Embolization Success Rates?

Hey all,

Left temporal lobe avm here. As many of you know, its near the speech / motor skills area. I was given the options for GK or embolization/craniotomy. I’ve been reading reports on onyx embolization’s and the conclusions are mixed in regards to it causing a stroke, rupture or other deficits during the procedure or right after.

For those of you who have had embolizations done, could you share your stories. Did it cause a rupture? Did it trigger a stroke? Was it successful? What did you experience right after the embolization?

Any information would be helpful. I need to make a decision and I have been postponing.

Thank you all.

Read my threads on here

Most important is the hands you put yourself in. Of course along with you exact specific case. . . .It varies so much

I was very fortunate, to say the least

To add; Embolization success rates have been at their best within the last 3-5 years. . . A first shot average, I believe is about 20% currently < but, don’t quote me on this, it’s what I gathered from all the research I did on my own


Like t’other Mike, I have an AVM in the dura mater and a fairly singular connection from an artery straight into my right transverse sinus. On the MRI, it appeared like a single white dot.

My embolization story is here, documented in the weeks following. If you click on the date against each, you can see where it is in the time line. I had my embo on something like 3 April 2017. All good now but took a long time to feel ok. The doc put this down to quite a high flow connection being shut off in one go that had been gushing forwards and backwards in my major sinuses.

Any questions, very happy to help.

I think the apparent “low” success rate for embolization is that it is often the case that docs plan to attack an AVM via embolization in one, two or more sittings. My doc suggested possibly two sittings; as it happened, he was happy with just one.

The risks are principally that the catheter can rip the artery or that a blob of glue gets dropped (or pushed via high flow blood) to somewhere that it was not intended.


Hi Mike,

What do you mean exactly? The first embolization has a success rate of 20% or less? That is a pretty high risk procedure. I feel pretty doomed with that percentage.

Thanks for the response Dick,

“I think the apparent “low” success rate for embolization is that it is often the case that docs plan to attack an AVM via embolization in one, two or more sittings. My doc suggested possibly two sittings; as it happened, he was happy with just one”.

I was told it is better to do multiple embolizations rather than 1 and the neuro I am currently seeing mentioned less is more when it comes to embo to reduce risks.

Has your avm been ‘cured’? I will check out your thread when I have some time to read it all. Did you have to do a craniotomy?

I’m all good. I just had the one embolization. It took me a loooong time to feel better, though. Our interpretation of that is that the flow I had was quite high flow, creating high pressures on places it shouldn’t and low pressures in other places it shouldn’t and it took me a long time to get used to the new balance and how that felt. It still felt “wrong” for 18 months or so afterwards but putting that our of my mind and just getting on with life got me to today.

Thanks for the prompt reply.

Did they just leave it embolized indefinitely? I was under the impression that leaving onyx in there for the rest of your life carried risks and normally they remove the avm after the embolization even if its 100% ?

Just the embolization. It seems to me that in the US, embolization is most often used as a precursor to surgery. In the UK, or with a DAVF as @mike_az_21 has experienced in the US, embolization alone seems to be done. My embo used PHIL glue, not onyx.

My 20% approximation is based on “one shot kills” - where the AVM/dAVF is completely obliterated on the first embolization attempt

Like Dick mentioned, it’s all dependent on your situation/case & your neurological team’s approach

Here in the US, at BMI - embolizations are the most common practice & are considered to be a permanent solution. This has become the case in the very recent years.

They are also considered “home of the GK” - but, according to my convos with all of the team members - embo’s are the 1st route they try to go for - especially for cases like mine, where physical removal(craniotomy & resects) are almost impossible

But, in many cases it does require more than one embolization - being considered by them the luckiest person alive, well - one shot did the trick for me. They were looking to achieve 95-98% on first attempt if all went well - it went better than great - 100% on the first try

Do either of you know how successful or how often issues occur with embolization? I tried doing some research to find some numbers but it is difficult to find. I then started reading about people experiences to try to gauge how often they happen and how risky it is for issues like stroke, glue to become free and travel through vessels, cause a rupture, etc. I dont get the impression that it is equal to or less risky than a standard angiogram.

I understand there are many variables. I guess it comes down to who is doing the procedure and the issues that may arise from there. I’d hate to go in for an embo and come out with a stroke or other deficits. Is it even worth the risk at that point. Sounds like Dick had some issues after his embo with headaches etc which took a very long time to get better. Concerning stuff for sure.


