What is hemispherotomy?

A functional hemispherotomy is a highly complex surgery that’s reserved for the most severe cases of uncontrolled epileptic seizures coming exclusively from one side of the brain. The surgery disconnects the right and left sides of the brain from one another. When the healthy side of the brain is separated from the damaged side of the brain, seizures can no longer travel across the corpus callosum (the band of nerves at the top of the brain that connects the two hemispheres) and disrupt healthy brain activity. The surgery takes several hours and is performed by experienced pediatric neurosurgeons within our Epilepsy Center.

How do you decide it’s the best option for my child?

We bring together a large epilepsy team of pediatric epileptologists, neurosurgeons, neurologists, fellows, residents, nurse practitioners, nurses, case managers, and neurodiagnostic technologists to review every detail of your child’s medical history, tests, and images to decide the best path forward. Testing often includes electro- and neurodiagnostic testing such as electroencephalogram (EEG), which records brain activity and charts seizure activity, and functional MRIs, which map important functions, such as movement, vision, and speech in the brain.

When do you perform a hemispherotomy?

Hemispherotomy is performed when other treatments to control seizures fail, such as with seizures that don’t respond to medication. Hemispherotomies are most successful for seizures that originate from one side of the brain, rather than both. Hemispherotomy is typically performed in early childhood, to take advantage of the rewiring potential at a young age, but we can perform it at any age.

Why is timing important with a hemispherotomy?

Performing a hemispherotomy early on in a child’s life helps maintain normal development. There is a window of opportunity for brain development, and the older a child gets, the less adaptable the brain becomes. With each year, tracts in the brain (neural pathways made up of several nerve fibers grouped together that carry information between parts of the brain, the brain stem, and the spinal cord) become harder to rewire. If the brain cannot create new neural pathways, a child runs the risk of losing function, which could cause the child to fall behind developmentally.

The good news is that the brain is very adaptable, and when one half of the brain is damaged, the other half often creates new tracts to maintain function.

Why Stanford Children’s Health for a hemispherotomy?

Our pediatric epilepsy neurosurgery team in our Epilepsy Center is nationally respected and is guided by input from our pediatric epileptologists and neurologists. The Pediatric Epilepsy Center at Lucile Packard Children’s Hospital Stanford focuses on identifying the epilepsy cause and treating seizures with leading-edge techniques. We are accredited by the National Association of Epilepsy Centers as a level 4 epilepsy center. Level 4 epilepsy centers have the professional expertise and facilities to provide the highest-level medical and surgical evaluation and treatment for patients with complex epilepsy.

Our pediatric neurosurgeons are guided by the latest, most advanced neurosurgery tools called Synaptive navigation. The tools include an ultra-high-resolution camera-telescope/microscope mounted on a robotic arm that provides a high-quality 3-D view of the brain. For the hemispherotomy, the tractography feature empowers our pediatric neurosurgeons to visualize the left-to-right-running tracts, to make it easier to ensure that they are all disconnected. Lucile Packard Children’s Hospital Stanford was the first pediatric hospital in the world to use the Synaptive platform.

How successful is hemispherotomy in stopping seizures?

According to published research studies, approximately 77% of patients receiving hemispherotomy are seizure free after surgery, while the remaining patients achieve some level of improvement. At Packard Children’s, we have excellent outcomes in children who are good candidates for this procedure to stop the seizures.

What are the risks associated with a hemispherotomy?

The biggest risk is an incomplete disconnection of neural tracts from one side of the brain to the other, which can be addressed with additional imaging and surgery. In order to stop seizures, all tracks must be disconnected. Other uncommon risks include hydrocephalus, hemorrhage, and, rarely, death. The operative team includes not only surgeons but also a highly specialized pediatric neuroanesthesia team and pediatric neurointensivists for postoperative care, who all contribute to the best possible outcomes for your child.

Is it related to a hemispherectomy?

While the name is similar, the procedure is different. A hemispherotomy disconnects tracts between the two sides of the brain and brain stem or makes small holes in the brain to disengage damaged parts, while an anatomic hemispherectomy removes all damaged brain tissue on one side of the brain. A hemispherectomy adds risk due to the amount of tissue loss, so we prefer to perform a hemispherotomy.