Troubles neurologiques

Visual Navigation System used to Coagulate Bleeding in a Semibiological Model

Abstract

Petra Heinen, Athanasios K Petridis, Homajoun Maslehaty and Martin Scholz

Objective: Endoscopical procedures in the ventricles for the treatment of hydrocephalus or removal of solid tumors are commonly used in neurosurgery. Even a minimal blood amount leads to a complete loss of visibility (“red out”) endangering the patient. To enable coagulation of a bleeding vessel in “red-out” we developed and tested the VNSoftware- System.

Methods: An optical-positioning-system (OPS) receives signals from 3 infrared Light-Emitting-Diodes (LED) on the endoscope and digitalized endoscopic images are created reproducing the real position of the endoscope. An imaging software correlates the transmitted images (max 8/sec) with the positional data. The virtual images of the VN-Software are available next to the real image of the endoscope-camera. In cases of bleeding a “red-out-sensor” activates the “virtual mode” and the surgeon can navigate the endoscope based on the positional coordinates and the saved images of the software program. The bleeding vessel can be localized and coagulated.

Results: When the target region included a radius of 2 mm around the epicenter the success rate was 96.9%. Only in 3.1% of the experiments the target was missed of more than 2 mm. The mean precision in all experiments was 0.81 mm around the epicenter. The mean time of target finding and coagulation was 48.23 sec.

Conclusion: Localizing a bleeding vessel in a “red-out” condition with the VN-Software is reliable and will improve endoscopical safety in removal of highly vascularised tissue. The VN-software showed a high precision-rate in finding a given target in “red-out” conditions.