Apparatus and methods for making cochlear implant electrode arrays

A method of forming an electrode array from an electrode array blank, the electrode array blank including a flexible body, defining an exterior surface, a longitudinal axis and a perimeter that extends around the longitudinal axis in planes perpendicular to the longitudinal axis, and a plurality of longitudinally spaced electrically conductive contacts that are below the exterior surface of the flexible body, the method comprising the steps of:

• forming a first window in the flexible body that extends through the exterior of the flexible body to a first one of the electrically conductive contacts, the first window defining a first window perimetric center;
• forming a second window in the flexible body that extends through the exterior of the flexible body to a second one of the electrically conductive contacts, the second window defining a second window perimetric center that is perimetrically offset from the first window perimetric center when the flexible body is straight and not twisted around the longitudinal axis;
• and
• prior to forming the first and second windows, determining an amount that the second window perimetric center should be perimetrically offset from the first window perimetric center.