Archived Content

The content on this page is provided for reference purposes only. This content has not been altered or updated since it was archived.

Medical Devices

Onyx® Liquid Embolic System (LES) - P030004

Photo of Onyx® Liquid Embolic System (Onyx® HD-500)This is a brief overview of information related to FDA's approval to market this product. See the links below to the Summary of Safety and Effectiveness and product labeling for more complete information on this product, its indications for use, and the basis for FDA's approval.

Product Name: Onyx® Liquid Embolic System (LES)
Applicant: Micro Therapeutics, Inc.
Address: 2 Goodyear, Irvine, California 92618
Approval Date: July 21, 2005
Approval Letter:

What is it? The Onyx® LES is an artificial material used to block blood flow in the treatment of abnormally formed (malformed) blood vessels in the brain. This material is used to block the flow of blood before surgical treatment of the malformed vessels.

How does it work? The Onyx® LES is injected through a thin hollow tube (a catheter) into the blood vessels of the brain at the location of the abnormal vessels. Upon contact with blood, the material solidifies so that the flow of blood to the malformed vessels is blocked.

When is it used? Malformed blood vessels in the brain may rupture and cause bleeding into the surrounding brain tissue. In order to prevent such bleeding, it may be necessary to surgically remove the malformed vessels. The surgeon may decide that blocking the blood flow to these malformed vessels before removing them can make the surgical procedure easier.

What will it accomplish? The clinical study of this material (Onyx® LES) demonstrated that its use performed the same as another blocking agent (TRUFILL® n-Butyl Cyanoacrylate Liquid Embolic System) in its ability to block blood flow in the malformed brain vessels. This material is an additional tool for surgeons to use during brain surgery.

When should it not be used? It should not be used by surgeons who have not had adequate training. Physicians should contact a Micro Therapeutics, Inc. sales representative for information on training courses.

Additional information: 
Summary of Safety and Effectiveness and labeling are available at:

Page Last Updated: 09/04/2013
Note: If you need help accessing information in different file formats, see Instructions for Downloading Viewers and Players.
Language Assistance Available: Español | 繁體中文 | Tiếng Việt | 한국어 | Tagalog | Русский | العربية | Kreyòl Ayisyen | Français | Polski | Português | Italiano | Deutsch | 日本語 | فارسی | English