Onyx glue causing edema?

I had an attempted embolization done 2 years ago. They did one round of inserting the onyx glue. When this went wrong, we proceeded with 3 rounds of gamma knife. This led to half my brain having edema.

I am now researching if onyx glue could cause edema and some studies have shown that yes it can! As well as seizures.

My neurosurgeon said he can’t do anything about the swelling and there is no cure. And there’s no reason for me to see neurosurgery again.

After this appointment… I started thinking, why is my swelling so bad and not getting any better years later as neuros have promised? All this time the neuros have told me it’s cause of gamma knife. REPEATEDLY. So that was instilled into my head. Then a light bulb went off and I thought hey well mri’s always show this shiny black matter in the middle of the edema (the onyx glue)… what if it’s irritating my brain further?! And what if that’s the reason my swelling isn’t getting better? I’m not sure why this never came across their minds or maybe they just didn’t want to deal with my situation.

Even though I was able to do my research, I don’t think there will ever be a success story for me. I will forever have glue in my brain, and it could potentially be the reason why I have so much edema and swelling. Probably will have seizures forever too. Seems like there’s no solution.

Just wanted to share because I feel really let down.


Hello! That’s a useful post! I would say that in 5 years of hanging round here, this is the first time I remember hearing anyone cite Onyx as a possible cause of edema. So in that regard, I’m not surprised that your neurosurgeon has referred to the radiotherapy: it is much more common to have issues of edema related to the radiotherapy than to the Onyx. But your plight is familiar: it is quite typical for doctors to focus in on the more likely causes of trouble and if the real cause is a rare condition, that gets left to the very last and quite often requires a degree of insistence that the less common gets investigated.

If you’ve got some references that you’ve found that make the case, it could help people in future if you post them here.

Big hug from me,


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I’ve spoken to a neuro icu nurse friend of mine for a while after my procedure. He actually said that brain swelling does happen in some patients from the Onyx Glue itself.

What he said tho, is that it just happens to some almost right away post embolization. Also, some cases are much worse than others. And, he said that it never really gets mentioned by anyone.

Not that you want to hear this, but is resection an option for you? Is the AVM operable?

Very sorry to hear about your probs with this

Personally, since I have the same stuff in my head - I always think & thank my body for accepting this foreign material - so far, at least

Hi Richard! Thank you, & I agree! There are not too many studies out there about post-embo edema so I’m assuming my neurosurgeons have not fully looked into it yet. But I do have some references regarding post-onyx complications:

  1. ‘One patient who suffered severe cerebral edema after embolization’

‘Some draining veins of the brain AVMs drain both nidus and normal blood flow, so except for cerebral hemorrhage, postoperative brain edema is also correlated with obstruction of draining veins. In one of the cases subtotally obliterated in our group, the intact draining veins were not found in the postoperative angiogram. The obstruction of normal blood flow was caused by thrombosis of the draining vein and then resulted in severe brain edema. Thrombosis of draining vein is an important factor towards AVM embolization complications and no effective way has been found except controlling the obliteration rate of the nidus, which deserves attention and further discussion.’

  1. ‘Peri-AVM edema was present in 75% of MRIs performed within one month of Onyx treatment and may represent a possible etiology for seizures.New onset seizures post-Onyx embolization are not uncommon. Further study of seizure prevention is warranted.’

This article discusses seizures and embolizations.

From these 2 articles I’ve read, there is no clear “onyx causes edema and with radiation edema added on it gets worse.” But with these little bits and pieces of information I was just able to think of some possible reasons why my swelling is the way it is.

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I did see in the articles that it usually happens right away after the procedure. Then I was wondering if there will be more studies following up with patients to see if effects come up months or years later because as you’ve mentioned, it’s a foreign object in our brain.

My avm has been completely obliterated from gamma knife (grateful for some good news!) so I’m just left with edema and glue.

But you’re right, always good to be thankful for everything and that we’re still even functioning today.

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My thoughts exactly,

Me personally, I feel fine(considering) but i can def feel the 3+ cc’s of Onyx glue in there about 70% of the time right now

It’s impossible to explain to my wife or anyone else “normal” - but, it feels just like it sounds - foreign object in there(nothing severe)

I was never diagnosed with edema, myself

But, in your case - what can you do? It sure doesn’t sound like it feels well. It’s great that it’s completely obliterated. But, this shouldn’t be permanent - I would think