The predictors of surgical outcome and relevance of pathological severity were determined in 166 consecutive patients with intractable epilepsy and focal cortical dysplasias treated surgically at Konkuk University Medical Center, and National University Hospital, Seoul, Korea. Poor surgical outcome was associated with incomplete resection of epileptogenic area, mild pathologic features, and secondary tonic-clonic seizures. Patients with severe pathologic features had MRI abnormalities. MRI findings, EEG, PET and ictal SPECT were not associated with surgical outcomes. 
COMMENT. Patients with focal cortical dysplasia and intractable epilepsy are at risk of a poor surgical outcome, when associated with incomplete resection, mild pathologic features, or secondary tonic clonic seizures. Incomplete resection of focal cortical dysplasia was the main predictor of poor postsurgical outcome in 149 pediatric patients operated at the Miami Children's Hospital .
In practice, a negative MRI does not exclude a subtle cortical dysplasia that may underly refractory seizures. Newer imaging techniques may uncover small dysplasias amenable to treatment in specialized epilepsy and surgical centers.