2010 Copyright @ Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited. Active Middle Ear Implant Application in Case of Stapes Fixation: A Temporal Bone Study *†Arnaud Deve `ze, *Kanthaiah Koka, *‡Ste ´phane Tringali, §Herman A. Jenkins, and *§Daniel J. Tollin *Department of Physiology and Biophysics, School of Medicine, University of Colorado Denver, Aurora, Colorado, U.S.A.; ÞDepartment of Otolaryngology, University La Me ´diterrane ´e UMR MD2 PPCOE, Assistance Publique Ho ˆpitaux de Marseille, Marseille; þDepartment of Otolaryngology, University Claude Bernard Lyon 1, CNRS UMR 5020, Hospices Civils de Lyon, Pierre-Be ´nite, France; and §Department of Otolaryngology, School of Medicine, University of Colorado Denver, Aurora, Colorado, U.S.A. Hypothesis: Driving the oval window directly with an active middle ear implant (AMEI) can produce high levels of input to the inner ear. Background: Treatment of otosclerosis bypasses the stapes with a piston that penetrates the vestibule. Although this treats the conductive component of hearing loss, it does not treat the sensorineural part, which can be improved using an additional conventional hearing aid. Active middle ear implants have been proposed to be an alternative in treating otosclerosis in cases of mixed hearing losses. Methods: Seven temporal bones were prepared to expose the stapes and round window (RW). Stapes and RW velocities were measured while driving with an AMEI the stapes head with a bell-shaped tip. The stapes footplate was then fixed with acrylic cement; fixation was confirmed through attenuated RW velo- cities. A cylinder tip (0.5 mm) was then used to drive the inner ear through a stapedotomy with and without interposition of fascia. Results: Driving the stapes with an AMEI produced mean maximum equivalent ear canal sound pressure levels (SPL) of 138 dB (0.25Y8 kHz at 1 V [RMS]). Stapes fixation caused a È25-dB attenuation. Driving with a cylinder tip through the stapedotomy produced 114 dB SPL (24 dB less than normal) and 110 dB SPL (28 dB less than normal) performance with and without fascia, respectively. Performance with fascia was greater than without. Conclusion: Driving the oval window with an AMEI in a sce- nario of stapes fixation was demonstrated to be feasible, with per- formance comparable to traditional AMEI coupling to the incus or stapes. These possibilities offer new perspectives to treat mixed hearing loss in case of fixed footplate. Key Words: Active middle ear implantVFasciaVOtosclerosisVStapedotomy. Otol Neurotol 31:1027Y1034, 2010. Hearing rehabilitation of patients with mixed hear- ing loss associated to stapes fixation represents a chal- lenge. This situation presents in otosclerosis and less commonly to tympanosclerosis. Conductive hearing loss in otosclerosis can be corrected with various refinements of the original stapedectomy operation (1). Other alter- natives are conventional or bone-anchored hearing aids (BAHAs) (2Y4). Despite technological improvements in conventional hearing aids, they suffer from poor acceptance by patients potentially able to benefit by their use (5Y10). Super- imposition of a conductive loss onto a sensorineural markedly increases demands in serviceable amplification. Although the BAHA is available for auditory rehabilita- tion, adequate cochlear reserve as measured by conduc- tion threshold is required for successful use (4,11). The BAHA’s percutaneous abutment, although producing excellent coupling for the inner ear stimulation, suffers from chronic inflammatory reaction (11,12), cutaneous overgrowth, and extrusion of the pillar. Rates of com- plications and revision surgery are not negligible and ultimately influence the patient satisfaction (13,14). Active middle ear implants (AMEIs) represent a devel- oping technology devoted initially to treatment of sen- sorineural hearing loss in failure or contraindication of hearing aid application (15Y17). Recent advances include applications of AMEI in conductive and mixed hear- ing loss (10,18Y28). Animal and human experiments Address correspondence and reprint requests to Kanthaiah Koka, Ph.D., Department of Physiology and Biophysics, University of Colorado Denver, Mail Stop 8307, Research Complex 1-N, Rm 7106, 12800 E 19th Avenue, PO Box 6511, Aurora, CO 80045; E-mail: kanthaiah.koka@ucdenver.edu This study was supported in part by an Otologics LLC educational grant (to H.A.J. and D.J.T.). The authors have no conflict of interest. Otology & Neurotology 31:1027Y1034 Ó 2010, Otology & Neurotology, Inc. 1027