Cochlear Implants
by Cochlear Guest Author

Understanding reliability and why it matters

November 29, 2018
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Guest author: Wade Colburn

Wade Colburn

 

 

Of all the different factors in counseling your patient on a cochlear implant, the reliability of the implant is likely one factor that comes to mind. Once a patient commits to a cochlear implant, it is important to know that a reliable and properly functioning implant is the basis for hearing. Furthermore, a reliable implant can reduce the need for a possible revision in the future. All manufacturers claim to have the most reliable 1,2,3 implants, but this can’t be the case.

Let’s take a closer look at what goes in to reliability reporting.  Reliability is measured as Cumulative Survival Percentage (CSP), which is the probability of survival of a device within a given time period, and Cumulative Failure Percentage (CFP), which is the probability of failure of a device within a given time period.

Reliability reporting is done each and every year and should be reported according to the European and Global Consensus Statement on Cochlear Implant Failures and Explantations1. This consensus detailed how device failures and reliability should be reported and established the seven principles of best practice reporting.

In the latest reports of each cochlear implant manufacturer, the CSP was reported as follows: Cochlear TM Profile Series – 99.82% within 4 years 2, Med-El Synchrony Series – 98.16% within 3 years 3, Advanced Bionics HiRes 90K Advantage – 99.29% within 5 years 4. While this may seem like a small percentage difference, the fact is these numbers result in the following likelihood of failure:

  • Cochlear Profile: 1 in 556 devices fail within 4 years.
  • Advanced Bionic HiRes 90K Advantage: 1 in 141 devices fail within 5 years
  • MED-EL Synchrony: 1 in 55 devices fail within 3 years

This way of looking at reliability is powerful and the reason Cochlear stands behind having the best reliability in the industry establishing itself as the most chosen manufacturer in the world.

Reliability Graph

The difference in CSP seems very small (<1%), but it can translate to a big difference with tremendous impact to patients. To establish this evidence supporting Cochlear as #1 in implant reliability, the following calculations were made:

  • Convert failure rate (CFP) based on Cumulative Survival Percentage (CSP)
  1. Cochlear Profile (4 Years)  99.82% (CSP) = 0.18% failure rate
  2. AB HiRes 90K (5 Years) 99.29% (CSP) = 0.71% Failure Rate
  3. MedEl Synchrony (3 Years)  98.16% (CSP) = 1.84% Failure Rate
  • Based on this failure rate, we establish how many will have failed after 1000 implantations (1000 implants x failure rate):
  1. Cochlear Profile (4 Years) = 1000*.0018 = 1.8 Failures in 1000 Implants
  2. AB HiRes 90K (5 Years)= 1000*.0071 = 7.1 Failures in 1000 Implants
  3. MedEl Synchrony (3 Years) = 1000*.0184 = 18.4 Failures in 1000 Implants
  • Last we establish the number of implants for every failure: 1000/ # of Failures per 1000
  1. Cochlear Profile (4 Years) = 1000/ 1.8 = 1 in 556 within 4 years
  2. AB HiRes 90K= 1000/7.1 = 1 in 141 within 5 years
  3. MedEl Synchrony = 1000/18.4 = 1 in 55 within 3 years

Understanding reliability is essential to making the best decision for your patients. To learn more about reliability reporting at Cochlear and see the full Reliability report.

About our guest author:

Wade is the Product Manager for 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, but comes from an engineering background with the medical device field, including previous otology experience.

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References:
  1. European Consensus Statement on Cochlear Implant Failures and Explantations. Otol Neurotol. 26: 1097-1099, 2005.
  2. Cochlear Nucleus Implant Reliability Report. Volume 16 | December 2017. D1335113. Cochlear Ltd; 2018
  3. Hearing Implant Reliability Reporting | MED-EL [Internet]. Medel.com 2018 [cited 15 Oct 2018] Available from: https://www.medel.com/us/reliability-reporting/
  4. 2018 Global Implant Reliability Report. 027-N025-02 Rev B. Advanced Bionics AG and affiliates; 2018.
Author

Cochlear Guest Author

In an effort to keep our content fresh and reflective of a diverse industry, Cochlear Americas features a mix of employees and professional partners to contribute to Cochlear ProNews as Guest Authors.

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Journal Club: Matched Cohort Comparison Indicates Superiority of Precurved Electrode Arrays

February 10, 2020

By Wade Colburn, Biomedical Engineer and Product Manager – Implants, Cochlear Americas

Matched Cohort Comparison Indicates Superiority of Precurved Electrode Arrays

JT Holder, RJ Yawn, AM Nassiri, RT Dwyer, A Rivas, RF Labadie, RH Gifford

Otology Neurotology (2019) 40(9): 1160 – 1666

In today’s busy clinical environment, clinicians who value research-based practice often struggle to keep up with current literature.  To help, we offer a ProNews Blog monthly feature – Journal Club!  Each month, rotating guest authors will present a current journal article summary.

This month’s Journal Club explores a recent 2019 study from Vanderbilt University, Matched Cohort Comparison Indicates Superiority of Precurved Electrode Arrays. Researchers analyzed the two primary types of electrode arrays within the marketplace: lateral wall or straight array and pre-curved or perimodiolar.  Very seldomly are the array types compared using matched groups.

Historical studies have suggested the benefits of placing the electrode closer to the nerve, but often did not contain a comparison group.  This article explores the comparison between pre-curved and lateral wall electrode design and demonstrates the superiority of pre-curved.

