Hemispherotomy is a highly specialized neurosurgical procedure often considered a last resort treatment for patients typically children suffering from severe epilepsy that originates in one hemisphere of the brain. It is a life altering surgery aimed at improving quality of life in individuals who do not respond to medications or less invasive interventions.
Hemispherotomy is not a common or first line treatment. Instead, it is a highly advanced neurosurgical intervention reserved for select patients who meet specific criteria. Unlike other epilepsy surgeries, hemispherotomy involves disconnecting an entire hemisphere of the brain to isolate the abnormal electrical activity responsible for the seizures. Though the concept may seem extreme, this procedure has helped hundreds of children regain control over their lives by drastically reducing or even eliminating seizures.
What Is Hemispherotomy?
Hemispherotomy is a neurosurgical procedure that functionally disconnects one hemisphere of the brain from the other. Unlike a traditional hemispherectomy, which involves the physical removal of part or all of a cerebral hemisphere, hemispherotomy involves cutting the communication pathways between the hemispheres while leaving most of the disconnected hemisphere intact.
The primary goal of the surgery is to stop or significantly reduce seizures by isolating the diseased hemisphere from the healthy one. Although radical, the procedure has shown remarkable success in children with conditions such as Rasmussen’s encephalitis, cortical dysplasia, Sturge Weber syndrome, and hemimegalencephaly.
Why Is Hemispherotomy Performed?
Hemispherotomy is usually recommended for children who have experienced intractable epilepsy from a very young age. In such cases, one hemisphere is significantly damaged or malformed, becoming a continuous source of debilitating seizures. If left untreated, these seizures can lead to cognitive decline, developmental delays, and poor quality of life.
Anti-epileptic medications often prove ineffective in these cases. When at least two medications have failed and the seizures can be localized to one hemisphere, hemispherotomy becomes a viable and often necessary option.
Types of Hemispherotomy Techniques
There are various surgical approaches to hemispherotomy, and the choice depends on factors such as the patient’s condition, anatomy, and the surgeon’s experience. The main types include :-
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Peri insular hemispherotomy :- Involves accessing the brain through the insular cortex.
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Vertical parasagittal hemispherotomy :- Uses a midline approach and is often less invasive.
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Trans sylvian hemispherotomy :- Performed through the Sylvian fissure, a natural brain groove.
Regardless of the approach, the ultimate goal remains the same: to sever the neural pathways that allow epileptic activity to spread from the diseased hemisphere to the rest of the brain.
The Procedure: What to Expect?
Hemispherotomy is performed under general anesthesia and typically takes 4–6 hours. The surgical team uses advanced imaging techniques like MRI and intraoperative navigation to map the brain in real-time. This ensures that only the intended areas are disconnected, preserving as much function as possible in the healthy hemisphere.
A craniotomy is first performed to expose the brain. Then, the surgeon carefully disconnects the corpus callosum (which links the two hemispheres), internal capsule, and other relevant white matter tracts. Once the disconnection is complete, the bone flap is replaced, and the incision is closed.
Post-surgery, the patient is transferred to the intensive care unit for close monitoring during the initial recovery phase.
Ideal Candidates for Hemispherotomy
Not all epilepsy patients qualify for hemispherotomy. The surgery is generally reserved for :-
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Children under the age of 10 with drug resistant epilepsy
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Patients whose seizures can be traced to one hemisphere
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Cases involving progressive neurological conditions like Rasmussen’s encephalitis
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Individuals with severe congenital brain malformations or acquired damage limited to one hemisphere
Pre-operative assessments include extensive neurological exams, EEG monitoring, neuroimaging, and neuropsychological evaluations. These help determine the extent of brain damage and the likely benefits versus risks of undergoing such an intensive procedure.
Recovery After Hemispherotomy
Recovery from hemispherotomy varies by individual but generally involves a hospital stay of 1–2 weeks. The first few days are spent in the ICU, followed by continued monitoring in a regular hospital ward. Swelling and discomfort are common but managed effectively with medications.
Postoperative rehabilitation is crucial for recovery and includes physical, occupational, and speech therapies. Since one hemisphere is functionally disconnected, some motor and sensory deficits especially affecting the side of the body opposite the disconnected hemisphere are to be expected. However, due to the remarkable plasticity of a young brain, many children can regain significant function over time.
Most children begin rehabilitation within days of surgery and continue for several months or even years. Long-term outcomes depend on the child’s condition before surgery, but many patients experience dramatic reductions in seizure frequency and improved cognitive and motor development.
Risks and Potential Complications
As with any major brain surgery, hemispherotomy carries risks. These may include :-
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Infection or bleeding
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Hydrocephalus (fluid buildup in the brain)
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Hemiparesis (weakness on one side of the body)
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Language or cognitive delays
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Seizure recurrence
However, these risks are carefully weighed against the potential benefits. For many children, hemispherotomy offers the only chance for a seizure-free or seizure-reduced life, along with improved developmental potential.
Long Term Outlook and Quality of Life
The long term success of hemispherotomy is quite promising, especially in carefully selected candidates. Studies have shown that up to 70–80% of patients achieve significant seizure control or complete seizure freedom after the surgery.
In addition to seizure reduction, many children demonstrate better attention, learning ability, and social interaction post-surgery. Continued follow-ups with pediatric neurologists, therapists, and psychologists play a vital role in maximizing outcomes.
It’s important to note that while some physical limitations may persist such as mild hemiparesis many children are able to attend school, engage in social activities, and lead fulfilling lives.
Advances in Hemispherotomy and Future Directions
Hemispherotomy is a constantly evolving field, with ongoing research aimed at improving surgical precision and minimizing side effects. Newer imaging technologies, robotic assistance, and minimally invasive approaches are being developed to make the procedure safer and more effective.
There is also growing interest in earlier surgical intervention, as early treatment often correlates with better developmental outcomes. As awareness and access to pediatric epilepsy surgery grow, more children worldwide stand to benefit from life changing procedures like hemispherotomy.
Conclusion
Hemispherotomy is a highly effective surgical treatment for children with severe, drug resistant epilepsy confined to one hemisphere. While it involves complex decision-making and an intensive recovery process, the potential for a seizure-free future and improved quality of life makes it a powerful option for many families.
