1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18192-1:2011Implants for surgery Wear oftotal intervertebral spinal discprosthesesPart 1: Loading and displacementparameters for wear testing andcorresponding environmenta
2、l conditions fortestBS ISO 18192-1:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18192-1:2011.It supersedes BS ISO 18192-1:2008 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CH/150/5, Surgical Implants - O
3、steosynthesis and spinaldevices.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 72706 1ICS
4、 11.040.40Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 March 2011.Amendments issued since publicationDate Text affectedBS ISO 18192-1:2011Reference numberISO
5、 18192-1:2011(E)ISO 2011INTERNATIONAL STANDARD ISO18192-1Second edition2011-03-01Implants for surgery Wear of total intervertebral spinal disc prostheses Part 1: Loading and displacement parameters for wear testing and corresponding environmental conditions for test Implants chirurgicaux Usure des p
6、rothses totales de remplacement des disques intervertbraux lombaires Partie 1: Paramtres de charge et de dplacement pour essais dusure et conditions environnementales correspondantes BS ISO 18192-1:2011ISO 18192-1:2011(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance wit
7、h Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing p
8、olicy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Ever
9、y care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specifie
10、d, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case
11、postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedBS ISO 18192-1:2011ISO 18192-1:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv 1 Scope1 2 Normative references1
12、3 Terms and definitions .1 4 Principle .2 5 Reagents and materials 3 5.1 Fluid test medium3 5.2 Test and control specimen.3 6 Apparatus.4 7 Procedure.8 8 Test report9 9 Disposal of test specimen 10 Annex A (informative) Statement of rationale for test methods.11 Annex B (informative) Load and displa
13、cement data for cervical implants .12 Annex C (informative) Load and displacement data for lumbar implants 13 Annex D (informative) Alternative loading conditions 14 Bibliography25 BS ISO 18192-1:2011ISO 18192-1:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization for
14、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 r
15、ight 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. Internation
16、al Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as
17、 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 document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. IS
18、O 18192-1 was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee SC 5, Osteosynthesis and spinal devices. This second edition cancels and replaces the first edition (ISO 18192-1:2008), of which it constitutes a minor revision. The main modifications are the introduction o
19、f the term “cycle limit” (an explicit statement that a different cycle limit can be used with appropriate justification) and the change of the required concentration of calf serum in the fluid test medium to 20 g protein/l. ISO 18192 consists of the following parts, under the general title Implants
20、for surgery Wear of total intervertebral spinal disc prostheses: Part 1: Loading and displacement parameters for wear testing and corresponding environmental conditions for test Part 2: Nucleus replacements BS ISO 18192-1:2011INTERNATIONAL STANDARD ISO 18192-1:2011(E) ISO 2011 All rights reserved 1I
21、mplants for surgery Wear of total intervertebral spinal disc prostheses Part 1: Loading and displacement parameters for wear testing and corresponding environmental conditions for test 1 Scope This part of ISO 18192 defines a test procedure for the relative angular movement between articulating comp
22、onents, and specifies the pattern of the applied force, speed and duration of testing, sample configuration and test environment for use for the wear testing of total intervertebral spinal disc prostheses. Both lumbar and cervical prostheses are addressed. This part of ISO 18192 is not applicabe to
23、partial disc replacements, such as nucleus replacements or facet joint replacements. The test method focuses on wear testing. Additional mechanical tests, such as fatigue testing, can be required. This part of ISO 18192 does not reproduce the complex in vivo loads and motions. The wear data obtained
24、 with this test method enables comparison between different types of implants, but can differ from the clinical wear performance. The user of this part of ISO 18192 can consider running additional wear tests addressing specific safety issues of the individual implant design under test. 2 Normative r
25、eferences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 14242-2, Implants for surgery Wear
26、of total hip-joint prostheses Part 2: Methods of measurement 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 axial rotation angular movement in the transverse plane around the Z-axis See Figure 1 c). 3.2 flexion/extension angular movement in
27、the sagittal plane around the Y-axis See Figure 1 a). BS ISO 18192-1:2011ISO 18192-1:2011(E) 2 ISO 2011 All rights reserved3.3 functional failure failure that renders the implant unable to resist the load and/or move as initially intended by the design of the implant 3.4 lateral bending angular move
28、ment in the frontal plane around the X-axis See Figure 1 b). 3.5 mechanical failure onset of a defect in the material EXAMPLE Initiation of fatigue crack. 3.6 origin centre of the coordinate system located at the instantaneous centre of rotation at the neutral position of the total disc replacement
29、NOTE The nominal centre is specified by the design. 3.7 user-defined failure any failure criterion that is established and controlled by the user considering the specific design of the implant to be tested 3.8 X-axis positive X-axis directed anteriorly See Figure 1. 3.9 Y-axis positive Y-axis direct
