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What is a hemispherectomy?
A hemispherectomy is a surgical procedure where half of your child’s brain is either totally or partially removed or disconnected from the rest of the brain. It is a rare surgical procedure done for epilepsy that is not responsive to medications.
The “hemi” part of “hemispherectomy” means “half” and refers to the cerebral (brain) hemisphere – half of the brain.
Who benefits from a hemispherectomy?
Your child might benefit from a hemispherectomy if they have these symptoms:
- Seizures (epilepsy), not controlled with medication.
- Weakness on one side of their body, including loss of the use of a hand and/or loss of peripheral vision.
- Abnormal finding on brain MRI that usually affects one side of the brain.
- Developmental delay because of seizures.
Two-thirds of children who undergo hemispherectomy are completely seizure-free and another 15-20% have a substantial reduction of seizures. If a child has persistent seizures after an initial procedure, they should be carefully evaluated to see if they could benefit from a repeat surgery.
How does a hemispherectomy help?
A hemispherectomy removes or disconnects the half of the brain that is causing seizures, which prevents it from causing further damage. A hemispherectomy is usually done in children and occasionally in adults. In these patients, the whole hemisphere is abnormal and responsible for causing seizures.
There are two types of hemispherectomies: functional (disconnective) and anatomic.
- Functional (disconnective): The functional technique involves removing a smaller area of the brain and disconnecting the side from the rest of the brain. It has less risk for complications. Hemispherotomy is a term used when the tissue removed is small.
- Anatomic: Anatomic hemispherectomies are usually performed on children who have persistent seizures despite the “functional/disconnective” hemispherectomy. This type of hemispherectomy is where the frontal, parietal, temporal and occipital lobes of the brain are removed. This procedure has higher risk for complications – there can be extra blood loss and fluid buildup.
The two types have fairly equal success. However, when a functional hemispherectomy does not lead to seizure freedom, redoing a functional hemispherectomy as an anatomic hemispherectomy may lead to seizure freedom in a third of patients.
How can I prepare for a hemispherectomy?
You can help ensure the best possible surgical outcome by understanding what to expect before, during and after a hemispherectomy procedure at Gillette Children’s. Here are a few resources to help you feel more prepared:
What should I expect with a hemispherectomy?
A hemispherectomy takes place under general anesthesia, which means your child is asleep throughout the procedure. The neurosurgeon will perform a craniotomy, opening the skull to access the brain.
During the procedure, the surgeon:
- Removes a piece of the skull.
- Peels back a section of the dura, the tough membrane that protects the brain.
- Uses special instruments to remove a hemisphere of brain or disconnect the hemispheres.
- Replaces the dura.
- Uses stitches or staples to secure the skull bone back into place.
Every child heals differently, and outcomes depend on the neurologic condition of your child before surgery.
After surgery, your child will spend two to three days in the pediatric intensive care unit (PICU) for close monitoring. Antiepileptic medications will be continued.
A brain CT or MRI may be performed on the first morning after the operation to assess your child’s brain. Once the surgical drains are removed, your child will be transferred to a regular pediatric nursing floor. PT, OT and speech therapy will be consulted based on the child’s needs. An average hospital stay slightly varies between patients and usually ranges from five to seven days. Length of stay decisions are made by the surgical team and are based on your child’s condition and recovery.
Upon discharge, rehabilitation services are often required to enhance recovery from hemispherectomy. Your child may be transferred to a rehab facility for intensive physical, occupational and speech therapy. This is usually followed by home or outpatient services. Outpatient therapy can be provided through hospitals and free-standing facilities and schools. Check with your individual school system to see if this is a service provided.
Most children have excellent long-term results following a hemispherectomy. Occasionally, however, some complications may occur:
- Early complications, which occur either while the operation is happening or immediately after it, include blood loss, electrolyte changes, hypothermia and aseptic meningitis.
- Fluid buildup in the brain, also called hydrocephalus - in less than 5% with disconnective/functional hemispherectomy, and slightly higher risk with anatomic hemispherectomy.
Hemispherectomy Services at Gillette Children's
If your child or family member has epilepsy, they may find relief with a hemispherectomy surgical procedure. Gillette Children’s is one of a few hospitals in the area to offer this type of surgery to treat epilepsy.
Your child will work with a wide range of specialists. Along the way, they may receive care from internationally recognized experts in areas including:
- Neurosurgery.
- Neurology.
- Pediatric Rehabilitation Medicine.
- Neuropsychology.
- Child life.
- Psychiatry.
- Psychology.
- Rehabilitation therapies.
- Radiology and imaging.
- Social work.
We provide lifelong support and education in a family-centered environment. Our multidisciplinary team will work closely with you to develop a customized treatment plan to fit the specific needs of your child.
Hemispherectomy Resources
- Learn more about pediatric epilepsy surgery at the Pediatric Epilepsy Surgery Alliance.
- Deep brain stimulation (DBS) involves implanting a medical device called a neurostimulator under the surface of the skin in the abdomen or chest. It is used to control seizure activity.
