Assessment before epilepsy surgery
Before any surgery, you will undergo an extensive assessment at the National Centre for Epilepsy (SSE) at Oslo University Hospital. The length of the assessment varies, depending, among other things, on how quickly we can record enough epileptic seizures using video-EEG and complete other supplementary examinations, such as imaging. If the assessment shows that you can have surgery, you will be referred for surgery at the Department of Neurosurgery at Rikshospitalet.
The most common surgical method is to remove the epileptic focus—the area of the brain where the seizures start. If MRI scans show abnormalities in or near a suspected seizure-onset area, the likelihood of achieving a good result with or after surgery increases.
We can usually not remove the focus/area if it is located in parts of the brain that are essential for vision, hearing, movement, language or memory, because of the risk of unacceptable functional impairment. To map important functional areas more precisely for each patient, special tests may be needed before surgery, such as functional MRI (fMRI) or the Wada test.
Neuropsychological assessment and evaluation
Before surgery, it is important to assess brain function neuropsychologically. In addition, a physiotherapist and occupational therapist will assess your ability to control and coordinate your body’s movements, as well as your functioning and skills in everyday activities.
Intracranial monitoring
In some cases, further assessment is needed to determine exactly where the seizures start. This is done by recording EEG from electrodes placed inside the head (intracranial monitoring). After surgery to place intracranial electrodes, most people need to sleep quite a bit during the first 24 hours. Some may experience nausea and pain during the first few days.
Waiting for seizures during intracranial monitoring
As with other EEG examinations, we aim to record seizures in order to identify where they start, if possible. In addition, electrical stimulation through the electrodes is often needed to map patterns of spread in the brain, locate functions, and assess susceptibility to seizures in the different areas.
Intracranial monitoring lasts from a few days to two or three weeks, depending on how often you have seizures. Healthcare professionals continuously assess whether enough seizures have been recorded for the examination to end.
The waiting period during monitoring may feel long. You will need to spend most of your time near your bed, but you can watch TV, play video games, read books and do similar activities. You will remain in the monitoring room until enough seizures have been recorded. After intracranial monitoring, those who have had strip or depth electrodes will stay at Rikshospitalet for a few days. They will then be transferred to SSE or their local hospital. The waiting time between intracranial monitoring and possible surgery varies from patient to patient, depending on several factors, but is usually at least approximately six weeks. This is to reduce the risk of infection.
Those who have undergone intracranial monitoring with grid electrodes and are found to be eligible for epilepsy surgery are most often operated on at the same time as the grid is removed. You will then be transferred to SSE after approximately four days and can go home after approximately 10 days.
Admission for epilepsy surgery
Admission for epilepsy surgery takes place on the neurosurgical ward at Rikshospitalet. There, a neurosurgeon and nurse will give you information about the surgery, an anaesthetist will examine you, and blood samples will be taken.
There may be some waiting the day before epilepsy surgery. In the evening, you must wash your hair and wash yourself with antibacterial soap (Hibiscrub).
You must not eat or drink anything during the last six hours before surgery.
Medication
Take your epilepsy medication as usual; you may swallow it with a little water.
