- Hemispherectomy: Removal of a total hemisphere
- Hemispherotomy: Removal of part of the hemisphere
These types of surgeries treat seizures originating in an entire side, or hemisphere, of the brain. The two hemispheres control speech, memory and intelligence. The right hemisphere controls movement on the left side of the body and the left hemisphere controls movement on the right side. During the operation, surgeons disconnect the affected hemisphere from the other areas of the brain by cutting the electrical nerve pathways. The goal is to prevent seizures by separating the abnormal, seizure-causing tissues from the rest of the brain. Neurological function from the part of the hemisphere that has been removed sometimes relocates to the healthy side of the brain both before and after the surgery. A large percent of children may be seizure-free after the procedure.
After surgery, a child is often weak on one side. If surgery was in the right hemisphere, the left side of the body is weak and vice versa. The weakness can be permanent. Therefore, we limit this operation to children who either have severe seizures that greatly limit the quality of their life or are already weak on the affected side because of underlying brain illness, such as a stroke. Most children need to stay in the hospital after surgery for rehabilitation to help improve or manage this physical weakness.