Modified hanging manoeuvre facilitates inferior vena cava resection and reconstruction during extended right hepatectomy: A technical case report

Surgical relevance of anatomic variations of the right hepatic vein

BACKGROUND

Variations in the anatomy of hepatic veins are of interest to transplant surgeons, interventional radiologists, and other medical practitioners who treat liver diseases. The drainage patterns of the right hepatic veins (RHVs) are particularly relevant to transplantation services.

AIM

The aim was to identify variations of the patterns of venous drainage from the right side of the liver. To the best of our knowledge, there have been no reports on RHV variations in in a Caribbean population.

METHODS

Two radiologists independently reviewed 230 contrast-enhanced computed tomography scans performed in 1 year at a hepatobiliary referral center. Venous outflow patterns were observed and RHV variants were described as: (1) Tributaries of the RHV; (2) Variations at the hepatocaval junction (HCJ); and (3) Accessory RHVs.

RESULTS

A total of 118 scans met the inclusion criteria. Only 39% of the scans found conventional anatomy of the main hepatic veins. Accessory RHVs were present 49.2% and included a well-defined inferior RHV draining segment VI (45%) and a middle RHV (4%). At the HCJ, 83 of the 118 (70.3%) had a superior RHV that received no tributaries within 1 cm of the junction (Nakamura and Tsuzuki type I). In 35 individuals (29.7%) there was a short superior RHV with at least one variant tributary. According to the Nakamura and Tsuzuki classification, there were 24 type II variants (20.3%), six type III variants (5.1%) and, five type IV variants (4.2%).

CONCLUSION

There was significant variation in RHV patterns in this population, each with important relevance to liver surgery. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

Venous drainage of the left liver: an evaluation of anatomical variants and their clinical relevance

AIM

To evaluate the variations in venous drainage from the left liver.

MATERIALS AND METHODS

A retrospective evaluation was performed of all consecutive abdominal computed tomography (CT) examinations at a tertiary referral facility between 1 January and 30 June 2018. Osirix (Pixmeo SARL, Bernex, Switzerland) was used to examine the major hepatic veins and their tributaries in each scan. The classification of variants as proposed by Nakamura and Tsuzuki was used to describe the findings. The following information was collected: ramification pattern, number, length and diameter of middle (MHV) and left (LHV) hepatic vein tributaries. Two researchers collected data independently, and the average measurements were used as the final dimensions.

RESULTS

Of 102 examinations evaluated, only 27 demonstrated the conventional venous drainage patterns. The LHV and MHV combined to form a common trunk that emptied into the inferior vena cava (IVC) in 75 (73.5%) cases. The common trunk had a mean length of 8.89 mm and mean diameter of 20.18 mm. Other patterns included Nakamura and Tsuzuki type I (27.5%), type II (29.4%) and type III variants (16.7%). In addition, 4.9% of patients had absent superior middle veins and 80% had supernumerary short hepatic veins (4%).

CONCLUSION

Only 26.5% of patients in this population had conventional venous drainage from the left liver. Surgeons and radiologists in hepatobiliary practice should be aware of these variants in order to minimise morbidity when performing invasive procedures.