Epilepsy Surgery Handbook

Epilepsy is a common neurological disorder, characterized by recurrent seizures, that affects nearly 2.5 million people in the United States. A seizure is an electrical discharge from brain cells that disrupts normal function, producing a change in a person's consciousness, movement, and/or sensation. There are many different types of seizures and people with epilepsy may experience more than one type. The kind of seizure a person has depends on which part and how much of the brain is affected by the electrical disturbance that produces seizures.

Seizures are generally divided into two different types: generalized seizures and partial seizures.

A generalized seizure occurs when a burst of electrical energy sweeps through the whole brain at once, causing a loss of consciousness, falls, convulsions or muscle spasms.

Partial seizures occur when the electrical disturbance occurs in just one part of the brain, but occasionally it spreads and can cause a generalized convulsion or fall. This is called a partial seizure that is secondarily generalized. People with partial seizures often describe a warning or a change in feeling or movement at the beginning of the seizure. The warning is sometimes called an aura and is a partial seizure. Partial seizures may be called simple partial seizures or complex partial seizures. In simple partial seizures, the person is fully aware of the experience; in complex partial seizures, there is a change in awareness during the seizure. In the majority of people, seizures can be controlled with appropriate medications. However, it is estimated that 30 to 40 % of patients with epilepsy are not controlled with currently available medical therapy. Patients may be candidates for surgical treatment of their epilepsy in an attempt to achieve better or complete seizure control. Patients whose seizures are caused by specific abnormalities such as tumors or vascular lesions may consider surgery if they feel their quality of life would be significantly improved.

There are several factors that must be addressed before surgery is considered:

• Poor control of seizures with more than one medication
• A clear diagnosis of seizure type and syndrome
• Testing to rule out a metabolic, degenerative or structural cause
• Patient and family education to ensure knowledge of medication effects and side effects, as well as alternative treatment options.

Some seizures treated with surgery include:

• Those originating in the temporal lobe
• Any seizure with a focal onset
• Seizures with drop attacks
• Seizures coming from an entirely disordered hemisphere.

Overall, the most important element of a successful surgical outcome is patient selection. Selecting the most appropriate treatment requires a detailed presurgical evaluation to identify seizure type, seizure frequency, site of seizure onset, psychological and social functioning, and the degree of disability. This type of evaluation is best carried out in a multi-disciplinary center experienced in the investigation and treatment of epilepsy.

The goal of epilepsy surgery is to identify an abnormal area of brain tissue from which the seizures originate, and to remove it without causing any significant impairment. The brain is divided into two sides called hemispheres. Each side of the brain is then divided into lobes. The major lobes are temporal (sides of the brain), frontal lobes (front of the brain), parietal lobes (middle of the brain) and occipital lobes (back of the brain). An operation to remove all or part of these areas is called a lobectomy. It is sometimes possible to stop the seizures by removing the part of the brain that produces them. A lobectomy may be performed when a person has seizures that start in the same lobe every time. This surgery is only proposed if it can be safely done without damaging vital functions.

Temporal lobectomy is the most common type of epilepsy surgery. Success rates of 55 to 70% have been reported.

Extra temporal resection is performed when a clear-cut tumor, vascular malformation or other lesions is present. The brain is removed from areas outside the temporal lobes. It can be particularly difficult to localize seizures in the frontal lobes.

Corpus Callosotomy interrupts the spread of seizures by sectioning or disconnecting the nerve fibers (corpus callosum) that connect one side of the brain to the other. The corpus callosotomy is indicated in some patients with "drop attacks". The goal is to prevent the spread of seizure discharge to both sides of the brain. It does not stop seizure activity, but may limit the frequency and severity, especially of seizures that cause falls, thus lessening the risk for serious injury.

Hemispherectomy is most commonly performed in children with severe epilepsy and may be the most successful kind of epilepsy surgery.

The recommendation to consider surgery is initially made by the epilepsy surgery team, a comprehensive group composed of neurologists, neurosurgeons, psychologists, psychiatrists, nurses, social workers, EEG technologists and occupational therapists. Many or all of these specialists will be involved in the care of individuals who are considering epilepsy surgery. The treatment team considers both the medical and emotional needs of the patients and their families during the evaluation process. The decision to recommend surgery can take from several weeks to several months.

