Liver cancer ranks seventh in global cancer prevalence and stands as the third leading cause of cancer-related deaths. Surgical resection is considered the gold standard for treatment of liver malignancies and has witnessed a shift toward minimally invasive techniques in recent decades. Surgeons rely on laparoscopic observations, preoperative imaging, and laparoscopic ultrasound for image guidance. However, these methods pose challenges in accurately representing the complex three-dimensional (3D) structure of the liver in a two-dimensional (2D) view. Surgical navigation devices aim to enhance this process by providing additional information for improved lesion localization and vascular structure visualization with respect to tracked surgical instruments. This study's objective was to establish an electromagnetically guided laparoscopic liver resection workflow at Netherlands Cancer Institute – Antoni van Leeuwenhoek (NKI-AvL) to be implemented into clinical practice.

A method was developed for tracking instruments in laparoscopic surgery, with a focus on the laparoscopic sealer/ divider. An adapter was developed with an embedded electromagnetic sensor to allow tracking. Calibration employed a dedicated device, followed by a comprehensive validation process encompassing usability, sterilizability, attachment reproducibility, and calibration accuracy. The adapter was produced from a non-ferromagnetic material, ensuring sterilizability and straightforward surgeon attachment, exhibiting positive results in reproducibility and virtual visualization. Nevertheless, the calibration accuracy, at 2.5 mm, could be enhanced, primarily through calibration method adjustments. Additionally, a fast calibration method for the laparoscopic ultrasound (LUS) probe adapter was developed, involving a dedicated calibration tool. Validation assessments to ascertain its reproducibility showed positive results. However, accuracy measurements can be further improved as ultrasound calibration method evaluation showed a root mean squared error (RMSE) of 3.6 mm. This is important as the navigation performance relies on the calibration accuracy of the tracked LUS probe. The workflow for navigated laparoscopic liver resection was tested using a liver phantom. It demonstrated the navigation system's capacity to register preoperative and intraoperative images with a mean target registration error (TRE) of 3.7 mm and showed promising augmented reality views. Additionally, this test led to workflow enhancements related to liver sensor placement and visualization techniques.

The developed navigation workflow for laparoscopic liver resection integrated Aurora EM tracking, tracked laparoscopic instruments, and software for intraoperative liver 3D model visualization. While feasible in an operating setting during phantom tests, further enhancements in visualization and accuracy are needed. A clinical study will be conducted to determine intraoperative feasibility, providing valuable experience to technical physicians and surgeons. In the near future, the presented navigation method may enhance laparoscopic resection accuracy and reduce disease recurrence. A clinical study at NKI-AvL will soon validate this navigation system for clinical use.

Surgical ablation is a well-accepted treatment for liver malignancies due to its ability to preserve the surrounding healthy liver tissue as opposed to surgical resection. Precise intraoperative localization of the lesion and correct needle placement are crucial factors for complete tumor ablation. These are difficult tasks due to interpatient variability and technical limitations of current technologies. Surgical navigation provides a live virtual representation of the surgery by showing the position of surgical instruments with respect to the critical anatomy. Navigation can improve tumor localization during surgical resection and it is therefore expected to similarly improve tumor ablation. The development and the clinical implementation of surgical navigation for hepatic tumor ablation were therefore explored in this thesis. A sterilizable adapter was developed carrying an electromagnetic (EM) sensor. This adapter is attachable to the ablation needle in order to track the surgical instrument. The tracking accuracy for this adapter calculated with respect to an EM tracked calibrated block was comparable to the Aurora 6DOF probe, a pointer currently used in the standard workflow of surgical navigations. With the use of this adapter, a virtual representation of the ablation needle could be presented to the surgical team. The workflow for navigated liver ablation was tested intraoperatively by three hepatobiliary surgeons. A cross-hair (i.e., bullseye) view was preferred by the surgeons to guide the ablation needle to the center of the target lesion. In this view, the tumor was visualized as if looking through the tip of the ablation needle. With the system usability score (SUS) of 65, refinement of the software visualization was indicated. Nonetheless, the surgeons want to use the system frequently and responded that it aided in localizing tumor(s), reducing complications, obtaining negative ablation margins and increasing certainty in decisions and actions. Next, a method for validation of the needle tip tracking accuracy at final needle placement was proposed and showed a mean accuracy of 2.2 mm in phantom experiments.
In conclusion, a workflow for open navigated liver ablation was developed and the first in vivo experiments have been performed which showed promising results. Intraoperative validation will be performed on 28 patients.