S240 – Human Cochlear Implant Histopathology

bone anatomy may lead to an increased incidence of CSF gusher in cochlear implant surgery. Computerized tomography of the temporal bone can assist in the surgeon in evaluation and planning for cochlear implantation. S238 – Clip-fixation or Crimping? Results of 4 Stapes Prostheses Daniel F A’Wengen, MD (presenter) OBJECTIVES: Learn about possible differences of results by 4 different stapes prostheses. METHODS: In this retrospective study, all 126 contiguous patients undergoing stapes surgery for otosclerosis are included. All surgeries were performed by 2 surgeons. 4 different types of stapes prostheses were used in separate time intervals. Starting with teflon-platinum wire prosthesis, to gold piston, to titanium piston, to the self-retaining titanium Clip-piston. RESULTS: Pre- and postoperative pure tone and speech audiograms are compared. The best results were achieved by the Clip-Piston. Improvement in PTA over other pistons was 4 dB with p⫽ 0,027 (Mann-Whitney). Bone conduction levels were better by 2 dB. In speech audiometry intellegibility was better by 3 dB with p⫽0,024 (Mann-Whitney). CONCLUSIONS: The tight self-fixation of the Clip-Piston to the long process of the incus achieved the best results in pure tone and even more so in speech audiometry. The reason might be due to reduced slippage of the stapes prosthesis at the attachment to the incus. As other studies have shown, tight fixation of a stapes prosthesis provides the best results. The Clip-Piston achieves this by its spring action and without the danger of heat and strangulation as by other stapes pistons. S239 – Labyrinthine Changes in Otitis Media Shruti Siddharth Joglekar, MD (presenter); Armin Farajzadeh Deroee, MD; Norimasa Morita, MD; Sebahattin Cureoglu, MD; Patricia Schachern; Michael M Paparella, MD; Steven K Juhn, MD OBJECTIVES: Otitis media causes labyrinthine changes and subsequent sensorineural hearing loss. The aim of this histopathologic study was to evaluate the extension of inflammation to the inner ear and its effects. METHODS: Out of 614 temporal bones with otitis media, 47 (30 cases) with chronic and 35 (21 cases) with purulent were selected for histopathologic study. Subjects with a history of acoustic trauma, head trauma, ototoxic drugs and other otologic and systemic diseases affecting the inner ear were excluded. The pattern of labyrinthine inflammation was classified as localized purulent, localized serous, generalized seropurulent and generalized serous. Inner ear findings were compared to age-matched controls. RESULTS: 19% of temporal bones with chronic and 9% of

P155 temporal bones with purulent otitis media showed labyrinthine inflammatory changes. In chronic otitis media, inflammatory changes were: 56% localized purulent; 22% localized serous; 11% generalized seropurulent; and 11% generalized serous. Inflammatory changes in temporal bones with purulent otitis media included: 67% localized purulent; and 33% generalized seropurulent. Pathological findings included: serofibrinous precipitates and inflammatory cells in the scala tympani of basal turn and cochlear aqueduct; significant decrease in area of stria vascularis (p ⫽ 0.033); and loss of hair cells in the organs of Corti. No significant difference was found in area of spiral ligament area or number of fibrocytes in diseased and control bones. CONCLUSIONS: Middle ear/inner ear interaction in otitis media can result in labyrinthine inflammation and cochlear damage. Early diagnosis and treatment of otitis media is important in preventing inner ear damage. S240 – Human Cochlear Implant Histopathology Helen Xu, MD (presenter); Natasha Pollak, MD; Sebahattin Cureoglu, MD; Michael M Paparella, MD OBJECTIVES: 1) To exam the histopathology of multichannel cochlear implant temporal bones. 2) To evaluate the relationship of residual spiral ganglion cell counts to clinical hearing performance. METHODS: 8 temporal bones from 4 cochlear implant patients were examined histologically. Paired comparisons were made between implanted and nonimplanted temporal bones. Clinical performance data was obtained from patient charts. RESULTS: There were varying amounts of inflammation (fibrosis and ossification) in the basal turn of the cochlear in all implanted temporal bones. Trauma to the facial nerve at facial recess site was noticed in 1 case. Compared with nonimplanted ears, 2 implanted bones with less than 10-year duration of implantation had no significant changes of spiral ganglion cell population. One case with prolong implant duration (15 years) showed about 36% decrease of spiral ganglion cells at the implanted site. The case with best speech recognition (89% with CID sentence) had the highest residual spiral ganglion cells (30% of normal spiral ganglion cell population). 2 cases with poor clinical performance (⬍10% with CID sentence) had the residual spiral ganglion cells at 11% and 22%. The case with moderate clinical performance (30% with CID sentence) had 14% of normal spiral ganglion cell population. Surviving dendrites varied from 5% to 30% among 4 cases with no relationship to clinical performance. CONCLUSIONS: Our findings suggest prolonged implantation may affect spiral ganglion cell population. There is no reverse relationship between residual spiral ganglion cells in implanted temporal bones to clinical speech performance observed from our limited cases.

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