How to expand the safe limits in hepatic resections?

The size of the remnant liver after an extended hepatectomy is currently the main limiting factor for performing curative hepatic surgery in patients with tumors and liver metastasis. The current guidelines for extended hepatectomies require that the future remnant liver volume needs to be higher than 20% of the original liver in healthy organs, of 30% in livers with steatosis or exposed to chemotherapy, and of 40% in patients with cirrhosis in order to prevent the "small-for-size" syndrome, characterized by the development of liver dysfunction with ascites, coagulopathy and cholestasis. Observations from the use of small liver grafts in liver transplantation and an increased surgical experience has improved our understanding of the mechanisms responsible for the development of liver dysfunction after extended hepatectomies. Increasing the size of the future liver remnant, the introduction of the "small-for-flow" concept with the perioperative monitoring and modulation of portal blood flow and pressure, and the exploration of the potential effects of regeneration preconditioning, are all promising strategies that could expand the indications and increase the safety of liver surgery.