Endoscopy 2012; 44 - A05
DOI: 10.1055/s-0032-1329278

Multisensor navigation for visualization of the configuration of flexible endoscopes

A Schneider 1, D Wilhelm 1, M Polski 1, A Fiolka 1, A Meining 1, H Feussner 1
  • 1Adress available at: European Society of Gastrointestinal Endoscopy (ESGE), HG Editorial & Management Services, Mauerkircher Str. 29, 81679 Munich, Germany

Objective: For pure NOTES procedures flexible endoscopes are one precondition. However controlled steering is only possible for the tip of the scope, whereas the rest part of the endoscope places itself uncontrollable in the abdomen. Due to this fact, navigation of instruments is challenging and, moreover, adjacent structures could be injured by unintentional pressure or unintended instrument movements. Even more, the endoscopes tip position can only be assumed out of the images which could be challenging especially in an inverted position.

To overcome these problems, we developed a navigation system for the endoscope tip and the whole flexible shaft which can be used for simple visualization of the configuration or even more in a 3D dataset of the specific patient.

Method: A new navigation catheter, consisting out of seven consecutively placed 5D sensors, was positioned in the working channel of a flexible endoscope and connected to an electromagnetic tracking system.

Sensor values were read with a frequency of 30 Hz. Since simple connection and visualization of the sensor points would be very confusing, we developed an algorithm to calculate a NURBS (non uniform B-Spline)-curve, which allows a smooth visualization.

For rigid registration with the 3D anatomical CT-dataset, a simple registration and scaling algorithm is used.

Results: With the new multisensory catheter tracking sensor, inserted in the working channel of an endoscope, it has become possible to visualize the bending of the tip as well as the whole shaft in correlation with the anatomy.

Accuracy of sensor values as well as the calculated NURBS-curve for representation was proven in a technical setup and found sufficient for use during NOTES procedures.

Conclusion: Up to now, there was no adequate technology for representation of the configuration of a flexible endoscope in three-dimensionally anatomical datasets. There were previous attempts; however, all these techniques were unrelated to the anatomy.

With our system it could be shown, that a direct relationship to the anatomy could be easily combined by configuration visualization.