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Updated: Aug 24, 2026
Anteromesial Temporal Lobectomy for Medically Intractable Temporal Lobe Epilepsy: An Operative Study
Published on: August 15, 2025
Gamma knife surgery in mesial temporal lobe epilepsy: a prospective multicenter study
Jean Régis1, Marc Rey, Fabrice Bartolomei
1Stereotactic and Functional Neurosurgery Department, Timone Hospital, Marseille (APM), France. j.regis@ap-hm.fr
Purpose:
This article is the first prospective documentation of the efficacy and safety of gamma knife surgery (GKS) in the treatment of drug-resistant epilepsies of mesial temporal lobe origin.
Methods:
From July 1996 to March 2000, three European centers selected 21 patients with mesial temporal lobe epilepsy (MTLE) for a temporal lobectomy. The preoperative investigations included video-EEG with foramen ovale electrodes, magnetic resonance imaging, neuropsychological testing, and the ESI-55 quality-of-life questionnaire. In place of a cortectomy, radiosurgical treatment was performed by using the Leksell Gamma Knife (LGK) at a dose of 24 +/- 1 Gy at the margin. The target included the anterior parahippocampal cortex and the basal and lateral part of the amygdala and anterior hippocampus (head and body). One patient (a heavy smoker) died of a myocardial infarction. Twenty patients were available for prospective evaluation. A minimum 2-year follow-up period included clinical, neuropsychological, and radiologic evaluations.
Results:
At each 6-month follow-up evaluation, the frequency of seizures was significantly smaller than that at the previous visit. The median seizure frequency of 6.16 the month before treatment was reduced to 0.33 at 2 years after treatment. At 2 years, 65% of the patients (13 of 20) were seizure free. Five patients had transient side effects, including depression, headache, nausea, vomiting, and imbalance. There was no permanent neurological deficit reported except nine visual field deficits. No neuropsychological deterioration was observed 2 years after treatment. The quality of life was significantly better than that before surgery.
Conclusions:
The safety and efficacy of the radiosurgical treatment of MTLEs appears good in this group of patient over short-to-middle term. Delay of the seizure cessation was the major disadvantage of GKS. A longer follow-up period is required for confirmation of these results.
Insights
Gamma knife surgery (GKS) effectively treated drug-resistant mesial temporal lobe epilepsy (MTLE), with 65% seizure-free at two years. While safe, GKS showed a delayed seizure cessation compared to traditional surgery.
Area of Science:
- Neurosurgery
- Epileptology
- Radiosurgery
Background:
- Mesial temporal lobe epilepsy (MTLE) is a common cause of drug-resistant epilepsy.
- Traditional treatments like temporal lobectomy carry risks of neurological deficits.
- Gamma Knife Surgery (GKS) offers a less invasive alternative.
Purpose of the Study:
- To prospectively evaluate the efficacy and safety of GKS for drug-resistant MTLE.
- To document outcomes in terms of seizure control and quality of life.
Main Methods:
- Twenty-one patients with MTLE underwent radiosurgery using the Leksell Gamma Knife.
- Targeted irradiation of the hippocampus and amygdala was performed.
- Patients were followed for a minimum of two years with clinical, neuropsychological, and radiological assessments.
Main Results:
- Median seizure frequency reduced from 6.16 to 0.33 per month at two years.
- 65% of patients achieved seizure freedom.
- Transient side effects were reported, but no permanent neurological deficits, though nine visual field deficits occurred.
Conclusions:
- GKS demonstrates good short-to-middle-term safety and efficacy for MTLE.
- Delayed seizure cessation is a notable disadvantage of GKS.
- Longer follow-up is necessary to confirm sustained efficacy and safety.
