S. Tombrock

The VN Project: Endoscopic Image Processing for Neurosurgery

We developed a navigation support system for endoscopic interventions that allows three-dimensional (3-D) information to be extracted from endoscopic video data and superimposed onto such live video sequences. The endoscope is coupled to a position measurement system and a video camera as components of a calibrated system. In this article we show that the radial distortions of the wide-angle endoscopic lens system can be successfully corrected and an overall accuracy of about 0.7 mm is achievable. Tracking on live endoscopic video sequences allows accurate 3-D depth data to be obtained from multiple camera views.

Consideration of ergonomic aspects in the development of a new endoscopic navigation system

During the development of new navigation systems, the ergonomic aspects of the accompanying software are seldom taken into account. The VN system is a navigation system working with real and previously stored neuroendoscopic images. The latter enable the module to execute virtual back movement, e.g. in case of bleeding. Several other modules are offered. The aim of the study was the ergonomic analysis of different modules and their learning curves in cadaveric heads. The endoscope was navigated by the neurosurgeon while another person operated the computer. A total of 128 experiments were performed with two software versions. When the landmark tracking module was used, a real learning curve could be observed. By contrast, testing the measurement module did not produce a learning curve. A significant reduction of the time required by the three modules investigated could be observed with software version 2. The module for virtual back movement works best with a minimum time of 20 s for image storage. During machine-human interactions ergonomic software use is important, especially if operative procedures are performed.