Usefulness of 3-dimensional computed tomography for caudate lobectomy by transhepatic anterior approach

Improvement of precision and safety of resection of caudate lobe by the transhepatic anterior approach using preoperative 3-dimensional computed tomography.

The 3D-computed tomography images of 32 patients who underwent hepatectomy for hepatocellular carcinoma and metastatic tumors were reviewed. The usefulness of 3D-computed tomography was assessed on the basis of its depiction of the portal branch distribution of the caudate lobe and of the position of the parenchymal division plane in the transhepatic anterior approach.

1) Number of portal vein branches in the caudate lobe: 1 to 5 (average, 2.75) portal vein branches were detected in the caudate lobe at the optimal angle (left-posterior 135 degrees) by 3D-computed tomography: P1l-sup in 84.3%, P1r-sup in 71.9%, P1r-inf in 71.9%, P1l-med in 15.6% and P1-trunk in 3.1%. 2). We classified the structure of the caudate lobe into four types, one type having two subtypes, based on the 3D-computed tomography findings of its portal branch distribution: Type 1: presence of 1rs, 1ri, 1ls; Type 2a: absence of 1ri; Type 2b: absence of 1rs; Type 3: absence of 1ls; Type 4: presence of 1t alone. Type 1 was observed in 16 of the 32 patients (50.0%), type 2a in 4 (12.5%), type 2b in 8 (25.0%), type 3 in 3 (9.4%) and type 4 in 1 (3.1%). 3) When the tributary of the right hepatic vein draining segment 5 (RV5) can be detected (type 1: 81.3%), the right surface of the middle hepatic vein should be exposed; whereas its left surface should be exposed when RV5 cannot be detected (types 2 and 3: 18.7%).

Preoperative 3D-computed tomography images enable more accurate diagnosis of intrahepatic tumor location and facilitate detection of the portal veins of the caudate lobe, thus simplifying both caudate lobectomy and the selection of which side of the division plane and of the middle hepatic vein to divide the liver parenchyma in the transhepatic anterior approach, and allowing complete preservation of the circulation of the remnant liver.