Encyclopædia Neurochirurgica
Brain arteriovenous malformation
1. Ruptured AVM versus unruptured AVM
In patients with incidental AVMs, the benefits of treatment, the best therapeutic modality and the overall long-term outcome following treatment are controversial. The patient’s clinical situation and the natural history of the lesion are perhaps the most important considerations when deciding whether and how to treat [12]. The objective is to treat only the patient with AVM in which the perceived risks of treatment are less than the presumed natural history risk.
As reported in the natural history the previous history of bleeding is fundamental in therapeutic decision, because it increases the risk of rebleeding.
There are some extreme situations in which the decision to treat (young patient with history of bleeding and small or medium AVM) or not to treat (patient with more than 50 years, without history of bleeding and large AVM) are very clear. However, the majority of cases are not so easy and classifications may help us in treatment decisions.
Following the analysis of malformations according to the Spetzler-Martin grading scale and Lawton sub-classification of grade III AVM of Spetzler-Martin, we follow the guidelines at Figure 5 and Figure 6 as screening for treatment. Therefore the AVM treatment must be individualized and many other factors must be taken into account such as: patient’s wishes, age of the patient, AVM’s risk factors for rupture, experience of the team.
- Figure 5 AVM unruptured
- Guideline to unruptured AVM
1 Spetzler-Martin Grading System (1986) [95]
2 Lawton sub classification of grade III AVM of Spetzler-Martin [45]
3 Usually surgery. Radiosurgery for patients with poor clinical condition. Embolization for AVMs with a single feeding artery (Item VII-2.1.).
4 Usually Surgery. Surgery when S2V0E0. Surgery or radiosurgery when S1V1E0. Radiosurgery when S1V0E1. (S=size; V=Drainage Venous; E= Eloquent). Embolization for small AVMs with a single feeding artery. (Item VII-2.1.).
5 Item VII-2.2.1.
6 Item VII-2.2.2.
- Figure 6 AVM ruptured
- Guideline to ruptured AVM
1 Spetzler-Martin Grading System (1986) [95]
2 Lawton sub classification of grade III AVM of Spetzler-Martin [45]
3 Item VII-2.1.
4 Item VII-2.2.1.
5 Item VII-2.2.2.
6 Usually conservative treatment. Partial treatment in patients of elevated risk factors such as intra-nidal aneurysm and high flow arteriovenous fistulas with progressive neurological deficit. (Item VII 2.2.3. and Item 2.3.)