What is the role of each member of the care giving team? Epileptologist: A neurologist specializing in epilepsy. He/she determines the direction of patient care, orders appropriate tests and interprets the test data.

• Neurosurgeon: A surgeon specializing in the brain who has expertise in epilepsy surgery. He/she works closely with the neurologist.
• Neuropsychologist: Specializes in the brain and behavior, focusing on the impact of memory, insight, and cognition through interview and neuropsychological testing.
• Neuropsychiatrist: A psychiatrist specializing in neurological issues and the psychiatric impact of surgery. Treatment focuses on consultation and medication.
• Clinical Nurse Specialist: Specializes in psychosocial issues, pre and post-surgical care, medication treatment of epilepsy, and patient education.
• Neuro-Clinical Social Worker: Specializes in psychosocial issues of epilepsy, pre and post-surgical care, resources, community programs, and patient education.
• EEG Laboratory Technicians: Specializes in inpatient EEG monitoring, and monitoring during Wada tests and surgery.

While there are some variations in the evaluation of patients for epilepsy surgery, some general guidelines exist. The evaluation has many components and the goals are to classify the different kinds of seizures, as well as the frequency, severity, and duration of each type.

The primary components of the pre-surgical evaluation include:

• A detailed clinical history and physical examination
• A high-resolution MRI
• Functional imaging: This is a brain scan to evaluate brain metabolism. A PET scan may be used to identify areas of hypometabolism (decreased glucose uptake), which may be associated with a seizure focus identified by other studies. A single photon emission computer tomography (SPECT scan) may be used to evaluate blood flow
• Continuous video EEG monitoring. An inpatient hospital stay of three to seven days for 24-hour video and EEG monitoring. The patient’s medications may be reduced so a seizure is more likely to occur, with the goal of localizing where the seizures originate
• Neuropsychological testing. Neuropsychological assessment can provide essential data to help identify specific areas of decreased or altered brain function that may be related to where seizures originate. Language function, memory (verbal and visual) and visuospatial capability are examined
• Assessment of psychosocial functioning. A psychological, social and psychiatric assessment is performed. The expectations of surgery and the post-operative adjustment are explored

• If, after an inpatient stay and video EEG monitoring, a seizure focus is suspected, but the start of the seizures is unclear, some form of implanted (invasive) electrodes may be indicated

Intracranial studies are more invasive than scalp EEG studies, and involve a separate surgical procedure. Depth electrodes are used to assist with lateralizing (determining whether the right or left side of the brain is the seizure onset) and localizing (determining where the seizures originate) seizure onset, and are usually placed in both hemispheres using local or general anesthesia. Intracranial electrodes can be placed in areas that are not easily sampled by routine scalp electrodes, and can give more precise EEG information.

The patient usually spends one night in the Intensive Care Unit to monitor for signs and symptoms of increased intracranial pressure, bleeding, and infection, and is usually transferred to the Epilepsy Monitoring Unit the next day. The patient’s activity is restricted in the first few days post-operatively, and epilepsy monitoring may take place for seven to nine days.

The Wada test is used to determine which side of the brain is most responsible for language and short-term memory. The study is done in the Radiology Department and is an outpatient day procedure.

The patient fasts from midnight the night before, but morning medications may be taken before the procedure. The patient reports to the EEG Lab first and is then brought to the Radiology Suite. A catheter is placed in the artery and an injection of contrast material is given. Next, sodium amytal is injected into one side of the brain. Commands are given to the patient during this period when one hemisphere is essentially asleep, allowing the doctors to determine function of the other side of the brain.

Once the patient has returned to baseline following the first injection, sodium amytal is injected into the other internal carotid artery using the same procedure.

Medications, including Advil and aspirin, should be avoided before surgery because of their effects on bleeding time. Once the surgery is complete, the patient remains in the Neurology Intensive Care Unit for 24 to 48 hours, continues on his or her seizure medications, and is closely observed for seizure activity. The patient stays in the hospital up to a week and then returns home to recuperate. Post-operative pain varies among patients.

