Evaluation of cochlear morphology and scalar position of a new slim and perimodiolar electrode array

Objective: Electrode array design and its influence on speech perception is of interest in CI surgery. The aim of this study is to evaluate scalar position and specific points of dislocation in relation to cochlear morphology in patients implanted with a new and slim perimodiolar electrode array.

Materials and Methods Patients were implanted using the slim modiolar electrode array (=SMA) (=532 / 632 electrode array of Cochlear^TM). Postoperative imaging was performed via cone beam computed tomography (CBCT) and the scans were analyzed regarding cochlear morphology (distances A and B and cochlear height), scalar location of the electrode array, basal insertion depth and apical insertion angle. Furthermore, electrode array design and surgical protocols were evaluated.

Results 78 ears implanted with the SMA were retrospectively included. The CBCT scans showed 73 initial scala tympani (ST) insertions without dislocation. Two ears showed a dislocated array, one at 77° and the other at 163°. Three arrays were inserted into scala vestibuli (SV) via cochleostomy. These patients showed no signs of obliteration. Cochlear morphology showed no influence on angular insertion depth and scalar position.

Conclusion The SMA showed a very low rate of scalar dislocations due to its slim electrode array design (2.7 %). Scala vestibuli insertions happened in patients with cochleostomy only. We could identify two specific points of dislocation depending on electrode array design. 

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Publication History

Article published online:
24 May 2022