I think my issues were to do with how big a change the embo made to my head. Before I had the op, I had a flow into my right transverse sinus, which is a major horizontal vein across the back of your head. Your sagittal sinus comes down the back of your head to the middle, meets the short sinus that is coming from within and splits into the two transverse sinuses which then flow down past each ear as the sigmoid sinuses. The consequence of the high flow into my right TVS was that I was getting “retrograde” flow back up probably the sigmoid sinus, and higher pressure past my ears and maybe even retrograde into my short sinus. So I felt really quite dizzy with all that going on. When the embo was done, everything was very upset by the glue and the contrast but the feeling of dizziness didn’t go away as quickly as I expected and I had what I took to be a bit of a relapse about 6 months afterwards but the docs concluded it was all just still settling down and nothing untoward could be seen on subsequent scans.

In terms of success rate / complications, my doc told me that I had a 5% risk of “bad stuff happening” (i.e. stroke, including death) during the procedure. He didn’t separate that out into 5% complications and 1% death or anything like that but my reading of it was that that means that one in twenty of his patients have something go awry. I was one of the nineteen.

The risks with an embolization are those the same as for an angiogram (e.g. risk that the catheter or guide rupture the artery) plus the risk of a bit of glue flowing to where you didn’t want it to go. I do think there is a bit of science to the mix of onyx used as to how quickly it goes off (solidifies) and how fast a flow you have at the site, so the doc does need to be appropriately adept at dropping the glue at the right point, in the right way to do everything intended without glueing up something unintended. There’s a lot of timing involved in the procedure. I read here recently of someone whose catheter got stuck in the glue but I think that is very rare.

I am quite sure it is just as complex to go and have a craniotomy (probably more so) as to do something like this, so I still look upon embolization as lower risk than that. In my mind, the key questions were:

  • Do I think I need the operation? If we left it alone, would it be better or worse?

  • Am I confident in the doctor who is doing the work?

In my case, I was completely convinced that my DAVF was developing quite quickly and my symptoms were worsening month by month (not year by year) so question 1 was a “yes”. And when I met the consultant interventional radiologist, he had a strange bedside manner but he stuck me as more of an “engineer” than a psychologist: knew exactly what he was going to do mechanically to my head but wasn’t switched on to any emotional needs I might have. “I’ll take the engineer!” I thought. It doesn’t matter if he’s not really taking me on a comfortable journey: if I need to trust my brain to someone, I think this is the man.

So it was.

I’d do it again if needed. Honestly. It was a perfectly gettable-throughable thing. I was as bothered as anything beforehand but I got through it fine and I’d say most of my worries were simply about the unknown.

Hope this helps,


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Totally, agreed on why Dick said - main thing, is that you don’t want to rupture/hemorrhage < that’s what will cause the most severe issues

The embolization procedure is nowhere near as bad as most hemorrhages can go

Hey all - quick question… angio I was awake… are you awake for embolisation?

are you awake for embolisation?



I had the doctors attempt embolization in 2012, but they discovered the artery hooked, so they couldn’t reach it. This winter, they tried venous embolization, only to discover there are two veins, not just one, from the AVM. So that was unsuccessful, because blocking one vein would have caused a third bleed. (Thank goodness they pulled out first.) I am waiting for a third Gamma Knife surgery.

My AVM was also in the left temporal lobe. I was given the choice of craniotomy or GK. I went with GK and began getting better month by month. It completely occluded within 3 years. The AVM was active and a fast grower with a bleed, so I have quite a few issues from the damage it caused prior to GK. But I’m much better than I was before and it’s over and done. Over and done are the key words. It’s a huge decision. Wishing you well whichever path you take. Good luck my friend.



I would take the treatment if it’s available.
I never knew I had an avm and it just ruptured, which then meant over 1 year of in hospital time.
It’s a risk like most things but the chances of a full recovery post rupture May well be lower.

Good luck


Thanks for the response Tim. Sounds like you have a really tough time. I hope you are doing better now. I often think that if something happens, I’ll think “I should have gotten treatment” just as you said. Did you have yours removed?

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Hi Mike

Yes I had mine removed which unfortunately means there is a 4 inch scar on the back of my head.
However I am fully independent and have survived over 30 years now.
I live in Nottingham in UK. You’ll make the right decision for you but get as much information first.


Do neurosurgeons normally do the embolizations or is it a different team/person? What has been your experiences?