The custom made device was produced by Med-El Company. It has a "cork" like stopper instead of the usual silicon ring to prevent gusher. There are two types of electrodes consisting of different length. Standard one is 25 mm (contact space 1.7 mm) and the short one is 20 mm (contact space 1.3 mm). It was used in 50 patients with different inner ear malformations. Thirteen patients had gusher, and 11 patients oozing during cochleostomy. One patient with initial prototype of the cork electrode had to be revised because of persistent oozing around the electrode. Another patient had slow extrusion of the electrode most probably due to CSF (cerebrospinal fluid) pulsation and had to be revised. Both patients had no more CSF fistula.