CBCT‐based navigation system for open liver surgery: Accurate guidance toward mobile and deformable targets with a semi‐rigid organ approximation and electromagnetic tracking of the liver

Abstract

Purpose: The surgical navigation system that provides guidance throughout the surgery can facilitate safer and more radical liver resections, but such a system should also be able to handle organ motion. This work investigates the accuracy of intraoperative surgical guidance during open liver resection, with a semi-rigid organ approximation and electromagnetic tracking of the target area. Methods: The suggested navigation technique incorporates a preoperative 3D liver model based on diagnostic 4D MRI scan, intraoperative contrast-enhanced CBCT imaging and electromagnetic (EM) tracking of the liver surface, as well as surgical instruments, by means of six degrees-of-freedom micro-EM sensors. Results: The system was evaluated during surgeries with 35 patients and resulted in an accurate and intuitive real-time visualization of liver anatomy and tumor's location, confirmed by intraoperative checks on visible anatomical landmarks. Based on accuracy measurements verified by intraoperative CBCT, the system's average accuracy was 4.0 ± 3.0 mm, while the total surgical delay due to navigation stayed below 20 min. Conclusions: The electromagnetic navigation system for open liver surgery developed in this work allows for accurate localization of liver lesions and critical anatomical structures surrounding the resection area, even when the liver was manipulated. However, further clinically integrating the method requires shortening the guidance-related surgical delay, which can be achieved by shifting to faster intraoperative imaging like ultrasound. Our approach is adaptable to navigation on other mobile and deformable organs, and therefore may benefit various clinical applications.

Modern Image-Guided Surgery: A Narrative Review of Medical Image Processing and Visualization

“…By generating a defined EM field in which EM micro-sensors are tracked, rigid, and flexible, medical instruments embedded within these sensors can be tracked without obstruction. Researchers have usually used EMT for deep in vivo organ tracking and movement of the transducer [ 40 , 70 , 71 , 72 , 73 ]. By using external tracker tools, object tracking can achieve millimeter or sub-millimeter accuracy, but additional tools could mean limitations in medical use or incur extra expenses.…”

Hybrid operating room applications for precision hepatobiliary surgery: A narrative review

“…This meant that the navigation was mainly valuable during the early phase of the resection before major tissue deformations occurred. More recently, Ivaschenko et al developed a navigation system capable of correcting for tissue deformation using electromagnetic tracking by assuming the liver segments acted like a locally rigid body 49 . Electromagnetic sensors were placed intraoperatively to track organ and patient motion, and intraoperative cone‐beam CT registration was used to calibrate the system.…”

Leberchirurgie 4.0 - OP-Planung, Volumetrie, Navigation und Virtuelle Realität

“…Der erste Ansatz nutzt initial eine oberflächenbasierte Registrierung mittels bestimmter Landmarken oder intraoperativem Oberflächenscanning [40,41]. Ein andere Ansatz verwendet intraoperative Bildgebungen wie das Cone-Beam-CT oder den Ultraschall, um die Registrierung zu präzisieren [42,43]. Die operations-und atembedingten Deformierungen insbesondere der intrahepatischen Strukturen werden bei beiden Ansätzen mittels biomechanischer Berechnungen simuliert und auf die Simulation übertragen [44,45].…”