Quality control after insertion of the nucleus contour and contour advance electrode in adults

To evaluate the quality of insertion of the Nucleus Contour and the newly developed Contour Advance electrode in adult cochlear implant recipients and to compare results of speech performance tests with regard to electrode position.

A total of 43 adult patients with a history of progressive hearing loss having received a Nucleus cochlear implant, 21 of which had received a Contour electrode and 22 a Contour Advance electrode, were evaluated by rotational tomography after surgery. Electrode position was determined to be in scala tympani, scala vestibuli, or with a dislocation from one scala to the other. Speech test results were collected for Freiburg numbers, Freiburg monosyllables, and Oldenburg sentence tests 1 yr after surgery.

The Contour array presented with a high rate of scala vestibuli insertions and a high rate of dislocations from scala tympani to scala vestibuli, whereas the Contour Advance array showed a high rate of scala tympani insertions with very few dislocations and few scala vestibuli insertions. Speech tests results varied with respect to the location of the intracochlear electrode position, with insertions into the scala tympani being significantly superior to the scala vestibuli.

Results of studying the Contour array influenced the surgical procedure that improved surgical ability to perform insertions into the scala tympani by using the Contour Advance array. In addition, a comparison between Contour and Contour Advance electrode demonstrated an improved mechanical behavior of the Contour Advance electrode with a decrease of dislocation rate. The use of the Contour Advance electrode allows a more atraumatic electrode insertion, which is of interest with extending indications and the use of further advanced coding strategies. The intracochlear electrode position with regard to speech performance results demonstrated advantages of scala tympani insertions.