ASTM F2193-20

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: F2193 − 18a F2193 − 20
Standard Specifications and Test Methods for
Components Used in the Surgical Fixation of the Spinal
Skeletal System
This standard is issued under the fixed designation F2193; 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 These specifications and test methods are intended to provide a comprehensive reference for the components of systems
used in the surgical fixation of the spinal skeletal system. The document catalogs standard specifications that specify material,
labeling, and handling requirements. The specifications and test methods also establish common terminology that can be used to
describe the size and other physical characteristics of spinal components and performance definitions related to the performance
of spinal components. Additionally, the specifications and test methods establish performance requirements and standard test
methods to consistently measure performance-related mechanical characteristics of spinal components.
1.2 These specifications and test methods are part of a series of standards addressing systems used in the surgical fixation of
the spinal skeletal system. These specifications and test methods concentrate on the individual components, which are found in
many spinal fixation systems. If the user is interested in evaluating the next level in the spinal fixation system chain, the
interconnections between individual components and subassemblies (two or more components), the user should consult Guide
F1798. At the highest level in this chain is Test Methods F1717, which is used to evaluate an entire construct assembled from many
components and involves numerous interconnections and several subassemblies.
1.3 It is not the intention of these specifications and test methods to define levels of performance or case-specific clinical
performance for spinal components addressed by this document. Insufficient knowledge to predict the consequences of using any
of these components in individual patients for specific activities of daily living is available. Furthermore, it is not the intention of
this document to describe or specify specific designs for the individual components of systems used in the surgical internal fixation
of the spinal skeletal system.
1.4 These specifications and test methods may not be appropriate for all types of spinal surgical fixation systems. The user is
cautioned to consider the appropriateness of this document in view of the particular implant system and its potential application.
1.5 This document includes the following specifications and test methods that are used in determining the spinal component’s
mechanical performance characteristics:
1.5.1 Specification for Metallic Spinal Screws—Annex A1.
1.5.2 Specification for Metallic Spinal Plates—Annex A2.
1.5.3 Specification for Metallic Spinal Rods—Annex A3.
1.5.4 Test Method for Measuring the Static and Fatigue Bending Strength of Metallic Spinal Screws—Annex A4.
1.6 Unless otherwise indicated, the values stated in SI units shall be regarded as the standard.
1.7 This standard may involve hazardous materials, operations, and 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.
These specifications and test methods are under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and are the direct responsibility
of Subcommittee F04.25 on Spinal Devices.
Current edition approved April 1, 2018Feb. 1, 2020. Published May 2018April 2020. Originally approved in 2002. Last previous edition approved in 2018 as
F2193 – 18.F2193 – 18a. DOI: 10.1520/F2193-18A.10.1520/F2193-20.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2193 − 20
2. Referenced Documents
2.1 ASTM Standards: General
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
E467 Practice for Verification of Constant Amplitude Dynamic Forces in an Axial Fatigue Testing System
E1823 Terminology Relating to Fatigue and Fracture Testing
E1942 Guide for Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics Testing
F382 Specification and Test Method for Metallic Bone Plates
F543 Specification and Test Methods for Metallic Medical Bone Screws
F565 Practice for Care and Handling of Orthopedic Implants and Instruments
F983 Practice for Permanent Marking of Orthopaedic Implant Components
F1582 Terminology Relating to Spinal Implants
F1717 Test Methods for Spinal Implant Constructs in a Vertebrectomy Model
F1798 Test Method for Evaluating the Static and Fatigue Properties of Interconnection Mechanisms and Subassemblies Used
in Spinal Arthrodesis Implants
F1839 Specification for Rigid Polyurethane Foam for Use as a Standard Material for Testing Orthopaedic Devices and
Instruments
F2503 Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment
F2943 Guide for Presentation of End User Labeling Information for Musculoskeletal Implants
2.2 ASTM Standards: Materials
D4020 Specification for Ultra-High-Molecular-Weight Polyethylene Molding and Extrusion Materials
F67 Specification for Unalloyed Titanium, for Surgical Implant Applications (UNS R50250, UNS R50400, UNS R50550, UNS
R50700)
F136 Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant
Applications (UNS R56401)
F138 Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants
(UNS S31673)
F648 Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants
F1295 Specification for Wrought Titanium-6Aluminum-7Niobium Alloy for Surgical Implant Applications (UNS R56700)
F1314 Specification for Wrought Nitrogen Strengthened 22 Chromium–13 Nickel–5 Manganese–2.5 Molybdenum Stainless
Steel Alloy Bar and Wire for Surgical Implants (UNS S20910)
F1472 Specification for Wrought Titanium-6Aluminum-4Vanadium Alloy for Surgical Implant Applications (UNS R56400)
2.3 ISO Standards:
ISO 14630 Non-active Surgical Implants—General Requirements
3. Terminology
3.1 Unless otherwise defined in these specifications and test methods, the terminology used in this document that is related to
spinal implants will be in accordance with the definitions of Specification F382, Specification F543, and Terminology F1582.
