Abstracts

Rationale: It is commonly held that mesial temporal lobe epilepsy (mTLE) due to mesial temporal sclerosis (MTS) is the most prevalent form of focal epilepsy, and that it is refractory to medical treatment. In MTS patients, data show that anterior temporal lobectomy (ATL) provides a much greater likelihood of seizure freedom than medical therapy in controlled trials. However, controlled trials select candidates who are already medically refractory and have necessarily brief followup. We examined the rate of long-term seizure control in patients with mTLE who have not undergone epilepsy surgery. Methods: The University of Virginia Epilepsy Database of 2,898 patients was queried to identify all current patients classified as mTLE with MTS. MRI reports and medical records were reviewed to confirm the presence of unilateral MTS and other characteristics. Patients seen within the last 3 years were included. Patients were excluded if they had other pathology potentially causing epilepsy or experimental therapy such as radiosurgery. Seizure frequency was captured during clinic interviews and recorded over at least the last 3 years. Seizure frequency graphs and records were reviewed to determine the exact number of seizures reported over the prior 24 months and the total duration of seizure freedom. Patients were sorted into categories of "good" seizure control if seizure free or only a single seizure in the most recent 24 mo., and "poor" seizure control if more than one seizure occurred in the last 24 mo. Results: A total of 96 patients had confirmed MTS with follow-up within the last 3 years. Out of 47 patients who did not have ATL, 12 (26%) had "good" seizure control and 35 (74%) had "poor" seizure control. Out of 49 patients who underwent ATL, 33 (67%) had good control and 16 (33%) had poor control, p< 0.01. Patients were followed for an average of 106 mo. in the ATL group and 117 mo. in the non-ATL group. Conclusions: ATL clearly provides the greatest chance of seizure freedom for patients with mTLE due to MTS but our results suggest that a quarter of mTLE patients may have sustained seizure freedom with medical therapy alone. This suggests that the natural history of this disorder is not uniformly a relentless course of pharmacoresistance. Further research is needed to determine the duration of seizure freedom when mTLE due to MTS is treated without surgery and the factors determining which patients become seizure free.