30、ed laterally to the left See Figure 1. 3.10 Z-axis positive Z-axis directed superiorly See Figure 1. 3.11 cycle limit number of cycles at which the test is terminated if no functional failure has occurred 4 Principle The inferior and superior components of a test specimen are placed in position in t
31、he configuration intended for clinical use. The test apparatus transmits a specified time-varying force between the components, together with specified relative angular displacements. A load soak control specimen, if polymers are the object of investigation, is subjected to the same time-varying for
32、ce to determine the creep of the test specimen and/or the amount of mass change due to fluid transfer. The test takes place in a controlled environment simulating physiological conditions. BS ISO 18192-1:2011ISO 18192-1:2011(E) ISO 2011 All rights reserved 3a) Flexion/extension b) Lateral bending c)
33、 Rotation Figure 1 Definition of the angular movements and coordinate axes 5 Reagents and materials 5.1 Fluid test medium Calf serum diluted with de-ionized water (balance) to a concentration of 20 g 2 g protein/l. The fluid test medium may be filtered through a 2 m filter if desired. To minimize mi
34、crobial contamination, the fluid test medium should be stored frozen until required for test. An antimicrobial reagent (such as sodium azide) may be added. Such reagents can be potentially hazardous. The addition of 20 mmol/l EDTA solution may be used to bind calcium in solution and to minimize prec
35、ipitation of calcium phosphate on to the bearing surfaces. The effect of EDTA depends on the material combination tested. The addition of EDTA shall be justified by the user. Routine monitoring of the pH of the fluid test medium should be undertaken. If it is, the values shall be included in the tes
36、t report see 8 k) 6). 5.2 Test and control specimen Between the inferior and superior components shall be the articulating surface of the inferior and superior components, attached by its normal immediate backing (for example bone cement or a machined replica of the inner surface of the backing), un
37、less this is impractical due to physical features of the implant system. If the component forming the articulating surface is fixed to the backing by a rim/snap-fit system, the machined replica shall provide the same fixation conditions. If it is not practical to use the normal backing or cement fix
38、ation due to physical features of the implant system, the support system for the inferior and/or superior component should represent normal design features and conditions of use but should allow removal of the component for measurement of wear without destruction. A recommended minimum sample number
39、 of six should be used for wear testing. If less than six specimens are tested, appropriate justification shall be given. NOTE The number of specimens tested can be the subject of national legislation. At least one additional sample shall be used to correct weight gain by fluid uptake (load soak con
40、trol). The load soak control shall be loaded according to the load profile given for the type of implant. The user may decide not to use a soak control when testing materials that do not absorb surrounding fluid (for example metal materials). BS ISO 18192-1:2011ISO 18192-1:2011(E) 4 ISO 2011 All rig
41、hts reserved6 Apparatus 6.1 Testing machine, capable of producing the angular displacements specified in Table 1 and Figures 2 and 3 in association with the corresponding forces specified in Table 2 and operating at a frequency of (1 0,1) Hz based on one cycle being the shortest repetitive interval
42、for all motions and loads combined. Table 1 Angular displacements of the testing machineImplant Angle Flexion/extension Axial rotation Lateral bending min. 7,5 4 6 Cervical max. 7,5 4 6 min. 3 2 2 Lumbar max. 6 2 2 The angular displacements indicated may be varied according to data given by the test
43、 requester. Table 2 Load parameters of the testing machineImplant Load N max. 150 Cervical min. 50 max. 2 000 Lumbar min. 600 The load parameters indicated may be varied according to data given by the test requester. A defined level of shear loading shall be implemented for lumbar implants being res
44、trained in the transverse plane. Shear loading is achieved by inclining the implant with respect to the axial load axis in the sagittal plane at the reference position (see Figure 4). Certain designs can be sensitive to shear loads. The user may intensify the test conditions by increasing the shear
45、load and/or adding alternating load directions. NOTE 1 It is the responsibilty of the user of this part of ISO 18192 to be aware that a certain amount of shear load is generated by the motion of the device with respect to the axial load. With regard to the implant design, it is intended that the use
46、r give a justification for intended physiological conditions, especially for motion of any articulating surfaces during the load and motion cycle. NOTE 2 See Annex A for load and motion rationale. All angular displacement curves and load curves are smooth. The curves shall reach the given values at
47、0 %, 25 %, 50 % and 75 % of the motion cycle within the tolerances given in 6.4. Sample data sets are provided in Annexes B and C. The angles refer to a moving coordinate system. The intended sequence of the angular transformation is: lateral bending flexion/extension axial rotation. NOTE 3 The sequ
48、ence of the axial rotations slightly impacts the motion and the final position after each motion step (Euler angles). Due to the small angles applied, Euler sequences differing from the above result in almost identical relative motions. The Euler sequence chosen can be selected according to the mech
49、anical set-up of the wear testing machine. NOTE 4 The load curve is sinusoidal. BS ISO 18192-1:2011ISO 18192-1:2011(E) ISO 2011 All rights reserved 5Key X cycle (%) Y angle () Z load (N) 1 flexion/extension 2 lateral bending 3 rotation 4 load The lateral bending is shifted 90 relative to the flexion/extension axis; the axial rotation and the lateral bending are 180 out of phase. Figure 2 Phasing of the displacement and load curves for cervical prostheses BS ISO 18192-1:2011ISO 1819