While there are risks in all surgical procedures, including the placement of depth electrodes and grids, most brain surgeries for epilepsy appear to be relatively safe. The success rate is determined either as a percentage of people who are seizure free, or whose seizures have reduced dramatically. Success depends on the type of epilepsy and operation performed. Complications can occur in about 2 out of every 100 of these operations. Depending on the kind of surgery that is performed, possible complications include partial losses of vision, motor ability, memory, or speech. Short-term memory problems after surgery are common; however, this is usually temporary and improves over time.

We recommend that a family member or friend stay at home with the patient for a week to help during recuperation. After three to eight weeks, the patient can usually return to normal activities. If returning to a job, we recommend four to six weeks to return part-time, and two to three months to return to full-time employment. It is usually recommend that patients stay on anti-epileptic medications for one to four years after surgery, though some patients may have to continue medication indefinitely to maintain seizure control.

Following discharge from the hospital, it is important to continue to document seizure occurrence. Talking about the need to continue medication following surgery is an important part of the educational process. Whether or not seizure control is improved, ongoing emotional and psychosocial support is essential. Patients may be reluctant to report symptoms for a variety of reasons, including fear that the surgery was not successful, or a desire to stop taking seizure medications. The nurse and social worker will continue to play a key role in assessing, supporting, and educating the patient and family as they confront the fears and realities of the outcome of the surgery.

"After so many years of feeling isolated, I found a group that does understand and can respond to the experience of having epilepsy surgery. A special bond has developed where we share information, coping strategies, and help each other keep a positive attitude."

Feelings can intensify after surgery. "Will I have a seizure?" "Will my memory be okay?" "Will my medications decrease?"

"After so many decisions, tests and procedures prior to surgery, I needed help to rebuild my life after surgery. Some important issues for me included driving, memory concerns, employment and health insurance. Most importantly, just being heard! Some of us have enjoyed greater seizure control than others but we are there to share the good and the bad."

"I was teased and ashamed of my seizures, so I did not complete high school. I was alone much of the time, fearful of having a seizure and had low self-esteem. Post-surgically I am more and more comfortable, supported and productive. It takes time but I keep working at it."

"I am now seizure free for 14 months. I never let my epilepsy control me, although it was hard sometimes. I am an occupational therapist and enjoy helping others. In some ways epilepsy helped me to try harder and to be who I am. The post-surgery support group helps me to cherish each day, educate others and receive love and support. We all really understand each other."

"Doctors see the inside of the brain, but not the adjustments needed after surgery. The first year post-surgery can have its challenges, as surgery can’t fix everything! Social issues were hard for me and I yearned for those who could understand. People who go through this surgery really understand. After two surgeries, and controlled seizures, I am feeling more comfortable and safer in social situations and I am working!"

"My fellow group-mates taught me how to remember things by keeping journals, writing cliff notes, and using electronic devices. It's good to have people to travel with on this journey. I am not alone. I became a mom recently, a goal I didn’t know I could reach!"

"Life is one big circle. Life was pretty great growing up, no worries, only fun. Seizures affected my life and I had some pretty chaotic times. School and relationships were pretty difficult, as were family relationships. Things are getting better with the help of computers and I have returned to school. Life is starting to get back to beginnings again."

"I was 18 years old when my seizures began. I have never really let it get me down, but having seizures after surgery was difficult. I would do it all over again, as how would I ever know? I have 2 beautiful children, although my house is like a fortress. Every precaution is taken and we have a safe household. With the help of education, medical alert bracelets, safe strollers and lots of love, I do not have to live in a cocoon with my children. People with epilepsy should be active, contributing members of society, just like everyone else."

"I had surgery in 1964. There was no one to talk to at the time before or after surgery. The benefits of a support group and a comprehensive medical team are a long awaited welcome to me. Burdens shared and understood are bearable burdens." "My life changed at age 30, when I was diagnosed with temporal lobe epilepsy. My behavior (told to me by others) made no sense to me. I needed help. After several medication trials, and lots of counseling, I did have long term monitoring, a Wada test and surgery was recommended. Surgery proved to be successful in controlling my seizures but I didn’t know how to move on with my life. Having gone to other support groups, I recommended it to my social worker. Proudly, it has helped me and others to feel connected!"