What is epilepsy surgery?
Epilepsy surgery involves a brain operation to control epileptic seizures.
Different types of epilepsy require different types of operations.
Who is a candidate for epilepsy surgery?
In general, epilepsy surgery may be considered in people of any age, from
infancy to adulthood. The best candidates for epilepsy surgery are:
- People with epileptic seizures that cannot be controlled satisfactorily
with medication and whose lives would be improved if seizures were
controlled. The definition of "satisfactory" control varies from person to
person.
- People with a brain abnormality that can be identified as the cause of
seizures. Some abnormalities such as brain tumors may require surgery even
if seizures are well controlled with medication.
Which types of epilepsy respond to surgery?
1. Focal resective surgery is performed in people
with partial epilepsy, in which seizures arise from a small part of the
brain. It involves removing a small part of the brain, with the intent of
sparing important neurological functions such as movement, sensation, speech,
and memory. The most common location of surgery is in the temporal lobe (under
the temple). Partial epilepsy may be caused by a scar from birth, injury or head
trauma, brain tumors, arteriovenous vascular malformations (a tangle of blood
vessels resulting in fewer than normal connections between capillaries),
infections, or abnormal brain development.
2. Hemispherectomy is performed in people with
abnormalities of one hemisphere (side) of the brain. Conditions such as
Sturge-Weber disease, Rasmussen’s encephalitis, hemimegalencephaly, or perinatal
stroke may injure a large area on just one side of the brain. People with these
disorders typically have severe neurologic problems, such as paralysis and loss
of sensation on one side of the body. With this procedure, a portion of the
damaged brain is removed, and the rest of the hemisphere is disconnected from
the good portions of the brain to prevent the seizures from spreading.
3. Callosotomy involves cutting part of the corpus
callosum, a large bundle of nerve fibers that connect the two sides of the
brain. The goal is to prevent spreading of seizures from one side of the brain
to the other. Callosotomy is usually performed in people with severe
generalized tonic (stiffening) or atonic (limp) seizures that cause falling and
injuries ("drop attacks").
4. Subdural electrode insertion involves placing
electrode arrays directly in contact with the brain in order to better localize
the region(s) of the brain responsible for seizure onset. They also can be used
to stimulate the underlying brain tissue and document the presence of cortex
that supports important motor or language function. This technique is especially
useful in patients who have medically intractable epilepsy and normal anatomy
documented by magnetic resonance imaging.