An implantable electrode system, adapted for insertion into a cochlea, includes an elongate electrode array stored within a sheath. The electrode array has a multiplicity of electrode contacts carried on a flexible elongate carrier, which carrier is adapted for insertion into one of the spiraling ducts, e.g., the scala tympani, of the cochlea, and further has longitudinal channel or lumen that passes therethrough. 3-6 mm from the distal end of the electrode array. To insert the electrode system into the cochlea, a stylet wire is inserted into the channel or lumen of the electrode array while the electrode array is held within the sheath. The sheath is then removed, and the electrode array is then gently guided and pushed through a cochleostomy into the cochlea by extending the stylet wire to a desired depth. As the electrode array is thus inserted into the cochlea, the stylet wire is retracted and the electrode array remains implanted within the cochlea.