Thank you. Francisco Gonzalez Llanos from Toledo near Madrid, Spain, is going to talk to us about how to plan microsurgical treatment of AVMs. Thank you. Good morning. Thank you, Jax, for the invitation, as always. Following Michael Laughton's metaphor about the AVMs, comparing them with war, I would remind you this old Latin saying, If you want to avoid the war, prepare yourself for the war. And this is important. If you want peace in AVM surgery, you want to prepare for the worst scenarios and try to master and to foresee everything that might happen during surgery before. Of course, microsurgery is only one of the treatment options we have for AVMs. We have also observation. It's another way of treating or offering the best. I mean, offering the best for the patient sometimes, and then embolization and radiosurgery. I show you this case, this 48-year-old enraptured. And this is a very small, I call micro or nano or whatever AVM. And it was scheduled for an endovascular treatment. They said they could do it, but I convinced them that it was easier for us now. In the neuro-navigation era, for us, it's very easy. You would agree with me that it was treated. And this is another case. This case was sent from the neurologist in one of the hospitals I work in, there to the neuroradiologist for embolization. They said, we can prepare this for you with embolization, but you treat it. I told them that this case, for me, the safest way to treat this AVM is surgically, without embolization, because of the location and because of the size of the lesion. And this is what we did. And this is good for us to check the surgery in general of AVMs. We try to locate the feeders of the AVM as soon as possible and try to stay as close to the AVM as possible and then leave the vein for the end. It's almost always the same in all the AVMs. The problem is that not always we have that good scenario. With a small AVM, with feeders, very easy and very handy to control them early in the operation. And sometimes, definitely, like this one, we can say this is an AVM, a pure intraventricular AVM from the left side. You see it's located in all the temporal horn of the left side and the atrium. You see involvement of the perforators with even flow aneurysm in some of the perforators. I would be crazy if I say the surgical option is the best way. In this case, we treated first with embolization. We felt we had several entrances to the AVM, and this was the result. We combined this with a little of radiosurgery for the rest of the AVM, and it was okay. So I think surgery is only one of the options we have for the treatment of AVMs, but it's still the most important of all. But as you see in this case, terrific result with endovascular. We have to remember that they are congenital, but they can develop after birth, and they express growth factors, and this explains the changes the AVMs experience during the life of the patients, but also the changes they have even during the surgery because it's not only about hemodynamics. It's about growth factors. There are alternative stimuli like venous hypertension. Like in the fistulas, we have to consider. The natural history, you've talked about it before, but even in ARUBA, they recognize a 2.2% risk of bleeding with 1% of mortality. So we have to try to beat the natural history of the disease. There are bleeding risk factors. We have to consider before planning the operation, and these factors are related sometimes with the arteries, with the arterial aneurysms, sometimes with the veins, venous stenosis and venous aneurysms. With the size, it's a matter of discussion, but maybe the small size are more prone to bleed. A single draining vein, diffuse morphology, deep location, a lot of factors. But one important thing is that the hemorrhagic presentation is very important because we have to try, of course, to treat all the AVMs that have bled, no matter where it is. If possible, we have to do it. The results cannot be generalized, of course, and now we've seen a different combination of endovascular and microsurgery or radiosurgery with embolization. The problem with embolization here in the treatment of AVMs is that I think it's very useful, but we, as surgeons, complain about embolization because if you don't get a very, very good embolization, it turns into a pain in the neck because it's a harder lesion and you still have risk of bleeding. And the radiosurgeon says that it's more difficult for the AVM to collapse if you use embolization, but I still do feel that embolization is an important part of the treatment, of course. This is our series. We have operated more than radiated and we don't use the embolization alone, always combined. Of the preoperative studies, angiography, of course, is the most important, but I would say CT and CTF in urgent cases to assess the MRH is important, but I think nowadays we have to study carefully the MRI because it provides us with the exact accurate location of the AVM and an assessment of the nidus, and we can say if it's diffuse or not. In other words, if there is brain inside the AVM, very important, especially in elegant areas. And then we define the grade and we say we decided we are going to do or not embolization. What would be the best situation for an embolization? In those cases where the feeders are deep, and temporal cases are a good example. The feeders coming from the PCA are very easily treated by embolization, and it would be the last thing we see during the surgery. This would be the case when we have to divide rapture from non-rapture AVMs. With rapture AVMs, we have to treat them, of course, because it's probably the most important factor for re-bleeding. But we prefer to wait for four or three days. It's not the same as with aneurysms, except in those cases with arterial aneurysms, especially in posterior fossa, in cerebellar AVMs, if the aneurysm is the one bleeding, we have to treat it like a regular aneurysm, the same day. We have problems with several patients waiting because re-bleeding of the aneurysm. So this is the only urgent scenario for an AVM. Of course, the first thing, the question we ask ourselves, can we treat this AVM? And we assess the size and the location. Like in this case, bleeding AVM, speech area, but very easy to accomplish because of the hematoma. We do it as soon as possible. But with a rapture, we should be more conservative and offer radiosurgery to almost every patient as an option. Of course, if we are surgeons and we feel we can do more for the patient with the surgery, we tell the patients, but we have to offer radiosurgery. And we have to assess, and this is very important, because it's different from my hospital to your hospital to the other. We have to assess our own risk for each case and then try to study all the characteristics of the AVM, size, location, speed of flow, everything. We still follow the special classification. And we can sum it up. Grades 1 and 2, very good for treatment, especially surgery. Grades 4 and 5, more conservative. And grade 3, this is the group more interesting because we have to individualize all the cases to study. Michael Laughton provided us with the correction of the classifications using aids, diffused needles, and bleeding, very important. But