Endoscopy-based navigation

		The combination of video-based tracking through the endoscope view and optoelectronic tracking of the endoscope allows to obtain accurate minimally-invasive tracking of the vertebrae.

The primary focus was to overcome difficulties in current computer-assisted minimally invasive surgeries on anterior parts of thoracic/lumbar vertebrae. The main difficulty is in rigidly fixing the dynamic reference base (DRB) to vertebrae, which has to be done with a long stylus allowing it to protrude out from the opposite abdominal wall or it is fixed to the iliac crest and stringent immobilisation of the patient is ensured. These methods are susceptible to instability and hence inaccuracy. A hybrid tracking technology has been developed where video-based 2D-3D tracking is combined with the optoelectronic tracking (Optotrack®) for computer-assisted navigation in laparoscopic ventral-spine surgeries. Our preliminary study shows that the technology is quite robust and capable of tracking the markers with high precision (mean positional error 0.6 mm and mean rotational error was 1.65° for 2 cm marker). Continuous tracking of the marker was possible up to 13 cm distance. To our knowledge we are the first whose accuracy is appropriate for laparoscopic ventral-spine surgeries. We are currently combining this hybrid tracking technology and fluoroscopy-based navigation system into a clinically useable and robust system.