ASTM F763-22

Standard Practice for Short-Term Intramuscular Screening of Implantable Medical Device Materials

SIGNIFICANCE AND USE
4.1 The use of in vivo implantation techniques for characterizing the biocompatibility of implantable materials to be utilized in various medical applications enables the assessment of such materials not achieved by other procedures. Physical characteristics (that is, form, density, hardness, surface finish) can influence the type and severity of the tissue response to the test materials.  
4.2 This practice is intended as a short-term screening procedure for determining the acceptability of candidate materials. It may be utilized prior to using the long-term tests described in Practice F981. It is recommended that for some applications, additional tests, including long-term implantation studies, may be required to assess the final suitability of the candidate materials.  
4.3 This practice may not be appropriate for all types of implant applications. The user is cautioned to consider the appropriateness of the method in view of the materials being tested, their potential applications, and the recommendations contained in Practice F748.
SCOPE
1.1 This practice provides guidelines for short-term testing or screening of candidate materials, both porous and dense, as to the local effects of the material that is implanted intramuscularly. This method may not be applicable for absorbable materials, depending on the absorption profile of the test material. The tissue reactions will be evaluated in comparison to those evoked by control materials that are accepted as clinical implant materials. This is a short-term (less than 30 days) screening procedure for determining acceptability of candidate materials.  
1.2 This practice, along with other appropriate biological tests (including other appropriate ASTM tests), may be used in the biocompatibility assessment of the candidate materials for use in the fabrication of devices for clinical application.  
1.3 This experimental protocol is not designed to provide a comprehensive assessment of the systemic toxicity, carcinogenicity, or mutagenicity of the material since other standards address these issues.  
1.4 This practice is one of several developed for the assessment of the biocompatibility of materials. Practice F748 provides guidance for the selection of appropriate methods for testing materials for a specific application.  
1.5 The values stated in SI units, including units officially accepted for use with SI, are to be regarded as standard. No other systems of measurement are included in this standard.  
1.6 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.  
1.7 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: 31-Aug-2022
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.16 - Biocompatibility Test Methods

Relations

• Refers: ASTM F603-12(2020) - Standard Specification for High-Purity Dense Aluminum Oxide for Medical Application
• Effective Date: 01-Aug-2020
• Refers: ASTM F138-19 - Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants (UNS S31673)
• Effective Date: 01-Dec-2019
• Refers: ASTM F603-12(2016) - Standard Specification for High-Purity Dense Aluminum Oxide for Medical Application
• Effective Date: 01-Oct-2016
• Refers: ASTM F748-16 - Standard Practice for Selecting Generic Biological Test Methods for Materials and Devices
• Effective Date: 01-Apr-2016
• Refers: ASTM F138-13a - Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants (UNS S31673)
• Effective Date: 01-Oct-2013
• Refers: ASTM F648-13 - Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants
• Effective Date: 01-Jul-2013
• Refers: ASTM F138-13 - Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants (UNS S31673)
• Effective Date: 01-Apr-2013
• Refers: ASTM F86-12a - Standard Practice for Surface Preparation and Marking of Metallic Surgical Implants
• Effective Date: 01-Dec-2012
• Refers: ASTM F136-12a - Standard Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant Applications (UNS R56401)
• Effective Date: 01-Dec-2012
• Refers: ASTM F136-12 - Standard Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant Applications (UNS R56401)
• Effective Date: 01-Nov-2012
• Refers: ASTM F86-12 - Standard Practice for Surface Preparation and Marking of Metallic Surgical Implants
• Effective Date: 15-May-2012
• Refers: ASTM F75-12 - Standard Specification for Cobalt-28 Chromium-6 Molybdenum Alloy Castings and Casting Alloy for Surgical Implants (UNS R30075)
• Effective Date: 15-May-2012
• Refers: ASTM F603-12 - Standard Specification for High-Purity Dense Aluminum Oxide for Medical Application
• Effective Date: 01-Jan-2012
• Refers: ASTM F136-11 - Standard Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant Applications (UNS R56401)
• Effective Date: 15-Dec-2011
• Refers: ASTM F648-10a - Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants
• Effective Date: 01-Dec-2010

Overview

ASTM F763-22, titled Standard Practice for Short-Term Intramuscular Screening of Implantable Medical Device Materials, is an internationally recognized guideline developed by ASTM International. This standard provides a practical protocol for evaluating the local biocompatibility of candidate implantable materials in vivo, specifically through short-term (less than 30 days) intramuscular implantation in laboratory animals, such as New Zealand white rabbits. It serves as a rapid screening tool to assess the acceptability of candidate materials before investing in more extensive long-term studies required for regulatory and clinical approval.

