ISO 12891-3:2000
(Main)Retrieval and analysis of surgical implants — Part 3: Analysis of retrieved polymeric surgical implants
Retrieval and analysis of surgical implants — Part 3: Analysis of retrieved polymeric surgical implants
Retrait et analyse des implants chirurgicaux — Partie 3: Analyse des implants chirurgicaux en polymères retirés
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 12891-3
First edition
2000-02-15
Retrieval and analysis of surgical
implants —
Part 3:
Analysis of retrieved polymeric surgical
implants
Retrait et analyse des implants chirurgicaux —
Partie 3: Analyse des implants chirurgicaux en polymères retirés
Reference number
ISO 12891-3:2000(E)
©
ISO 2000
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ISO 12891-3:2000(E)
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ISO 12891-3:2000(E)
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references .1
3 Term and definition .1
4 Procedures for retrieval, handling and packaging.1
5 Analysis of the implant interfaces .2
5.1 Implant/tissue interface.2
5.2 Implant/implant interfaces .2
6 Analysis of the implant .2
6.1 General.2
6.2 Standard forms .2
6.3 Stage I investigation — Macroscopic examination (non-destructive).2
6.4 Stage II investigation — Microscopic examination (mostly non-destructive) .3
6.5 Stage III investigation — Material investigation (mostly destructive).3
6.6 Provisions relating to surface-treated coated implants .4
6.7 Provisions relating to biodegradable implants .5
7 Implant performance .5
Annex A (informative) Standard form for guiding the analysis of retrieved polymeric surgical implants .6
Annex B (informative) Test methods for the evaluation of polymeric materials .10
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ISO 12891-3:2000(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 12891 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 12891-3 was prepared by Technical Committee ISO/TC 150, Implants for surgery.
ISO 12891 consists of the following parts, under the general title Retrieval and analysis of surgical implants:
� Part 1: Retrieval and handling
� Part 2: Analysis of retrieved metallic surgical implants
� Part 3: Analysis of retrieved polymeric surgical implants
� Part 4: Analysis of retrieved ceramic surgical implants
Future parts will deal with other relevant aspects of surgical implant retrieval and analysis.
Annexes A and B of this part of ISO 12891 are for information only.
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ISO 12891-3:2000(E)
Introduction
The investigation of retrieved implantable surgical implants and adjacent tissues can be of diagnostic value in case
of clinical complications, can deepen the knowledge about clinical implant performance and interactions between
implants and the body, provide information on implant performance and safety, and thus further the progress of the
development of biocompatible implant materials and devices with improved functional longevity.
This International Standard, with its several parts, gives guidance on the retrieval, handling, and analysis of surgical
implants and associated biological specimens which are removed from patients routinely, during revision surgery,
post mortem or for other reasons. The aim is to provide guidance in limiting iatrogenic damage to associated
biological material which could obscure the investigation results, and in gathering data at the proper time and
circumstance to validate the study. In associated portions of the various parts of ISO 12891 protocols for the
collection of data and examinations are provided relating specific types of material in relation to their typical
applications. For particular investigation programs, additional, more specific protocols may be required. If special
analytical techniques are employed, the appropriate procedures should be specified.
This part of ISO 12891 offers guidelines for the analysis of retrieved polymeric surgical implants to limit damage to
them, to indicate typical investigation techniques, and to allow comparisons between investigation results from
different sources. These guidelines may also serve for the documentation of clinical investigations. They may be
useful as well for retrieval and analysis studies in animals. Further parts of this International Standard describe the
detailed procedures for the retrieval and handling, and analysis methods applicable to surgical implants
manufactured from other than polymeric materials.
ISO 12891-1 gives general guidelines on retrieval and handling, and applies to this and the other parts of
ISO 12891 which are related to the analysis of different categories of material. In the informative annexes B and C
of ISO 12891-1, examples are included for the collection of clinical and retrieval data. These data sets are not
repeated in the other parts of ISO 12891; they may be reduced or expanded depending on the retrieved surgical
implant, possibly attached or accompanying biological material, and the purpose of the retrieval and analysis.
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INTERNATIONAL STANDARD ISO 12891-3:2000(E)
Retrieval and analysis of surgical implants —
Part 3:
Analysis of retrieved polymeric surgical implants
1 Scope
This part of ISO 12891 provides guidance on the analyses of retrieved polymeric surgical implants. Three stages of
investigations are described that are increasingly destructive. Guidance is given on the choice of stage and type of
investigation corresponding to the type of implant and purpose of the investigation.
NOTE This part of ISO 12891 should be applied in accordance with national regulations or legal requirements regarding
the handling and analysis of retrieved implants and tissues and associated biological material.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 12891. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 12891 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 12891-1:1998, Retrieval and analysis of surgical implants — Part 1: Retrieval and handling.
ASTM D-883, Standard Terminology Relating to Plastics.
3 Term and definition
For the purposes of this part of ISO 12891, the following term and definition applies.
3.1
polymeric surgical implant
medical device consisting of polymeric material intended to be inserted into the body by surgical techniques
NOTE 1 The device is hereafter addressed as "implant".
