A 25-year-old man has focal epilepsy with secondary generalization not controlled by valproate and levetiracetam. MRI shows a focal cortical dysplasia in the right temporal lobe. EEG confirms concordant ictal onset zone. He is being considered for epilepsy surgery. Which factor most strongly PREDICTS good surgical outcome (Engel Class I)?

• A Duration of epilepsy >10 years
• B Family history of epilepsy suggesting genetic etiology
• C Multiple seizure types with bilateral spread
• D Identifiable structural lesion (MRI-positive) concordant with EEG focus ✓

Explanation

The strongest predictor of excellent surgical outcome (Engel Class I = seizure-free) in focal epilepsy surgery is the presence of a concordant structural lesion on MRI (lesion-positive) that matches the EEG ictal onset zone. Mesial temporal lobe epilepsy with hippocampal sclerosis and temporal lobe focal cortical dysplasias have the best resective surgery outcomes. Bilateral spread, genetic etiology, and long epilepsy duration are associated with poorer outcomes. MRI-negative focal epilepsy has substantially lower surgery success rates.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.