Surgery reduces epileptic seizures
BMJ 1996; 313 doi: https://doi.org/10.1136/bmj.313.7054.383 (Published 17 August 1996) Cite this as: BMJ 1996;313:383
Surgery can give long term relief from seizures for a proportion of epileptic patients, a cohort study has found. Doctors found that five years after anterior temporal lobectomy was performed on 89 patients with refractory epilepsy, 80 of them (90%) were free of seizures or had less than a fifth of the seizures that they had before the operation.
Doctors from the Comprehensive Epilepsy Center at the University of Pennsylvania conclude in this week's JAMA (1996;276:470-5) that all patients with intractable epilepsy should be assessed for surgery as soon as the nature of their condition is apparent.
The patients selected for surgery all had complex partial or secondary generalised partial seizures that had occurred at least monthly for more than a year. In addition, they had each showed no response to at least three different anticonvulsant drugs.
Seizures stopped in 62 patients (70%) after surgery while eight patients (9%) had fewer than three days of seizures a year or had seizures only at night. In 10 patients (11%) the operation resulted in a drop in seizure rate of more than 80%, while in five patients (6%) the frequency of seizures fell by less than 80%. Four patients who had persistent seizures after surgery died during the study—one of suicide and three of sudden and unexplained causes that were probably related to seizures.
If seizures are going to return they do so within two years of surgery, say the investigators. More than half of them recurred within the first six months of follow up. No significant cognitive or linguistic deficits occurred in patients who underwent surgery.
The benefit of surgery was that unemployment among patients whose seizures stopped fell by more than half. But patients whose seizures persisted continued to have difficulties gaining employment.
According to Dr Pam Crawford, consultant neurologist at York District Hospital, a similar success rate is seen in the United Kingdom, but not all those who might benefit are offered an operation. “Selecting and assessing patients consumes a lot of resources. It takes a multidisciplinary team and a lot of hard work,” she said.
“Even before we can operate we need to localise the seizure focus and undertake detailed neuropsychology assessment, magnetic resonance imaging, and often positron emission tomography. In addition, there are very few specialist teams in this country who can do it.”
According to a report commissioned by the International League against Epilepsy, between 1% and 3% of patients developing epilepsy will need surgery. This means that about 1000 patients should be assessed each year, although Dr Crawford estimates that the true number of patients being put forward for surgery is only a fraction of this. “Over the last five years more surgery for epilepsy is being done and it will probably increase in the future, but surgery is still largely underresourced,” she said.
Positron emission tomography helps to locate the focus of epileptic seizures before surgery
