Unusual grafts for living-donor liver transplantation.

PURPOSE: Unusual grafts, including extended left liver plus caudate lobe, right anterior section, and right posterior section grafts, are alternatives to left and right lobe grafts for living-donor liver transplantation. This study aimed to investigate unusual grafts from the perspectives of recipients and donors. METHODS: From 2016 to 2021, 497 patients received living-donor liver transplantation at Severance Hospital. Among them, 10 patients received unusual grafts. Three patients received extended left liver plus caudate lobe grafts, two patients received right anterior section grafts, and five patients received right posterior section grafts. Liver volumetrics and anatomy were analyzed for all recipients and donors. We collected data on laboratory examinations (alanine aminotransferase, total bilirubin, international normalized ratio), imaging studies, graft survival, and complications. A 1:2 ratio propensity-score matching method was used to reduce selection bias and balance variables between the unusual and conventional graft groups. RESULTS: The median of Model for End-stage Liver Disease score of unusual graft recipients was 13.5 (interquartile range 11.5-19.3) and that of graft-recipient weight ratio was 0.767 (0.7-0.9). ABO incompatibility was observed in four cases. The alanine aminotransferase level, total bilirubin level, and international normalized ratio decreased in both recipients and donors. Unusual and conventional grafts had similar survival rates (p = 0.492). The right and left subgroups did not differ from each counter-conventional subgroup (p = 0.339 and p = 0.695, respectively). The incidence of major complications was not significantly different between unusual and conventional graft recipients (p = 0.513). Wound seromas were reported by unusual graft donors; the complication ratio was similar to that in conventional graft donors (p = 0.169). CONCLUSION: Although unusual grafts require a complex indication, they may show feasible surgical outcomes for recipients with an acceptable donor complication.

Caudodorsal approach combined with in situ split for laparoscopic right posterior sectionectomy.

BACKGROUND: Laparoscopic right posterior sectionectomy (LRPS) was technically challenging and lack of standardization. There were some approaches for LRPS, such as caudal approach and dorsal approach. During our practice, we initiated pure LRPS using the caudodorsal approach with in situ split and present several advantages of this method. METHODS: From April 2018 to December 2021, consecutive patients who underwent pure LRPS using the caudodorsal approach with in situ split at our institution entered into this retrospective study. The key point of the caudodorsal approach was that the right hepatic vein was exposed from peripheral branches toward the root and the parenchyma was transected from the dorsal side to ventral side. Specially, the right perihepatic ligaments were not divided to keep the right liver in situ before parenchymal dissection for each case. RESULTS: 11 patients underwent pure LRPS using the caudodorsal approach with in situ split. There were 9 hepatocellular carcinoma, 1 sarcomatoid hepatocellular carcinoma, and 1 hepatic hemangioma. Five patients had mild cirrhosis and 1 had moderate cirrhosis. All the procedures were successfully completed laparoscopically. The median operative time was 375 min (range of 290-505 min) and the median blood loss was 300 ml (range of 100-1000 ml). Five patients received perioperative blood transfusion, of which 1 patient received autologous blood transfusion and 2 patients received blood transfusion due to preoperative moderate anemia. No procedure was converted to open surgery. Two patients who suffered from postoperative complications, improved after conservative treatments. The median postoperative stay was 11 days (range of 7-25 days). No postoperative bleeding, hepatic failure, and mortality occurred. CONCLUSION: The preliminary clinical effect of the caudodorsal approach with in situ split for LRPS was satisfactory. Our method was feasible and expected to provide ideas for the standardization of LRPS. Further researches are required due to some limitations of this study.

A comprehensive framework of the right posterior section for tailored anatomical liver resection based on three-dimensional simulation system.