3.2 Unless otherwise defined in these specifications and test methods, the terminology related to mechanical testing that is used
in this document will be in accordance with the definitions of Terminology E6, Terminology E1823, Specification F382,
Terminology F1582, Test Methods F1717, and Guide F1798.
3.3 Terminology—General:
3.3.1 expansion head screw, n—threaded anchor that is designed so that the head can be elastically deformed, through
mechanical means, to establish an interconnection with another spinal construct element.
3.3.2 locking screw, n—threaded anchor that is rigidly connected to the longitudinal element of the spinal construct.
3.3.3 self-locking screw, n—threaded anchor design that undergoes a deformation process at the end of the insertion process
which results in the screw’s locking to the mating spinal construct element.
3.3.4 shaft screw, n—threaded anchor having an unthreaded shank equal to its thread diameter.
3.4 Terminology—Geometric:
3.4.1 rod diameter (mm), n—length in mm of a chord passing through the center of the rod’s cross-section.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), 1 rue de Varembe, Case postale 56, CH-1211, Geneva 20, Switzerland.
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3.4.2 rod length (mm), n—overall dimension measured in mm between the ends of a given rod.
3.5 Terminology—Mechanical/Structural:
3.5.1 0.2 % offset displacement (mm), n—permanent displacement equal to 0.002 times the test gage section length for the
specific test, in mm. The test gage section length is equal to the bending moment arm for spinal screw tests. The test gage section
length is equal to the center span distance for spinal plate and rod tests where the loading rollers are directly contacting the test
specimen (Fig. A2.1 and Fig. A3.1). The test gage section length is equal to the unsupported distance between the ends of the
extension segments for spinal plate and rod tests where extension segments are used to load the test sample (Fig. A2.2). (distance
0B in Fig. A4.1).
3.5.2 axial pull-out load (N), n—tensile force in N required to fail or remove a screw from a material into which the screw has
been inserted when tested in accordance with Specification and Test Methods F543, Annex A3.
3.5.3 bending fatigue runout moment (N·m), n—value in N-m of the maximum moment that can be applied to a spinal
component where all of the tested samples have experienced 2 500 000 loading cycles without a failure at a specific R-ratio.
3.5.4 bending moment arm, L (mm), n—distance in mm between the point where the test sample is gripped (typically the axis
of the longitudinal element) and the line-of-action for the applied force prior to any deformation of of the assembly. (See dimension
L of Fig. A4.2).
3.5.5 bending stiffness, S (N/mm), n—slope in N/mm of the initial linear elastic portion of the load versus total displacement
curve (slope of line 0m in Fig. A4.1).
3.5.6 bending ultimate moment (N·m), n—maximum bending moment in N-m that can be applied to a test sample. This would
correspond to the bending moment at Point E in Fig. A4.1.
3.5.7 bending yield moment (N·m), n— bending moment in N-m necessary to produce a 0.2 % offset displacement in the spinal
component. If the specimen fractures before the test reaches the 0.2 % offset displacement point, the bending yield moment shall
be defined as the bending moment at fracture (point D in Fig. A4.1).
3.5.8 exposed length (mm), n—linear distance measured in mm between the surface of the test block that the screw is embedded
in during the test and the location where the screw is anchored (typically the axis of the longitudinal element) in the test fixture
(see Fig. A4.2).
3.5.9 gross failure, n—permanent displacement resulting from fracture or plastic deformation in excess of the yield
displacement that renders the spinal component ineffective in fulfilling its intended function.
