is maintained. Impact testing
F3292 preferentially), and maintained according to good labo-
will then be performed using a vertical drop weight apparatus.
ratory practice.
The inserter should not contact or share load with the foam
A1.4.3 All tests shall have a minimum of five test samples.
blocks at any point during the testing.
A1.5 Calibration and Standardization
A1.6.5 The drop weight (1 kg) is to be dropped on the
device from the appropriate height (distance measured from
A1.5.1 The load cell and the digital indicator to be used for
bottom edge of drop weight to the impact platform, or top of
monitoring intraspinal preload during the experiments shall be
inserter if platform is not used) that approximates the impact
calibrated.
energy based on impact velocity data. Each device will be
A1.6 Procedure
loaded according to a stair-step impact loading scheme. The
user may decide whether they use stair-step impact loading
A1.6.1 The foam blocks are to be inserted into the custom
scheme 1 (see Table A1.1) or scheme 2 (see Table A1.2).
fixture pockets so that the positions of the blocks are con-
However, the user shall use the same loading scheme for all the
strained in the Y and Z directions, and the preload constrains in
specimens of the test. The tolerance of the drop heights (shown
the X direction.
A1.6.2 The IBFDs are to be placed in between the two
prepared foam blocks. The IBFD should be positioned at the
Kienle, A., Graf, N., and Wilke, H. J., “Does Impaction of Titanium-coated
center (in axial plane view) of the foam blocks and the leading
Interbody Fusion Cages into the Disc Space Cause Wear Debris or Delamination?”
portion of the IBFD (Fig. A1.2) shall be placed into the foam The Spine Journal, Vol 16, No. 2, 2016, pp. 235–242.
F3631 − 24
TABLE A1.1 Stair-Step Impact Loading Scheme 1
steps (or 40 hits) are completed. For scheme 2 (Table A1.2), if
Calculated Calculated the implant survives one hit at a given load step, the loading
Velocity Number of
Energy Drop Height
conditions are ramped up to the next step. This pattern will
(m/s) Impacts
A
(J) (mm)
Step 1 1.4 1.0 100 4 continue until IBFD mechanical failure occurs or all the 40 hits
Step 2 2.0 2.0 200 4
are completed. The user can consider the test complete at 40
Step 3 2.4 2.9 300 4
hits in either scheme or the user can continue with additional
Step 4 2.8 3.9 400 4
Step 5 3.1 4.9 500 4
hits at the highest load level until failure.
Step 6 3.4 5.9 600 4
Step 7 3.7 6.9 700 4
A1.6.6 After each impact hit, visual inspection for mechani-
Step 8 4.0 7.8 800 4
cal failure shall be performed without moving the device from
Step 9 4.2 8.8 900 4
Step 10 4.4 9.8 1000 4
the test blocks and the test shall not be continued after
A
These drop heights were calculated based on standard specified 1 kg drop observing any mechanical failure of IBFD and/or inserter. The
weight.
user may use magnified images after a crack or other failure is
thought to be observed to verify observations and to distinguish
between failure modes. If the IBFD is undamaged after all 40
TABLE A1.2 Stair-Step Impact Loading Scheme 2
hits, inspection can be performed according to Practice F3292.
Calculated Calculated
Loading Drop Height Number of
A A
Velocity Energy
Step (mm) Impacts
A1.6.7 The impact resistance (N, number
...