Senior Neurosurgeons explain the difference between cerebral aneurisms and arteriovenous malformations (AVMs) and the types of treatments suggested by the Neurovascular Multi-Disciplinary Team.
Cerebral Aneurysms can arise from weaknesses (lesions) in the wall of the cerebral blood vessels. The cause of cerebral aneurysm formation is unknown, but most studies suggest that they occur in between 2% and 5% of the whole population. Unfortunately these weaknesses have a risk of rupture (“bursting”) and such an event has major implications. Treatment of these lesions depends if they have ruptured or not. Ruptured aneurysms (SAH) are a medical emergency and immediate hospital admission and review by a consultant neurosurgeon is required. A CT scan of the head is sufficiently diagnostic in 99% of the cases, however, some patients may require further tests like a lumbar puncture to confirm that a rupture has occurred. The aim of early treatment is to support the patient and secure the aneurysm to protect from repeat bleeds.
Endovascular Coiling or Craniotomy
Treatment can be either through the arteries/veins (endovascular coiling) or through an open operation (craniotomy). The decision on the best mode of treatment is taken after special investigations have been performed and the patient reviewed by a neurosurgeon with a special interest in the treatment of aneurysms.
Arteriovenous Malformations (AVMs) and a 'Nidus'
As King’s College Consultant Neurosurgeon Mr Ranj Bhangoo explains, “Normally blood flows from the heart to the arteries of the body. The arteries branch and get smaller until they become a capillary, which is just a single cell thick. In this way blood pressure drops to very low levels that the thinner walled veins can cope with. In an arteriovenous malformation (AVM), usually early in life, arteries connect directly to veins. This is a high-pressure shunt or fistula. Veins are not able to handle the pressure of the blood coming directly from the arteries. The veins stretch and enlarge and create what we call a ‘nidus’.”
The symptoms of AVMs vary depending on their type and location. While migraine-like headaches and seizures are general symptoms, most AVMs do not show symptoms until a bleed occurs. Common signs of brain AVMs include the following:
- sudden onset of a severe headache,
- a stiff neck,
- migraine-like headaches or a
- Bruit – a swishing sound in the ears
Surgery, endovascular therapy, and radiosurgery can be used alone or in combination to treat an AVM. Endovascular embolization is often performed before surgery to reduce the AVM size and risk of operative bleeding. Radiosurgery or embolization may be used after surgery to treat any remaining portions of the AVM. Your neurosurgeon will discuss with you all the options and recommend a treatment that is best for your individual case.