The effect of intraoperative imaging on surgical navigation for laparoscopic liver resection surgery

Abstract

Conventional surgical navigation systems rely on preoperative imaging to provide guidance. In laparoscopic liver surgery, insufflation of the abdomen (pneumoperitoneum) can cause deformations on the liver, introducing inaccuracies in the correspondence between the preoperative images and the intraoperative reality. This study evaluates the improvements provided by intraoperative imaging for laparoscopic liver surgical navigation, when displayed as augmented reality (AR). Significant differences were found in terms of accuracy of the AR, in favor of intraoperative imaging. In addition, results showed an effect of user-induced error: image-to-patient registration based on annotations performed by clinicians caused 33% more inaccuracy as compared to image-to-patient registration algorithms that do not depend on user annotations. Hence, to achieve accurate surgical navigation for laparoscopic liver surgery, intraoperative imaging is recommendable to compensate for deformation. Moreover, user annotation errors may lead to inaccuracies in registration processes.

Figure 1

Laparoscopic liver frames from in-vivo study. (A) Is the original image, (B) shows the reprojected cauterization point centroids, used for TRE assessment, (C) shows the reprojection of the liver parenchyma and (D) shows some branches from hepatic and portal veins as AR. The AR frames in (C,D) show the error of the overlay.

Figure 2

Average TRE in [mm] (±σ) of AR using intraoperative and preoperative 3D with user-defined markers with different number of markers (N) used for registration.

Figure 3

TRE between users for preoperative and intraoperative images, significant differences were found between users, demonstrating how user influence can cause significant differences.

Figure 4

Average TRE in [mm] (±σ) of AR using intraoperative and preoperative images with a variable number (N) of either user-defined markers or inserted fiducials. This shown with different number of markers used for registration. N.B. Calculated over only three animals.

Figure 5

Fiducial Localization Errors, in [mm] computed across three animal trials based on the annotations from five clinicians. Annotations were performed on 3D liver models from intraoperative CT scans. Labeled red spheres indicate position of the fiducials and yellow areas cover median user-induced error for the specific marker.

Figure 6

Decrease of TRE in [mm] when increasing number of markers (N) for image-to-patient registration, significance levels comparisons between pairs of number of markers are in between brackets (p-values).

Figure 7

Difference between pre- and intraoperative shapes of the liver post pneumoperitoneum.

Figure 8

Diagram of transformations used to perform AR for liver surgery.