living - donor liver transplantation ( ldlt ) is widely performed for end - stage liver diseases . adult - to - adult ldlt is successfully performed , when appropriate preoperative evaluations , surgical procedures , and postoperative management techniques are established . graft volume is one of the key factors for both donor safety and recipient survival . in adult - to - adult ldlt , the size of the left - lobe graft is frequently insufficient , and the size of the right - lobe graft usually satisfies the liver volume . however , the donation of right - lobe graft has a higher risk to the donor than that of left - lobe graft . right posterior segmental graft ( rpsg ) has been introduced as an alternative graft procedure to increase safely the number of donor candidates . rpsg is a partial liver graft of couinaud 's segments 6 and 7 with the right hepatic vein ( rhv ) . however , rpsg has not been widely used because of the lack of popularity of rpsg and technical concerns . here model for end - stage liver disease score was 33 points , and he was registered in the ldlt program . donor candidates were limited in this case , and his 36-year - old spouse was the only candidate , although she was abo incompatible . segmental territories of portal and hepatic veins were also analyzed , and liver volume was calculated as measured liver volume ( ml )    0.91 ( mevis software ; mevislab , bremen , germany ) . estimated estimated graft volume , estimated ratio of liver remnant , and estimated graft - to - recipient weight ratio ( grwr ) were evaluated in grafts with left lobe , right lobe without middle hepatic vein ( mhv ) , and posterior segment ( table 1 ) . in posterior segmental graft , the estimated graft volume was 469  ml , and the estimated ratio of liver remnant was 0.49 . no anomalies were detected in portal and hepatic veins for posterior segmental graft ( fig . c ) . territory of drainage veins from segments 5 and 8 that flowed into the mhv was 189  ml ( ratio in liver remnant , 0.42 ) , although that flowing into the rhv was 95  ml ( ratio in liver remnant , 0.21 ) ( fig . no anomalies were detected in biliary ducts , and the posterior branch located in the front of the portal vein for the posterior segment ( fig . a tube was inserted from the cystic duct to the common bile duct ( fig . rouviere 's fosse was dissected according to the hepatic artery and portal vein ( fig . anterior and posterior branches of the hepatic artery and portal vein were skeletonized , respectively ( fig . the demarcation line was marked by temporary clamping of the portal vein for the posterior segment ( fig . the cut line was carefully considered based on the demarcation line and rhv ( fig . liver resection was performed using an ultrasonic aspirator / dissector ( cavitron ultrasonic surgical aspirator ; valleylab inc . , boulder , co , usa ) and saline - irrigating bipolar ( fig . the biliary duct , hepatic artery , and portal vein for the posterior segment were cut ( fig . thus , rpsg was harvested , and graft perfusion was completed by histidine  tryptophan  ketoglutarate solution . the rhv , portal vein , and biliary duct were sutured , and thereafter , no biliary leakage was confirmed by cholangiography with dye ( fig . the operative time was 18  h 13  min , and blood loss was 8910  ml . native liver volume was 2500  g. actual graft weight was 390  g , and actual grwr was 0.54 . the portal vein was reconstructed with an interposition using the recipient 's left internal jugular vein ( fig . hepatic arterial reconstruction was achieved using interpositions of the recipient 's left gastric and splenic artery ( fig . 4f ) , because the diameter of the hepatic artery in the graft was 1.0  mm . initial , recirculated and final pressures of the portal vein were 17 , 25 , and 22  mmhg , respectively . hepatic arterial thrombosis , liver abscess , and severe infection triggered a poor postoperative course , and the recipient died at postoperative day 77 because of sepsis . the diameters of the segmental branches of the hepatic artery and portal vein may be small in rpsg , and surgeons must exercise some ingenuity in adjusting the anastomoses to an adequate length and diameter in the recipient operation . some variations in the biliary duct are often observed in the posterior segment . although variation in the solitary posterior biliary branch is possibly favorable for rpsg , biliary drainage of rpsg may be plural at the cut line of the biliary plate . hence , detailed investigation of biliary drainage is also important , as well as the portal vein and hepatic artery . short , small , and weak orifices of the second - order branches of the portal vein , hepatic artery , and biliary may cause intractable complications , and these complications can directly lead to a recipient 's death . from the view point of the nutrition support