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CAS-hno - Computer-Assisted Surgery



The group “Computer-Assisted Surgery and Electrode Development” (CAS-hno) is an interdisciplinary research group of engineers, physicians, and natural scientist at the Department of Otolaryngology whose common focus is the development of technologies and methods for surgical rehabilitation of the inner ear (cochlea).

This includes research activities dedicated to the design and development of surgical assistance devices in order to improve surgical techniques - with special focus on the minimally invasive access to the inner ear. Based on high-resolution imaging and pre-operative patient-specific planning different technologies of image-guided surgery systems, mechatronic assistance devices as well as micro-stereotactic frames are incorporated into the surgical workflow for a highly accurate and less traumatic surgical intervention.

The second research focus lies on the improvement of the electrode array of a cochlear implant (CI) including the insertion technique. In this field, our research group covers the complete design and development process. Starting with imaging and three-dimensional (3D) modelling of the human inner ear, the methods used include: development of improved electrode designs using computer aided design (CAD) software and finite element analysis (FEA); the simulation and optimization of the insertion process; experimental characterization of the electrode arrays by manual and/or automated insertion in artificial cochlear models and/or temporal bone specimens. Of special interest is the functionalization of the electrode array by integrating of actuators (e.g. using shape memory materials, fluid mechanical actuators, and tubular manipulators) for an individual adaption of the shape of the implant to the helical shaped inner ear in order to improve hearing preservation.

Scientific expertise

Image acquisition

  • imaging of the inner ear and lateral skull base
  • imaging of cochlear implants after insertion
  • computed tomography (CT), digital volume tomography (DVT), micro-CT, 3D histology (microgrinding)

Image processing and software development

  • visualization and processing of medical images
  • manually and semi-automated segmentation
  • trajectory planning
  • bone thickness calculation and visualization
  • visualization of cochlear anatomy using rotating midmodiolar slice planes
  • software development using C++, VTK, ITK, Matlab, Mathematica, LabView

3D modelling

  • anatomica models of the lateral skull base and the surgical approach
  • finite element models of the human inner ear and the electrode array
  • physicial replica of the human inner ear (artificial cochlear model)

Medical device development and evaluation

  • surgical assistance devices for minimally invasive cochlear implantation surgery
  • surgical tools and medical devices such as
    • image-guides surgery systems
    • medical robots
    • micro-stereotactic frames (surgical templates)
    • manual and automated insertion tools
    • drilling tools, laser hand pieces, and endoscopes

CI electrode development

  • functionalization (shape memory inlays, fluid-mechanical actuators, tubular manipulators,…)
  • individualization (length, thickness, shape change,…)
  • virtual prototyping using finite element analysis
  • simulation and optimization of the individual insertion process

CI electrode characterization

  • using 3D bending test
  • determination of curling behavior
  • manual and automated insertion tests in artificial cochlea models and human temporal bone specimens
  • force measurement
  • histology and evaluation of insertion trauma

Contact: Dr.-Ing. Thomas S. Rau

VIANNA - Institut für Audioneurotechnologie
der Klinik für Hals-, Nasen-, Ohrenheilkunde
Medizinische Hochschule Hannover
Stadtfelddamm 34
30625 Hannover

phone: +49 511/532-3025

About The VIANNA research team