Hypothesis: The safety of implanting a titanium microactuator into the lateral wall of cat scala tympani was assessed by comparing preoperative and postoperative auditory brainstem response (ABR) thresholds for 1 to 3 months.
Background: The safety of directly stimulating cochlear perilymph with an implantable hearing system requires maintaining preoperative hearing levels. This cat study is an essential step in the development of the next generation of fully implantable hearing devices for humans.
Methods: Following GLP surgical standards, a 1-mm cochleostomy was drilled into the lateral wall of the scala tympani, and a nonfunctioning titanium anchor/microactuator assembly was inserted in 8 cats. The scala media was damaged in the 1 cat. ABR thresholds with click and 4- and 8-kHz stimuli were measured preoperatively and compared with postoperative thresholds at 1, 2, and 3 months. Nonimplanted ear thresholds were also measured to establish statistical significance for threshold shifts (>28.4 dB). Two audiologists independently interpreted thresholds.
Results: Postoperatively, 7 cats implanted in the scala tympani demonstrated no significant ABR threshold shift for click stimulus; one shifted ABR thresholds to 4- and 8-kHz stimuli. The eighth cat, with surgical damage to the scala media, maintained stable click threshold but had a significant shift to 4- and 8-kHz stimuli.
Conclusion: This cat study provides no evidence of worsening hearing thresholds after fenestration of the scala tympani and insertion of a titanium anchor/microactuator, provided there is no surgical trauma to the scala media and the implanted device is securely anchored in the cochleostomy. These 2 issues have been resolved in the development of a fully implantable hearing system for humans. The long-term hearing stability (combined with histologic studies) reaffirm that the microactuator is well tolerated by the cat cochlea.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1097/MAO.0000000000000281 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Outer hair cells stir cochlear fluids.
Elife
January 2025
Department of Mechanical Engineering, University of Rochester, Rochester, United States.
We hypothesized that active outer hair cells drive cochlear fluid circulation. The hypothesis was tested by delivering the neurotoxin, kainic acid, to the intact round window of young gerbil cochleae while monitoring auditory responses in the cochlear nucleus. Sounds presented at a modest level significantly expedited kainic acid delivery.
View Article and Find Full Text PDFCochlear Implant Electrode Placement and Music Perception.
JAMA Otolaryngol Head Neck Surg
January 2025
Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee.
Importance: Cochlear implants enable improvements in speech perception, but music perception outcomes remain variable. Image-guided cochlear implant programming has emerged as a potential programming strategy for increasing the quality of spectral information delivered through the cochlear implant to improve outcomes.
Objectives: To perform 2 experiments, the first of which modeled the variance in music perception scores as a function of electrode positioning factors, and the second of which evaluated image-guided cochlear implant programming as a strategy to improve music perception with a cochlear implant.
Postoperative dizziness after cochlear implant surgery: can it be caused by air?
Front Neurol
December 2024
Department of Otorhinolaryngology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Objectives: Multiple studies have described the onset and variable incidence of postoperative acute vertigo following cochlear implant (CI) surgery. However, postoperative imaging has not yet been specifically evaluated with special focus on vertigo. The aim of this study is to assess the incidence and causes of new-onset, acute postoperative vertigo following CI surgery using cone beam computed tomography (CBCT).
View Article and Find Full Text PDFCharacterization of Tip Fold-Over Using Fluoroscopy and Intracochlear Pressure in Cadaver Specimens.
Laryngoscope
December 2024
Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, U.S.A.
Article Synopsis
- The study examined cochlear implant array malpositioning, particularly focusing on a specific issue called tip fold-over, which can impair speech perception and cause other complications.
- Researchers conducted experiments using cadaveric human heads to measure intracochlear pressure and observe the mechanics of tip fold-over events during the insertion of electrodes.
- Three distinct types of tip fold-overs were identified, with significant pressure changes linked to electrode twisting; this recognition could improve surgical techniques and monitoring during cochlear implant procedures.
Round Window Accessibility Prediction in Cochlear Implant Surgery.
J Int Adv Otol
November 2024
Department of ENT Head and Neck Surgery, Faculty of Medicine and Pharmacy of Marrakech, Cadi Ayyad University, University Hospital Center Mohammed VI, Marrakech, Morocco.
Background: Clear identification of the round window (RW) through the facial recess is a key surgical step for successful cochlear implantation (CI) surgery, which may be very challenging in some cases. Objective is to predict round window (RW) accessibility during CI surgery using high-resolution computed tomography (HRCT).
Methods: We retrospectively reviewed preoperative HRCT scans of 142 patients who underwent CI surgery via the standard posterior tympanotomy approach at our ENT Head and Neck Surgery department.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!