What did the study investigate?

Goals of the study:

  1. Better understand how electrode type affects programming parameters and patient outcomes to choose the best device for an individual
  2. Compare a newer generation precurved electrode with a straight electrode utilizing matched groups

Why is this important? 

In the cochlear implant industry there are multiple electrode variants and choices between manufacturers. With that comes various evidence showing how implant technology, surgical technique and placement of the device can impact the outcome. Specifically, the authors call out that electrode design, intrascalar location, surgical approach and atraumatic insertion technique could impact performance.  Various studies in the marketplace highlight the benefits of both lateral wall and precurved electrode types, but few draw a direct comparison using matched groups.

Straight arrays have a history of atraumatic insertions and greater potential for structural preservation, while precurved arrays have the outcome benefit of stimulation specificity.1 Due to recent changes in electrode design, this study aimed to compare a new perimodiolar array to a straight array. Authors hypothesized that the arrays would show similar hearing preservation rates, while the perimodiolar array would show better speech understanding scores and preferable programming parameters due to the lower electrode-to-modiolus distance.

How did they do it? 

Here is your need-to-know: 

  • 29 precurved array patients
    • 17 male/ 12 female
  • 29 straight array patients
    • 19 male/ 10 female
  • Retrospectively reviewed aggregate clinical database and matched CI532 electrode recipients with CI422/CI522 recipients, controlling age and preoperative hearing thresholds
  • Standard cochlear implantations via round window (RW), extended round window (ERW) and cochleostomy (C)
    • CI422/CI522 Group: RW=23, ERW=3 and C=3
    • CI532 Group: RW=18, ERW=5, C=6
  • Speech recognition scores (CNC Word Recognition, AzBio Sentence Recognition in quiet, AzBio Sentence Recognition in +5 dB SNR), residual acoustic hearing thresholds (LFPTA at 125, 250, 500 Hz) and quality of life questionnaire data (Speech Spatial Qualities -SSQ) were obtained for patients both pre-operatively and post-operatively (6 months).
  • Programming software parameters (pulse duration, maxima and datalogging) were also analyzed
  • Matching controlled for age, preoperative LFPTA, preoperative CNC scores and daily processor usage

Results1

Age, preoperative LFPTA, preoperative CNC scores and daily processor usage were matched within the study to determine significance in the outcome measures and software parameters.  The study found that impedances and pulse duration were significantly lower for the CI532 group, but there was no difference in overall charge between groups. Further, the study found that the CI532 group had significantly better post-operative CNC and LFPTA.

Table 1, provided below, outlines the parameters that were matched and analyzed within the study.

The study compared the speech outcomes directly. While only CNC had a significant difference, Figure 2 from the publication outlines the performance of the devices in CNC, AzBio Quiet and AzBio +5 dB.

The authors call out that “the most notable finding of the current study is that the CI532 group had significantly better post-operative acoustic LFPTA.”  They continue, “This difference in results could be explained by lower rates of translocation for the CI532, which suggests less trauma of the cochlear structures”.

Further investigation shows that the observations regarding lower impedances and differences in pulse duration allow for the center to implement greater maxima, which has been known to have a positive impact on speech understanding in complicated listening situations.1

Results of this study indicate that there are many advantages to a perimodiolar array including closer proximity to the modiolus and decreased translocation rates. More research will be conducted in regards to this new perimodiolar array to assess the performance benefit and the potential for equivalent or better preservation rates, historically associated with lateral wall arrays.

Learn more about perimodiolar electrodes by accessing the publication and stay tuned for next month’s edition of Journal Club!

About our guest author: Wade Colburn is the Product Manager, Cochlear Implants at Cochlear Americas. Wade is responsible for managing product lifecycle and providing technical support to customers.  Wade is a biomedical engineer from North Carolina State University with extensive experience within otology prior to joining Cochlear.

References:

  1. Holder, J. T., Yawn, R. J., Nassiri, A. M., Dwyer, R. T., Rivas, A., Labadie, R. F., & Gifford, R. H. (2019). Matched Cohort Comparison Indicates Superiority of Precurved Electrode Arrays. Otology & Neurotology, 40(9), 1160–1166. doi: 10.1097/mao.0000000000002366

Science Spotlight

3 practical Science Spotlights for optimal care

June 18, 2021

1. New Active Osseointegrated Steady-State Implant System

The aim of this international, multicenter study was to demonstrate clinical performance, safety and benefit of the Cochlear™ Osia® System, an active osseointegrated steady-state transcutaneous bone conduction hearing implant system that uses piezoelectric technology.

2. Speech Understanding and Quality-of-Life Outcomes After Cochlear Implantation

The purpose of this study  was to measure speech understanding in quiet, speech understanding in noise, and health utility using a cochlear implant and hearing aid (bimodal hearing) in 96 subjects versus their pre-operative condition of two hearing aids (HAs).

3. Speech perception and QoL effectiveness CI in a group of adults 65 years or older

The purpose of this study was to to explore speech perception and quality-of-life (QoL) effectiveness of cochlear implants (CI) in a group of adults 65 years or older compared with an optimized bilateral hearing aid (HA) condition, and to examine the improvement on the AzBio Sentence Test for Medicare beneficiaries who meet the expanded criteria of a score of 41% – 60% in the best-aided condition.

For more article summaries, read this article and subscribe to Cochlear ProNews!

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