Purpose: To examine whether surgery is indicated for posterior cortex epilepsy secondary to ulegyria.
Patients and methods: Ten patients who underwent surgery for posterior cortex epilepsy with ulegyria and were followed for more than 2 years were included. All patients underwent comprehensive presurgical evaluations. Five patients underwent intracranial electroencephalography (EEG) studies. The posterior cortex including the magnetic resonance imaging (MRI) lesion was resected in all patients. Postoperative follow-up period was 2-12 (mean 6) years.
Results: Nine patients had a history of perinatal distress including asphyxia and prolonged labor. Age at seizure onset was 5-11 years, except one patient. Three patients had visual field defects preoperatively. Ulegyria was unilateral in four patients and bilateral but unilateral-predominant in six patients. In most of the cases, the lesions were in the posterior cerebral artery area or the watershed area between middle cerebral and posterior cerebral arteries. In four of five patients who underwent intracranial EEG, seizure onset zones extended outside the lesions. Postoperative seizure outcome was Engel's class I in seven cases, and class III in three cases. Three of four patients whose seizure onset zones were not completely resected achieved class I outcome. Four of six patients with bilateral lesions achieved class I outcome.
Conclusion: Ulegyria due to perinatal distress is considered to be a major cause of posterior cortex epilepsy. Long-term postoperative seizure outcome is favorable. Resection of MRI lesion is important for seizure relief. Bilateral lesions should not be excluded from surgical indication. The usefulness of intracranial EEG may be limited.