Screening for local tissue responses to implant materials is critical in the development of medical devices. ASTM F763-22 is widely used by manufacturers, researchers, and regulatory bodies to ensure that new or modified biomaterials intended for use in devices such as orthopedic implants, dental devices, or other surgical products do not elicit adverse local tissue reactions.

Key Topics

• Biocompatibility Assessment: Emphasizes the importance of in vivo testing to evaluate how candidate materials interact with muscle tissue compared to clinically accepted control materials.
• Screening Procedure: Outlines a short-term, less-than-30-days protocol that provides an early indication of tissue compatibility.
• Applicability: Covers both porous and dense materials, but may not be suitable for all absorbable or biological materials, depending on their absorption profile and specific application.
• Comparison with Controls: Requires that test materials be assessed alongside control materials known for their established biocompatibility in clinical use.
• Histopathological Evaluation: Involves gross and microscopic analyses of implant sites to determine inflammatory or adverse tissue responses.
• Limitations: Does not address systemic toxicity, carcinogenicity, or mutagenicity; focuses on local tissue response only.

Applications

ASTM F763-22 is utilized in multiple contexts within the biomedical device industry:

• Pre-Clinical Material Screening: Enables rapid identification of unsuitable candidate materials, saving time and resources before progressing to long-term or more complex in vivo studies (e.g., ASTM F981).
• Research and Development: Essential in the early phases of new implant development, including orthopedic, dental, and other medical devices where material performance in biological tissue is a concern.
• Regulatory Submissions: Assists in building a comprehensive biocompatibility profile for regulatory submissions by providing data from validated and recognized short-term in vivo studies.
• Quality Assurance: Offers a standardized approach for ongoing evaluation of new batches or modifications of implantable materials to maintain compliance and product safety.

Related Standards

Organizations working with ASTM F763-22 may also reference several related international standards to ensure a comprehensive biocompatibility assessment:

• ASTM F981 – Practice for Assessment of Compatibility of Biomaterials for Surgical Implants with Respect to Effect of Materials on Muscle and Insertion into Bone (recommended for long-term studies).
• ASTM F748 – Practice for Selecting Generic Biological Test Methods for Materials and Devices (provides guidance on choosing appropriate biocompatibility tests).
• ISO 10993-6:2016 – Biological evaluation of medical devices – Part 6: Tests for local effects after implantation (global reference for similar evaluations).
• ASTM F86, F136, F138, F648, and others – Specifications and practices for materials frequently used as controls in biomedical implantation studies.

Practical Value

By following ASTM F763-22, developers and manufacturers of implantable medical devices can:

• Implement a consistent, reliable, and internationally recognized screening method for early identification of adverse tissue responses.
• Support device safety and efficacy claims with validated data, facilitating Regulatory acceptance and market access.
• Optimize resource allocation by focusing long-term studies only on materials that have demonstrated acceptable local compatibility.

Keywords

biocompatibility, short-term implantation, implantable medical device materials, tissue compatibility, intramuscular screening, in vivo testing, orthopedic devices, ASTM standards, local tissue response, material screening, preclinical evaluation.

