Biliary architecture of livers exhibiting right-sided ligamentum teres: an indication for preoperative cholangiography prior to major hepatectomy

Abstract

Objective: To obtain information about the basic biliary anatomy of livers with right-sided ligamentum teres (RSLT).

Summary of background data: RSLT is a relatively rare anomaly with a reported incidence of 0.2-1.2%. Although the portal/hepatic venous and arterial anatomy of livers with RSLT has already been established, the biliary architecture of such livers remains unclear.

Methods: RSLT was detected in 48 patients during 12,071 consecutive image readings (0.4%). Of these patients, the cholangiograms of 46 patients were analyzed, and their intrahepatic biliary tree confluence patterns were classified.

Results: The following four unique biliary confluence patterns were identified in livers with RSLT: the symmetrical type (23/46), independent right lateral type (13/46), total left type (6/46), and total right type (1/46). Analyses of the portal and arterial branching patterns of these livers showed that there were no correlations between their biliary confluence patterns and their portal or arterial ramification patterns.

Conclusion: The basic biliary architecture of livers with RSLT was clarified. As the RSLT patients' anomalous biliary confluences differed from those seen in normal livers and were difficult to predict, preoperative cholangiography should be performed prior to complex hepatobiliary surgery involving livers with RSLT to ensure patient safety.

Figure 1

a) The appearance of a liver with right-sided ligamentum teres. Please note the reversed anatomy and the small gap between the ligamentum teres and gallbladder. b) A scheme of the relationships between hepatic segments and anatomical landmarks. RHV: right hepatic vein, MHV: middle hepatic vein, LHV: left hepatic vein, GB: gallbladder, LT: ligamentum teres, RL: right lateral portal vein, RPM: right para-median portal vein, LPM: left para-median portal vein, LL: left lateral portal vein

Figure 2

A classification of intrahepatic portal ramification patterns. a) Shindoh's independent right lateral type, b) bifurcation type, c) trifurcation type

Figure 3

Shindoh's classification of intrahepatic arterial ramification patterns. The major three types are classified based on the position of the left hepatic artery

Figure 4

Typical MRCP images of the intrahepatic bile ducts of RSLT livers. a) Symmetrical type; b) independent right lateral type; c-1) total left type; c-2) a frequent variation of the total left type, in which an independent branch drained a minor area of the right anterior segment (Sg 5) (arrow); d) total right type

Figure 5

Scheme of the intrahepatic bile duct confluence patterns seen in RSLT livers. “U” indicates the right umbilical portion, and the gray line represents the intrahepatic portal vein. a) Symmetrical type, b) independent right lateral type, c) total left type, d) total right type

Figure 6

Correlations between each biliary confluence type and portal/arterial ramification patterns. No significant correlations between biliary type and portal/arterial type were detected. IRL: independent right lateral type, Bi: bifurcation type, Tri: trifurcation type. Arterial branching patterns were studied in 42 out of 46 patients (the evaluable patients)