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Surgery was once an option only for adults with a long
history of intractable seizures. Today, surgery is a
widely accepted treatment for children with severe seizures.
In fact, the ability of a child’s brain to re-organize
function following surgery makes younger people particularly
good candidates for surgery. The side effects of antiepileptic
drugs (AEDs) and the well-documented risk of developmental
dysfunction among children who are given AEDs at an
early age and for a long period of time are two other
reasons why surgery may be considered.
There are several surgical procedures available
to control the severity and/or frequency of seizures.
The type of seizures a patient has and their location
within the brain are important factors in determining
which surgery is performed.
Vagal Nerve Stimulation
Vagal nerve stimulation is a possibility for some children
with epilepsy. The body has two vagus nerves, one that
travels up the left side of the neck and one on the
right. One of the left nerve’s jobs is to relay information
to areas of the brain that are believed to produce seizures.
When this nerve is stimulated by a low level of electrical
current, some people find that their seizures are less
frequent or less severe. Vagal nerve stimulation has
most commonly been used for patients with partial seizures.
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- An incision
is made in the lower neck to place an electrode
around the vagus nerve.
- The stimulator
is implanted under the skin in the chest wall
through a second incision.
- Similar
to a heart pacemaker, the stimulator emits an
electrical impulse every five minutes that stimulates
the vagus nerve.
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A small, battery-operated device called a vagal nerve
stimulator can be surgically implanted in a person’s
body. It can be programmed to deliver stimulation at
regular intervals, or it can be activated with a magnet
when a patient anticipates a seizure. The surgery involves
implanting the device’s generator under the skin in
the patient’s upper left chest. A connecting wire is
guided under the skin and attached to the vagus nerve,
which is located on the left side of the neck. The operation
lasts about two hours, and a common temporary side effect
of the surgery is hoarseness, as the vagus nerve is
located near the voice box. Sometimes people experience
coughing or a tingling in their throat when the stimulator
is activated; adjusting the amount of current can remedy
this side effect.
The vagal nerve stimulator’s effectiveness varies.
Most patients can expect a 50 percent reduction in seizures,
with others experience better or worse results. The
device is not considered to be a cure, so patients generally
continue taking anti-epileptic medication. In cases
where the stimulator has proven highly effective, the
doctor may decide that a patient’s medications can be
reduced.
Other Surgical Options
A temporal lobe resection, where part of the brain
from which the seizure originates is removed, is commonly
performed on adults and children alike.
Two procedures that are almost exclusively done
on younger patients are corpus callosotomy (to relieve
severe generalized seizures) and hemispherectomy. When
seizures originate in one half of the brain and spread
to the other, a corpus callosotomy can be performed
to sever the neural connections between the brain’s
two hemispheres. This "disconnection" is not
a cure, but it can reduce the severity of the seizures.
Corpus callosotomy can also keep seizures from spreading
to other areas of the brain. However, partial seizures
may increase after surgery.
Hemispherectomy, the removal of about one-half
of the brain, is reserved for children with severe,
frequent, and often life-threatening epilepsy that cannot
be controlled by medication. The seizures originate
from one side of the brain, and typically, the child
has some degree of paralysis on the opposite side of
the body.
Removing half of someone’s brain is a radical concept,
and there could be some very serious complications,
including fluid build-up in the brain, infection, and
coma. There is permanent loss of hand mobility on the
side opposite of the removed hemisphere and vision may
also be affected. For many of these children, hemispherectomy
significantly or completely controls seizures and enables
the youngsters to function well with improved behavior
and intelligence. Especially in younger children, the
remaining half of the brain compensates for the missing
half.
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Epilepsy
and Children
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