Perimodiolar Electrodes in Cochlear Implant Surgery

• Published in: Acta oto-laryngologica 2001-01, Vol.121 (2), p.216-219
• Main Author: Wolfgang Karl Gstoettner, Oliver Adunka, Peter Franz, Jafar Hamzavi, Hanns Plenk Jr, Martin Susani, Wolf Baumgartner, Jan Kiefer
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cochlea - injuries; Cochlea - pathology; Cochlear Implants; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Electrodes, Implanted; Electrostimulation Hearing Nerve Human Temporal Bones Neurostimulation; Equipment Failure Analysis; Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics; Humans; Medical sciences; Non tumoral diseases; Otorhinolaryngology. Stomatology; Prosthesis Design; Risk Factors; Scala Tympani - pathology; Spiral Ganglion - pathology; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the ear, the auditive nerve and the facial nerve
• ISSN: 0001-6489; 1651-2251
• DOI: 10.1080/000164801300043569

Perimodiolar-positioned cochlear implant electrodes have been developed in order to bring the electrode contacts as close as possible to the spiral ganglion cells, which are the target of electrostimulation. This results in lower electrical thresholds, higher dynamic ranges and less channel interaction when compared with normal implant electrodes which are usually located peripherally within the scala tympani. In this study we evaluated 4 different types of perimodiolar electrode: the Clarion Preformed electrode, the Clarion Preformed electrode with positioner, the Nucleus Contour electrode and the Med-El Perimodiolar Combi 40 electrode. These devices require different approaches to achieve a perimodiolar electrode position. The electrodes were inserted in fresh human temporal bones. After processing these bones with the electrodes in situ by employing a sawing, grinding and polishing technique, the inner ear structures as well as the electrode positions could be evaluated in detail. All electrode types studied had a more or less perimodiolar position; however, each type produced a certain amount of trauma to cochlear structures which is discussed in relation to mechanical properties. Further human temporal bone studies with improved perimodiolar cochlear implant electrodes are necessary in order to find an optimized type of electrode.