Long-term follow-up outcome after surgical treatment for lesional temporal lobe epilepsy

Lateral or neocortical temporal lobe epilepsy (TLE) is regarded as a distinct clinical entity from medial TLE. Surgery for neocortical TLE can be considered as a viable treatment option; however, there is very limited information available on aspects such as long-term seizure outcome. Thus, we retrospectively reviewed our ten surgical cases of lateral TLE with a minimum 2 year follow-up outcome.

The series comprised four male and six female patients, ranging in age from 3 to 46 years (mean: 28.8 years). Seven cases were found to be drug-resistant. Invasive pre-surgical evaluation for intractable epilepsy was performed in six patients.

The pathologic lesions were removed completely in nine cases. Lesionectomy alone was performed in four cases and total epileptogenic focus resection was confirmed in four cases. The epileptogenic regions within eloquent areas were preserved in two cases. The medial temporal structure was intact and preserved in all cases. Neuropathologic diagnoses were cavernoma in three cases, astrocytoma (grade 2) in two cases, arteriovenous malformation in two cases, gliosis in two cases and ganglioglioma in one case. The mean duration of follow-up was 6.5 years (range: 2.2-9.3 years). Outcomes categorized according to Engel classes were class I (E1) in six cases and class II (E2) in four cases. Patients who had post-operative seizures may also achieve long-term seizure decrease or freedom in three cases: case 5 (E4-E2), case 6 (E4-E2) and case 7 (E3-E1). Thus, worthwhile improvement was achieved in 100% of the cases in this series, with 60% of patients being seizure-free during the followed-up period.

The controlled long-term follow-up results suggested that surgery for lesional TLE can be considered as a viable treatment option to control seizure with a low morbidity rate and good outcomes.