before donation , we routinely checked the liver / spleen ratio in the ct value , and alimentary therapy and exercise regimen were introduced if this value 1.1 . liver needle biopsy was performed only in suspicious case of non - alcoholic steatohepatitis . in the present case , actual liver volume and grwr were 390  g and 0.54 , respectively , although estimated graft volume and grwr were 469  ml and 0.65 . deciding on the actual cut line for rpsg involves some difficulties , because segmental areas based on inflows and outflows are complicated in the right lobe . segmental territory based on inflow and that based on outflow never overlap completely , even in the same segment . preoperative recognition of territories based on imaging studies is important to make a decision about the cut line and to harvest the rpsg . in terms of mhv anatomy for rpsg harvest , mhv territory from segments 5 and 8 in the liver remnant should be preserved for the donor safety . venous drainage territory of segments 5 and 8 flowed into the mhv is strictly calculated beforehand , because unexpected congestion and/or massive bleeding during surgery in these segments mean a donor risk after surgery . the mhv was confirmed by ultrasound during surgery , and we intend to preserve the mhv territory as possible . only small peripheral branches of mhv detected on the transaction surface were ligated by ultrasonic aspirator / dissector without venous reconstruction . in the recipient operation , we intentionally controlled portal venous pressure ( pvp ) during ldlt , because pvp > 15  mmhg results in an eventful postoperative course and poor outcome . final pvp in this recipient was 22  mmhg , and this higher pvp may trigger severe complications and poor outcome . sugawara et al . suggested that the selection of rpsg could be a useful option and increase the living - donor pool for ldlt . however , rpsg has not been widely used in ldlt , for several reasons , such as lack of popularity of rpsg , technical concerns , and surgical difficulties . the selection of rpsg based only on donor liver volume criteria might be unfeasible , because of the complicated pedicular anatomy of the posterior segment . as described above , detailed preoperative studies of inflow , outflow , and biliary drainage are important , and careful evaluation is required for the choice of rpsg . rpsg is a useful tool for ldlt , but should be never simply chosen based on graft volume . t. hori , k. ogawa , and t. kaido performed donor surgery . y. ogura and k. ogawa performed recipient surgery . f. oike , y. ogura , and k. ogawa provided key points for donor selection and surgery . s. uemoto supervised this report.key learning pointsright posterior segment graft ( rpsg ) for living - donor liver transplantation involves technical difficulties.we report a case of rpsg harvest in a living donor . right posterior segment graft ( rpsg ) for living - donor liver transplantation involves technical difficulties.we report a case of rpsg harvest in a living donor . right posterior segment graft ( rpsg ) for living - donor liver transplantation involves technical difficulties .
introductionright posterior segmental graft ( rpsg ) is an alternative procedure for living - donor liver transplantation ( ldlt ) . 
 although the first case of rpsg was reported in 2001 , it has not been disseminated because of the lack of popularity , technical concerns , and surgical difficulties.presentation of casea 37-year - old man with primary sclerosing cholangitis . 
 his spouse was the only transplantation candidate , although she was abo incompatible . 
 preoperative investigations revealed that left - lobe graft was insufficient for the recipient and that right - lobe graft was accompanied by donor risk . in rpsg , estimated graft - to - recipient weight ratio ( grwr ) and estimated ratio of liver remnant were reasonable . in the donor operation , the right hepatic vein ( rhv ) and demarcation line were confirmed , and intraoperative cholangiography was performed . 
 the cut line was carefully considered based on the demarcation line and rhv . 
 the rpsg was harvested . 
 actual grwr was 0.54 . unfortunately , this recipient showed a poor course and outcome after ldlt.discussionsegmental branches of vessels and biliary duct may be not suitable for reconstruction , and surgeons must exercise some ingenuity in the recipient operation . 
 segmental territory based on inflow and that based on outflow never overlap completely , even in the same segment . 
 the selection of rpsg based only on liver volume may be unfeasible . 
 liver resection should be carefully considered based on preoperative imaging , and demarcation line and rhv during surgery.conclusionrpsg is a useful tool for ldlt 
 . however , detailed studies before surgery and careful consideration during surgery are important for rpsg harvest .