Abstracts

Since MR imaging and PET were introduced to the field of epilepsy, substantial progress occurred in surgical treatment of epilepsy. We evaluated the surgical outcome in a single institute after the routine use of MR imaging and PET.
From the 1994, 641 patients underwent surgical treatment in Seoul National University Hospital. Among them, we evaluated 456 patients having more than 2 years of follow-up postoperatively. Male patients were 280. Age ranged 1 to 59 with a mean of 26.5 years. Follow up duration ranged 24 to 96 months with a mean of 53 months. Temporal lobe epilepsy was the most common one (304 patients) followed by frontal lobe (68 patients), multilobar/multifocal (46), parietal lobe (21), and occipital lobe (21). Hippocampal sclerosis was the most frequent pathological substrate (212), followed by cortical dysplasia (128), tumor (58), vascular anomaly (11), and others (32). Surgical outcome was classified using Engel[rsquo]s. Cortical dysplasia was graded using Mischel[rsquo]s. Prognostic factors included sex, age at seizure onset, age at surgery, duration of seizure, principal seizure type, seizure frequency, presence of secondary generalization, pathology, and lobar location. Statistical analysis was performed using SPSS package. Chi-square test, Fisher[rsquo]s exact test, linear-by-linear association test, and Spearman correlation analysis were used.
Engel class I (seizure-free) was obtained in 302 patients (66.2%), II (rare seizure) in 41 (9.0%), III 57 (12.5%), and IV 60 (13.2%). Sex, age at seizure onset, duration of seizure, seizure frequency, and presence of secondary generalization were not statistically significant to the surgical outcome. Frontal lobe epilepsy had the worst outcome followed by parietal, occipital, lateral temporal, and medial temporal lobe epilepsy. Pathology was a significant prognostic factor. Hippocampal sclerosis had the best outcome followed by moderate or severe cortical dysplasia. Mild cortical dysplasia had the worst outcome in pathology. On the principal seizure type, complex partial seizure had better outcome than simple partial seizure. Age at surgery was also significant (chi-square, p=0.019), but its relationship was not linear. Younger age (below 15 years) had more chance getting either seizure free outcome or no worthwhile improvement than older age (over 31 years).
With surgical treatment for epilepsy, over 85% patients could achieve reasonable seizure control. Statistical analysis revealed frontal lobe epilepsy, mild cortical dysplasia and simple partial seizure for worse prognostic factors. Surgery to younger age patients not always produced better outcome.