Forschungsinformationssystem Universität Greifswald

Oliver Dziemba (Projektleitung) - Klinik und Poliklinik für Hals-Nasen-Ohrenkrankheiten, Kopf- und Halschirurgie
Holger Kaftan (stellvertretende Projektleitung) - Klinik und Poliklinik für Hals-Nasen-Ohrenkrankheiten, Kopf- und Halschirurgie

Klinik und Poliklinik für Hals-Nasen-Ohrenkrankheiten, Kopf- und Halschirurgie

1. Background and Aim Cochlear implantation is a known, established therapy of severe to profound hearing loss and deafness. A functional cochlear nerve is the basis for successful Cochlea implantation. Quality assured implantation and fitting of cochlear implants (CI) is based on several pre-, intra- and postoperative audiological measurement methods. Particularly in the intraoperative situation objective measurement methods can be used only. Verification of CI electrode position is an important part of the intraoperative measurements during the implantation process. Intraoperative electrode localization checks are usually based on CT scan and conventional X-Ray and lead to an additional radiation exposure for the patient and not least for the surgeon and the other staff at the operation room. Additionally the imaging procedure represents a substantial cost factor within the surgical procedure. Spread Of Excitation measurement (SOE) is an alternative intraoperative electrophysiological method avoiding especially imaging techniques. Several studies have shown that this objective method can detect be used for verification of electrode position and is therefore suitable as a fast and cost efficient procedure. (Grolman et al. 2009, Walkowiak et al. 2010). For evaluation this method needs standardized measurement protocols and electrode specific normal values (Dziemba et al. 2016). Directly after positioning of the implant, the reference electrode MP1 and the insertion of the slim modiolar electrode array a defined series of ECAP measurement will be done. All measurements are to be made with the CE-approved software “Custom Sound EP 4.x” (CS-EP). The post-processing of the measurement data will be done in order to achieve a minimum signal quality (Hey and Müller-Deile 2015). The selection of the patients for the normal group will be done according to findings of Müller et al. 2015. The primary goal of this prospective study is the further development of the SOE measuring method and adaption to the slim modiolar electrode array to detect electrode tip-fold-over during surgery without using CT imaging methods. The secondary goal of this prospective study is to recover further normal values of an advanced SOE measurement method based on the findings of Dziemba et al. 2016. 2. Methods Experimental setup - Cochlear™ Nucleus® Profile with slim modiolar electrode (CI532) - Cochlear™ Nucleus® Profile with slim straight electrode (CI522) - Cochlear™ Nucleus® Profile with Contour Advance® electrode (CI512) - Cochlear™ Custom Sound EP® Version 4.3 or higher Subjects All CI-Patients, recruited from the pool of patients of the Department of Otorhinolaryngology and Head and Neck Surgery, University Medicine Greifswald, with the decision to get an implant of Cochlear™. Five subjects will be implanted during the pilot phase. 40 subjects will be included during Phase 2 4. Inclusion criteria for normal group • Significant ECAP amplitudes on all electrodes needed for regular SOE measurements • Normal findings on ECAP threshold measurements (Müller et al. 2015) Measurement setting and sequence additional to clinical routine 1. ECAP threshold of all 22 electrodes 2. Spread Of Excitation measurement 3. imaging of the electrode array 3. Expected Results Normative values Normative values for advanced SOE measurement series to verify correct electrode position. 4. References [1]. Dziemba OC, Mir-Salim P, Müller A. References for electrophysiological measurements for intraoperative verification of placement for several types of CI electrodes [German]. Z Audiol 2016; 55:50–6. [2]. Grolman W, Maat A, Verdam F, et al. Spread of Excitation Measurements for the Detection of Electrode Array Foldovers. Otol Neurotol 2009; 30:27–33. [3]. Hey M, Müller-Deile J. Accuracy of measurement in electrically evoked compound action potentials. J Neurosci Methods 2015; 239:214–22. [4]. Müller A, Hocke T, Mir-Salim P. Intraoperative findings on ECAP-measurement: Normal or special case? [eng]. Int J Audiol 2015; 54:257–64. [5]. Walkowiak A, Kostek B, Lorens A, Obrycka A, Wasowski A, Skarzynski H. Spread of Excitation (SoE) - A Non-Invasive Assessment of Cochlear Implant Electrode Placement. Cochlear Implants Int 2010; 11:479–81.