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: F763 − 22
Standard Practice for
Short-Term Intramuscular Screening of Implantable Medical
Device Materials
ThisstandardisissuedunderthefixeddesignationF763;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This practice provides guidelines for short-term testing
Barriers to Trade (TBT) Committee.
or screening of candidate materials, both porous and dense, as
to the local effects of the material that is implanted intramus-
2. Referenced Documents
cularly. This method may not be applicable for absorbable
2.1 ASTM Standards:
materials, depending on the absorption profile of the test
F75 Specification for Cobalt-28 Chromium-6 Molybdenum
material. The tissue reactions will be evaluated in comparison
Alloy Castings and Casting Alloy for Surgical Implants
to those evoked by control materials that are accepted as
(UNS R30075)
clinical implant materials. This is a short-term (less than 30
F86 Practice for Surface Preparation and Marking of Metal-
days) screening procedure for determining acceptability of
lic Surgical Implants
candidate materials.
F90 Specification for Wrought Cobalt-20Chromium-
1.2 This practice, along with other appropriate biological
15Tungsten-10NickelAlloy for Surgical ImplantApplica-
tests (including other appropriateASTM tests), may be used in
tions (UNS R30605)
the biocompatibility assessment of the candidate materials for
F136 Specification for Wrought Titanium-6Aluminum-
use in the fabrication of devices for clinical application.
4Vanadium ELI (Extra Low Interstitial)Alloy for Surgical
1.3 This experimental protocol is not designed to provide a
Implant Applications (UNS R56401)
comprehensive assessment of the systemic toxicity,
F138 Specification for Wrought 18Chromium-14Nickel-
carcinogenicity, or mutagenicity of the material since other
2.5Molybdenum Stainless Steel Bar andWire for Surgical
standards address these issues.
Implants (UNS S31673)
F562 Specification for Wrought 35Cobalt-35Nickel-
1.4 This practice is one of several developed for the
20Chromium-10Molybdenum Alloy for Surgical Implant
assessment of the biocompatibility of materials. Practice F748
Applications (UNS R30035)
provides guidance for the selection of appropriate methods for
F563 Specification for Wrought Cobalt-20Nickel-
testing materials for a specific application.
20Chromium-3.5Molybdenum-3.5Tungsten-5Iron Alloy
1.5 The values stated in SI units, including units officially
for Surgical Implant Applications (UNS R30563) (With-
accepted for use with SI, are to be regarded as standard. No
drawn 2005)
other systems of measurement are included in this standard.
F603 Specification for High-Purity Dense Aluminum Oxide
1.6 This standard does not purport to address all of the
for Medical Application
safety concerns, if any, associated with its use. It is the
F648 Specification for Ultra-High-Molecular-Weight Poly-
responsibility of the user of this standard to establish appro-
ethylene Powder and Fabricated Form for Surgical Im-
priate safety, health, and environmental practices and deter-
plants
mine the applicability of regulatory limitations prior to use.
F748 PracticeforSelectingGenericBiologicalTestMethods
1.7 This international standard was developed in accor-
for Materials and Devices
dance with internationally recognized principles on standard-
F981 Practice for Assessment of Compatibility of Biomate-
ization established in the Decision on Principles for the
rials for Surgical Implants with Respect to Effect of
1 2
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Surgical Materials and Devices and is the direct responsibility of Subcommittee contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
F04.16 on Biocompatibility Test Methods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Sept. 1, 2022. Published September 2022. Originally the ASTM website.
approved in 1982. Last previous edition approved in 2016 as F763 – 04 (2016). The last approved version of this historical standard is referenced on
DOI: 10.1520/F0763-22. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F763 − 22
Materials on Muscle and Insertion into Bone 5.2.3 Preparation of Rabbits—Animals should be examined
prior to surgery to assess their health status to ensure that they
2.2 ISO Standards:
arefreefromanydiseaseorcondition(forexample,infections)
ISO 10993-6:2016 Biological evaluation of medical
that may interfere with the conduct of the study and study
devices—Part 6: Tests for local effects after implantation
outcomes. On the day of the implantation or up to 20 h before
3. Summary of Practice
implantation, clip the fur of the animals on both sides of the
spinal column. Remove loose hair and scrub the area with
3.1 Under aseptic conditions, test or control material is
appropriate disinfectant prior to surgery. Appropriate anesthe-
surgically implanted into a muscle or group of muscles of the
sia and analgesia for the specific veterinary patient and
anesthetized animal.The size of the implant should not impede
continuous monitoring in the peri-anesthetic period should be
the normal movement of the animal.After a period of time, the
implemented.
animals are euthanized and subjected to a necropsy with
comprehensive histopathological assessments. The tissue reac-
5.3 Selection of Control Materials:
tions to implants of the candidate material during the subacute
5.3.1 Selection of control material(s) should be based on
to acute time periods of healing are compared with tissue
their prior acceptable use in medical applications similar to
reactions to control materials that evoke a well-characterized
those proposed for the candidate test material and is not
response. The implants are not subjected to major stress while
restricted to those listed in 5.3.2.
in situ.
5.3.2 Metallic control materials, which have been demon-
strated to elicit minimal tissue reactions, are the metal alloys,
4. Significance and Use
such as in Specifications F75, F90, F136, F138, F562,or F563,
4.1 The use of in vivo implantation techniques for charac- or a ceramic, such as alumina (Specification F603). A suitable
terizing the biocompatibility of implantable materials to be
