gms | German Medical Science

79. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

30.04. - 04.05.2008, Bonn

Modelling of inner ear geometry for cochlear implantation – anatomical variability and patient-specific planning of insertion

Meeting Abstract

  • corresponding author Thomas S. Rau - Department of Otolaryngology, Medical University of Hannover, Hannover, Germany
  • author Hubertus Eilers - Institute of Robotics, Leibniz University of Hannover, Hannover, Germany
  • author Martin Leinung - Department of Otolaryngology, Medical University of Hannover, Hannover, Germany
  • author Andreas Hussong - Institute of Robotics, Leibniz University of Hannover, Hannover, Germany
  • author Thomas Lenarz - Department of Otolaryngology, Medical University of Hannover, Hannover, Germany
  • author Omid Majdani - Department of Otolaryngology, Medical University of Hannover, Hannover, Germany

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 79th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Bonn, 30.04.-04.05.2008. Düsseldorf, Köln: German Medical Science; 2008. Doc08hno15

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/hno2008/08hno15.shtml

Veröffentlicht: 8. Juli 2008

© 2008 Rau et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction: The development of mechatronic assistance devices provides the possibility to position cochlear implant electrodes (CI) with high precision within the spiral cochlea in an optimized location. Such a perimodiolar positioning is assumed to reduce electrical thresholds and improve speech perception. Knowledge of the individual anatomy is necessary for this highly precise planning because of spread in the anatomical variability. Furthermore an appropriate software solution has to be developed in order to define the desired final position pre-operatively.

Methods: Flat-panel based computed tomography imaging was performed on 23 fresh frozen human temporal bones (voxel size 200³ µm³) and the cochlea was segmented. Subsequently height and dimension of the basal turn of the cochleae were measured. A custom made 3-dimensional software was used to approximate the dimensions of the basal turn by a spiral function.

Results: The median height of the cochlea amount to 9.1 mm with a range from 8.4 mm to 9.8 mm. The longitudinal axis of the basal turn varied from 6.2 mm to 7.3 mm (median 6.8 mm) and corresponding transverse axis ranged from 3.8 mm to 5.0 mm. Fitting parameters of the spiral approximation confirm this high variability.

Conclusion: The determined variability of the inner ear geometry confirmed previous studies and underlines the necessity of patient-specific CI insertion planning. A custom made software module allows the import of individual geometry data and manual definition of supporting point for a mathematical description of the final position of the electrode carrier. By these means an optimized, perimodiolar implant positioning can be determined in the context of robot-assisted cochlear implantation.


References

1.
Escudé B, James C, Deguine O, Cochard N, Eter E, Fraysse B. The size of the cochlea and predictions of insertion depth angles for cochlear implant electrodes. Audiol Neurootol. 2006;11(Suppl 1):27-33.