3.5.10 insertion depth (mm), n—linear advancement in mm of the screw into the test block measured relative to its seated
position at the test block’s surface prior to testing.
3.5.11 median bending fatigue moment at N cycles (N·m), n—value in N-m of the maximum moment that can be applied to a
spinal component for which 50 % of the test specimens of a given sample can be expected to survive N loading cycles at a specific
R-ratio.
3.5.12 permanent displacement (mm), n—total displacement in mm remaining after the applied load has been removed from the
test specimen.
3.5.13 torsion yield moment (N·m), n— applied torque in N-m at which the screw reaches its proportional limit when tested in
accordance with Specification and Test Methods F543, Annex A1. The value is determined by using an offset method with a 2°
angular offset.
3.5.14 total displacement (mm), n—distance in mm, in the direction of the applied load, which the load application point has
moved relative to the zero load intercept of the initial linear segment of the load versus displacement curve (point 0 in Fig. A4.1).
3.5.15 yield displacement (mm), n—total displacement in mm associated with the bending yield strength (distance 0A in Fig.
A4.1).
4. Significance and Use
4.1 Spinal implant constructs are typically a compilation of several components. Screws, plates, and rods are integral
components of many spinal implant constructs. These components are designed to transfer load between the bone and the
longitudinal or transverse element, or both. These specifications and test methods identify specifications for such components and
define standard equivalent test methods that can be used when evaluating different related component designs.
4.2 Since the loading of spinal components in-vivo may differ from the loading configurations addressed in these specifications
and test methods, the results obtained from this document may not predict in-vivo performance of either the components or the
construct as a whole. Such tests can, however, be used to compare different component designs in terms of relevant mechanical
performance characteristics.
4.3 The performance-related mechanical characteristics determined by these specifications and test methods will supply the user
with information that may be used to predict the mechanical performance of different design variations of similar (function and
indication) spinal construct components.
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5. Requirements
5.1 The following spinal components shall conform to the requirements of the listed standard specification:
5.1.1 Screws—Standard Specification for Metallic Spinal Screws (see Annex A1).
5.1.2 Plates—Standard Specification for Metallic Spinal Plates (see Annex A2).
5.1.3 Rods—Standard Specification for Metallic Spinal Rods (see Annex A3).
6. Marking, Packaging, Labeling, and Handling
6.1 Mark spinal components using the methods specified in Practice F983.
6.2 Markings on spinal components shall identify the manufacturer or distributor. When size permits, the following information
should be legibly marked on the spinal component (items listed in order of preference):
6.2.1 Manufacturer’s name or logo,
6.2.2 Material and, when applicable, the ASTM designation,
6.2.3 Catalog number,
6.2.4 Manufacturing lot number, and
6.2.5 If the component is manufactured according to an ASTM specification, the ASTM designation.
6.3 Packaging shall be adequate to protect the spinal component during shipment.
6.4 Package labeling for spinal components shall include the following information:
6.4.1 Manufacturer and product name,
6.4.2 Catalog number,
6.4.3 Lot or serial number,
6.4.4 Material and, when applicable, the ASTM designation for the material, and
6.4.5 The sterility condition of the packaged spinal component.
6.5 Package labeling may elect to follow guidance in Guide F2943 for package label presentation.
6.6 Product labeling may include marking for safety in the Magnetic Resonance Environment in accordance with Practice
F2503.
6.7 Spinal components shall be cared for and handled according to the requirements specified in Practice F565.
7. Materials
7.1 The manufacturer is responsible for ensuring that materials used to manufacture spinal components are suitable for
implanting into the body. Material suitability can be verified with the methods described in ISO 14630.
7.2 The manufacturer should also consider the materials of other spinal components within the spinal implant construct when
selecting a material. Avoid the mixing of materials within a spinal implant construct in order to prevent the development of
undesirable corrosion conditions.
7.3 All spinal components that are made of materials that have an ASTM standard designation shall meet those requirements
given in the ASTM standards. The following is a list of some materials that have been used for spinal components:
7.3.1 Unalloyed Titanium (see Specification F67).
7.3.2 Wrought Titanium–6Aluminum–4Vanadium ELI (Extra Low Interstitial) Alloy (see Specification F136).
7.3.3 Stainless Steel Bar and Wire (see Specification F138).
7.3.4 Wrought Titanium–6Aluminum–7Niobium Alloy (see Specification F1295).
7.3.5 Wrought Nitrogen Strengthened – 22Chromium–12.5Nickel–5Manganese–2.5Molybdenum Stainless Steel Bar and Wire
(see Specification F1314).
