In cochlear implant, the electrode array is most commonly placed at?
Ans. C. Scala tympani > B. Round window. (Ref ENT Secrets 52-59)The electrode array of cochlear implant is placed in scala tympani through the cochleostomy which is positioned relative to round window.A Cochlear implant (Cl):# It is a listening device that can provide auditory abilities to individuals with severe to profound SNHL who do not benefit from hearing aids.# Current implants have multiple electrodes, which transmit more sound information. These devices require surgical implantation and extensive postoperative therapy.# CIs have internal and external components.- The internal electrode array and receiver are surgically implanted under the skin above and behind the ear.- The external parts include a microphone, a speech processor, and a transmitting coil.# Several locations are used for the placement of the Cl electrodes:- Intracochlear: electrodes placed in the scala tympani of the cochlea- Extracochlear: electrodes placed outside the cochlea in the promontory, round windowIntraneural: electrodes placed directly in the modiolus# To ensure the success of inserting electrode arrary into the scala tympani, many authors in the field of cochlear implant have been successful in performing cochleostomy from the promontory rather than going through the round window niche.# The classical surgical technique of cochleostomy is by the facial recess approach and through the round window niche. The Jacobson's Nerve serves as important landmark to allow us to drill and to overcome the difficult zone or in cases were basal turn of scala tympani is obliterated.# Contraindications for Cochlear Implantation- The absolute contra for cochlear implantation are the absence of a cochlea (either normal or malformed should be present) and absence of a cochlear nerve.
Oval window
Round window
Scala tympani
Lateral semicircular canal
Ear