No authors have reported on the anatomic features of the independent right posterior portal vein variant and its relevance to left hepatic trisectionectomy. The purpose of this study was to review vasculobiliary systems according to portal vein anatomy, to clarify the anatomic features of the right posterior portal vein variant, and to discuss its operative implications for left hepatic trisectionectomy.METHODS
In a radiologic study, the 3-dimensional anatomy of the portal vein, hepatic artery, and bile duct were studied in 200 patients who underwent computed tomography. In a surgical study, medical records were retrospectively reviewed for 463 patients who underwent hepatectomy for perihilar cholangiocarcinoma.RESULTS
In the radiologic study, an independent right posterior portal vein variant was observed in 19 patients. The following observations were made in association with the portal vein variant: (1) a supraportal or combined type right posterior hepatic artery was never found; (2) an infraportal right posterior bile duct was observed at a significantly greater frequency than in patients with normal portal vein anatomy; and (3) the volume of the right posterior sector was significantly larger than in normal portal vein anatomy (37.4 ± 6.1% vs 27.3 ± 5.1%, P < .001). In the surgical study, the independent right posterior portal vein variant was observed in 41 (8.9%) patients. Of the 135 patients who underwent left hepatic trisectionectomy, 28 (20.7%) had this portal vein variant.CONCLUSION
Independent right posterior portal vein variants exhibit anatomic features that are advantageous for performing left hepatic trisectionectomy.