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Proven atraumatic electrode arrays

The electrode arrays that are inserted into the cochlea stimulate the hearing nerve and open up the full spectrum of sound. Working with such delicate parts of the ear, they need to be flexible, smooth and soft so they don’t damage the cochlea in any way. The Neuro Zti and Digisonic® SP cochlear implants can be used with two proven types of electrode arrays designed for easy insertion and an atraumatic process.

Oticon Medical offers two different and proven electrode arrays, EVO and CLASSIC. Deciding which to use will depend on the cochlea’s anatomy, your medical history and your surgical needs.

EVO, the atraumatic electrode array

The EVO electrode array is designed to preserve the fragile structures of the cochlea. This is particularly important when there is residual hearing1. Its smooth surface, small diameter, thin end and flexibility help ensure a gentle, trauma-free, easy insertion2 so that the cochlear structures are preserved as much as possible.

The EVO has some push-rings at the base that provide a “safe” point to manipulate and hold the array. They enable improved array insertion, as well as mechanical sealing of the cochlea, and are designed to minimise the risk of infection and/or CSF (cerebrospinal fluid) leakage.

  • Active length: 24 mm
  • Insertion length: 25 mm
  • Diameter: from 0.5 mm to 0.4 mm

Watch how the EVO electrode array is inserted into the cochlea


The CLASSIC electrode array has an optimised stiffness profile that makes it compatible with difficult insertions. It is straight with a shape memory conforming structure and has dimensions that facilitate deep cochlear insertion (26 mm).

The soft end of the electrode array is designed to reduce cochlear trauma. Similar to the EVO array, the CLASSIC has push-rings at the base to make it easier to seal the array’s entry point into the cochlea to help minimise the risk of infection and/or CSF (cerebrospinal fluid) leakage.

  • Active length: 25 mm
  • Insertion length: 26 mm
  • Diameter: from 1.07 mm to 0.5 mm


The specific characteristics of EVO significantly reduce insertion forces by 32%2 compared to the CLASSIC electrode array.

EVO electrode
Classic electrode

Depth of insertion (degrees)

The electrode design

The Neuro Zti electrode arrays hold full-band platinum iridium electrodes that are manufactured using a highly precise and reproducible micro-machining process.

The full-band electrode design helps to ensure optimised orientation and positioning of the electrode into the cochlea. This improves stimulation of the hearing nerves, and reduces impedance and low-charge density stimulation.




1Bento R.F., Danieli F., Magalhães A.T., Gnansia D., Hoen M. (2016). Residual Hearing Preservation with the EVO Cochlear Implant Electrode Array: Preliminary Results. Int Arch Otorhinolaryngol. 2016 Feb 17; doi: 10.1055/s-0036-1572530.
2Nguyen. Y., Miroir. M., Kazmitcheff. G., Sutter. J., Bensidhoum. M., Ferrary. E., Sterkers. o., Bozorg Grayeli. A. 2012. Cochlear implant insertion Forces in Microdissected human Cochlea to Evaluate a Prototype Array. Audiol Neurotol 17: 290-298.

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