polymeric control material is found in polyethylene (Specifi-
utilized in various medical applications enables the assessment cation F648).
of such materials not achieved by other procedures. Physical
NOTE 1—Use of positive controls are not routinely recommended for
characteristics (that is, form, density, hardness, surface finish)
implantation testing. They may be considered, for example, if there is a
can influence the type and severity of the tissue response to the
need to demonstrate the responsiveness of the test system to implantation
challenges.
test materials.
NOTE 2—A negative control is a well-characterized material with
4.2 This practice is intended as a short-term screening
minimal or no known biological responses.
procedure for determining the acceptability of candidate ma-
NOTE 3—Certain materials (for example, polymers) may elicit a greater
tissue response than the negative control material. In addition, porous
terials. It may be utilized prior to using the long-term tests
materials may not be available to be used as controls in implantation
described in Practice F981. It is recommended that for some
studies of a porous test material. In such cases, incorporation of and
applications, additional tests, including long-term implantation
comparison to a similar marketed medical device material may be
studies, may be required to assess the final suitability of the
considered, if available.
candidate materials.
5.3.3 If the appropriate control material is expected to elicit
4.3 This practice may not be appropriate for all types of
a tissue response greater than that normally observed with
implant applications. The user is cautioned to consider the
negative control polymer or the alloys cited above, samples of
appropriateness of the method in view of the materials being
these latter materials may be implanted as controls on the
tested, their potential applications, and the recommendations
surgical technique.
contained in Practice F748.
5.3.4 Implant studies should use test and control articles
with similar size and geometry to avoid confounding the
5. Test Preparation
healing response. Alternatively, reliability of the comparison
5.1 Laboratoryrabbits,rats,orotheranimalsmaybeusedas using dissimilar size and/or geometry between test and control
animal models. The following procedure is written for New articles should be justified.
Zealand White (NZW) rabbit (Oryctolagus cuniculus), a com-
6. Test Articles
monly used laboratory animal model, but the procedure can be
adapted to other appropriate animal models.
6.1 Fabrication—Each implant shall be fabricated, finished,
anditssurfacecleanedinamannerappropriateforitsprojected
5.2 Animal Model and Implantation Sites:
application in humans. Dense metal implants should be fin-
5.2.1 Choose healthy adult rabbits that weigh more than
ished in accordance with Practice F86. The size, shape, and
2.5 kgandwithparavertebralmusclesthataresufficientlylarge
surface of test and control implants shall be as similar as is
to allow for implantation of the test or control specimens.
practically possible.
5.2.2 The paravertebral muscles are the commonly used
anatomical site of implantation in NZW rabbits. In addition,
6.2 Implantsize,shape,weight,andthicknessoftestarticles
the thigh muscle of rabbits may be used for implantation of
may vary depending on the animal species and implant site.
smaller test articles. (The gluteal muscles of rats have been
Discs (8 mm diameter), rods, and wedges (≤6 mm in length)
used as test sites by some investigators.)
may be appropriate for rats or rabbits. The edges of the
4 5
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., Fish, R., Danneman, P. J., Brown, M., and Karas, A. (Eds.), Anesthesia and
4th Floor, New York, NY 10036, http://www.ansi.org. Analgesia in Laboratory Animals, Academic Press, 2011.
F763 − 22
specimens should be as smooth as possible to avoid additional muscles on one side of the spine of each rabbit, about 2.5 cm
mechanical trauma upon implantation. The test article charac- from the mid-line and parallel to the spinal column, and about
teristics (for example, size, geometry, thickness) shall be 2.5 cm apart from each other. In a similar fashion, four articles
described and justified. of the control material should be implanted in the correspond-
ing muscle on the opposite side of the spine of each animal. If
6.3 Implantation Period:
other animal models are considered, the number of implanted
6.3.1 The implantation of all test or control specimens into
articles per animal and the distance between the implanted
any one animal shall be done at the same surgical session.
articles shall be justified.
6.3.2 The time points for implantation assessments should
7.1.5 When using a sterile needle for insertion, a sterile
be justified. Implant evaluation should be performed at 7 days
stylet should be inserted into the needle to hold the test
for assessment, and 14 to 30 days to capture initial and delayed
specimen in the tissue while withdrawing the needle. With
responses to the test and control materials so that the range of
trocar implantation, the test specimen should be inserted after
healing and possible adverse tissue responses are evaluated.A
withdrawing the central point and a stylet should be used to
minimum of three animals shall be used for each study group
hold the sample while withdrawing the cannula.
at each study time point, unless otherwise justified.
7.1.6 If excessive bleeding is observed after implantation of
NOTE4—Duringthefirsttwoweeksafterimplantation,thereactiondue
a test article, a duplicate test article should be placed at another
to the surgical procedure itself may be difficult to distinguish from the
site on the test article side. The incision should be closed after
tissue reaction of the implant.
NOTE 5—Some investigators have found that extending the test to
implantation is complete, if applicable. If excessive bleeding is
include a third group of animals maintained for 90 days to achieve a
observed during or after implantation, a justification shall be
steady state can provide additional data on the short-term host responses
provi
...