Background: The anatomical right posterior sectionectomy (ARPS) is a technically challenging procedure. We aimed to develop and validate a novel framework of the right posterior section for a safe and tailored anatomical liver resection (ALR) based on a three-dimensional (3D) simulation system. Methods: 3D hepatectomy simulations of healthy participants who underwent contrast-enhanced computed tomography of the upper abdomen were retrospectively reviewed to develop the framework according to the relationship between the simulated plane determined by the right posterior portal pedicle (RPP) and the course of the right hepatic vein (RHV) trunk. The framework was validated in the practice of ARPS for hepatocellular carcinoma (HCC) prospectively. Results: Scans from 336 eligible participants were assessed. The framework was summarized into four types: normal, caudal-redundant, cranial-deficient, and combined types, accounting for 43.4% (146/336), 25.3% (85/336), 18.5% (62/336), and 12.8% (43/336) respectively. The caudal-redundant type was associated with the variable portal branches of the RPP or segment 6 branch across the ventral side of RHV. The mean aberrant volume proportion in type IIa was significantly greater than that in type IIb (P<0.001), which were 7.0%±3.5% and 4.4%±1.8% respectively. The cranial-deficient type was associated with the aberrant segment 7 portal pedicle originating from the right portal trunk or the dorsal portal branch of segment 8 crossing over to the RHV. The median aberrant volume proportion in type IIIa was significantly greater than that in type IIIb (P<0.001), which were 10.9% (8.5-13.3%) and 4.0% (3.0-6.1%), respectively. The combined type represented a combination of the caudal-redundant type and the cranial-deficient type. The framework provided instructions on tailored ARPS in 6 patients with HCC by maximizing lesion removal and functional liver remnant with favorable perioperative outcomes. Conclusions: Precise preoperative planning with an individualized surgical approach based on our framework allows safe anatomical liver resections for cases with lesions in the right posterior section.

Estimation of the Right Posterior Section Volume in Live Liver Donors: Semiautomated CT Volumetry Using Portal Vein Segmentation.

RATIONALE AND OBJECTIVES: To determine the accuracy of semiautomated CT volumetry using portal vein (PV) segmentation to estimate volume of the right posterior section (RPS) graft compared to intraoperative measured weight (W) in live liver donors. MATERIALS AND METHODS: Among 23 donors who donated RPS grafts for liver transplantation in our institution from April 2003 to August 2016, 17 donors with CT scans within 3 months of liver procurement and PV anatomy of type I-III were included. RPS volumes were retrospectively evaluated by semiautomated CT volumetry (RPSVCTV) and by measurement of standard liver volume (SLV) and PV area ratio (RPSVSLV). RPS volumes were compared to W for correlation coefficients, (absolute) difference, and (absolute) percentage deviation. Linear fitting was performed to identify the method that yielded the greatest correlation with W. RESULTS: Mean values of RPSVCTV, RPSVSLV, and W were 503.4 ± 97.8 mL (346.6-686.0), 516.54 ± 146.20 (274.06-776.32), and 518.8 ± 122.4 (370.0-789.0), respectively. RPSVCTV was strongly correlated with W (r = 0.9414; p < 0.0001), whereas RPSVSLV was only moderately did (r = 0.5899; p = 0.0127). RPSVCTV showed a significantly smaller absolute difference (35.20 ± 30.82 vs. 104.79 ± 60.27, p = 0.004) and absolute percentage deviation (6.61 ± 4.90 vs. 19.92 ± 10.37, p < 0.0001) from W. Equation correlating RPSVCTV and W was W = -74.7191 + 1.1791 RPSVCTV (R2 = 0.8862; p < 0.001). CONCLUSION: RPSVCTV yields smaller absolute difference than RPSVSLV for estimating intraoperative measured weight of RPS in live liver donors. Semiautomated CT volumetry using PV segmentation is feasible for the estimation of the volume of the RPS of the liver, and RPSVCTV was strongly correlated with W (r = 0.9414; p < 0.0001).

A New Classification of the Right Portal Vein Using 64 Channel Multi-dectector CT (MDCT)

PURPOSE: Portal branching patterns (ramification) that differ from those previously described are occasionally encountered during liver surgery. We studied the portal vein branching patterns by performing 64 MDCT. METHODS: A total of 100 patients with normal liver underwent MDCT during arterial portography. Next, the 3 dimensional portograms were reconstructed and the portal branching patterns were assessed. RESULTS: In 80 (80%) of the 100 patients we examined, the right anterior portal vein bifurcated into the ventral and dorsal branches. Only 20 percent of the patients showed the classic pattern, that is, bifurcating into the right anterior superior (P8) and right anterior inferior branches (P5). The portal branches in segment 5 showed many variations in their origins and numbers. The portal branches in segment 7 originated from both the right anterior and posterior portal veins, and not just the right posterior portal vein. CONCLUSION: Instead of dividing the right liver into the superior and inferior segments, we proposed that the right liver can be divided into 3 segments, which are designated as the right anterior, middle and posterior segments. In the view of the vascular watershed, the division of the right anterior and posterior sections by using the right hepatic vein might be inaccurate.