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Brain & Spine AVMs and Dural Arteriovenous Fistulas

Expert endovascular embolisation to close abnormal blood vessel tangles in the brain and spine reducing the risk of catastrophic bleeding and progressive neurological damage.

Neuro-Interventional Procedure

What are Arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs)?

Arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs) are abnormal connections between arteries and veins in the brain or spinal cord, bypassing the normal capillary network. This causes high-pressure arterial blood to flow directly into low-pressure venous channels, leading to progressive vascular stress, potential rupture, and neurological damage.

Endovascular Embolisation: The Treatment Approach

Endovascular embolisation is the cornerstone of modern AVM and dAVF treatment, either as definitive therapy or as a preoperative step before surgery or radiosurgery. Using microcatheters navigated through the cerebral vasculature under biplane fluoroscopy, liquid embolic agents (Onyx, NBCA) or coils are injected to occlude the nidus or fistula point from the inside.

For complex AVMs, staged embolisation sessions reduce the lesion systematically, each time safely devascularising a portion. This multi-disciplinary approach combining embolisation, microsurgery, and stereotactic radiosurgery (Gamma Knife) offers the best outcomes for complex lesions.

How is the Embolisation Performed?

  • General anaesthesia is used to ensure complete immobility during the precise navigation
  • A catheter is advanced from the femoral artery into the cerebral or spinal circulation using biplane X-ray guidance
  • A microcatheter is further advanced into the feeding arteries of the AVM or fistula
  • Liquid embolic material (typically Onyx a non-adhesive polymer) is slowly injected, filling the nidus or fistula and penetrating deeply into the abnormal vessel tangle
  • Careful angiographic monitoring ensures normal arteries are not compromised during injection
  • Post-embolisation angiography assesses the degree of obliteration achieved
  • For dAVFs, a single session often achieves cure if the fistula point is completely obliterated
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Benefits of Endovascular Treatment

Haemorrhage Prevention

Obliterating the AVM or fistula eliminates the risk of life-threatening brain or spinal cord bleeding.

Symptom Relief

Patients with pulsatile tinnitus, eye symptoms, or myelopathy often experience significant improvement after treatment.

Surgical Facilitation

Pre-operative embolisation devascularises large AVMs, making surgical resection dramatically safer.

No Open Surgery Required

Many fistulas can be cured entirely through the catheter-based approach with no incision on the head or spine.

Frequently Asked Questions

Small, compact AVMs with a single feeding artery may be cured by embolisation alone. However, most brain AVMs require a combination of embolisation (to reduce size and blood flow), followed by microsurgical resection or stereotactic radiosurgery for definitive obliteration. The treatment strategy is individualised based on AVM grade (Spetzler-Martin scale), location, and patient factors.
Dural fistulas often require just 1–2 sessions. Brain AVMs typically require 2–5 staged sessions depending on their size and complexity, spaced 4–6 weeks apart. Each session systematically closes off feeding vessels, progressively reducing the AVM's size and flow before definitive treatment.
Procedural neurological complication rates range from 3–8% depending on AVM location and complexity. Risks include ischaemic stroke (from catheter in the cerebral circulation), haemorrhage from inadvertent normal vessel occlusion, or normal perfusion pressure breakthrough after devascularisation. These risks are weighed against the natural history risk of AVM rupture, which carries a much higher morbidity.
Pulsatile tinnitus a rhythmic whooshing or ringing in the ear synchronised with the heartbeat is the hallmark symptom of a transverse sinus or sigmoid sinus dural AVF. Embolisation of the fistula point effectively eliminates this sound in the majority of patients, often immediately after the procedure.
Not necessarily. The ARUBA trial highlighted that for unruptured brain AVMs, the cumulative risk of treatment may exceed the natural history risk for some lesions, particularly small, deep AVMs in eloquent brain regions. Management decisions require careful multi-disciplinary discussion balancing rupture risk (lesion size, venous drainage pattern) against treatment risk. Some patients may be appropriately managed conservatively with observation.
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