7.3.6 Wrought Titanium Ti-6Al-4V Alloy (see Specification F1472).
8. Keywords
8.1 bend testing–plate; bend testing–rod; bend testing–screw; bend testing–surgical implants; fatigue test–plate; fatigue
test–rod; fatigue test–screw; fatigue test–surgical implants; orthopedic medical device–plate; orthopedic medical device–rod;
orthopedic medical device–screw; orthopedic spinal devices; performance; spinal arthrodesis; surgical devices; terminology; test
methods–surgical implants
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ANNEXES
(Mandatory Information)
A1. SPECIFICATION FOR METALLIC SPINAL SCREWS
A1.1 Scope
A1.1.1 This specification describes metallic spinal screws that are used as anchor elements in spinal arthrodesis implants for the
surgical fixation of the skeletal spinal system.
A1.2 Classification
A1.2.1 Classify spinal screws according to the classification methods identified in Specification F543.
A1.2.2 Spinal screws can also be classified with regard to the screw’s interconnecting capabilities with other spinal fixation system
components such as expansion head, locking, and self-locking.
A1.3 Marking, Packaging, Labeling, and Handling
A1.3.1 Dimensions of spinal screws shall follow the nomenclature established in Section 3.
A1.3.2 In addition to the requirements of Section 6, add the screw diameter on the spinal screw labeling (when size permits).
A1.3.3 In addition to the packaging information contained in Section 6, include the screw diameter and screw length.
A1.4 Materials
A1.4.1 Select spinal screw materials in accordance with the requirements and recommendations of Section 7.
A1.5 General Requirements, Performance Considerations, and Test Methods
A1.5.1 Drive Connection—Suggested drive recesses for spinal screws can be found in Specification F543, Annex A6.
A1.5.2 Torsion Properties—Determine the screw’s torsion strength characteristics (torsional yield moment, maximum torque, and
breaking angle) using the test method of Specification F543. Annex A1.
A1.5.3 Driving Torque Requirements—Determine the driving torque requirements (insertion and removal torque) for self-tapping
and self-drilling spinal screws according to the test method found in Specification F543, Annex A2 with the following conditional
requirements:
A1.5.3.1 Manufacture the test blocks from Grade 20, Specification F1839 rigid polyurethane foam whose length is no less than
the insertion depth of the test being conducted.
A1.5.3.2 Conduct the driving torque tests at a motor speed of 30 r/min.
A1.5.3.3 Specific Screw Performance Tests—Measure the driving torque of the longest length spinal screw of a given design until
the insertion depth is equal to the screw’s thread length.
A1.5.3.4 Comparative Screw Performance Tests—Measure the driving torque until an insertion depth is reached that is equal to
the shortest maximum screw thread length possible for the screw designs being compared.
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A1.5.4 Axial Pull-Out Load—Determine the screw’s axial pull-out load using the standard test method of Specification F543,
Annex A3 with the following conditional requirements:
A1.5.4.1 Manufacture the test blocks from Grade 20, Specification F1839 rigid polyurethane foam.
A1.5.4.2 Insert each screw into the test block at a motor speed of 30 r/min.
A1.5.4.3 Specific Screw Performance Tests—Insert the shortest spinal screw of a given design until the insertion depth is equal
to the screw’s thread length.
A1.5.4.4 Comparative Screw Performance Tests—Insert each spinal screw until an insertion depth is reached that is equal to the
shortest maximum screw thread length possible for the screw designs being compared.
A1.5.5 Bending Properties—Determine the screw’s bending structural stiffness, bending yield moment, bending ultimate moment,
bending fatigue runout moment, and when applicable, the median fatigue bending moment at 2 500 000 cycles using the test
methods described in Annex A4.
A2. SPECIFICATION FOR METALLIC SPINAL PLATES
A2.1 Scope
A2.1.1 This specification describes metallic spinal plates that are used as longitudinal elements in spinal arthrodesis implants for
the surgical fixation of the skeletal spinal system.
