Many patients with epilepsy find their condition adequately controlled with medication. However, for about 30% of epilepsy patients, the medications are ineffective or have intolerable side effects. In these cases, it may be a good idea to consider brain surgery.
Surgery for epilepsy is a procedure intended to help control seizures and improve quality of life of epilepsy patients by removing or isolating the brain area that causes the seizures. There are two main procedures available, one of which removes the area of the brain that causes seizures, and the other is a technique that interrupts the nerve pathways through which seizures develop.
It is thus important that the area of the brain causing the seizures is clearly visible and removable. It is also critical that this area not be responsible for critical life functions such as movement, sensation, or language. The decision to perform surgery is a delicate one that must involve extensive testing, evaluation and consideration between the patient and his medical team.
Effectiveness of Epilepsy Surgery
Success rates for epilepsy surgery vary and depend on the surgical technique employed. Success rates range from 50% and 80%, with some people becoming completely seizure-free after the procedure and others for whom their frequency is notably reduced. There are cases in which a second surgery is recommended. However, it is important to note that most patients must take anti-seizure medication for a year or perhaps more after surgery, as control of seizures can take time to be established.
Candidates for Surgery
Epilepsy patients whose seizures are not well controlled by medication or who find the medication intolerable may be candidates for surgery. You must have tried at least two different anti-seizure medications to be considered for surgery. In addition, patients whose seizures are debilitating despite the use of medication are also possible candidates. However, these patients must not have any other chronic or disabling medical condition such as heart disease or cancer. It is also important that the patient’s seizures always originate from the same area of the brain.
The most appropriate procedure for a patient will depend on the kind of seizures they have and the part of the brain where the seizures originate. There are a number of options available, including:
Temporal lobe epilepsy is one of the most common forms of epilepsy.
If your seizures originate in the temporal lobe, which is one of the cerebrum’s four main lobes, brain tissue in this lobe can be removed to reduce the incidence of seizures. About 90% of patients experience a reduction or even a cessation of seizures with this procedure.
This approach is used when there is an injury or isolated defect, such as a tumor, that is causing the seizures. Removal of the injured area or growth is usually very effective in reducing or eliminating seizures caused by the lesion.
- Corpus callostomy
With this procedure, the two hemispheres of the brain are cut to disable communication between them and to prevent the seizure activity from spreading from one side of the brain to another. This type of surgery is only appropriate for patients with extremely intense seizures that put life at risk.
- Functional hemispherectomy
With this procedure, the 2 brain hemispheres are disconnected, and a limited amount of brain tissue is removed. This procedure is usually only used in children under 13 years of age, in whom one hemisphere is not working correctly.
- Multiple subpial transection (MST)
With this approach, the surgeon makes several shallow cuts to interrupt the transmission of seizure signals to other parts of the brain. This technique is best for patients whose seizures originate in critical parts of the brain that cannot be removed.
Like any surgery, epilepsy surgery carries certain risks, including:
- Infection, bleeding, and an allergic reaction to anesthesia, as with any type of surgery.
- The surgery may exacerbate seizures rather than alleviate them, or may create new neurological deficits. These deficits could affect critical functions such as vision, movement, and speech.
- There is also the risk of surgical failure, meaning that in the end it does not reduce the occurrence of seizures.
It is very important to carefully discuss the risks and benefits of possible surgery with your medical team before making a decision.