Branching patterns of the left portal vein and consequent implications in liver surgery: The left anterior sector

Comprehensive evaluation of the ramification patterns of hepatic vascular anatomy based on three-dimensional visualization technology

The liver segmentation method proposed by Couinaud is widely accepted by surgeons because of its convenience and practicality. However, this conventional eight-segment classification does not reflect realistic details of the liver and thus requires further adjustments to promote improvements in surgical strategies. This study aimed to explore the ramification patterns of the hepatic vasculature comprehensively. A total of 197 eligible patients meeting the study criteria were enrolled for three-dimensional reconstruction analysis. In the left hemiliver, the portal vein bifurcated into P2 and umbilical portion (UP) in 172 (98.3%) patients. The P4b of 103 patients (103/172, 59.9%) whose P4b branched from the right horn of the left portal vein (LPV) diverged from the main trunk of the UP. In the right paramedian sector (RPMS), the entire portal trunk directly bifurcates into P8vent and P8dor. Simple branching of P5 off the trunk of the RPMS was observed in 78 patients (78/130, 60%). The anterior fissure vein (AFV) was identified in 86 (86/148, 58.1%) patients. V8d entered the right hepatic vein (RHV) in all the patients. In 75.3% (113/150) of all the patients, V5d joined the RHV. In the right lateral sector (RLS), more than half (71/133, 53.4%) of the patients had an arch-like type. We summarize different patterns of liver vascular branches, providing a valuable reference for clinical surgery and liver transplantation. Cranio-caudal segmentation is more common than ventral-dorsal segmentation. The AFV can be regarded as a reliable anatomical landmark for subsegmentation in segment 8. In addition, the absence of AFV was associated with the P8 pattern.

Left Anterior Sectorectomy: An Alternative to Left Hepatectomy for Tumors Invading the Distal Part of the Left Portal Vein

BACKGROUND

Liver tumors invading the distal part of the umbilical portion of the left portal vein usually require left hepatectomy. The recent introduction of the concept of left anterior sector, an independent anatomo-functional unit including the anterior portion of the left liver and supplied by the distal part of the umbilical portion of the left portal vein, could represent the rational for an alternative surgical approach. The aim of this study was to introduce the novel surgical procedure of ultrasound-guided left anterior sectorectomy.

METHODS

Among 92 consecutive patients who underwent hepatectomy, 3 patients with tumor invading the distal part of the umbilical portion of the left portal (two with colorectal liver metastases and one with neuroendocrine tumor liver metastases) underwent left anterior sectorectomy alone or in association with liver multiple metastasectomies.

RESULTS

Mean operation time was 393 min; post-operative morbidity and mortality were not observed. After a mean FU of 23 months (range 19-28), no local recurrence occurred.

CONCLUSIONS

In presence of tumors invading the distal part of the umbilical portion of the left portal, left anterior sectorectomy could be considered as an anatomic radical surgical option that is safe but more conservative than a left hepatectomy.