Vessel-Guided Mesohepatectomy for Liver Partition and Staged Major Parenchyma-Sparing Hepatectomies with Super-Selective Portal Vein Embolization or Enhanced ALPPS to Achieve R0 Resection for Colorectal Liver Metastases at the Hepatocaval Confluence

SIMPLE SUMMARY: Up to 80% of disease relapse within 2 years after resection of colorectal cancer liver metastases occurs in patients with high burden of disease. Increase in life expectancy with new chemotherapy protocols opens the new challenge of maintaining quality of life after disease relapse and of offering subsequent surgical options when feasible. First-order glissonean-pedicles division recurrence should be absolutely avoided since it may hamper the subsequent administration of systemic treatments and worsen patient’s quality of life due to biliary involvement. To this end, selected cases of metastases at the hepatocaval-confluence were treated with vessel-guided mesohepatectomy of segments 1 and 4 en-bloc with the middle hepatic vein. This minor liver resection induces a major hepatic scaffold modification, transforming the liver into a paired organ. This novelty led us to use for the first time liver augmentation techniques in a parenchyma-sparing context, observing a liver regeneration never described before. Based on our results, this surgical approach may represent a new option for patients affected by colorectal liver metastases selected in the frame of an experienced multidisciplinary environment including dedicated oncologists, anesthesiologists, radiologists, pathologists and surgeons. ABSTRACT: Background. R0 minor parenchyma-sparing hepatectomy (PSH) is feasible for colorectal liver metastases (CRLM) in contact with hepatic veins (HV) at hepatocaval confluence since HV can be reconstructed, but in the case of contact with the first-order glissonean pedicle (GP), major hepatectomy is mandatory. To pursue an R0 parenchyma-sparing policy, we proposed vessel-guided mesohepatectomy for liver partition (MLP) and eventually combination with liver augmentation techniques for staged major PSH. Methods. We analyzed 15 consecutive vessel-guided MLPs for CRLM at the hepatocaval confluence. Patients had a median of 11 (range: 0–67) lesions with a median diameter of 3.5 cm (range: 0.0–8.0), bilateral in 73% of cases. Results. Grade IIIb or more complications occurred in 13%, median hospital stay was 14 (range: 6–62) days, 90-day mortality was 0%. After a median follow-up of 17.5 months, 1-year OS and RFS were 92% and 62%. In nine (64%) patients, MLP was combined with portal vein embolization (PVE) or ALPPS to perform staged R0 major PSH. Future liver remnant (FLR) volume increased from a median of 15% (range: 7–20%) up to 41% (range: 37–69%). Super-selective PVE was performed in three (33%) patients and enhanced ALPPS (e-ALPPS) in six (66%). In two e-ALPPS an intermediate stage of deportalized liver PSH was necessary to achieve adequate FLR volume. Conclusions. Vessel-guided MLP may transform the liver in a paired organ. In selected cases of multiple bilobar CRLM, to guarantee oncological radicality (R0), major PSH is feasible combining advanced surgical parenchyma sparing with liver augmentation techniques when FLR volume is insufficient.