Institute for
Robotics and Process Control

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Robot Assisted Endoscopic Sinus Surgery

Problem Description

Today most operations in nasal sinuses (caves in the skull near the nose), for example the removal of adenoids, are accomplished minimal-invasively through the natural opening of the nose with the help of an endoscope. The endoscope acts as a light source in one direction and a camera in the other direction. The surgeon, holding the endoscope in one hand, does not see the place of operation directly but a camera picture of it on a screen. In the other hand she/he usually holds an instrument, e.g. a special knife used to cut away tissue. Normally, this causes some bleeding. So a sucker (another instrument) is needed to remove the blood and the cut tissue from the nose. The surgeon often switches between these instruments during an operation. This increases the duration of the operation and makes the process cumbersome and unergonomic for the surgeon.
It would be beneficial for the surgeon to be able to hold two instruments at once. Some surgeons have tried to work with a human assistant, who guides the endoscope during an operation. But even trained teams had problems separating the available space and also communication problems. Often the surgeon did not see the regions of his interest. Furthermore, a human assistant gets tired after a while. Thus, the camera picture begins to tremble after some minutes of operation.

endoscope_from_old_to_new.jpg
A robotic manipulator takes the guidance of the endoscope

Project Description

Within the scope of an cooperative research project with the Klinik und Poliklinik für Hals-Nasen-Ohrenheilkunde/Chirurgie(External) of the "Rheinische Friedrich-Wilhelms-Universität Bonn" we are investigating methods that allow a robotic manipulator to guide an endoscope during an endonasal operation completely autonomously. The objective of the project is an intelligent guidance of the endoscope that fulfils the following requirements:
  • The tip of a selected instrument is always in the center of the camera view.
  • The endoscope is placed in such a way that the surgeon has as much as possible free space for his own movements.
  • Critical structures of the patient (e.g. brain, eyes) have to be avoided and fragile structures have to be touched carefully and only if necessary.

Methods

  • The statistical analysis of instrument and endoscope movements as well as correlations between these movements can be used to generate a knowledge base for automatic motion planning algorithms. Thereto the movements of instruments and the endoscope are recorded with the help of an external tracking system and analyzed afterwards.
  • CT- and/or MRT-data are used to define the work space of the robot inside the nose. We would like to automatically segment the volume data and generate a 3D model of the sinuses of every patient, so that critical areas and boundaries between air, soft structures and bones are known. This information can be used to calculate the configuration space of the robot.
  • The tip of an instrument can be estimated by vision algorithms that detect instruments in the picture of the endoscope camera. This estimated position allows the robot to move the endoscope in such a way that the tip of the instrument is always in the center of the view.
  • Furthermore, we need tactile information of the endoscope when it gets in contact with the environment. This information is needed for the security of the patient and for the dynamic adaptation of the robot work space, which may change during an operation. For example, some internal structures (ethmoid bone) have to be cleared out and removed.

Videos



"Demonstration of our endoscope guidance robot with automated instrument tracking and following"
Video download: fess-robot-op_short.avi (AVI/MS MPEG4, 33.5MB)


"Demonstration of a Prototype for Robot Assisted Endoscopic Sinus Surgery"
Published in: Video proceedings of ICRA2010
Video download: icra2010_prototype.wmv (Windows Media, 92.7MB)


Tracking of instruments in endoscopic images
Video download: instrument_tracking.wmv (Windows Media, 17.1MB)

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