Application of "banana cochleostomy" and looped electrode insertion for cochlear implantation in children with common cavity malformation and cystic forms of cochlear hypoplasia.

Objectives: Patients with profound hearing loss due to inner ear malformations may benefit from cochlear implantation; however, the surgery may present a substantial problem for the cochlear implant surgeon due to anatomical variations. The authors describe a new surgical and technical advancement for implantation in patients with small inner ear cavities that make the surgery easier and safer. On the basis of experience involving five consecutive surgeries performed in four patients with inner ear malformations, we present the advantages and application possibilities of the technique.

Methods: The technique does not change the surgical approach in general; however, modification of the cochleostomy shape and looping of the cochlear implant electrode enables safe advancement of the electrode with optimal positioning in the cavity. Additionally, these modifications protect against the insertion of the electrode into the internal auditory canal minimizing the risk of gushing and extracochlear stimulation.

Results: The present technique has been used in five cases of cystic implantable inner ear spaces in three independent institutions by different surgeons. It has proven to be a reliable, relatively easy and safe procedure performed with very good anatomic and initially functional effects (positive intraoperative neural response telemetry measurements).

Conclusions: We hope that utilization of the "banana cochleostomy" and insertion of the looped cochlear implant electrode in the implantable cystic spaces of children with malformed inner ears will facilitate and simplify the surgical technique in this difficult procedure and additionally, in revision surgical cases. To our knowledge, the looped insertion and banana-shaped cochleostomy have not been reported previously.