Use of bioresorbable polymers in cochlear implants and other implantable devices

DETAILED DESCRIPTION In view of the above-mentioned disadvantages of the prior art, it is an objective of the present invention to provide a cochlear electrode assembly which has a first, relatively straight configuration so that it can be readily implanted, and a second, curved configuration to conform to the cochlea of a patient, using a material which dissolves in body fluids.
A further objective is to provide an assembly which has relatively few parts so that its cross-section is not too large for implantation.
Another objective is to provide an assembly which can be manufactured relatively easily and inexpensively.
Other objectives and advantages of the invention shall become apparent from the following description.
Briefly, an electrode assembly constructed in accordance with this invention includes an electrode carrier constructed and arranged to support a plurality of electrodes suitable for defining an electrode array for application for cochlear stimulation signals.
The carrier is preferably preshaped into a curved configuration selected to insure that the electrodes are disposed in close proximity to the modiola of the scala tympani.
Prior to implanting, the carrier is imbedded in a relatively straight sheath or alternatively a stiffening elements is applied to maintain the carrier in a linear configuration.
The sheath or the stiffening element is made of a bioresorbable material, such as a polymer which dissolves in the cochlear fluid after implantation.
Preferably the carrier is provided with biasing fins which in the linear configuration are folded against the carrier.
Once the sheath is dissolved, the biasing fins flex outwardly away from the carrier to engage the walls of the scala tympani to urge the carrier toward the modiola.
Alternatively, the carrier is pre-formed so that after the sheath dissolves, the carrier assumes the curved shape.