Electrophysiological effects of electrode pull-back in cochlear implant surgery.
CONCLUSIONS
The surgical technique of electrode pull-back had a significant improving effect on the spread of excitation (SOE). However, the long-term clinical and audiological outcome of this modified surgical technique should be a subject of further studies.


OBJECTIVE
To observe the intraoperative electrophysiological effects of a surgical electrode insertion technique (i.e. pull-back) in cochlear implantation.


METHODS
The influence of the pull-back technique on intraoperatively recorded electrophysiological parameters (including T-NRT, ECAP amplitude, SOE) was investigated in a prospective, non-randomized, intraoperative study. In addition, we observed the correlation of insertion depth and SOE differences after a controlled electrode pull-back. We implanted 13 patients (aged 18-76 years) with a Nucleus 24CI RE cochlear implant with a perimodiolar electrode.


RESULTS
After a controlled pull-back, a significant decrease of the SOE at different electrodes (upon recording from electrodes 5, 10, 15) was observed. Electrode 10 was the SOE area with the most significant and homogeneous changes after pull-back. The change in the ECAP amplitudes was highly variable in correlation with the changes in the SOE.
Todt
Ingo
I
Department of Otolaryngology at UKB, Hospital of the University of Berlin, Charité Medical School, Berlin, Germany. todt@gmx.net
Basta
Dietmar
D
Seidl
Rainer
R
Ernst
Arne
A
D000158:Acoustic Impedance Tests; D000293:Adolescent; D000328:Adult; D000368:Aged; D003051:Cochlea / Q000000981:diagnostic imaging / Q000601:surgery; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D055724:Electrophysiological Phenomena; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D055815:Young Adult