title: Variations of the middle and inferior right hepatic vein: application in 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.
authors.affiliation: Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung Medical College, Taiwan, ROC.
authors.forename: Y F
authors.initials: YF
authors.lastname: Cheng
authors.forename: T L
authors.initials: TL
authors.lastname: Huang
authors.forename: C L
authors.initials: CL
authors.lastname: Chen
authors.forename: T Y
authors.initials: TY
authors.lastname: Chen
authors.forename: C C
authors.initials: CC
authors.lastname: Huang
authors.forename: S F
authors.initials: SF
authors.lastname: Ko
authors.forename: B Y
authors.initials: BY
authors.lastname: Yang
authors.forename: T Y
authors.initials: TY
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D001783:Blood Flow Velocity; D005260:Female; D006498:Hepatectomy / Q000379:methods* / Q000592:standards; D006503:Hepatic Veins / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014463:Ultrasonography; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000503:physiopathology