**2.5 Cochleostomy**

The RW niche is lowered down by drilling the tegmen and pillars of the RW till good exposure of the RW membrane is achieved, and then cochleostomy is performed. In classic CI, cochleostomy is drilled as a separate opening inferior and slightly anterior to the RW membrane [6].

### **2.6 Electrode insertion**

The device is brought up to the surgical field, and then the electrode is inserted into the cochlea either by using the fine-tipped micro forceps or by using the specific instruments manufactured for insertion of the selected electrode type.
