An elongate electrode carrier member for implantation in a location
external to the cochlear canals to position at least one, and likely
many, electrodes sufficiently proximate to the organ of Corti to
effectively deliver stimulation signals to the auditory nerve fibers of
the cochlear. Generally, the carrier member is dimensioned to be
implanted in a crevice, channel or pocket formed between the spiral
ligament and bony capsule of the cochlear. Embodiments of the carrier
member preferably have a minimized volume to accommodate insertion into
such a crevice. In addition, embodiments of the carrier member comprise
an elongate bulbous central region having electrodes disposed on the
medial surface thereof, and elongate tapered side regions laterally
extending from the central region. The side regions have rounded edges
and are preferably flexible, while the carrier is configured to coil or
turn toward the medial surface. This construction facilitates
implantation of the carrier member: the carrier member has sufficient
longitudinal strength to maintain its form and direction while being
pushed into the surgically-formed crevice, and coils in a longitudinal
plane to follow the contour of the cochlear, while the side regions serve
to guide the direction of travel, flexing out of the lateral plane as
necessary to avoid damaging anatomical structures. Once implanted,
embodiments of the carrier member are urged to remain in its implanted
position due to one or more of either the side regions extending into the
corners of the crevice, and/or due to the curved lateral surface of the
carrier member which approximates the curvature of the endosteum along
the basal turn of the cochlea.