June 2008: Sound Partnership Newsletter

For more than 25 years, Cochlear has delivered unsurpassed hearing performance
with the most reliable implant devices on the market.

Dear Colleague,
Cochlear is pleased to bring you the June Cochlear Newsletter.

Recent Research

In the May Cochlear Newsletter, we included a summary of the Adunka and Buchman paper that highlighted the variability in cochleostomy locations among North American surgeons.  This month’s newsletter includes a summary of the Briggs, Tykocinski, Stidham & Roberson paper titled “Cochleostomy site: implications for electrode placement and hearing preservation."

Summary

Briggs R, Tykocinski M, Stidham K, Roberson J.  Cochleostomy site: Implications for electrode placement and hearing preservation. Acta Oto-Laryngologica, 125:870-876, 2005.

Objective of the Study
The objective is to review the results of previous temporal bone electrode insertion safety studies, and of post-mortem temporal bone histology of CI recipients.  The aim is also to review previous anatomic studies of the cochleostomy region.

Study Design

• In Melbourne, 14 temporal bones were studied with three different electrode designs.  “An initial precurved electrode array” was inserted with a cochleostomy placed anteroinferior and separate to the round window niche.  Contour and Contour Advance electrode arrays were inserted with a cochleostomy placed directly inferior to and in contact with the round window membrane.
• In Palo Alto, 27 human temporal bones were dissected and measured to demonstrate the anatomic details of the relevant area.

Key findings in the paper include

• A cochleostomy that is anterior to the round window niche “may open both scala tympani and scala vestibuli and will expose the attachment of the basilar membrane.”
• Electrode insertion into a cochleostomy that is anterior to the round window niche will “always result in local damage to the attachment of the basilar membrane and may result in the insertion of the array into the scala media or scala vestibuli."
• “Siting the cochleostomy immediately anterior or anteroinferior to the round window niche places both the basilar membrane and spiral ligament at risk, and the array may well be inserted into the scala vestibuli.”
• The paper includes a detailed description of the anatomy of the scalae near the round window.
• “The anatomy indicates that a cochleostomy positioned anterior to the round window not only places the basilar membrane and spiral ligament at risk during insertion, but also increases the possibility of insertion of the electrode array into the scala vestibuli.”
• The authors “recommend that the cochleostomy is directly inferior to the round window membrane and hence initial visualization of the round window is necessary.”  This will often require removal of the bony overhang of the round window niche (called the subiculum).
• The importance of visualizing the round window niche is emphasized.  In cases where there is limited access the authors recommend to drill a generous posterior tympanotomy including skeletonizing the facial nerve to allow complete visualization of the round window niche.

Cochlear Training

We are pleased to announce next year's schedule for the Introductory Workshop Program. Cochlear's Introductory Workshop is designed for audiologists new to working with cochlear implants, and will prepare them for working with their first cochlear implant patients from the evaluation through the initial activation. It includes theory, practicum, hands on activities, and is presented in an interactive format.

If you have any questions regarding this program, please contact Linda Figini, Manager of Professional Education & Training: lfigini@cochlear.com

• The workshops will last 2½ days, and they will be strictly focused on cochlear implants
• Course is free of charge; attendees are responsible for travel and accommodation
• Registration is available online: www.regonline.com/614509

Thank you for reading and for your continued support.

Cochlear