A2.2 Classification
A2.2.1 Plates intended for spinal applications can be classified with regard to the following characteristics:
A2.2.2 Preferred Anatomic Location—The spinal region where the plate is indicated (such as cervical, thoracic, lumbar, and
sacral) and position (anterior versus posterior).
A2.2.3 Preferred Use Limited to Specific Procedures—The type of surgical procedure where the plate is indicated (such as
reconstruction, trauma, deformity, degenerative).
A2.3 Marking, Packaging, Labeling, and Handling
A2.3.1 Dimensions of bone plates shall follow the nomenclature established in Section 3.
A2.3.2 In addition to the requirements of Section 6, include the plate length on spinal plate labeling.
A2.4 Materials
A2.4.1 Select spinal plate materials in accordance with the requirements and recommendations of Section 7.
A2.5 Performance Considerations and Test Methods
A2.5.1 Determine the spinal plate’s bending structural stiffness, bending yield moment, bending ultimate moment, bending fatigue
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runout moment, and, when applicable, the median bending fatigue moment at 2 500 000 cycles using the methods of Specification
F382 and in accordance with the following requirements.
A2.5.2 Configure the four-point bending test fixtures so that the loading rollers (inner rollers that are located dimension “a” apart)
are positioned in accordance with the requirements of Table A2.1 (see also Fig. A2.1).
A2.5.3 Position the test fixture support rollers (outer rollers that are located dimension “h” from the nearest loading roller) far
enough away from the loading rollers so that the test article is free to respond to the applied bending moment (see Fig. A2.1). Under
ideal conditions, position the support rollers in accordance with the recommended dimensions of Table A2.1. The dimension “h”
may be reduced to a/2 in order to accomodate testing of shorter plates, but this condition must be documented in the final report.
A2.5.4 Maintain the test fixture configuration consistent for comparative tests.
A2.5.5 Only unused and untested specimens shall be included in the sample for a given spinal plate design. Include only final form
and finished components in the sample.
Static Tests
A2.5.6 The sample size used for static tests shall be determined according to the methods defined in Practice E122 for any given
loading condition. If insufficient information is available to determine a suitable sample size with Practice E122, use a minimum
sample size of five.
A2.5.7 Load the test specimen during static tests at a displacement rate not to exceed 10 mm/min.
Fatigue Tests
A2.5.8 Test at least two specimens at each of three different maximum moment levels. One of the three maximum moment levels
shall satisfy the maximum runout moment condition. Several references have been compiled that can provide the user with
guidance and recommendations for selecting suitable sample sizes for fatigue studies used to develop an M-N diagram. (1 and 2)
A2.5.9 Conduct the recommended fatigue test in a laboratory air environment at room temperature. Other test environments
(simulated body fluid, 9-g NaCl per 1000 mL water saline, a saline drip, or water) may be used while testing, but the suitability
of using the respective test environment must be justified, given the accelerated nature of the laboratory fatigue test. If an
alternative test environment is used, record all pertinent parameters related to the environmental conditions (temperature, pH,
solution strengths, and so forth) before, during, and after the test.
A2.5.10 Apply sinusoidal cyclic loads in load control at an R ratio of 0.10 for testing of devices intended for either the lumbar
and thoracic spine regions. Apply sinusoidal cyclic loads in load control at an R ratio of -1.0–1.0 for testing of devices intended
for the cervical spine region. Fig. A2.2 illustrates a test setup for spinal plates that is capable of applying fully reversed loads (R
= -1).–1). Other R ratios may be used but must be documented in the report.
A2.5.11 The user shall determine the frequency at which to conduct the fatigue test, but the maximum frequency of cyclic loading
shall be 30 Hz.
TABLE A2.1
Spinal Location h (mm) a (mm)
Cervical 35.00 35.00
Thoracic and Lumbar 76.00 76.00
The boldface numbers in parentheses refer to the list of references at the end of this standard.
