Surgery for epilepsy

Great Ormond Street Hospital (GOSH) has had a programme for surgery for treating epilepsy in children since 1992. GOSH has the facilities needed for the investigations, tests and treatment your child may need. These facilities are specifically for children and the specialists who use them have many years’ experience of children with epilepsy.

Since 2012, the NHS has made epilepsy surgery a nationally commissioned service and in England there are four centres designated as part of the Children’s Epilepsy Surgery Service (CESS). The recognised centres are Birmingham, Bristol, Liverpool/Manchester, and GOSH in partnership with King's Health Partners. We work closely with the UCL Institute of Child Health (ICH), with many of the team working in both GOSH and the ICH.

GOSH CESS team also works in collaboration with King’s Health Partners (KHP) and Young Epilepsy (YE). KHP brings together King’s College London and three successful NHS Foundation Trusts (Guy’s and St Thomas’, King’s College Hospital and South London and Maudsley). KHP also have a long-established very experienced children’s epilepsy surgery service and are the South East Thames region centre for children’s neuroscience.

YE is based on a beautiful 60 acre rural campus in the village of Lingfield on the Surrey, Sussex and Kent borders. YE provides medical assessment, rehabilitation, care and education for children and young people with epilepsy and other neurological conditions. At YE, the Neville Childhood Epilepsy Centre provides inpatient interdisciplinary assessments and rehabilitation packages for children and young people aged three to 19.

These partnerships mean that we can draw on the expertise of professional staff from all of these organisations, to provide a high standard of service for children and young people, with the benefit of the latest medical research.

The Epilepsy Team is multidisciplinary. Members of the multi-disciplinary team (MDT) include neurologists, neurosurgeons, neuropsychiatrists, neuropsychologists, developmental specialists, neurophysiologists, EEG physiologists, nurse specialists, nurses, neuroradiologists, social workers, speech and language therapists, occupational therapists, play specialists, physiotherapists and administrative staff.

The brain is like an electrical circuit, with impulses flowing from nerve to nerve in an organised fashion. Sometimes people experience disorganisation of such activity. This causes a sudden burst of electrical activity in the brain cells, deep in the brain, which causes the epileptic seizure or fit.

The cause of this seizure may differ from child to child. The seizure may start in one part of the brain (focal epilepsy) or the whole brain at the same time (generalised epilepsy). Focal epilepsy may spread to involve the whole brain (secondary generalisation).

The aim of the 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.

We usually recommend surgery for children with focal epilepsy who continue to have troublesome seizures despite trying antiepileptic medicines. 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.

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.

When your child is referred here by your local medical team, he or she will have an initial outpatient visit to see one of the paediatric neurologists. During this visit, the neurologist will discuss your child’s history in great detail and carry out a full examination. This is to see which type of epilepsy your child has, review his or her treatment and talk about any problems. The neurology team will also discuss the role of the operation with you and which investigations your child will need.

Your child will need a series of investigations to find out whether there is a specific area of 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. We may ask other hospitals to assist us in completing our investigations as not all of the tests are available at GOSH.

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, 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.

Your child may need various investigations to decide exactly where the seizures are coming from, and whether that part of the brain is performing any vital function. Not all children will undergo every investigation. Which investigations are performed will depend on the type of epilepsy your child has and whether the doctor feels they are appropriate when deciding about epilepsy surgery.

This is the brain wave test. Your child has probably had one or more of these before, either at this hospital or elsewhere. An EEG usually takes half an hour to an hour. This test shows whether there is abnormal seizure activity in certain areas of the brain between seizures.

This is an EEG performed as an inpatient over a longer period of time, sometimes several days and nights with a video camera. This test is used to record a number of seizures. If the seizures are not very frequent, we may need to reduce your child’s anti-epileptic medicines while he or she is in hospital. We shall need to find out whether the seizure(s) recorded are typical for your child and review the EEG to see where the seizures originate from electrically and how they spread.

