360° View of Cochlear
Implant Safety and Reliability

The Lowest Incidence of Scalar Deviation

To preserve the delicate structures of the cochlea, the electrode array must be placed fully in the scala tympani. If the electrode deviates into the scala vestibuli, it allows the endolymph and perilymph fluids to mix. This could impair essential nerve function and destroy any residual hearing. This may also permanently negatively affect a recipient’s hearing performance and leave them unable to benefit from new technologies such as improved coding strategies.^{[ft][ft][ft][ft]}

The scala tympani is separated from the scala vestibuli by incredibly delicate structures that measure only a few microns in diameter. Data from systematic literature reviews demonstrate that stiff, pre-shaped arrays are far more likely to penetrate the basilar membrane and cross into the scala vestibuli. Scalar deviation is also more likely with stiff straight arrays. MED-EL FLEX electrode arrays had the lowest overall rate of scalar translocation in comparison to those from Cochlear and Advanced Bionics.^[ft][ft][ft]

The Lowest Incidence of Tip Fold-Over

With pre-curved electrode arrays, the tip of the electrode array can also become lodged and fold over upon itself. This tip fold-over complication can seriously compromise the interface between the electrode contacts and the cochlea, and often limits coverage to less than three-fourths of a single turn in the cochlea. ^{[ft][ft][ft][ft][ft][ft]}

With MED-EL FLEX electrodes, tip fold-over is rare. Our unique, rounded electrode design with FLEX-Tip Technology helps our electrode arrays to gently adapt to the anatomy of each individual cochlea, so there is a very minimized risk of the tip becoming lodged or folding over.

Data from a systematic literature review of 46 studies (N=8163 ears) demonstrate that MED-EL has the lowest reported rate of tip fold-over at 0.14%, compared to Advanced Bionics at 0.63%, and Cochlear with 3.47%.

Results of a meta-analysis of 46 peer-viewed publications (N = 8,163 ears). See references at end of the full report.

Even the Smallest Cochleae Can Accommodate a FLEX Electrode

As the cochlea nears the apex, the cross section of the scala tympani tapers in diameter to approximately 0.7 mm at 720°. This is why it is important to ensure the array can safely fit in the cochlear duct. However, with other thin arrays, the electrode array only covers the basal turn where a reduced diameter is not necessary.

Our lateral wall FLEX arrays use a tapered FLEX-Tip for the five apical electrode contacts, making FLEX series the thinnest full-length electrode arrays available. With a tip diameter of 0.4 x 0.5 mm or less, the FLEX-Tip can be safely and reliably placed in the second turn of the scala tympani without harming the basilar membrane.^[ft] In other words, the FLEX-Tip is designed to be like tiny toes easily fitting into the narrow end of a shoe.

“This study represents a wide variability in cochlear morphology and suggests that even in the smallest cochlea, the scala tympani can accommodate a 0.4 mm diameter electrode up to 720°. Additionally, all lateral wall array trajectories were within the anatomically accommodating insertion zone.”

Micuda et al., 2024^[ft]