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FIG. A2.1 Spinal Plate Test Configuration
FIG. A2.2 Spinal Plate Test Configuration, R = -1–1 Loading
A2.5.12 The user of this test method should select the necessary fatigue moment levels to establish the endurance limit of the
metallic spinal plate and develop a curve of cyclical moment versus the number of cycles to failure. This trend shall be comprised
of at least six data points. One maximum moment level should have specimens that do not fail before 2 500 000 cycles. Initial
fatigue loading conditions may be determined primarily by the user’s experience. In the absence of such experience, initial fatigue
moments corresponding to 75, 50, and/or 25 % of the yield moment as determined in the static test may serve as a starting point
for establishing the fatigue characteristics. The precision of the endurance limit shall be established by ensuring that the lowest
moment that results in a failed construct is not greater than 1.25× the highest established run-out moment. For example, if the
highest established run-out moment is 2.0 Nm then the lowest moment that results in a failed construct shall not be greater than
2.5 Nm. A regression analysis shall be conducted on the moment versus number of cycles to failure data.
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A3. SPECIFICATION FOR METALLIC SPINAL RODS
A3.1 Scope
A3.1.1 This specification describes spinal rods that are used as longitudinal elements in spinal arthrodesis implants for the surgical
fixation of the skeletal spinal system.
A3.2 Classification
A3.2.1 Spinal rods indicated for spinal applications can be classified with regard to the following characteristics:
A3.2.2 Preferred Anatomic Location—The spinal region where the rod is indicated (such as cervical, thoracic, lumbar, and sacral)
and position (anterior versus posterior).
A3.2.3 Preferred Use Limited to Specific Procedures—The type of surgical procedure where the rod is indicated (such as
reconstruction, trauma, deformity, degenerative).
A3.3 Marking, Packaging, Labeling, and Handling
A3.3.1 Dimensions of spinal rods shall follow the nomenclature established in Section 3.
A3.3.2 In addition to the requirements of Section 6, include the rod diameter and rod length on spinal rod labeling.
A3.4 Materials
A3.4.1 Select spinal rod materials in accordance with the requirements and recommendations of Section 7.
A3.5 Performance Considerations and Test Methods
A3.5.1 Determine the spinal rod’s bending structural stiffness, bending yield moment, bending ultimate moment, bending fatigue
runout moment, and when applicable, the median bending fatigue moment at 2 500 000 cycles using the methods of Specification
F382 and in accordance with the following requirements.
A3.5.2 Fit the test fixture with 90° “V” alignment notched rollers. This roller profile will allow the testing of a range of rod sizes
with a single roller set. Such rollers will also prevent the application of the load at the most highly stressed point on the
circumference of the rod.
A3.5.3 Configure the four-point bending test fixtures so that the loading rollers (inner rollers that are located dimension “a” apart)
are positioned in accordance with the requirements of Table A2.1 (see also Fig. A3.1).
A3.5.4 Position the test fixture support rollers (outer rollers that are located dimension “h” from the nearest loading roller) in
accordance with the recommended dimensions of Table A2.1.
A3.5.5 Maintain the test fixture configuration consistent for comparative tests.
A3.5.6 Only unused and untested specimens shall be included in the sample for a given spinal plate design. Include only final form
and finished components in the sample.
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FIG. A3.1 Spinal Rod Test Configuration
Static Test Method
A3.5.7 The sample size used for static tests shall be determined according to the methods defined in Practice E122 for any given
loading condition. If insufficient information is available to determine a suitable sample size with Practice E122, use a minimum
sample size of five.
A3.5.8 Load the test specimen during static tests at a displacement rate not exceeding 10 mm/min.
Fatigue Test Method
A3.5.9 For fatigue studies, test at least two specimens at each of three different maximum moment levels. One of the three
maximum moment levels shall satisfy the maximum runout moment condition. Several references have be compiled that can
provide the user with guidance and recommendations for selecting suitable sample sizes for fatigue studies used to develop an M-N
diagram. (1 and 2)
A3.5.10 Conduct the recommended fatigue test in a laboratory air environment at room temperature. Other test environments
(simulated body fluid, 9-g NaCl per 1000 mL water saline, a saline drip, or water) may be used while testing, but the suitability
of using the respective test environment must be justified, given the accelerated nature of the laboratory fatigue test. If an
alternative test environment is used, record all pertinent parameters related to the environmental conditions (temperature, pH,
solution strengths, and so forth) before, during, and after the test.
A3.5.11 Apply sinusoidal cyclic loads in load control at an R ratio of 0.10 for testing of devices intended for either the lumbar
and thoracic spine regions.
...