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: F763 − 04 (Reapproved 2016) F763 − 22
Standard Practice for
Short-Term Intramuscular Screening of Implant Implantable
Medical Device Materials
This standard is issued under the fixed designation F763; 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 practice provides guidelines for short-term testing or screening of candidate materials, both porous and dense, as to the
local effects of the material on animal tissue in which it is implanted. that is implanted intramuscularly. This method may not be
applicable for absorbable materials, depending on the absorption profile of the test material. The tissue reactions will be evaluated
in comparison to those evoked by control materials that are accepted as clinical implant materials. This is a rapid short-term (less
than 30 days) screening procedure for determining acceptability of candidate materials.
1.2 This practice, along with other appropriate biological tests (including other appropriate ASTM tests)tests), may be used in the
biocompatibility assessment of the candidate materials for use in the fabrication of devices for clinical application.
1.3 This experimental protocol is not designed to provide a comprehensive assessment of the systemic toxicity, carcinogenicity,
teratogenicity, or mutagenicity of the material since other standards deal with address these issues.
1.4 This practice is one of several developed for the assessment of the biocompatibility of materials. Practice F748 provides
guidance for the selection of appropriate methods for testing materials for a specific application.
1.5 The values stated in SI units units, including units officially accepted for use with SI, are to be regarded as standard. No other
unitssystems of measurement are included in this standard.
1.6 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.
1.7 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:
F75 Specification for Cobalt-28 Chromium-6 Molybdenum Alloy Castings and Casting Alloy for Surgical Implants (UNS
R30075)
This practice is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee F04.16
on Biocompatibility Test Methods.
Current edition approved April 1, 2016Sept. 1, 2022. Published June 2016September 2022. Originally approved in 1982. Last previous edition approved in 20102016 as
F763 – 04 (2010).(2016). DOI: 10.1520/F0763-04R16.10.1520/F0763-22.
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
F763 − 22
F86 Practice for Surface Preparation and Marking of Metallic Surgical Implants
F90 Specification for Wrought Cobalt-20Chromium-15Tungsten-10Nickel Alloy for Surgical Implant Applications (UNS
R30605)
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)
F562 Specification for Wrought 35Cobalt-35Nickel-20Chromium-10Molybdenum Alloy for Surgical Implant Applications
(UNS R30035)
F563 Specification for Wrought Cobalt-20Nickel-20Chromium-3.5Molybdenum-3.5Tungsten-5Iron Alloy for Surgical Implant
Applications (UNS R30563) (Withdrawn 2005)
F603 Specification for High-Purity Dense Aluminum Oxide for Medical Application
F648 Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants
F748 Practice for Selecting Generic Biological Test Methods for Materials and Devices
F981 Practice for Assessment of Compatibility of Biomaterials for Surgical Implants with Respect to Effect of Materials on
Muscle and Insertion into Bone
2.2 ISO Standards:
ISO 10993-6:2016 Biological evaluation of medical devices—Part 6: Tests for local effects after implantation
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 biocompatibility assay—a comparison of the tissue response produced through the close association of the implanted
candidate material to its implant site within the host animal to that tissue response recognized and established as suitable with
control materials.
3. Summary of Practice
3.1 Under aseptic conditions, test specimens of the candidate material and of controls are inserted or control material is surgically
implanted into a muscle or group of muscles of the animal host. anesthetized animal. The size of the implant should not impede
the normal movement of the animal. After a period of time, the animals are euthanized. euthanized and subjected to a necropsy
with comprehensive histopathological assessments. The tissue reactions to implants of the candidate material during the
acutesubacute to subchronicacute time periodperiods of healing are compared with tissue reactions to control materials which have
a well characterized that evoke a well-characterized response. The implants are not subjectsubjected to major stress while in situ.
4. Significance and Use
4.1 The use of in vivo implantation techniques for characterizing the biocompatibility of implantable materials to be utilized in
various medical applications provides a unique enables the assessment of such materials not achieved by other procedures. Physical
