Cochlear implant surgery typically requires a wide-field mastoidectomy to access the cochlea. This portion of the surgery can leave a visible and palpable depression behind the patient's ear, which can be cosmetically displeasing to the patient. For the surgeon, a wide-field mastoidectomy is challenging to perform because bone must be gradually removed by freehand drilling guided primarily by visual feedback in an effort to detect, yet avoid, vital anatomy including the facial nerve which controls motion of the face. Toward overcoming these issues and standardizing surgery, imaged-guided, minimally invasive approaches have been developed in which the cochlea is accessed using a single pre-planned drill trajectory. This approach promises decreased invasiveness, but the limited surgical view and long narrow opening to the cochlea present significant challenges for inserting electrode arrays. This paper describes the first cadaver experiments using a new manual insertion tool which provides a roller mechanism to enable the physician to deploy a cochlear implant electrode array through the narrow drilled hole created by this minimally invasive, image-guided access technique. Results demonstrate that the new tool enables consistent and successful insertions similar to insertions with the traditional tool while increasing the ease of the insertion and freeing the surgeon to monitor progress and make fine adjustments as needed.