What is Epilepsy Surgery
Surgery for Epilepsy: Medications can control seizures well in ~ 70% of people. But in 30% of patients, medicines are not effective and in few of these patients, brain surgery to remove the focus causing epilepsy may be a good option for seizure freedom or even a significant reduction in the disabling seizures. Epilepsy Surgery has been an accepted form of treatment for over 50 years. With advances in MRI techniques and new surgical techniques along with ways of identifying areas to be removed, Epilepsy surgery procedures being done with good success. Surgery can be performed on both children and adults. However, it is not a suitable treatment for everyone who has epilepsy, or for everyone where medications are ineffective.
Surgery is considered only if the area of the brain where the seizures start, can be clearly identified, and if the area to be removed is not responsible for any important functions, like sensation and movement, language. Surgery may help 30% of the people with epilepsy whose seizures do not get controlled well in spite of medical treatment. Epilepsy surgery is a highly specialized procedure and performed by highly experienced surgeons only in few centers. Epilepsy surgery is considered only when the person is thought to have a very good chance of becoming seizure-free after surgery. This is considered in people whose seizures can be shown to arise in one area of the brain. Over 70% of people who have epilepsy surgery become completely seizure free.
Advantages of Epilepsy surgery
Surgery for epilepsy is advancing continuously with new techniques, new equipment and an increasing number of Neurosurgeons interested in delivering this service. There are a steadily growing number of people undergoing this surgery and many of those people going on to enjoy a much better quality of life. The success of modern surgery for epilepsy has caused a widespread interest in this type of treatment, with people accepting this preferable to a lifetime being on medication.
Who should undergo Epilepsy Surgery
To find out whether someone is suitable for this type of surgery a number of things will need to be taken into account by the consultant Neurologist or epileptologist.
Surgery will be considered if the person has no other medical problem which would make them unsuitable for this type of surgery and anti-epileptic drug treatment has been tried but still the seizures are uncontrolled. The seizures should be arising from one localized area of the brain and the person's ability to function normally should not be affected by removing this part of the brain. The affected part of the brain can be removed without causing further damage to any other part of the brain and the areas of the brain responsible for speech, sight, movement or hearing are not close to the part of the brain to be removed.
What are the tests conducted before surgery
The first thing a doctor has to establish when considering surgery as an option is to establish the patient's suitability. Will surgery be possible and, if so, will it be beneficial To get good information about the epileptogenic zone to be removed, few tests are done before surgery. These may include MRI scans, video telemetry, psychological tests.
Video EEG-The aim is to study the person having several seizures while the EEG is connected.
MRI brain-The surgeon will also want to have an up-to-date image of the patient’s brain and this means having an MRI scan
SPECT & PET- PET (positron emission tomography) and SPET (single positron emission tomography), which involve injecting tiny traces of radioactive substances into the body and watching which part of the brain they reach
These tests are available only in specialized centers.
In some instances, invasive EEG mapping is done in which the surgeon will place special electrodes onto the surface of the brain itself to know the area of the beginning of the seizures, although this is only done in a small number of cases. The type of surgery that a patient undergoes will depend greatly on what the surgeon hopes to achieve.
After all the tests have been performed the cases will be discussed in the patient management meeting of the multidisciplinary team for Epilepsy evaluation and surgery and a decision about the need for surgery and planning of surgery will be done. This will be discussed with the patient and family members about the chances of seizure control and the risks involved in the case and a final decision about epilepsy surgery will be taken.
What are the types of surgeries performed?
Temporal lobectomy - This is the commonest surgery performed and nearly 80% will be seizure free after surgery and a larger part of the temporal lobe is removed; Hemispherectomy - sometimes used to treat very severe epilepsy in children with damage to one whole side of the brain. The damaged side of the brain is disconnected from normal brain;
Lesionectomy: Removal of a lesion such as a tumour or a cyst
Corpus callosotomy - again sometimes used to treat children with very severe epilepsy, this operation involves cutting the fibres that connect the two halves of the brain.
After the surgery
Despite the lengthy and very difficult nature of brain surgery, most patients make a rapid recovery and are usually up and about within a couple of days.
Between eight and fifteen weeks later, most people are able to return to work. Some aspects, like waiting for the nerves that supply sensation to the skull, may take some time to recover.
Some people may experience seizures just after the operation due to temporary swelling. This does not mean that the operation has failed.
Depending on the person’s own doctor, it may be some time before the patient can start reducing their medication Up to 75 to 80% of patients notice a dramatic reduction in the number of seizures after surgery, especially temporal lobectomy and many finding that their seizures appear to have stopped. They can then look at reducing or stopping their medication in consultation with their doctor. Most of the times the medicines should be continued up to one year after surgery after which a gradual reduction of the medicines can be done.
Vagus nerve stimulation
VNS is a relatively new type of treatment for epilepsy. It aims to reduce the number, length and severity of seizures a person has. VNS is a treatment for epilepsy where a small generator is implanted under the skin below the left collar bone. This is connected to a lead with three coils at one end. These coils are wrapped around the vagus nerve in the left side of the neck in a small operation. The VNS stimulates the vagus nerve at intervals to reduce the frequency and intensity of seizures.
How epilepsy surgery is planned
Good communication between the doctor and the patient is important with all epilepsy treatment, but especially when surgery is being considered. The patient and the family should have a realistic picture of the benefits, the risks, and the chances of complete or partial control of epilepsy afterwards. The emotional aspects related to epilepsy needs to be evaluated and managed before and after epilepsy surgery. People may feel disappointed if they are not totally seizure free or if they have to go on continuing the antiepileptic medicine usage after the surgery. Sometimes people also develop depression. It is better if both the patient and the family know what to expect and have talked about them with the multidisciplinary medical team (which may include neurologists, neurosurgeons, nurses, and psychologists) before any operation takes place. It may be stressful and difficult to meet the new expectations that others may have, or to adjust to being a person without seizures after having them for so long. In most cases, these reactions are temporary. Like other issues that may arise in connection with epilepsy surgery, they can be handled.