Abstract.Organ deformation between preoperative image data and the patient in the OR is the main obstacle for using surgical navigation systems in liver surgery. Our approach is to provide accurate navigation via intraoperative 3D ultrasound. These ultrasound data are augmented with preoperative anatomical models and planning data as an important additional orientation aid for the surgeon. We present an overview of the whole ultrasound navigation system as well as an approach for fast intraoperative non-rigid registration of the preoperative models to the ultrasound volume. The registration method is based on the vessel center lines and consists of a combination of the Iterative Closest Point algorithm and multilevel B-Splines. Quantitative results for three different patients are presented.

Optoelectronic navigation with section mode visualization in 2 orthogonal planes does sufficiently display intraoperative 3D data and enables accurate ultrasound-based navigation of liver resections.

Three-dimensional ultrasound-based optoelectronic navigation technology improves intraoperative orientation and enables parenchyma-preserving surgery with high precision.

Optical tracking of surgical instruments and simultaneous electromagnetic registration of organ position is feasible in liver resection.

The proposed registration method is fast enough for clinical application in liver surgery. Initial accuracy results are promising and must be further evaluated, particularly in the operating room.