We conducted an animal experiment to investigate the effects of mechanical trauma to the round window with the placement of a model electrode inserted into the scala tympani
on the cochlear reserve, and to determine the efficacy of topical steroids in preventing hearing loss in such a situation.
The cochleostomy must be made inferior and slightly anterior to the round window rather than anterior to ensure scala tympani
insertion and to decrease the likelihood of insertion induced intracochlear damage, particularly the basal membrane and organ of corti during electrode insertion.
The cochleostomy was drilled in the promontory, anteroinferiorly to the membrane of round window to enter the scala tympani
where the electrode was inserted.
When surgery was attempted, cochleostomy revealed complete obliteration of the scala tympani
The implant is a neural stimulator with an electrode array surgically placed near the auditory nerve fibers in the scala tympani
of the cochlea.
The three fluid spaces (scala media, scala tympani
and scala vestibuli) are separated by the two membranes (basilar membrane and Reissners membrane).
It was also demonstrated that when electrodes are chronically implanted in the scala tympani
of cats through an incision in the round window, the surgical trauma need not cause permanent cochlear damage.
Although they are of equivalent or longer length than the standard electrodes, they travel a greater span of distance since their position is on the outside wall of the scala tympani
The real mammalian cochlea is compound from three fluid spaces (scala media, scala tympani
and scala vestibuli) which are mutually divided by two membranes (basilar membrane and Reissner's membrane).
Three widely accepted goals for the development of future CI electrode arrays are (1) deeper insertion into the scala tympani
(ST) to access lower frequency cochlear neurons; (2) greater operating efficiency, defined as a reduction in the stimulus charge required to produce a comfortable loudness level; and (3) reduced intracochlear damage associated with surgical insertion.