title: A novel perfusion-based method for cochlear implant electrode insertion.
abstract: A cochlear implant (CI) restores partial hearing to profoundly deaf individuals. CI electrodes are inserted manually in the cochlea and surgeons rely on tactile feedback from the implant to determine when to stop the insertion. This manual insertion method results in a large degree of variability in surgical outcomes and intra-cochlear trauma. Additionally, implants often span only the basal turn. In the present study we report on the development of a new method to assist CI electrode insertion. The design objectives are (1) an automated and standardized insertion technique across patients with (2) more apical insertion than is possible by the contemporary methods, while (3) minimizing insertion trauma. The method relies on a viscous fluid flow through the cochlea to carry the electrode array with it. A small cochleostomy (∼100-150 um in diameter) is made in scala vestibuli (SV) and the round window (RW) membrane is opened. A flow of diluted Sodium Hyaluronate (also known as Hyaluronic Acid, (HA)) is set up from the RW to the SV opening using a perfusion pump that sets up a unidirectional flow. Once the flow is established an implant is dropped into the ongoing flow. Here we present a proof-of-concept study where we used this technique to insert silicone implants all the way to the cochlear apex in rats and gerbils. In light-microscopic histology, the implantation occurred without cochlear trauma. To further assess the ototoxicity of the HA perfusion, we measured compound action potential (CAP) thresholds following the perfusion of HA, and found that the CAP thresholds were substantially elevated. Thus, at this point the method is promising, and requires further development to become clinically viable.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA. Electronic address: sk3646@cumc.columbia.edu.
authors.forename: Sushrut
authors.initials: S
authors.lastname: Kale
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA.
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: Cervantes
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10025, USA.
authors.forename: Mailing R
authors.initials: MR
authors.lastname: Wu
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA.
authors.forename: Dominic V
authors.initials: DV
authors.lastname: Pisano
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA.
authors.forename: Nakul
authors.initials: N
authors.lastname: Sheth
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10025, USA.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Olson
mesh_terms: D000200:Action Potentials; D000818:Animals; D001489:Basilar Membrane / Q000473:pathology; D003051:Cochlea / Q000473:pathology*; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D004566:Electrodes; D004567:Electrodes, Implanted; D005849:Gerbillinae; D006309:Hearing; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry; D010477:Perfusion; D051381:Rats; D012405:Round Window, Ear / Q000601:surgery; D013701:Temporal Bone / Q000601:surgery
chemical_list: D006820:Hyaluronic Acid