Indications for posthepatectomy hepatic vein reconstruction from functional and morphological studies: clamping test and hepatic vein branch distribution determined by three-dimensional computed tomography.

BACKGROUND/AIMS: Indications for hepatic vein reconstruction for preserving remnant liver function after hepatectomy were assessed using the clamping test and the findings of preoperative 3D-CT (3-dimensional computed tomography). METHODOLOGY: Fifteen patients who underwent hepatectomy for malignant tumors in segment VII or VIII, or both, were examined with preoperative 3D-CT and an intraoperative clamping test. RESULTS: On the basis of changes in right hepatic venous pressure during clamping, we classified all patients into 3 types: the persistent elevation type (P-type, 8 patients), the no elevation type (N-type, 3 patients) and the transitory elevation type (T-type, 4 patients). Hepatic venous hemoglobin oxygen saturation (ShvO2) decreased significantly in the P type but hardly changed in the T and N types during the clamping test. Both the inferior right hepatic vein (IRV6) and the tributary of the middle hepatic vein draining segment V (MV5) were detected by preoperative 3D-CT in the T and N types. CONCLUSIONS: Assessments of hepatic vein branch distribution using preoperative 3D-CT served to predict the results of the hepatic vein clamping test. The results of preoperative 3D-CT were useful as indications for hepatic vein reconstruction.

Subdivision of liver anterior segment into two units according to hepatic venous drainage.

BACKGROUND/AIMS: In anatomic liver resection, consideration of the distribution of the hepatic vein is important for maximizing remnant liver function. We have examined the anterior segment of the liver tomographically and subdivided it according to the hepatic venous distribution. METHODOLOGY: Thirty patients in whom liver tumors were diagnosed and who were examined by three-dimensional computed tomography were reviewed. Portal and hepatic venous distributions in the anterior segment were analyzed using the tomograms obtained, and the anterior segment was divided into the ventral and dorsal units. RESULTS: S8d was present in only 23 cases, out of which in 14 cases, drainage veins were present. When P8d was supplied by P8, S8d together with S8a were classified into the ventral unit (8 cases). When P8d was supplied by P8c, S8d and S8b and S8c were in the dorsal unit (4 cases). S5a was in the ventral unit in 26 cases and the dorsal unit in 4 cases. S5b was in the ventral unit in 11 cases and in the dorsal unit in 19 cases. The ventral unit was drained by the middle, and the dorsal by the right, hepatic vein. CONCLUSIONS: Three-dimensional computed tomography made it possible to classify the anterior segment into ventral and dorsal units according to the distribution of the hepatic vein. This new classification makes possible new operative procedures in which resection is limited to one of the units with or without one or more segments, and which result in better remnant liver function.

Usefulness of three-dimensional computed tomography for anatomic liver resection: sub-subsegmentectomy.

BACKGROUND: Precise subtotal hepatectomies based on the vascular anatomy revealed by preoperative three-dimensional computed tomography (3D-CT) were reviewed to examine the usefulness of 3D-CT. METHODS: The clinical records and 3D-CT images of 20 patients with 24 hepatomas less than 50 mm in diameter who underwent hepatectomy for hepatocellular carcinoma and metastatic tumors and the usefulness of 3D-CT were assessed. Couinaud's classification of liver subsegments and Takayasu's classification of sub-subsegments were used as the criteria for the anatomic division. RESULTS: The accuracy in localizing tumors in a small subsegment of the liver was 75% (18 of 24 tumors) for conventional CT and 100% (24 of 24 tumors) for 3D-CT (p < 0.05). 3D-CT images made it possible to perform complete resection confined to the portal unit containing the tumor in patients with poor liver function. This method allowed complete preservation of the circulation of the remnant liver, thus reducing complications. CONCLUSIONS: The 3D-CT technique provides more accurate diagnosis and a realistic virtual image of a tumor's location in the liver and so makes possible the anatomic resection of the liver. Because diagnostic errors could result in such clinical complications as postoperative bile leakage, this is a useful technique for hepatectomy, especially for sub-subsegmentectomy.