Stereotactic ablations and stimulation Stereotactic lesions of deep cerebral structures for epilepsy control have generally poor results and essentially abandoned years ago. Though these procedures are no longer in use, their theoretical foundations have encouraged modern stimulation techniques of these deep brain structures. Deep brain stimulation of the thalamus is actively being considered and experimental trials in the United States anticipated. Approved by the FDA in July 1997 VNS has already improved many persons quality of life. Implantation of an electrode to stimulate the left vagus nerve is far less risky than craniotomy for brain surgery and it is reversible.
Side effects are generally well tolerated.
The procedure in experienced centers is performed in just over one hour and the patient stays in the hospital only over-night. The ability to regulate the device with a hand held magnet allows some patients with auras to abort their seizures. It was noted by neurologists in the 19th century that pressure on the carotid artery and vagus nerve in the neck could abort seizures. Stimulation of the vagus nerve in animals was shown to decrease epileptic activity in the EEG and also decrease the frequency and severity of seizures. Several controlled human trials were then conducted in patients with partial epilepsy, all demonstrating a significant reduction in seizures with minimal side-effects.