Comparison of different electrode arrays in regard to scalar dislocation

Introduction:

Optimizing speech discrimination is a founding block for participation in society. A high surgical standard is an important aspect, especially avoiding dislocation of the electrode array as this may diminish the audiologic result.

Question: Incidence and point of dislocation of different electrode arrays.

Methods:

Cone beam CTs with multiplanar reconstructions were analyzed in regard to position of the electrode array. They have been acquired after surgeries 2013 – 2016. Adult patients without anatomical anomalies and excluding revision surgeries receiving an implant by Cochlear have been included.

Results:

360 implantations have been included. The implants comprised CI522 (n = 2), CI24RECA (64), CI422(85), CI512(99), CI522(84), CI532(23). 330 were inserted in scala tympani, 25 of those changed scala to vestibuli. 30 were inserted into scala vestibuli, 4 of those dislocated. The point of dislocation appeared to be at 190 ° after insertion. Changes of scalae after primary insertion into scala tympani happened in 11,7% when using CI24RECA, 0% with CI422, 20% with CI512, 1,2% when using CI522 and 0% in the case of CI532.

Conclusion:

Perimodiolar electrode arrays showed more tendency for dislocation than lateral wall electrodes. The delicate perimodiolar electrode array of the CI532 seems to be unproblematic as well. Most of the dislocations were found directly opposite of the point of insertion, furthering the hypothesis that the contact with the lateral wall may facilitate deviation.

Publication History

Publication Date:
23 April 2019 (online)