Subdural grid and strip placement:

Criteria for surgical intervention and investigation using cortical surface electrodes included intractable seizures and a unilateral focus believed to be cortical, temporal or extra-temporal. The grid and strip electrodes most often used initially are either a 4x8 or 8x8 electrode contact grid array (AdTech Medical Instruments; Racine, Wisc., USA) and were modified depending on the result of the pre-operative assessment or operative limitations. Surface recordings of each electrode on the grid are obtained in the operating room to ensure good contact with the brain surface prior to closure.