Supplementary Material for: Contralateral Hippocampal Stimulation for Failed Unilateral Anterior Temporal Lobectomy in Patients with Bilateral Temporal Lobe Epilepsy

Aims: To prospectively study the surgical outcomes of unilateral anterior temporal lobectomy (ATL) in patients with intractable bilateral temporal lobe epilepsy (TLE) as well as two-staged contralateral hippocampal stimulation in patients after failed unilateral ATL. Methods: Eighteen carefully selected patients with bilateral TLE underwent unilateral ATL. Five cases with failed ATL underwent two-staged contralateral hippocampal stimulation. Seizure control and changes in intelligence quotient (IQ), memory quotient, and quality of life (QOL) were analyzed 2-5 years after treatment. Results: In the patients with unilateral ATL, the percentages seizure free were 55.6% (10/18), 50.0% (9/18), and 44.4% (4/9) at the 1-, 2-, and 5-year follow-up visits, respectively. There were significant difference in seizure control between the patients with unilateral ATL and the 12 cases in the medication group. Significant differences were also found in changes in the patients' QOL and full-scale IQ at the 2-year follow-up between the surgical and medication groups. Five patients who underwent contralateral hippocampal stimulation after failed unilateral ATL experienced 80-100% seizure reductions, and 80% were seizure free 1 year after hippocampal stimulation. Conclusion: Unilateral ATL provides good seizure control and does not cause serious memory or IQ injury in carefully selected patients with true bilateral TLE. Contralateral hippocampal stimulation is a useful approach for patients who experience unilateral ATL failure.