Computer planned, image-guided combined resection and ablation for bilobar colorectal liver metastases

Abstract

For patients with extensive bilobar colorectal liver metastases (CRLM), initial surgery may not be feasible and a multimodal approach including microwave ablation (MWA) provides the only chance for prolonged survival. Intraoperative navigation systems may improve the accuracy of ablation and surgical resection of so-called "vanishing lesions", ultimately improving patient outcome. Clinical application of intraoperative navigated liver surgery is illustrated in a patient undergoing combined resection/MWA for multiple, synchronous, bilobar CRLM. Regular follow-up with computed tomography (CT) allowed for temporal development of the ablation zones. Of the ten lesions detected in a preoperative CT scan, the largest lesion was resected and the others were ablated using an intraoperative navigation system. Twelve months post-surgery a new lesion (Seg IVa) was detected and treated by trans-arterial embolization. Nineteen months post-surgery new liver and lung metastases were detected and a palliative chemotherapy started. The patient passed away four years after initial diagnosis. For patients with extensive CRLM not treatable by standard surgery, navigated MWA/resection may provide excellent tumor control, improving longer-term survival. Intraoperative navigation systems provide precise, real-time information to the surgeon, aiding the decision-making process and substantially improving the accuracy of both ablation and resection. Regular follow-ups including 3D modeling allow for early discrimination between ablation zones and recurrent tumor lesions.

Keywords: Colorectal liver metastases; Computer navigation; Image-guidance; Microwave ablation; Tumor.

Figure 1

Planning data (as obtained from MeVis) depicting the 3D liver model as calculated from the preoperative triphasic computed tomography scan. The image shows the hepatic veins (left hepatic vein in red, middle hepatic vein in orange-brown, right hepatic vein in green). The tumors are seen as yellow masses, distributed in both liver lobes.

Figure 2

CAScination navigation system as it is placed at the head end of the patient with the sterile-covered touch screen facing towards the surgical team. This allows for easy access and constant interaction with the 3D planning model displayed on the screen.

Figure 3

MeVis computed tomography data. Four MeVis computed tomography data sets taken preoperatively (upper left panel) and at three further separate postoperative time points (3 mo, upper right panel, 9 mo, lower left panel, and 12 mo, lower right panel). While the upper left panel shows the actual size of the ten liver lesions prior to surgery/ablation, color-coded to facilitate individual tumor follow-up, subsequent panels show the evolution of the ablation volumes with time. The magenta-colored new lesion, seen in the final two follow-up computed tomography scans, is depicted with arrowheads.