Video-EEG telemetry can be done at GOSH or at our partner unit, YE in Lingfield.

This is a type of brain scan that uses magnetic signals rather than x-rays to obtain a very detailed picture of the brain. This is to see whether there is a structural abnormality that may be causing the seizures. Your child may have had an MRI elsewhere. We will look carefully at any MRIs before we decide if we need to repeat the scan. If we do repeat the MRI scan, this is because either our scans will be more detailed, more up to date or we need more information that has not yet been obtained.

These are tests performed to see whether your child has any particular learning problems. This involves up to eight hours of games and puzzles split into several sessions. The tests can also tell us whether the part of the brain from which we think the seizures are coming is performing any useful function. This will help us decide whether removing it would cause problems. In young children, these assessments are performed by our Developmental Epilepsy Service.

A psychiatrist with experience of epilepsy surgery sees the children and their families as part of the initial assessment. This is, in part, to see what problems the epilepsy may be causing and whether surgery may help to relieve them. We will discuss the changes you hope for as a result of surgical treatment. You will also have an opportunity to discuss in detail any additional concerns you might have about emotional, behavioural or social problems, and whether additional treatments for these should be put in place. This is important because treating other problems will help maximise your child’s quality of life in conjunction with any operation they may have.

A PET scan is a special CT scan of the brain. Your child will be given an injection of a radio-active dye (tracer) into a vein. This tracer shows areas of hypo-metabolism in the brain (cold spots). This helps show us which areas of the brain may be involved in your child’s epilepsy. PET scans are performed at our partner site (the PET Imaging Centre at St Thomas’).

A SPECT scan gives a picture of blood flow within the brain. The pattern of blood flow may change during a seizure. The scan is performed after an injection of a radio-labelled dye which shows up on the scan. Two scans are needed, one where the injection has been given during a seizure and one where the injection has been given when your child has not had a seizure. These scans can give us more information as to where the seizures are starting. We will look at the two scans separately and also compare the two together to give us this information.

The brain works by a series of nerve impulses, which cause electrical signals within the brain. These signals (also called brainwaves) can be recorded through the scalp using an EEG. The electrical signals also produce weak magnetic fields, which can be measured through the skull and scalp using a MEG scan.

Other types of assessment, for example, speech and language therapy, occupational health, physiotherapy, ophthalmology, functional MRI and EEG-fMRI may be organised depending on the type of epilepsy, and the types of problems your child has. This will give us a set of results which we can use to see if surgery will help and to compare past surgery. These tests may need to be repeated before the team can decide about surgery.

All these investigations take place during an admission to Koala Ward and several outpatient visits.

When all the tests and assessments have been performed, the epilepsy MDT, including members from both GOSH and 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/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’. Drop attacks occur when the child suddenly drops to the ground, either stiff or floppy, and may harm themselves. 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.

When you and your child leave hospital, a nurse specialist will call you on the telephone 10 to 14 days later, to ask how your child is recovering and how the wound is healing.

We will arrange an appointment in the epilepsy surgery clinic. This is likely to be around six weeks after you leave hospital. At six months, your child will see his/her named epilepsy consultant at GOSH. Do not change/reduce/stop your child’s drugs until your doctor advises you to so do - this may not be for several months.

Coming up to 12 months after the operation, your child will need to have a few more investigations and check-ups. These may include an MRI, EEG, neuropsychology, physiotherapy, ophthalmology and a review in the epilepsy surgery clinic. We will continue to review your child at regular intervals for several years if needed. If all is well, your follow-up will be with your own local consultant paediatrician and/or consultant paediatric neurologist.

Our research team may also wish to contact you and your child from time to time over the years to help us improve our services and treatments. We would appreciate your continued help.

Your child and your family will go through a period of adjustment after the operation. We encourage you to discuss this as much as possible. We can make appointments for you with other specialists if necessary.

Last reviewed by Great Ormond Street Hospital: October 2013