Multiple subpial transections (MST) is a procedure during which nerve fibers are cut with a series of shallow cuts (transections) so the movement of seizure impulses is an interrupt. It is used in vital areas of the brain that control movement, feeling, language, or memory.
Also, it can be used as a treatment in children with a rare brain disorder that causes seizures and affects the parts of the brain that control speech and comprehension called Landau-Kleffner syndrome (LKS).
Epilepsy is a set of chronic neurological disorders characterized by seizures and the diagnosis of epilepsy implies that there is an abnormality in the brain and this abnormality will result in more epileptic seizures.
In most people, seizures can be controlled with medications but in some cases, a surgery can be an option and there are two types of epilepsy surgery: surgery during which an area of the brain which produces seizures is removed or surgery during which the nerve pathways through which seizure impulses spread within the brain are interrupt.
Also, different surgical procedures are available and their application depends on the type of seizures and the area of the brain where the seizures start.
A candidate for MST can be the person whose seizures cannot be controlled by medication and whose seizures begin in areas of the brain that cannot be safely removed.
Before the procedure, the candidate must undergo an extensive pre-surgery evaluation including electroencephalography (EEG), positron emission tomography (PET) and magnetic resonance imaging (MRI). Also, other tests can be performed to pinpoint the seizure focus and determine if surgery is possible.
During the procedure, the patient is put to sleep (general anesthesia) and the surgeon makes an incision in the scalp, removes a piece of bone and pulls back a section of the tough membrane that covers the brain (dura). The area is magnified with a surgical microscope and then a surgeon makes a series of shallow, parallel cuts (transection) over the entire area identified as the source of the seizure.
At the end of the procedure, the dura and bone are fixed back into place, and the scalp is closed using stitches or staples.
After surgery, the patient must stay in intensive care unit for 24 to 48 hours and in a hospital room for 3 to 4 days and it can return to normal activities, including work or school four to six weeks after surgery. Most patients will need to continue taking anti-seizure drugs for two or more years after surgery and when the seizure control is established, medications can be reduced or eliminated.
In about 70% of patients, seizure control is improved after MTS but the procedure is relatively new so there are no long-term outcome data available.
The side effects which can occur after MTS are:
- Scalp numbness
- Feeling tired or depressed
- Difficulty speaking,remembering or finding words
The risks of MTS include the risk of surgery failure, the risk of neurological deficits, swelling of the brain and like in many surgeries risks associated with the use of anesthesia.