Selective middle hepatic vein compression under ultrasound guidance: enhances detection of left-sided communicating veins and expands parenchyma-sparing liver surgery at the caval confluence.

The identification of communicating veins (CVs) has expanded the criteria for liver resection and enabled more conservative surgical approaches in patients with hepatic vein (HV) involvement. CVs are predominantly located on the right side, particularly between the middle and right hepatic veins (MHV-RHV), where selective clamping of the RHV facilitates their detection. However, left-sided CVs often remain undetected with standard imaging techniques. We proposed a novel ultrasound-guided selective MHV compression technique for intraoperative identification of left-sided CVs. Consecutive patients with tumors contacting or infiltrating the MHV at the caval confluence were prospectively enrolled. Outcomes included: (1) detection rate of left-sided CVs, (2) surgical strategy modifications based on CV identification, and (3) safety of CV-guided resections. Selective MHV compression was successfully applied in 21 patients. CVs were identified in 15 patients (71%): 12 patients (57%) had both left- and right-sided CVs, and 3 (14%) had unilateral CVs. In 12 patients (57%), CV identification led to modifications in the surgical plan, enabling parenchyma-sparing resections (PSRs): 4 underwent PSR with both MHV and RHV resection, 4 with MHV section alone, and 4 with RHV section alone. Median estimated future liver remnant volume was 52% (IQR 45-65). Major complications occurred in 1 patient (5%); no perioperative mortality was observed. Ultrasound-guided selective MHV compression is a safe and effective method for detecting left-sided CVs, offering a valuable adjunct to extend indications for parenchyma-sparing liver resections in tumors involving the caval confluence. Further validation in larger cohorts is warranted to fully establish its clinical impact.