Three-dimensional computed tomography analysis of variations in the middle hepatic vein tributaries: proposed new classification

Right hepatic venous system variation in living donors: a three-dimensional CT analysis

BACKGROUND

The right hepatic venous system consists of the right hepatic vein (RHV) and inferior RHVs (IRHVs). When the right posterior section is used as a graft for liver transplantation, understanding variations and relationships between the RHV and IRHVs is critical for graft venous return and hepatic vein reconstruction. This study aimed to evaluate variations in the hepatic veins and the relationships between them.

METHODS

The medical records and CT images of patients who underwent hepatectomy as liver donors were assessed retrospectively. The relationship between the veins was evaluated by three-dimensional CT.

RESULTS

The configuration of the posterior section was classified into one of eight types based on the RHV and IRHVs in 307 patients. Type 1a (103 of 307), type 1b (139 of 307) and type 2a (40 of 307) accounted for 91·9 per cent of the total. The diameter of the RHV extending towards the inferior vena cava had a significant inverse correlation with that of the IRHV (r²  = -0·615, P < 0·001). Type 1a, which had no IRHVs, had the RHV with the largest diameter; conversely, type 2a, which had a large IRHV, had the RHV with the smallest diameter.

CONCLUSION

The hepatic venous system of the right posterior section was classified into eight types, with an inverse relationship between RHV and IRHV sizes. This information is useful for segment VII resection or when the right liver is used as a transplant graft.

Anatomy of the Right Anterior Sector of the Liver and Its Clinical Implications in Surgery

BACKGROUND

Surgery remains the gold standard both for delimited hepatocellular carcinoma by selective anatomic liver segentectomy and for colorectal liver metastases by parenchymal sparing liver resection. Right anterior sector (RAS) (segments V-VIII; Couinaud) is the largest and most difficult sector to operate on. A better knowledge of its segmentation could prevent postoperative remnant liver ischemia and its impacts on patient's survival.

METHODS

A literature search was conducted in PubMed for papers on anatomy and surgery of the right anterior sector.

RESULTS

Segmentation of the RAS depended of the anatomic variations of the third-order portal branches. Cranio-caudal segmentation was the most commonly found (50-53%), followed by ventro-dorsal (23-26%), trifurcation (13-20%), and quadrifurcation types (5-11%). Ventral and dorsal partial or total subsegmentectomy seemed accessible in 47 to 50% of patients, including bifurcation, trifurcation, and quadrifurcation types, and could spare up to 22% of the total liver volume. The RAS hepatic vein was present in 85-100% of the patients and could be used as a landmark between RAS dorsal and ventral part in 63% of patients. Reported overall morbidity rate of RAS subsegmentectomy ranged from 33 to 59% among studies with a postoperative major complication rate (Clavien-Dindo ≥ III) ranging around 18% and a biliary leakage rate from 16 to 21%. In-hospital reported mortality rate was low (0-3%), and results were comparable to "classic" liver resections. RAS subsegmentectomy remains a complex procedure; median operating time ranged from 253 to 520 min and median intraoperative blood loss reached 1255 ml.

CONCLUSION

Better knowledge of RAS anatomy could allow for parenchymal preservation by using subsegmentectomy of the RAS, selective or as a part of a major hepatectomy.

Predictors of the Effectiveness of Prophylactic Drains After Hepatic Resection

BACKGROUND

Randomized clinical trials have demonstrated the limited efficacy of prophylactic drains following hepatic resection. However, many surgeons still insist on using prophylactic drains. This study was designed to identify patients who require prophylactic drains to manage or monitor postoperative complications after hepatic resection.

METHODS

Data were retrospectively collected from 316 patients who underwent hepatic resection and received a prophylactic drain. The patients were divided into two groups according to whether the drain was used to manage or monitor the following postoperative complications: bile leakage (prophylactic drains were used to monitor and treat bile leakage) and postoperative hemorrhage (the drainage fluid was macroscopically bloody and required drain fluid blood counts and monitoring to assess the need for transfusion or reoperation). The results were then validated in a separate cohort of 101 patients.

RESULTS

In 25/316 patients (7.9 %), the prophylactic drains were clinically effective, being used to manage bile leakage in 18 patients and hemorrhage in 8. Intraoperative bile leakage (P = 0.021) and long operation time (≥ 360 min) (P = 0.017) were independent predictors of bile leakage. Intraoperative blood loss (≥ 650 ml) (P = 0.0009) was an independent predictor of hemorrhage. In the subsequent 101 patients, prophylactic drains were clinically effective in patients with one of these predictors with sensitivity, specificity, and false-negative rates of 88.9, 62.0, and 1.7 %, respectively.

CONCLUSION

A prophylactic drain should be considered following hepatic resection for patients with intraoperative bile leakage, operation time of ≥ 360 min, or blood loss of ≥ 650 ml.