Hemispherotomy

What is hemispherotomy?

A functional hemispherotomy is a highly complex surgery 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, 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 Pediatric Epilepsy Center.

How to decide if this is the best option for my child?

We bring together a large epilepsy team to review every detail of your child’s medical history, tests, and images. This multidisciplinary group includes:

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 like movement, vision, and speech.

When do you perform a hemispherotomy?

A hemispherotomy is typically considered when other treatments fail, such as with seizures that don’t respond to medication. For the best success, it is best performed if:

  • Seizures are originating from one side of the brain.
  • Performing the surgery early in life helps maintain normal development. The younger the child, the more adaptable the brain is for “rewiring.”
  • As children age, neural tracts become harder to rewire. If the brain cannot create new pathways, a child runs the risk of falling behind developmentally.

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

Why choose Stanford Medicine Children’s Health for a hemispherotomy?

Our pediatric epilepsy neurosurgery team is nationally respected and operates within a Level 4 epilepsy center, as accredited by the National Association of Epilepsy Centers.

Our neurosurgeons utilize Synaptive navigation, the latest and most advanced neurosurgery toolset. Features include:

  • Ultra-high-resolution 3-D view: A camera-telescope/microscope mounted on a robotic arm.
  • Tractography: This allows surgeons to visualize the left-to-right-running tracts, making it easier to ensure all necessary disconnections are made.
  • World-leading expertise: Lucile Packard Children’s Hospital Stanford was the first pediatric hospital in the world to use the Synaptive platform.

How successful is a hemispherotomy in stopping seizures?

According to published research, 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.

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.

  • Uncommon risks: Hydrocephalus, hemorrhage, and, rarely, death.
  • Specialized support: Our operative team includes a dedicated pediatric neuroanesthesia team and pediatric neurointensivists for postoperative care to ensure the best possible outcomes.

What is the difference between a hemispherotomy vs. hemispherectomy?

While the names are similar, the procedures differ significantly:

  • Hemispherotomy: Disconnects tracts between the two sides of the brain or makes small holes to disengage damaged parts.
  • Anatomic hemispherectomy: Removes all damaged brain tissue on one side of the brain.

Because a hemispherectomy adds risk due to the amount of tissue loss, we prefer to perform a hemispherotomy.