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International
Standard
ISO 7197
Fourth edition
Neurosurgical implants — Sterile,
2024-07
single-use hydrocephalus shunts
Implants neurochirurgicaux — Systèmes de dérivation stériles,
non réutilisables, pour hydrocéphalie
Reference number
© ISO 2024
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements for shunts . 2
4.1 General .2
4.2 Radiopacity .2
4.3 Biocompatibility .2
4.4 Resistance to leakage .2
4.5 Control of the implanted shunt .3
4.6 Pressure-flow characteristics of the valve, the components and the pre-assembled shunt .3
4.7 Identification of shunts in vivo .3
4.8 Ability to withstand overpressure .3
4.9 Dynamic breaking strength .3
4.10 Behaviour under magnetic resonance imaging conditions .3
4.11 Bursting pressure .4
5 Specific requirements for components . 4
5.1 Valves .4
5.1.1 Reflux performance of shunts connecting the ventricle to the blood system .4
5.1.2 Long-term stability .4
5.1.3 Influence of the changed posture of the patient on the valve performance .4
5.2 Resistance of tubing and components .5
6 Marking and labelling of shunts . 5
7 Packaging. 5
8 Information supplied by the manufacturer . 5
8.1 General .5
8.2 Instructions for use .5
8.3 Implant card . .6
Bibliography . 7
iii
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
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related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 150, Implants for surgery, in collaboration
with the European Committee for Standardization (CEN) Technical Committee CEN/TC 285, Non-active
surgical implants, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This fourth edition cancels and replaces the third edition (ISO 7197:2006) which has been technically
revised.
The main changes are as follows:
— subclause 4.1 has been completely revised;
— terminology has been clarified and references have been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
A shunt is defined as an artificial connection of two compartments inside the body. For the treatment of
hydrocephalus, the ventriculo-atrial shunt has been introduced initially to control the intraventricular
pressure in the brain of the patients. Today ventriculo-peritoneal shunts are preferably implanted. In special
cases, a lumbo-peritoneal shunt is implanted. Normally, a hydrocephalus shunt includes a valve which
determines the resulting intraventricular pressure in the brain of the patients and influences the flow rate
through the shunt.
The following types of valve are currently commercially available.
a) Conventional differential-pressure valves (DP valves) are designed as ball-in-cone valves, membrane
valves or silicone slit valves: They have one characteristic opening pressure. If the difference pressure
between inlet and outlet exceeds this opening pressure the device opens. After opening, the different
types of DP valve show a wide range of different flow characteristics. Differences due to a changed
posture of the patient have no intended impact on the function of the devices.
b) Adjustable DP valves act like conventional DP valves: In contrast to non-adjustable devices, they
introduce the possibility of a non-invasive readjustment of the opening characteristic after implantation.
They do not take into account changes due to a changed posture of the patient.
c) Gravitation valves or hydrostatic devices that take into account the changed physics in a shunt due to a
changed posture of the patient: These devices aim to avoid an unphysiological negative intraventricular
pressure in the upright position of the patient, which can be the consequence of the hydrostatic pressure
in shunts with adjustable or not adjustable DP valves. There are three different hydrostatic devices
commercially available:
— flow-reducing devices,
— valves with a so-called “anti-siphon-device” or “siphon-control-device”, and
— gravity-assisted devices.
d) Other adjustable valves, for example:
— gravitation valves, which are adjustable hydrostatic devices present in addition to the characteristics
of hydrostatic devices (group 4) with the possibility of a non-invasive readjustment of the opening
performance of the device;
— adjustable anti-siphon-device valves;
— adjustable flow-reducing valves.
Due to the important technical differences, specific testing procedures are necessary to investigate the
performance of the different valves.
The benefit of this document for the surgeon and the patient is to understand the information given by the
manufacturer and to obtain standardized information about the performance of a well working product
with new design characteristics. The benefit for the manufacturer is to specify the important requirements
for shunts as a basis for investigations during development as well as for quality control during manufacture.
v
International Standard ISO 7197:2024(en)
Neurosurgical implants — Sterile, single-use
hydrocephalus shunts
1 Scope
This document specifies the performance requirements for sterile, single-use non-active hydrocephalus
shunts. This includes not only the valve, but also additional components such as tubes and reservoirs.
This document does not provide any recommendations on which type of valve is most suitable for any
specific context of use.
This document specifies the mechanical and technical requirements to manufacture shunts and the technical
information of the valve to be supplied by the manufacturer.
This document does not apply to active implants for the treatment of hydrocephalus.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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/TR 14283, Implants for surgery — Essential principles of safety and performance
ISO 14630:2024, Non-active surgical implants — General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TR 14283, ISO 14630 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
information supplied by the manufacturer
label, instructions for use, implant card, and any other information that is relate
...