[Cochleostomy during the intracochlear implantation. Anatomical conditions in children and adults].

Cochleostomy is an opening of the perilymphatic spaces of the cochlea. It is the most important moment in intracochlear implant surgery. There are contradictory opinions in the available literature regarding this surgical intervention. Cochleostomy is performed through the round window, the oval window, the promontory or through the apical turn of the cochlea. A microanatomical study was performed to evaluate which kind of cochleostomy would be most effective and safe for the main structures of the temporal bone. The distances between round window and round window niche structures, the jugular bulb, internal acoustic meatus, posterior semicircular canal, internal carotid artery and cochlear canalicule were measured. It was stated that all the dimensions were smaller in children of up to four years of age and the differences were statistically significant. Cochleostomy through the promontory, especially using the "soft" technique of endosteum opening is safe for all the structures, and in children it also protects the cochlear canalicule.