YY/T 0487-2010Sterile, single-use hydrocephalus shunts and components (English PDF)

Foreword

This Standard was drafted in accordance with rules given in GB/T 1.1-2009.

This Standard replaces YY 0487-2004 "Sterile, single-use hydrocephalus shunts and components".

Compared with YY 0487 2004, there are significant differences in terms of the technical contents and editorial aspect.

This Standard modifies and adopts ISO 7197:2006 "Neurosurgical implants - Sterile, single-use hydrocephalus shunts and components". The differences with the adopted international standard are listed in Appendix NA.

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 Jumbo-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.

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 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 might 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, e.g..

- gravitation valves. 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;

1 Scope

This Standard specifies safety and performance requirements for sterile, single-use non-active hydrocephalus shunts and components. This includes the components used in shunts, like valves, tubes and reservoirs.

This Standard gives no recommendation concerning the superiority of a certain type of valve.

For manufacturing, it defines the mechanical and technical requirements. This Standard defines the technical information of the valve, to be given by the manufacturer.

In respect to the different principles of the valve types, specific characteristics are defined for each group as declared by the manufacturer.

The benefit of this Standard 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 define the important requirements for shunts as a basis for investigations during development as well as for quality control during manufacture.

This Standard does not apply to active implants for the treatment of hydrocephalus.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this Standard.

YY 0334 General specification for surgical implants made of silicone elastomer

YY/T 0640-2008 Non-active surgical implants-General requirements (ISO 14630:2005, IDT)

ASTM F 2503-05 Standard Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment Page 7 of 14

3 Terms and Definitions

For the purposes of this document, the following terms and definitions apply.

4 General requirements for shunts

4.7 Identification of shunts in vivo The type of the valve as well as the direction of flow shall be detectable non-invasively.