@article{HerrmannMuellerGraffKaulitzetal.2022, author = {Herrmann, David P. and M{\"u}ller-Graff, Franz-Tassilo and Kaulitz, Stefan and Cebulla, Mario and Kurz, Anja and Hagen, Rudolf and Neun, Tilmann and Rak, Kristen}, title = {Application of intentional facial nerve stimulation during cochlear implantation as an electrophysiological tool to estimate the intracochlear electrode position}, series = {Scientific Reports}, volume = {12}, journal = {Scientific Reports}, number = {1}, doi = {10.1038/s41598-022-17732-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300197}, year = {2022}, abstract = {This proof of concept describes the use of evoked electromyographic (EMG) activation of the facial nerve for intraoperative monitoring of the electrode insertion during cochlear implantation (CI). Intraoperative EMG measurements from the facial nerve were conducted in nine patients undergoing CI implantation. Electric current pulses were emitted from contacts on the CI array during and immediately after electrode insertion. For control, the results of EMG measurements were compared to postoperative flat panel volume computed tomography scans with secondary reconstruction (fpVCT\(_{SECO}\)). During insertion, the EMG response evoked by the electrical stimulation from the CI was growing with the stimulating contact approaching the facial nerve and declined with increasing distance. After full insertion, contacts on the apical half of the CI array stimulated higher EMG responses compared with those on the basal half. Comparison with postoperative imaging demonstrated that electrode contacts stimulating high EMG responses had the shortest distances to the facial nerve. It could be demonstrated that electrically evoked EMG activation of the facial nerve can be used to monitor the progress during CI electrode insertion and to control the intracochlear electrode position after full insertion.}, language = {en} } @article{TaegerMuellerGraffNeunetal.2021, author = {Taeger, Johannes and M{\"u}ller-Graff, Franz-Tassilo and Neun, Tilmann and K{\"o}ping, Maria and Schendzielorz, Philipp and Hagen, Rudolf and Rak, Kristen}, title = {Highly precise navigation at the lateral skull base by the combination of flat-panel volume CT and electromagnetic navigation}, series = {Science Progress}, volume = {104}, journal = {Science Progress}, number = {3}, issn = {2047-7163}, doi = {10.1177/00368504211032090}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250268}, year = {2021}, abstract = {This study aimed to evaluate the feasibility and accuracy of electromagnetic navigation at the lateral skull base in combination with flat panel volume computed tomography (fpVCT) datasets. A mastoidectomy and a posterior tympanotomy were performed on 10 samples of fresh frozen temporal bones. For registration, four self-drilling titanium screws were applied as fiducial markers. Multi-slice computed tomography (MSCT; 600 µm), conventional flat panel volume computed tomography (fpVCT; 466 µm), micro-fpVCT (197 µm) and secondary reconstructed fpVCT (100 µM) scans were performed and data were loaded into the navigation system. The resulting fiducial registration error (FRE) was analysed, and control of the navigation accuracy was performed. The registration process was very quick and reliable with the screws as fiducials. Compared to using the MSCT data, the micro-fpVCT data led to significantly lower FRE values, whereas conventional fpVCT and secondary reconstructed fpVCT data had no advantage in terms of accuracy. For all imaging modalities, there was no relevant visual deviation when targeting defined anatomical points with a navigation probe. fpVCT data are very well suited for electromagnetic navigation at the lateral skull base. The use of titanium screws as fiducial markers turned out to be ideal for comparing different imaging methods. A further evaluation of this approach by a clinical trial is required.}, language = {en} }