characteristics (that is, form, density, hardness, surface finish) can influence the character type and severity of the tissue response
to the test materials.
4.2 This practice is intended as a rapidshort-term screening procedure for determining the acceptability of candidate materials. It
wouldmay be invokedutilized prior to using the long-term tests described in Practice F981. It is understoodrecommended that for
some applications, additional tests, including long-term implantation studies, may be required to assess the final suitability of the
candidate materials.
4.3 This practice may not be appropriate for all types of implant applications. The user is cautioned to consider the appropriateness
of the method in view of the materials being tested, their potential applications, and the recommendations contained in Practice
F748.
5. Test Preparation
5.1 Rabbits, Laboratory rabbits, rats, or other animals may be used as test hosts.animal models. The following procedure is written
The last approved version of this historical standard is referenced on www.astm.org.
Turner, E., Lawrence, W. H., and Autian, J., “Subacute Toxicity Testing of Biomaterials Using Histopathological Evaluation of Rabbit Muscle Tissue,” Journal of
Biomedical Materials Research, Vol 7, 1973, pp. 39–58.Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036,
http://www.ansi.org.
F763 − 22
for New Zealand white rabbits, White (NZW) rabbit (Oryctolagus cuniculus), a commonly used test host laboratory animal model,
but the procedure can be adapted with few alterations to other test hosts.appropriate animal models.
5.2 Test HostsAnimal Model and Implantation Sites:
5.2.1 Choose healthy adult rabbits that weigh more than 2.5 kg 2.5 kg and whosewith paravertebral muscles that are sufficiently
large to allow for implantation of the test or control specimens.
5.2.2 The paravertebral muscle shall serve as the test site for implants. muscles are the commonly used anatomical site of
implantation in NZW rabbits. In addition, the thigh muscle of rabbits may be used for implantation of smaller test articles. (The
gluteal muscles of rats have been used as test sites by some investigators.)
5.2.3 Preparation of Rabbits—Animals should be examined prior to surgery to assess their health status to ensure that they are
free from any disease or condition (for example, infections) that may interfere with the conduct of the study and study outcomes.
On the day of the implantation or up to 20 h before implantation, clip the fur of the animals on both sides of the spinal column.
Remove loose hair.hair and scrub the area with appropriate disinfectant prior to surgery. Appropriate anesthesia and analgesia for
the specific veterinary patient and continuous monitoring in the peri-anesthetic period should be implemented.
5.3 Selection of Control Materials:
5.3.1 Selection of control material(s) should be based on their prior acceptable use in medical applications similar to those
proposed for the candidate test material and is not restricted to those listed in 6.3.25.3.2.
5.3.2 Metallic control materials, which have been demonstrated to elicit minimal tissue reactions, are the metal alloys, such as in
Specifications F75, F90, F136, F138, F562, or F563, or a ceramic, such as,as alumina (Specification F603.). A suitable polymeric
control material is found in polyethylene Specification(Specification F648.).
NOTE 1—There are times when use of a positive control can help to clarify the character of the tissue response to the candidate test sample.Use of positive
controls are not routinely recommended for implantation testing. They may be considered, for example, if there is a need to demonstrate the
responsiveness of the test system to implantation challenges.
NOTE 2—A negative control is a well-characterized material with minimal or no known biological responses.
NOTE 3—Certain materials (for example, polymers) may elicit a greater tissue response than the negative control material. In addition, porous materials
may not be available to be used as controls in implantation studies of a porous test material. In such cases, incorporation of and comparison to a similar
marketed medical device material may be considered, if available.
5.3.3 If the most appropriate control material is expected to elicit a tissue response greater than that normally observed with
Negative Control Plasticnegative control polymer or the alloys cited above, samples of these latter materials may be implanted as
controls on the surgical technique.
5.3.4 Implant studies should use test and control articles with similar size and geometry to avoid confounding the healing response.
Alternatively, reliability of the comparison using dissimilar size and/or geometry between test and control articles should be
