Thirty seven patients, ages 7 to 18 years, who underwent temporal lobectomy for intractable seizures at the Mayo Clinic, Rochester, MN, between 1970 and 1983, were followed for a mean of 19 years (range 4 - 27 years). Mean age at seizure onset was 7.2 yrs (range 1-16), and mean age at surgery was 14.4 yrs (range 7-18). An excellent outcome (0-4 seizure frequency score based on Engel classification) was obtained in 31 (88%) patients at 5 years, and in 19 (60%) at 15 years. Of those followed at least 15 years, 40% (13/32) were seizure free at 5 years but had recurrence of seizures at 15-year follow-up; 9.5% (3/32) improved significantly; and 50% (16/32) were unchanged. Of 13 with long-term seizure recurrence (9 on medication), 6 had abnormal pathology including oligodendroglioma or ganglioglioma (4), ectopic neurons (1), and mesial temporal sclerosis in 1. Of 19 patients who improved or did not relapse, only 2 had abnormal pathology (astrocytoma and arachnoid cyst) (p=0.03). Long-term seizure recurrence was independent of a positive family history of epilepsy, history of head tauma, encephalitis, or febrile convulsions, or abnormal postoperative EEG. Only 3 of 32 followed were unemployed; 6 had no driver’s license. 
COMMENT. In this long-term study of children following temporal lobectomy for intractable seizures, of 88% with an initial excellent outcome by 5 years, half of the patients had recurrence of seizures by 15 years. The incidence of mesial temporal sclerosis in patients with long-term recurrence was only 2.7% in this series, compared to 14% in previous reported series. The poorer outcome with long-term follow-up should be considered in decisions to operate early in children with temporal lobe seizures.
The unpredictable nature of postoperative seizure relapse was stressed in a report of 282 temporal resections, mean age 26 years (range 4-59 years), from Kings College Hospital, London, UK (see Ped Neur Briefs 2001;15:5-6) . The relapse rate was approximately 20%, either immediately or after a 12 month seizure-free interval.
Previous studies of the natural history of recurrent seizures after resective surgery for epilepsy have shown that the outlook is better if seizure recurrence is delayed until after the first postoperative year. Also, changes in antiepileptic medication, dosages, or poor compliance may be important factors in recurrence of seizures. (see Progress in Pediatric Neurology II, PNB Publishers, 1994;ppl36-7).