CI532: The Perimodiolar Advantage


By guest author: Wade Colburn

Wade Colburn



Cochlear introduced our first perimodiolar electrode array in 2000. Perimodiolar arrays reduce the distance to the modiolus to improve performance1,2 and allow for more focused stimulation3,4. In a study conducted at Washington University by Holden et al5, they showed a correlation between the position of the electrode with respect to the modiolus (often referred to as the “Wrapping Factor”) and CNC word score. The group showed that those electrodes with proper perimodiolar placement had a lower wrapping factor and improved performance.

Cochlear continually innovates with the intent of making perimodiolar electrodes thinner, less traumatic and consistent in placement, and with the ultimate goal of improving patient performance. The perimodiolar advantage has been observed by many clinicians over the years, which is demonstrated by the fact that 2 out of every 3 Cochlear™ Nucleus® implants are perimodiolar6.  Cochler Slim Modiolar Electrode

Currently, two perimodiolar electrodes are available for purchase, the Contour Advance (CI512) and the new Slim Modiolar (CI532).  Contour Advance has been available since 2005 and is still used among surgeons. The new Slim Modiolar electrode improves upon a few key design elements and redefines any historical assumptions surrounding perimodiolar arrays, such as scalar translocations and limitations on surgical approach. While there are certain patients that can benefit from the stylet-based Contour Advance, the sheath-based Slim Modiolar has shown performance benefits7.

The Slim Modiolar electrode redefines the perimodiolar advantage in four major areas:


While the performance benefits of a perimodiolar electrode is well understood 1,2,3,4,5, a recent publication by Shaul et al7, demonstrated that in a matched population (post-lingual patients with all electrodes in scala tympani) phoneme score at 12 months was significantly better with Slim Modiolar (79.5% (mean), 14% (SD)) compared to Contour Advance (69.4% (mean), 17% (SD)).

Placement in Scala Tympani:

In multiple published surgical papers on Slim Modiolar, successful scala tympani location was seen in 90 to 100% of the patients 7,8,9,10. Slim Modiolar redefines the reputation of perimodiolar electrodes and presents an opportunity to combine the benefits of being close to the hearing nerve with consistent scala tympani location.

Preservation of Structures:

The Slim Modiolar is designed with a sheath-based delivery system, which allowed for a 60% reduction in volume compared to Contour Advance, making it designed to preserve the delicate inner ear structures. The thin design and smooth insertion with a sheath delivery showed in a temporal bone study that 98% of the bones that were implanted experienced “no trauma”. The Slim Modiolar is designed to preserve the natural structure of the cochlea.

Preference of Insertion:

Another benefit of the Slim Modiolar electrode is the ability to use the preferred surgical approach, including a round window insertion. Contour Advance design was limited to cochleostomy insertion, but Slim Modiolar is designed to be implanted via round window, extended round window and cochleostomy. In Aschendorff et al8, 44% of the cases were performed with round window insertion, 22% with extended round window and 34% with cochleostomy. This study demonstrated that Slim Modiolar could be implanted with all surgical approaches, while still maintaining consistent scala tympani location.

Slim Modiolar electrode (CI532) is designed intentionally to take the great elements of the Contour Advance and improve upon them to create an ideal electrode for your patients. Closer to the hearing nerve has proven to be a benefit and CI532 has redefined the perimodiolar advantage for the better.

To learn more about CI532 and practice insertions in a simulated model, contact your Cochlear representative.


About our guest author:

Wade Colburn is the Product Manager for the Cochlear™ Implant product portfolio within Cochlear Americas.  Wade’s responsibilities include product positioning and messaging, life-cycle management, new product launches and surgical support and training. Wade has recently joined Cochlear and comes from an engineering background within the medical device field, including previous otology experience.



  1. Lazard D. S, et al. Pre-, per- and postoperative factors affecting performance of postlinguistically deaf adults using cochlear implants: a new conceptual model over time. PloS one. 2012; 7:e48739
  2. Blamey P, et al. Factors affecting auditory performance of postlinguistically deaf adults using cochlear implants: An update with 2251 patients. Audiology & neuro-otology. 2013; 18:36-47.
  3. Hughes, ML, Abbas, PJ. Electrophysiological channel interaction, electrode pitch ranking, and behavioral threshold in straight versus perimodiolar cochlear implant electrode arrays. J Acoustic Soc Am. 2006; 119(3):1538-47.
  4. Cohen L., Richardson L., Saunders E., Cowan R. Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking. Hearing Research. 2003; 179 (1-2):72-87.
  5. Holden LK, Finley CC, Firszt JB, Holden TA, Brenner C, Potts LG, et al. Factors affecting open-set word recognition in adults with cochlear implants. Ear Hear. 2013; 34(3):342-60
  6. Internal sales data on file.
  7. Shaul C, Dragovic AS, Stringer AK, O’Leary SJ, Briggs RJ. Scalar localization of peri-modiolar electrodes and speech perception outcomes. J Laryngol Otol 2018; 1-7.
  8. Aschendorff et al. Clinical investigation of the Nucleus Slim Modiolar Electrode. Audiology & Neurotology. 2017; 22:169-179.
  9. Data on File: US Multicenter CI532 Study. 2018.
  10. Cuda, D, Murri, A. Cochlear Implantation with the nucleus slim modiolar electrode (CI532): a preliminary experience. European Archives of Oto-Rhino-Laryngology. 20017; 12:4141.
  11. EA32 Electrode Insertion Safety and Performance Study Report. Data on File (Document Number: 473386)
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