Surgical and histological boundary of the hepatic hilar plate system: basic study relevant to surgery for hilar cholangiocarcinoma regarding the “true” proximal ductal margin

• Published in: Journal of hepato-biliary-pancreatic sciences 2019-05, Vol.26 (5), p.159-168
• Main Authors: Kikuchi, Yutaro, Matuyama, Ryusei, Hiroshima, Yukihiko, Murakami, Takashi, Bouvet, Michael, Morioka, Daisuke, Hoffman, Robert M., Endo, Itaru
• Format: Article
• Language: English
• Subjects: Bile; Elastic fiber; Glisson capsule; Hilar cholangiocarcinoma; Limit of the proximal ductal margin; The hilar plate
• ISSN: 1868-6974; 1868-6982
• DOI: 10.1002/jhbp.617

Background We sought to expand the clinico‐anatomical limit of the proximal ductal margin (Limit‐PDM) for resectability of hilar cholangiocarcinoma (HCCA). Methods The practical boundary of the hilar plate (PBHP) was defined as the location where the bile duct (BD) could not be isolated by dissection. The distance between PBHP and two well‐known clinical landmarks of Limit‐PDM, the right edge of the bifurcation of the anterior and posterior branch of the right portal vein (Posterior‐Landmark) and the left edge of the umbilical portion of the portal vein (Left‐Landmark), and histological features around the PBHP were assessed using 55 adult cadaver livers. Results BD was almost always isolatable beyond the traditional clinical landmarks. The median distance was 6.9 mm (interquartile range [IQR] 6.0–8.3 mm) between the PBHP and the Posterior‐Landmark, and 8.9 mm (IQR 6.7–10.2 mm) between the PBHP and the Left‐Landmark. Histologically, the sheath surrounding the portal triad was loose, thick with few elastic fibers and small arteries near the hepatic hilum. Near the PBHP, the sheath was dense, thin, and abundant with elastic fibers and small arteries. Conclusions Limit‐PDM is more peripheral than the traditional clinical landmark‐based margin and histological transition near the PBHP was revealed. Highlight Basic anatomical investigation by Kikuchi and colleagues using adult cadaveric livers revealed that the bile duct may be dividable more peripherally than the clinical landmarks widely used in surgery for hilar cholangiocarcinoma, extending the proximal ductal margin. They also revealed a histological transition near the practical boundary of the hilar plate.