Oncological surgery on soft solid organs (e.g. the liver) is challenging because the surgeon has to remove the tumors with sufficient margin while avoiding damage to large blood vessels, which are both not visible from the eye. Therefore, surgeons rely mostly on intraoperative ultrasound as imaging modality to see tumors and critical structures. Sometimes, tumors are not even visible on intraoperative ultrasound which leaves the surgeon blind. Additionally, in recent years surgeries have become less invasive, from open surgeries with large incisions to laparoscopy or even percutaneous treatments. While the patients benefit in terms of shorter hospital stay and fewer complications, these procedures are more challenging due to the limited field of view and loss of haptic feedback.

Surgical navigation is an appealing idea to overcome these challenges. Despite its daily use in neuro and ENT surgery, surgical navigation is barely used in soft tissue surgery due to technical and clinical challenges related to organ deformation and motion. During the past years, we have developed different surgical navigation methods, especially for liver surgery, and evaluated them in the operating room. I will present you how the technology allowed to perform less invasive surgeries more efficient and how we tackled the challenge of guiding the surgeon using augmented reality on live ultrasound and laparoscopic video. Some of these methods have even made it into commercial products and are now used regularly to treat patients with liver cancer.