What is epilepsy surgery?

The aim of the epilepsy surgery is to remove the underlying cause of the seizures and therefore cure the epilepsy. In some cases, however, it may only be possible to reduce the frequency of seizures as the cause cannot totally be removed.

Epilepsy surgery may be an option in children with focal seizures (this is where one area of the brain is responsible for starting the seizure), where thier life is impacted on in a major way, despite using a range of antiepileptic drugs. Therefore, we will usually consider surgery after a few years of epilepsy. However, we may consider surgery where it is very clear at an early stage that seizures are particularly difficult. Due to modern methods of investigation, it is now possible to offer surgery much earlier in the course of the epilepsy and to younger children. There is no youngest age for surgery.

Patients with non-focal generalised types of epilepsy may also be suitable for surgery.

Children with epilepsy may have additional problems with learning and behaviour and/or special educational needs, and this may also contribute to a decision about surgery.

Your child will need a series of investigations to find out whether there is a specific area of the brain causing the seizures, and whether this could be removed without causing further problems for your child. This will involve various outpatient and inpatient visits, to build up as full a picture as possible of your child’s seizures.

The process of investigation and surgery is likely to involve a sequence of visits. Children move through the decision-making process as quickly as is needed for their clinical condition. Sometimes it is apparent in a few weeks that an operation is needed and this may go ahead quickly. For other children the decision process may take up to a year or longer, especially if it is a complex decision or the seizure profile changes. More usually the investigation and decision-making process takes between six and nine months. A summary of the pre-surgical evaluation process is provided in the

Investigations take place during an admission to Koala Ward and several outpatient visits:

Electroencephalogram (EEG)

Video–EEG telemetry monitoring

Magnetic Resonance Imaging (MRI)

Neuropsychology

Developmental Epilepsy Service

Neuropsychiatry

Ophthalmology

Occupational therapy

Physiotherapy

SPECT scans

Speech and language therapy

Functional MRI

Invasive Monitoring

PET scan

When all the tests and assessments have been performed, the epilepsy multi-disciplinary team (MDT), including members from both GOSH and King’s Health Partners (KHP), meet to look at the results at the Epilepsy Surgery MDT Meeting.

The team will discuss whether surgery is an option for your child. They will discuss whether all the seizures come from one area of the brain and whether the operation would make any existing physical or learning problems worse.

The epilepsy MDT will make one of four decisions:

• Surgery is to be offered; no further investigations are needed

• Surgery may be an option but further investigations are required

• Surgery may be an option in the future but not at the present time

• Surgery is not an option

At this clinic you will be able to meet the surgeon and he or she will explain which operation is proposed, what it entails and the risks and benefits to your child. An epilepsy consultant and specialist nurse will also be there. You will have the opportunity to ask questions, be given information to read about the proposed operation and allowed time to think about the information given to you before you decide whether you want your child to have the operation.

When you have decided, please ring the nurse practitioner – epilepsy surgery and write to the neurosurgeon to confirm you wish to proceed. The surgeon will then offer a date for the operation and we will let you know the date by letter or sometimes the Neurosurgery Medical PA will call by phone.

Different types of operation are used for different types of epilepsy.

This is considered when one part of the brain is thought to be responsible for the seizures. The operation removes the abnormal area of brain that is causing the epilepsy but leaves the parts that are still serving useful purposes. If the part of the brain causing the seizures is in the temporal lobe, the surgeon will perform a type of focal resection called a ‘temporal resection’. If the part of the brain causing the seizures is in one of the other lobes, then the operation will be called an ‘extratemporal resection’. There are a number of different types of extratemporal resection. If one of these is recommended for your child, we will discuss it with you in detail.

This operation disconnects or removes one half of the brain from the other. Children who may benefit from this procedure usually have a long history of weakness down one side of the body. This is usually the result of severe damage to the opposite side of the brain, which may have been present from birth. The child’s general development may have been slow but normal. If the seizures are considered to arise from the damaged part of the brain, it is removed or disconnected to stop the seizures. This may not lead to any further weakness as the brain has usually reorganised other functions to the unaffected side.

This is considered for children who have many different seizure types, including ‘drop attacks’.
This operation disconnects the two sides of the brain from each other but no tissue is removed. The aim of this procedure is to stop these ‘drop attacks’ but it will not affect the other seizure types.

This is often used alongside medicines to reduce the frequency or severity of seizures. A pulse generator, implanted into the chest, sends electrical signals to the vagus nerve in the neck. The vagus nerve transmits these signals to the brain, stopping the burst of electrical activity that causes seizures.

Healthy children usually cope well with the anaesthetic, but the risk increases if your child has other problems. Any surgery carries a small risk of infection or bleeding. There is a five per cent risk of complications, which may mean that your child could have to stay in hospital longer than expected. In general, there is a less than one and a half per cent chance that your child will suffer some damage to his or her brain that could result in weakness down one side of the body. This will in part depend on the parts of the brain involved. This will be discussed in more detail with regard to your own child.

The doctors could continue to try to control your child’s seizures with anti-epileptic medicines, VNS therapy or a special diet for epilepsy called the Ketogenic Diet. However, although there are new medicines available all the time, people who have not responded to them early have a smaller chance of responding with each new medicine tried. This means that there is only a small chance of medicines controlling your child’s seizures long term.

The epilepsy team will discuss the expected results of surgical treatment with you and your child. These vary according to the child’s particular circumstances. The results are often excellent in commonly performed operations; overall around 70 per cent of children will become free of seizures. However, for a small number of children surgery is unsuccessful. The main purpose of the complex series of investigations already outlined is to reduce the number of children for whom surgery is unsuccessful, and to give you as much information as possible about the chance of success.