Respiratory motion analysis: Towards gated augmentation of the liver

Laparoscopic surgery had a rapid development over the past decade. However, the view of the surgeon is limited to the image of the laparoscope. Augmented reality can provide further information to the surgeon by enabling a view inside the patient, and thus supporting a more precise and less invasive procedure. The limiting factors for realistic augmentation during liver surgery are movement and deformation of the organ due to respiratory motion. In our experiments we analyzed respiratory motion patterns of the liver caused by the respirator. Throughout our experiments we validated our assumption that repositioning after one breathing cycle is within a range of 1 mm. For an optimal augmentation of the liver in the laparoscopic image we suggest to adjust the respirator thus that we have a static exhalation phase of 2 to 3 s on which our augmentation is performed.