justified.
6. Test SpecimensArticles
6.1 Fabrication—Each implant shall be fabricated, finished, and its surface cleaned in a manner appropriate for its projected
application in humans. Dense metal implants should be finished in accordance with Practice F86. The size, shape, and surface of
test and control implants shall be as similar as is practically possible.
6.2 Implant sizes are left to the discretion of the investigator. Implants in the size range 1 by 10 mm (0.04 by 0.4 in.) to 3.2 by
12 mm (0.125 by 0.5 in.) have often been used. They may be of circular or square cross section. size, shape, weight, and thickness
of test articles may vary depending on the animal species and implant site. Discs (8 mm diameter), rods, and wedges (≤6 mm in
Fish, R., Danneman, P. J., Brown, M., and Karas, A. (Eds.), Anesthesia and Analgesia in Laboratory Animals, Academic Press, 2011.
F763 − 22
length) may be appropriate for rats or rabbits. The edges of the specimens should be as smooth as possible to avoid additional
mechanical trauma upon implantation. The test article characteristics (for example, size, geometry, thickness) shall be described
and justified.
6.3 Implantation Period:
6.3.1 The insertionimplantation of all implants test or control specimens into any one animal shall be done at the same surgical
session.
6.3.2 The time points for implantation assessments should be justified. Implant evaluation should be performed at 7 and 30 d so
that an accurate characterization of bothdays for assessment, and 14 to 30 days to capture initial and delayed responses to the test
and control materials can be made during the acute and subchronic stages of the healing tissue response. Three so that the range
of healing and possible adverse tissue responses are evaluated. A minimum of three animals shall be used for each sample period,
that is, 3 at 7 d, and 3 at 30 d.study group at each study time point, unless otherwise justified.
NOTE 4—During the first two weeks after implantation, the reaction due to the surgical procedure itself may be difficult to distinguish from the tissue
reaction of the implant.
NOTE 5—Some investigators have found that extending the test to include a third group of animals maintained for 90 d days to achieve a steady state
can provide additional data on the short-term host responseresponses to the implant material.
7. Procedure
7.1 Implantation:
7.1.1 The recommended method of implantation for delivering the test article to the implantation site is by hypodermic needle or
tube and trochar.trocar. For larger diameter samples, test articles, an incision of appropriate size will be required to permit passage
of the larger diameter tube. If this technique is not convenient, however, practical, other equivalent implantation techniques judged
appropriate may be used. These should be reported as in 9.18.1. The implantation shall be done using aseptic procedures.
7.1.2 Preparation of Test Specimens—Articles—The specimens test articles should be fabricated as described in 7.16.1 and
prepared for implantation following the procedure in either 8.1.2.17.1.2.1 or 8.1.2.27.1.2.2.
7.1.2.1 Sterilize each specimen test article as appropriate for final application and, using aseptic technique, insert it into a sterile
needle or tube; or,
7.1.2.2 Insert the specimen test article into a needle or tube, protect the ends with an appropriate cover, and sterilize the assemblies
in an appropriate manner.
NOTE 6—Allow for proper degassing if sterilizing agents such as ethylene oxide are used.
NOTE 7—If the materials to be tested are harder than the materials from which the handling instruments are made, there is the dangera risk of surface
contamination of the test specimensarticles by wearabrasion from the instruments which can affect the results (for example, ceramic test specimens
implanted with metal instruments). If such test specimens must be handled, accessory devices are needed to handle the test articles, soft textile or plastic
should be used between the implants and the instruments. Of course, care Care must be taken that none of these auxiliary protecting materials remain
to ensure that any accessories used to manipulate the test articles are not left in the implantation wound.site or surrounding tissues.
7.1.3 The animals should be anesthetized with a commonly used anesthetic agent deep enough to prevent muscular movement,
such as twitching. Properly scrub the clipped skin surface of the animal.following standard veterinary practices that are appropriate
for the animal species used for testing, to prevent muscle movement such as twitching and to follow animal welfare and use
practices.
7.1.4 Implant four specimens of the sample into the paravertebral muscleCareful incision can be made on each side of the back
through t
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