NOTE 2 The polymeric implant may be a component of a modular or multicomponent implant.
4 Procedures for retrieval, handling and packaging
Procedures for retrieval, handling, packaging and protection of personnel involved shall be in accordance with
ISO 12891-1.
NOTE As a precautionary measure, removed implants should be sterilized by an appropriate means that does not
adversely affect the implant or the planned investigation. Corresponding descriptions are found in ISO 12891-1:1998, annex A.
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ISO 12891-3:2000(E)
5 Analysis of the implant interfaces
5.1 Implant/tissue interface
A significant portion of the information associated with a retrieved implant device is often at the device/tissue
interface. Attention should be given to a study of particles in the peri-implant tissue. Where possible, a chemical
analysis of the byproducts of degradation of the implant and a study of the cellular response to the implant shall be
considered.
Since the appearance of the tissue may vary rapidly with its distance from the implant surface, it is important that
the tissue is analysed in its context with the implant (see also relevant subclauses of ISO 12891-1:1998, such as
4.5).
5.2 Implant/implant interfaces
Due to the properties of polymers, implants made of polymers can be comparatively soft. Therefore, in cases of
concern, interfaces between polymeric components and other components and their surroundings should be
checked for wear debris.
6 Analysis of the implant
6.1 General
This clause describes the different degrees of characterization to be considered when a retrieved implant is under
investigation. The analyses of the retrieved implant are divided into three stages, with the degree of
characterization and destruction increasing from stage I through stage III. The implant characterizations may
include macroscopic and microscopic examinations, chemical composition, as well as physical and mechanical
properties.
Because of the complexity of analyses of the variety of polymeric materials that may be used for implants, and
because of the large number of potential analyses and tests suggested in this standard, the investigation is divided
into different stages. The investigations selected to be performed should depend upon the reason for removal of
the implant and possible restrictions in destructive testing. Perform a minimum number of investigations for routine
removals where the implant is not suspect; more examinations for devices suspected of impaired function, and
extensive investigations for implants removed because of their performance, behavior or malfunction.
Perform a separate analysis for each component of a device, if possible and necessary. Consider other relevant
parts of this International Standard if materials other than polymers are involved.
6.2 Standard forms
A standard form indicating the information to be recorded in each stage of investigation is given in annex A. This
form in annex A is a framework. Portions of this form that do not apply in an implant analysis can be omitted. On
the other hand, the form may be expanded and modified.
A standard form for the recording of a minimum of clinical information and of additional clinical material is provided
in annex B of ISO 12891-1:1998.
6.3 Stage I investigation — Macroscopic examination (non-destructive)
6.3.1 Identification/Photography
Markings found on the implant such as logos, article numbers, lot numbers, dimensions etc., shall be recorded (see
annex A). Where useful, photographic documentation of relevant findings should be kept.
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ISO 12891-3:2000(E)
6.3.2 Visual examination
Observe the implant surface by suitable techniques to ascertain any mode of failure, surface alteration or
destruction, if such appears.
In no event shall any surface of a failed implant be destructively evaluated at this stage.
6.3.3 Low-power optical examination
Perform an overall examination under a low-power optical stereomicroscope. Record an estimate as to the degree
of findings as suggested in annex A.
6.3.4 Further evaluation
If at the conclusion of stage I further investigation is required to clarify observations made, or to evaluate other
characteristics or the failure mode of the implant, it shall be carried out subsequently in stage II.
6.4 Stage II investigation — Microscopic examination (mostly non-destructive)
6.4.1 General
Stage II evaluation should be carried out after stage I investigation, if deemed necessary, to further evaluate or
identify the characteristics and/or failure mode of the implant. This level of investigation primarily relates to an
assessment of the modes of failure and deterioration of an implant in the most non-destructive manner possible
(see annex A).
6.4.2 Microscopic examination
Use standard light optical or scanning electron microscopic examination techniques suitable for the material under
investigation.
Normal incidence of transmission light optical microscopy or polarizing, interference, phase-contrast or other light
optical microscopic techniques may be used, when applicable to the implant.
When scanning electron microscopy is applied, special preparation techniques may be required to provide
conductivity.
6.4.3 Fractographic examination
If the implant shows a fracture or crack, analysis of the fracture surface by suitable techniques may help to
ascertain the mode of fracture. In general, destructive evaluation should be avoided. If the device has mechanically
failed, it is important to be aware that it may be classified as legal evidence.
6.5 Stage III investigation — Material investigation (mostly destructive)
6.5.1 General
If further testing is necessary to assess the properties of the implant, the tests listed under stage III in annex A shall
be carried out as deemed necessary to further characterize the implant and its history.
For information, recognized test methods are listed in annex B.
6.5.2 Material characterization
6.5.2.1 It may suffice for a given explant study to verify by simple means the type of polymer indicated by the
manufacturer. If more details are required or the nature of the polymeric material is unknown, appropriate
techniques shall be used to determine the required physical and chemical properties. Such methods as differential
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