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Variations of the middle and inferior right hepatic vein: application in hepatectomy
Y F Cheng1, T L Huang, C L Chen
1Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung Medical College, Taiwan, ROC.
Insights
Variations in the middle and inferior right hepatic veins are common. Understanding these hepatic vein variations is crucial for planning safe right subtotal hepatectomy and minimizing surgical risks.
Area of Science:
- Hepatobiliary Surgery
- Vascular Anatomy
- Medical Imaging
Background:
- Anatomic variations of hepatic veins can impact surgical procedures.
- Right subtotal hepatectomy requires detailed knowledge of liver vasculature.
Purpose of the Study:
- To evaluate the anatomical variations of the middle right hepatic vein (MRHV) and inferior right hepatic vein (IRHV).
- To assess the clinical applicability of these variations for right subtotal hepatectomy.
Main Methods:
- Ultrasound examination of 400 normal livers.
- Measurement of hepatic vein size, drainage patterns, and distances between vessels.
Main Results:
- The inferior right hepatic vein (IRHV) drained segment 6 in 18% of cases, and the middle right hepatic vein (MRHV) drained segment 5 in 5.5% of cases.
- Both IRHV and MRHV were occasionally larger than the right hepatic vein (RHV).
- A hyperechoic edge was noted on hypertrophic IRHV walls.
Conclusions:
- Preoperative identification of MRHV and IRHV variations is vital for liver surgery.
- Understanding these variations aids in preserving liver segments and performing RHV resection safely.
- Elective clamping of hypertrophic MRHV and IRHV may reduce blood loss and malignancy spread during right hepatectomy.
Abstract:
We evaluated the anatomic variations of the middle right hepatic vein (MRHV) and inferior right hepatic vein (IRHV) and their clinical application to the possibility of right subtotal hepatectomy. In 400 of normal livers studied with ultrasound, the IRHV was found to drain segment 6 of the liver and flow into the inferior vena cava (IVC) in 72 (18%) cases. In 22 (5.5%) cases, the MRHV was found to drain segment 5 of the liver and flow into the IVC. The size of the IRHV ranged from 0.1 cm to 0.8 cm with an average of 0.46 cm. For the MRHV, the sizes ranged from 0.1 cm to 0.9 cm with an average of 0.34 cm. In 10/79 (12.6%) cases the IRHV and in 4/ 22 (18.1%) cases the MRHV were bigger than the right hepatic vein (RHV). The distance between the RHV and IRHV ranged from 3 cm to 5 cm with an average of 3.7 cm. The distance between the RHV and MRHV ranged from 3 cm to 3.3 cm with an average of 3.1 cm. A hyperechoic edge, similar to that of the portal vein, was observed at the wall of the hypertrophic IRHV and was 0.3 cm or larger in size. Preoperative delineation of this complex venous anatomy is very important. It provides vital information in the preoperative evaluation needed before performing a right subtotal hepatectomy with preservation of segment 6 or segment 5 of the liver, and with RHV resection. Prior to undertaking a right hepatectomy, clamping the hypertrophic MRHV and IRHV electively may minimize intra-operative blood loss and extrahepatic spread of the malignancy.