Ultrasound-based navigation during liver surgery

Image-guided navigation surgery allows for full utilization of pre-operative imaging during surgery, and has the potential of reducing both irradical resections and ablations, and morbidity. This is a first feasibility study towards clinical implementation of ultrasound-based navigation during liver surgery.

The aim of this study is to develop and evaluate a new ultrasound-based navigation system for guidance of resection and
ablation of liver lesions during liver surgery. The feasibility and accuracy of this in-house developed navigation system is
assessed during intraoperative use. A clinical workflow is set up for use during open surgery. The accuracy of registration
between intraoperative 3D ultrasound and preoperative images is assessed by means of the target registration error of selected
liver lesions.

N/A

Procedure:
Participation will not involve additional visits to the hospital for the patients. Informed consent will be obtained during preoperative outpatient clinic appointment or upon admission to the hospital at least one day before operation.
Prior to the surgery, a patient-specific 3D liver model, including the liver contour, hepatic vasculature and target lesions, is created from diagnostic MR images. This 3D model is used for navigation during resection (group 1) and ablation (group 2) in open surgery. On the day of the surgery, the surgical procedure will start according to the standard practice. After the laparotomy, a single 6 degrees of freedom electromagnetic (EM) marker is placed on the surface of the liver near the targeted lesion. This marker is used to record the exact location of the organ throughout the procedure. Subsequent, the surgeon performs an ultrasound sweep near the target lesion, that will be used to create a 3D ultrasound image of the organ. The liver is registered to the diagnostic MRI and the 3D model, and the targeted lesion is selected in the navigation system. Registration takes place manually (phase I) or automatically (phase II). The registration accuracy is assessed with the target registration error.
In case of ablation, the tracked ablation needle is placed according to the standard protocol. Just before the start of the ablation, a secondary ultrasound sweep is performed, visualizing the tumor and the tip of the RFA/MWA needle. This volume will be used to assess the accuracy of the automatic registration and the accuracy of the needle placement. After this, surgical resection continues according to the standard protocol.