Brain Arteriovenous Malformations (AVM) – Treatment

You’ve been diagnosed with an AVM — does it always need treatment?

Not always. An AVM is not a tumor that “must” be removed at all costs. It is a vascular abnormality with an annual risk of hemorrhage (often ~1–2% per year for asymptomatic lesions, but significantly higher when risk factors are present or after prior bleeding).

The key question is: Is the risk of intervention lower or higher than the risk of leaving it untreated? This is the foundation of every treatment strategy.

What is the goal of AVM treatment?

The goal is definitive eradication or the maximal possible reduction of hemorrhage risk, while preserving normal neurological function.

More specifically, we aim to:

• Prevent re-bleeding after a ruptured AVM
• Substantially reduce lifetime hemorrhage risk in younger patients
• Reduce or eliminate seizures when present
• Avoid significant neurological deficits

Ruptured vs unruptured AVM — when is treatment recommended?

Ruptured AVM: after a hemorrhage, the risk of another rupture during the first year can reach ~15%. For most patients, when technically feasible and safe, definitive treatment is recommended (surgery, endovascular therapy, and/or radiosurgery).

Unruptured AVM: the decision is more nuanced. Studies such as ARUBA suggested that, for some higher-risk unruptured AVMs, careful observation may be safer than aggressive intervention with a high procedural risk, at least in the short term.

How is an acute AVM hemorrhage managed?

In the acute setting, the priority is life-saving stabilization:

• Airway and breathing protection
• Blood pressure control and intracranial pressure (ICP) management
• Treatment of hydrocephalus (e.g., CSF diversion) when needed
• Emergency craniotomy and hematoma evacuation in cases of significant deterioration
• Correction of any coagulation abnormalities

Definitive AVM treatment is often not performed in the hyper-acute phase, but rather after 6–12 weeks, once brain swelling subsides and anatomical planes are clearer.

What is microsurgical AVM resection?

This is a specialized microscope-assisted operation in which the AVM is carefully isolated and completely removed. It is the most immediate and definitive treatment when anatomy is favorable.

Key steps typically include:

• Precise planning with MRI, CTA, DSA, and neuronavigation
• Access through the safest possible surgical corridor
• Stepwise occlusion of feeding arteries
• Preservation of the main draining vein until the end
• Final removal of the nidus, with intraoperative angiography when indicated

What are the risks & benefits of microsurgery?

Benefits:

• Immediate elimination of the AVM — effectively zero future hemorrhage risk
• In many cases, improvement or resolution of seizures
• No “latency period” as with radiosurgery

Risks:

• Intraoperative bleeding (especially if venous drainage is compromised too early)
• Permanent neurological deficits, depending on AVM location
• General surgical/anesthetic risks (infection, thrombosis, etc.)

What is endovascular AVM embolization?

Performed by an interventional neuroradiologist via a catheter introduced through the groin or wrist. The catheter is navigated into feeding arteries, and an embolic agent (e.g., NBCA, Onyx) is injected to “close off” abnormal vessels.

Goals of endovascular therapy

• Flow reduction (and rarely, complete cure for selected small AVMs)
• Targeted treatment of a ruptured AVM-associated aneurysm
• Pre-operative or pre-radiosurgical flow reduction
• Access to deep feeders that are difficult to reach surgically

Risks: ischemia, hemorrhage, deep venous thrombosis, catheter retention, and new neurological deficits.

What is stereotactic radiosurgery (SRS) for AVMs?

Highly focused radiation (e.g., Gamma Knife, LINAC) that does not remove the AVM immediately. Instead, it causes progressive vessel wall thickening and eventual closure over 2–3 years.

When is it preferred?

• Small to medium AVMs in deep or surgically challenging locations
• Patients with higher surgical risk
• Residual AVM after embolization or surgery

During the latency period before complete obliteration, bleeding risk still exists (often reduced, but not zero).

Potential delayed effects include edema, cyst formation, and changes in seizure frequency.

What does combined AVM treatment mean?

Many AVMs are best managed with a combination of modalities:

• Embolization to reduce flow → followed by microsurgical resection
• Targeted embolization of an aneurysm → radiosurgery for the remaining nidus
• Radiosurgery first → surgery for a smaller, more fibrotic residual lesion

A multimodality approach can break down a complex AVM into safer steps, reducing overall risk per stage.

How do we decide which treatment is right for you?

Treatment selection is fully individualized and based on:

• Spetzler–Martin grade (size, venous drainage, eloquence)
• Age, overall health, comorbidities
• History of hemorrhage
• Symptoms (bleeding, seizures, progressive deficit)
• Your preferences and acceptable risk threshold

At Neuroknife, decisions are made after multidisciplinary review (vascular neurosurgeon, interventional neuroradiologist, radiation oncologist, neuroanesthesiologist) and a thorough discussion with you and your family.

What are hospitalization and recovery like?

The course depends on the chosen modality:

• Microsurgery: typically 3–7 days in hospital, with 24–48 hours of close monitoring (HDU/ICU), progressive mobilization, and postoperative imaging.
• Embolization: typically 1–2 days in hospital, monitoring for neurological changes or access-site complications.
• Radiosurgery: usually outpatient or short stay, no incision, with long-term follow-up using MRI/angiography.

Some patients may need temporary leave from work or studies, driving restrictions if seizures occur, and rehabilitation (physio/speech therapy) when appropriate.