From the American Epilepsy Society 2009 Annual Course. Non-substrate-directed epilepsy and surgery: PRO and CON

The surgical treatment of epilepsy is the most efficacious therapeutic modality for patients with a medically refractory partial seizure disorder. Epilepsy surgery has been demonstrated to be both effective and well tolerated in individuals with medial temporal lobe epilepsy associated with mesial temporal sclerosis. The identification of an MRI pathological substrate may be useful in identifying the epileptogenic zone and the appropriate operative strategy, and is predictive of the long-term seizure outcome. Patients with a non-substrate-directed partial epilepsy often require a more rigorous presurgical evaluation because of issues regarding the lateralization and localization of the epileptic brain tissue. The surgical outcome may be most disappointing in individuals with localization-related epilepsy of extratemporal origin associated with a normal MRI study. The present discussion focuses on the selection of patients with extratemporal non-substrate-directed epilepsy for a presurgical evaluation. The important factors associated with an improved quality of life subsequent to epilepsy surgery include seizure remission and avoidance of operation-induced adverse effects.