As far as complications go, might get stuck in your brain has to be high up on the list of most terrifying. Recently, the FDA issued a warning regarding Covidien's Onyx liquid embolic product, stating that that is exactly what might happen if you use it. The FDA issued this warning after 100 reported cases of adverse events associated with Onyx, most of which involved the catheter delivering the product breaking and part of it remaining stuck in the patient. Nine of these cases led to patient death. Although the FDA did not recall Onyx, it did add Catheter entrapment to the list of possible complications that can occur from using the product.
Onyx is a liquid embolic generally used as a presurgical method for reducing blood loss and complications associated with arteriovenous malformation (AVM) surgery. If untreated, AVMs can lead to aneurysms and/or hemorrhaging, which is obviously a very serious problem. Manufactured by ev3 (later acquired by Covidien), Onyx has been available in the US for approximately 7 years and is being increasingly used instead of embolic glue, the original liquid embolic made of n-butyl cyanoacrylate. Liquid embolics are ideal for use in high-pressure situations because they are able to occlude vessels much more rapidly compared to other embolization methods, such as coils or particles.
The reality is that Onyx still remains a much superior alternative to embolic glue, where this same complication occurs much more frequently. When it comes down to it, this kind of surgery is risky in itself, and there is no perfect solution for performing it available just yet. So basically, given that approximately 6,000 Onyx procedures are performed annually in the US, this complication rate isn't too bad. And until a revolutionary new product comes out, physicians that we interviewed generally indicated that this warning will not affect their overall usage of Onyx. Additionally, it is worth noting that ev3/Covidien is currently in the process of developing a catheter with a tip that will intentionally break off, which could reduce the risk of catheter entrapment.
So, is a terrifying side effect a possibility, Yes. Do the risks of the surgery outweigh the potential benefits? According to physicians, not at all.