Selective versus non-selective temporal lobe surgery for epilepsy.

Over a 10-year period 100 temporal lobe operations were performed for non-lesional temporal lobe epilepsy (TLE). Seventy-two patients had conventional anterior temporal lobectomy (ATL) and 28 had selective amygdalohippocampectomy (AH). Forty-three ATL patients (60%) became seizure free compared to 6 AH patients (21%) (P < 0.005). An unsatisfactory outcome was obtained in 11 (15%) ATL patients and 14 (50%) AH patients (P < 0.01). Fourteen AH patients subsequently had a second ATL procedure; 6 improved, 3 becoming seizure free. There were no differences between the two groups in the incidence of mesial temporal sclerosis (MTS) or normal pathology. However, ATL patients had a higher concordance rate of preoperative investigations which may have made them more favourable surgical candidates. It was concluded that ATL was more likely to produce a seizure free outcome than AH and should be used as the routine surgical procedure for temporal lobectomy. However, AH can give a satisfactory outcome and may be preferred when a patient has good verbal memory and all preoperative tests are concordant.

Can the interictal EEG predict successful temporal lobectomy for epilepsy?

Scalp and sphenoidal electroencephalograms (EEGs) were examined retrospectively from 45 patients who had temporal lobe surgery for epilepsy in a Comprehensive Epilepsy Programme. Interictal EEG patterns were divided into 4 groups: group 1 (18 patients) showed phase reversal of sharp (8) or spike (10) waves about one sphenoidal electrode, group 2 (11 patients) showed unilateral sharp, spike or wave activity in scalp leads only; group 3 (8 patients) showed bilateral abnormalities which were 60%; lateralized and group 4 (8 patients) showed non-lateralized changes. Lateralized EEG patterns predicted the side of subsequent surgery in all 37 cases. All 18 patients in group 1 benefited from surgery (10 seizure free at 1 year) while 20 of 27 patients in the other 3 groups benefited (13 seizure free). These results favour group 1 (P < 0.05). By comparison, the magnetic resonance image scan predicted the side of surgery in 23 of 36 (64%) patients and single photon emission tomograph scans predicted the side of surgery in 11 of 24 (46%) patients who had ictal and interictal isotope injections. Focal sphenoidal electrode discharges predict successful temporal lobectomy for surgery.