Overview

Lennox-Gastaut syndrome (LGS) is a complex and rare condition, almost always seen in children before the age of 10 and can persist into childhood. It is characterised by abnormally slow sleep waves presented on the Electroencephalogram (EEG), causing multiple types of seizures that ultimately lead to cognitive and developmental impairment. These seizures can become resistant to even the most aggressive drug therapies. According to Rare Disease Advisor, the mortality rate for the syndrome in childhood remains between 3% to 7%. A combination of antiseizure medications is used, and in cases where these treatments don’t work, surgical options like Corpus callosotomy are used. In this article, I will explain the effects of LGS and how surgical interventions may help with persistent seizures. 

Understanding lennox-gastaut syndrome

LGS is a severe type of epilepsy where the nerve cells in the brain don’t signal to each other properly, leading to bursts of unregulated electrical activity. Most cases begin between the ages of 3 to 7 years, and approximately 90% of children with the condition continue to have seizures into adulthood. However, the onset of symptoms is said to be within the first year of life. 

The condition is associated with perinatal injuries, congenital infections, brain malformations, brain tumours or genetic mutations. Patients experience different types of seizures.² Some are called Atonic seizures or drop attacks, where the person suddenly loses control of their muscles and falls to the ground without warning. These can be very dangerous because they happen so quickly. Tonic seizures are the most common type, occurring most frequently during non-REM sleep.¹,² This is when a person’s body becomes very rigid due to uncontrollable muscle stiffness.

Seizures disrupt normal brain activity, which affects the development of children’s brains. The underlying brain damage or conditions causing LGS may already lead to cognitive dysfunction. This can lead to developmental delays like:

• Learning to walk later than expected
• The loss of skills already gained, especially during periods of frequent seizures
• Difficulty engaging in social interaction, speech or coordination
• Intellectual disability, such as the inability to process information and memory impairment

How is lennox-gastaut syndrome managed? 

Anti-seizure medications are offered in the initial stages of treatment, but sometimes the patients become resistant to the effects of the drugs and no longer become a viable option for long-term use. This is called drug-resistant epilepsy, when seizures continue even after trying more appropriate medications at the right doses.³

Other treatment options, such as dietary therapy and surgical procedures/implants, are used in combination to reduce the frequency of seizures or, if not, stop them entirely. Corpus callosotomy is one of the surgical procedures offered to LGS patients, but this particular one has been shown to be effective with patients who suffer from atonic seizures.⁴

What is a corpus callosotomy?

A corpus callosotomy is a kind of brain surgery that is used to treat severe epilepsy, typically when seizures don’t respond to medication. In this procedure, a bundle of nerve fibres called the corpus callosum, which connects the left and right sides of the brain, is safely cut to stop seizures from spreading from one side to the other. This structure, the corpus callosum, acts like a bridge, letting the two sides of the brain send messages to each other. In many people with LGS, seizure starts on one side and spread to the other side.⁴ Once this happens, the seizure becomes more intense and affects the whole body. The main goal of the procedure is to reduce the number and severity of the seizures. This procedure is typically done in severe cases where other treatments have failed. There are two types of callotomy:⁷

• Partial callosotomy (frontal part only: Typically, the first choice for many patients 
• Complete callosotomy (entire “bridge”): Used when partial callosotomy doesn’t reduce enough seizures 

It is performed under general anaesthesia by a neurosurgeon.

What to expect?

Up to 70–90% reduction in atonic seizures is seen in patients who undergo corpus callosotomy. Before the procedure, many factors are taken into account, such as the slow spikes and wave patterns on the EEG and the cognitive development of the patient, and any underlying brain conditions. Complete callosotomy achieves a more consistent seizure reduction, especially with atonic seizures. The procedure is considered relatively safe and effective. A significant number of children show noticeable positive changes in behaviour, attentiveness and overall quality of life.^8,9 The surgery is performed under general anaesthesia by a specialist neurosurgeon, usually after a referral from your local GP or epilepsy care team.

Before the surgery, you can expect to have blood tests to check overall health, as well as brain imaging, such MRI. An EEG will also be used to record the brain’s electrical activity and identify how seizures spread, which helps guide the surgical approach.

After the surgery, recovery usually takes a while, between 6 to 8 weeks. There are some short-term side effects, such as issues with coordination and speech, nausea, memory problems, and headaches. However, these effects should fade after a while.

Risks and side effects

All surgeries come with some risks. The medical professionals involved in your treatment should discuss the potential risks involved. Although corpus callosotomy is generally safe and effective, there are some general risks and side effects: 

• Dissconnection syndrome 
• Loss of coordination 
• Speech problems 
• Memory loss 

Summary 

• LGS is a severe type of epilepsy where the nerve cells in the brain don’t signal to each other properly, leading to bursts of unregulated electrical activity
• Corpus callosotomy is one of the surgical procedures offered to LGS patients, but this particular one has been shown to be effective with patients who suffer from atonic seizures, also known as “drop” attacks
• Callosotomy doesn’t stop all seizures or guarantee an epileptic free life; however, it greatly improves the quality of life for a lot of patients by reducing the frequency and intensity of seizures
• It’s not the first option, but for the right patients, it can be life-changing