These are formed before birth. The name is shortened for convenience to AVM. They
are congenital, meaning they are due to a defect of development. They are however
not hereditary. This means they are not inherited.
These AVMs may make their presence known with epilepsy. The patient has one or more
epileptic attacks and this leads to investigation and diagnosis.
When a bleed occurs the patient may either have severe headache and vomiting starting
suddenly. Another thing that may happen is the patient becomes unconscious for a
period. On waking up the patient may or may not have some degree of paralysis.
Aims of Treatment
If the problem is epilepsy then medicine is given to help with that. This may or
may not be enough. If the problem is bleeding then any damage left by the bleed is
treated with physiotherapy and rehabilitation. Damaged brain cannot be replaced or
It is important to understand that the treatment is aimed at preventing another
bleed or in bringing the epilepsy under control. Moreover, patients with epilepsy
may bleed later so again the aim of treatment is to prevent that happening.Thus the
purpose of the Gamma Knife is to destroy the AVM so that it may not bleed again.
One of the useful side effects is that this will usually improve or even stop the
AVMs may be treated by observation, though that is rarer today. Mostly interventions
are tried. The commonest forms of intervention are surgery, embolization and radiosurgery
Not all AVMs may be treated. Some are simply to big and complex. However, once a
decision is made to treat the lesion then a further decision must be taken as to
which treatment method is best. In many instances a combination of treatments may
The Gamma Knife cannot improve any symptoms due to damage done during a bleed. The
image to the right shows the destruction rate of AVMs at the
Gamma Knife Center. This chart illustrates also how the successful treatments increase
with time. These early results are amongst the best reported.
One of the nicest things about treating this condition is that the patient may in
principle return to work and forget the illness. The Gamma Knife also has the advantage
that it can treat AVMs which are not possible to treat in any other way.