Robotic Anatomic Right Hepatectomy for Recurrent Liver Tumor After Y-90 Radioembolization: Technique of Inflow Pedicle-Handling and IVC-Tumor Dissection.

[BACKGROUND] Major hepatectomy for patients after ytrium-90 (Y-90) treatment is technically difficult due to both intra- and extrahepatic fibroinflammatory changes induced by the radiembolization. Technical challenges at liver mobilization, inflow pedicle dissection and division, inferior vena cava (IVC) dissection, and parenchymal transection often discourage liver surgeons to use a minimally invasive approach in this circumstance. Although the robotic approach is considered best for technically difficult resections with potential vascular resection, detailed description of this operation in modern literature is limited. This report describes our standardized approach and the technical feasibility of robotic right hepatectomy after Y-90 radioembolization for recurrent colorectal liver metastasis with significant IVC contact.

[METHODS] A 63 year-old man with stage IV colon cancer presented with a recurrent 3.9 cm dorsal segment 7 hepatic lesion abutting the lateral wall of the IVC. He had previously undergone primary colonic resection using an open method, systemic chemotherapy treatment, and radioembolization 9 years earlier. Preoperative imaging with computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) scan confirmed an isolated hypermetabolic mass consistent with metastatic tumor. Robotic formal right hepatectomy was undertaken under intermittent Pringle maneuvers as necessary. Due to dense fibrosis around the right perihilar region from the radioembolization preventing safe individual inflow vascular dissection, the intrahepatic Glissonean approach was used to transect the right anterior and posterior pedicle individually after initial parenchymal transection. Significant hypertrophy of the left hepatic lobe and atrophy of the right hepatic lobe after radioembolization also led to a positional rotation of the hilar region, which added further complexity to the hilar dissection. Once the liver was open-booked, IVC-tumor dissection was performed using the dual-bipolar Maryland technique under a low central venous pressure condition (<5 mmHg).

[RESULTS] The procedure was completed uneventfully with minimal blood loss. The postoperative recovery was uncomplicated, leading to a hospital discharge on postoperative day 4. The final pathology report confirmed a metastatic adenocarcinoma with negative resection margins. At the 1-year follow-up assessment, the patient remained disease-free.

[DISCUSSION] Robotic major hepatectomy after Y-90 is a particularly difficult operation technically due to several factors. Fibrotic changes in the hepatic hilum due to postprocedural and radiation-induced inflammation often lead to challenging dissection around the hepatic artery and portal vein while gaining inflow vascular control. The atrophy-hypertrophy changes of the liver lobes also lead to a rotation/anatomic shift of the porta hepatis, making extrahepatic isolation of the hepatic artery and portal vein more challenging. The fibroinflammatory reaction after Y-90 is associated with increased adhesions to the diaphragm and paracaval region during right hepatic lobe mobilization. This is more clinically relevant in cases of large tumors near or in contact with the IVC, as in the current case. Separation of the tumor off the IVC wall may require venorrhaphy and advanced suturing skills to avoid major hemorrhage. Inflamed and fibrotic changes within the liver parenchyma also increase the technical challenge during deep hepatic transection, which often are associated with more bleeding from highly fragile intrahepatic capillaries when the liver is transected. Finally, the dissection and final transection of the right hepatic vein off the IVC is often technically demanding due to the fibrosis that occurs around the hepatocaval confluence making smooth application of linear vascular stapler somewhat technically challenging.

[CONCLUSION] Despite of the technical challenges related to radioembolization, robotic major hepatectomy with paracaval tumor dissection obtaining R-0 margins is safe and feasible. Previous Y-90 therapy did not preclude a successful application of minimally invasive robotic resection with excellent clinical and oncologic outcomes.