ASTM F2789-10
(Guide)Standard Guide for Mechanical and Functional Characterization of Nucleus Devices
Standard Guide for Mechanical and Functional Characterization of Nucleus Devices
SIGNIFICANCE AND USE
Nucleus devices are generally designed to augment the mechanical function of native degenerated nucleus material or to replace tissue that has been removed during a surgical procedure. This guide outlines methods for evaluating many different types of devices. Comparisons between devices must be made cautiously and with careful analysis, taking into account the effects that design and functional differences can have on the testing configurations and overall performance, and the possibility that mechanical failure may not be related to clinical failure and inversely, that mechanical success may not be related to clinical success.
These tests are conducted in vitro to allow for analysis of the mechanical performance of the nucleus device under specific testing modalities. The loads applied may differ from the complex loading seen in vivo, and therefore the results from these tests may not directly predict in vivo performance.
These tests are used to quantify the static and dynamic properties and performance of different implant designs. The mechanical tests are conducted in vitro using simplified loads and moments. Fatigue testing in a simulated body fluid or saline may have fretting, aging, corroding, or lubricating effects on the device and thereby affect the relative performance of tested devices. Hence, the test environment and the effect of that environment, whether a simulated body fluid, normal saline bath (9 g NaCl per 1000 mL H2O), or dry, is an important characteristic of the test and must be reported accurately.
Dynamic testing methods should be designed to answer the following questions, including but not limited to: Does the device still function as intended after cycling? Does it retain adequate performance characteristics (for example, mechanical and kinematic properties such as ROM)? Did the device wear or degrade? If there is evidence of wear or degradation of the device, it should be identified and quantified with reasonable methods generally ...
SCOPE
1.1 This guide describes various forms of nucleus replacement and nucleus augmentation devices. It further outlines the types of testing that are recommended in evaluating the performance of these devices.
1.2 Biocompatibility of the materials used in a nucleus replacement device is not addressed in this guide. However, users should investigate the biocompatibility of their device separately (see X1.1).
1.3 While it is understood that expulsion and endplate fractures represent documented clinical failures, this guide does not specifically address them, although some of the factors that relate to expulsion have been included (see X1.3).
1.4 Multiple tests are described in this guide; however, the user need not use them all. It is the responsibility of the user of this guide to determine which tests are appropriate for the devices being tested and their potential application. Some tests may not be applicable for all types of devices. Moreover, some nucleus devices may not be stable in all test configurations. However, this does not necessarily mean that the test methods described are unsuitable.
1.5 The science of nucleus device design is still very young and includes technology that is changing more quickly than this guide can be modified. Therefore, the user must carefully consider the applicability of this guide to the user’s particular device; the guide may not be appropriate for every device. For example, at the time of publication, this guide does not address the nucleus replacement and nucleus augmentation devices that are designed to be partially or completely resorbable in the body. However, some of the test recommended in this guide may be applicable to evaluate such devices. It has not been demonstrated that mechanical failure of nucleus devices is related to adverse clinical results. Therefore this standard should be used with care in evaluating proposed nucleus devices.
1.6 This guide is not intende...
General Information
Relations
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: F2789 − 10
StandardGuide for
Mechanical and Functional Characterization of Nucleus
1
Devices
This standard is issued under the fixed designation F2789; 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 1.6 Thisguideisnotintendedtobeaperformancestandard.
It is the responsibility of the user of this guide to characterize
1.1 This guide describes various forms of nucleus replace-
the safety and effectiveness of the nucleus device under
ment and nucleus augmentation devices. It further outlines the
evaluation.
types of testing that are recommended in evaluating the
performance of these devices. 1.7 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.2 Biocompatibility of the materials used in a nucleus
standard. Angular measurements may be reported in either
replacement device is not addressed in this guide. However,
degrees or radians.
users should investigate the biocompatibility of their device
separately (see X1.1). 1.8 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.3 While it is understood that expulsion and endplate
responsibility of the user of this standard to establish appro-
fractures represent documented clinical failures, this guide
priate safety and health practices and determine the applica-
does not specifically address them, although some of the
bility of regulatory limitations prior to use.
factors that relate to expulsion have been included (see X1.3).
1.4 Multiple tests are described in this guide; however, the
2. Referenced Documents
userneednotusethemall.Itistheresponsibilityoftheuserof
2
2.1 ASTM Standards:
this guide to determine which tests are appropriate for the
D2990Test Methods forTensile, Compressive, and Flexural
devices being tested and their potential application. Some tests
Creep and Creep-Rupture of Plastics
maynotbeapplicableforalltypesofdevices.Moreover,some
D6204Test Method for Rubber—Measurement of Unvulca-
nucleus devices may not be stable in all test configurations.
nized Rheological Properties Using Rotorless Shear Rhe-
However, this does not necessarily mean that the test methods
ometers
described are unsuitable.
E6Terminology Relating to Methods of MechanicalTesting
1.5 The science of nucleus device design is still very young
E111Test Method for Young’s Modulus, Tangent Modulus,
and includes technology that is changing more quickly than
and Chord Modulus
this guide can be modified. Therefore, the user must carefully
E132TestMethodforPoisson’sRatioatRoomTemperature
consider the applicability of this guide to the user’s particular
E328Test Methods for Stress Relaxation for Materials and
device; the guide may not be appropriate for every device. For
Structures
example,atthetimeofpublication,thisguidedoesnotaddress
E1823TerminologyRelatingtoFatigueandFractureTesting
thenucleusreplacementandnucleusaugmentationdevicesthat
F561 Practice for Retrieval and Analysis of Medical
are designed to be partially or completely resorbable in the
Devices, and Associated Tissues and Fluids
body. However, some of the test recommended in this guide
F1582Terminology Relating to Spinal Implants
may be applicable to evaluate such devices. It has not been
F1714GuideforGravimetricWearAssessmentofProsthetic
demonstrated that mechanical failure of nucleus devices is
Hip Designs in Simulator Devices
related to adverse clinical results. Therefore this standard
F1877Practice for Characterization of Particles
should be used with care in evaluating proposed nucleus
F1980Guide for Accelerated Aging of Sterile Barrier Sys-
devices.
tems for Medical Devices
F2267TestMethodforMeasuringLoadInducedSubsidence
1
ThistestmethodisunderthejurisdictionofASTMCommitteeF04onMedical
2
andSurgicalMaterialsandDevicesandisthedirectresponsibilityofSubcommittee For referenced ASTM standards, visit the ASTM website, www.astm.org, or
F04.25 on Spinal Devices. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved June 1, 2010. Published July 2010. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F2789–10. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
F2789 − 10
of Intervertebral Body Fusion Device Under Static Axial 3.2.5 fatigue life, n—The number of cycles, N, that the
Compression nucleus device can sustain at a particular load or moment
F2
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.