for us, the most important thing besides the patient, the age and everything, the status, the general status, are the size and the location because the rest of things are caused because of these two important characteristics, size and location. In this case, for example, we see this is deep but very small, and you have a good approach. This would be a perfect case for a surgical approach. That's what we did with this side in lateral position so you avoid retraction and very easy to take out. On the other hand, we have this one. This is much more difficult because it's small but it's deep, but it's located in a very, very dangerous area because of the perforators, the branches, and everything. I'm not stopping there. I skipped the surgery, but it's much more difficult. We have to be very cautious. This is another middle cerebral palyncho AVM. We sent it for embolization and radiosurgery, but it rebled, and we had to treat it. These cases are best treated with confined approach. That's much more riskier for surgery, but from time to time we have to do it. Problems related, we will see problems related with the feeding arteries, with the vein, and with the nidus. What are the traits of the feeding arteries? We have two kinds, pial vessels and perforating vessels. The problem starts, and again, it's due to the size of the location because of the perforators. We have large vessels, the pial vessels, the good guys, and then the perforators, the bad guys. This is a good example. Retrorhambic AVM, and you can see these small perforators. This changed everything. As you said, you have to comb and go down to try to control them as soon as you can in the operations. Of course, not risking the veins to do that, but this is the problem. From time to time, when you have this situation, you might have this. For us, it's very important to keep the patient. In this case, the patient was awakened in the same afternoon after the operation. I think it's a mistake. When you have small vessels, for grade 4 or even grade 3, we leave the patient at least 3, 4, or 5 days asleep after the operation. This is very important to deal with the small vessels. About the venous drainage, it can be superficial or deep, but it's always pathological because it's high flow, and it might present aneurysm or stenosis. This is a venous varix, a direct fistula. We send the patient for embolization, but it bled after that, and we have to treat it. I would say most of the fistulas could be treated endovascularly, but sometimes it's difficult because of the venous aneurysms. The venous aneurysms is always a factor you have to take into consideration before planning endovascular. We feel more confident with surgery in these cases. About the nidus. The nidus was, until the embolization and the accurate endovascular study, was something, a place the surgeons didn't study. We've learned a lot about the nidus because of the embolization at the micro study, the selective study of the AVMs. One important thing to comment is that sometimes they are multi-compartmental, and we have to take into account this. In this case, it's a young boy, a bleeding case, and studying carefully the AVM, we realized that it has two compartments, one frontal and one just in the middle, in the motor cortex. So we decided to try to treat the bleeding one. It was the safer, and sent the posterior for embolization. And I'm going to show you a couple of cases. This is a cerebellar, typical cerebellar, very easy. Whenever you have all the feeding arteries on the surface, and you don't have perforator, it's a very easy operation. In this case, you expose in a lateral position, and as soon as you open the dura, you have the uncontrolled feeders. Very easy. This is a much more complex case. In this case, we didn't offer treatment to the patient because of the risk, but we've been following this patient for years, and then it suddenly exploded, the AVM. And we had to treat it. We combined with endovascular, but the principle, it was the same. Much more difficult because of the small vessels, but we had to control the feeding artery. We found it, and we did it. And we finished it. And then, when we have AVMs facing the cisterns, like in this case, this is an anterior sylvian, we have to expose everything and try to respect all the vessels in passage. Here, we have a lot of vessels in passage. Here, there is no problem with the anterior sylvian because usually we can respect every vessel. But, like in this case, very easy case, you see the anterior colloidal at the bottom, but no problem. But, when we have it more posteriorly, like in the case I'm going to show you now, this is the end of this case, very straightforward case. Like in this case, we have an AVM involving the mesiotemporal, the left mesiotemporal with the colloidal fissure. Now, we have a really clear involvement of the anterior colloidal, but we control, we monitor the patient, and we put a temporary clip on the anterior colloidal, and we check everything during the surgery. So, in the end, you can treat these AVMs, but you have to control every vessel before, during, and after the surgery. So, thank you very much. Thank you. Any questions from the audience to Kiko? Please. I would like to commence on what I have to say. Basically, when you're doing large AVMs, not the small ones, it obviously takes a lot of time. And would you agree with me that most of the problems occur when you're towards the end of the surgery? That's probably when you try to get things done a little in a hurry, and you land up with problems. Have you ever wondered whether, like, you embolize, and they come back after months or whatever. We call them radiotherapy or whatever, because they never do the entire embolization in one go. Would you like to come back as a surgeon after, say, either a few days or weeks, if you have not taken out the entire AVM? You would like to stage the surgery. Do you ever contemplate that? Or would you like to get it out in one go? The first question, I agree that most of the problems, especially with big AVM, happens at the end of the surgery, at least when we have spent hours dissecting. But the problem was created beforehand, because we didn't plan the surgery well. If you get tired, especially if you have a problem with the deep vessels, it was a matter of strategy. You should have done this before, or something happened with the vein beforehand. So you have to plan everything. And for the stage surgery, I fully agree, but it's difficult to find, unless they're very big, huge AVMs with clear, very clear separate compartments, it's very difficult to achieve that. It's different. We're in another session now, comparing with a mangioblastoma. A mangioblastoma is a solid mangioblastoma. You go inside, and if it starts bleeding, they bleed like hell. But there is a capsule surrounding the thing, so you can achieve hemostasis. With an AVM, sometimes it's a way of no return. Maybe if you don't have any problem, and you have studied very accurately, you can stage the surgery. But if there is a problem, especially with big ones, sometimes you don't have the options to retrieve. You have to go on. Thank you very much, Kiko.

microsurgical treatment

AVMs

complications

observation

embolization

radiosurgery