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Page 4 of 6 Russolillo et al. Mini-invasive Surg 2023;7:3 https://dx.doi.org/10.20517/2574-1225.2022.74

● Hepatic veins are the proper boundaries between subsegments or segments. IOUS/LUS helps to identify
hepatic veins and their routes in the parenchyma. Using IOUS/LUS, hepatic veins are approached from the
root or peripheral sides according to the tumor position, type of segment, and liver morphology,
minimizing bleeding and split-vein damage.

Evaluation of venous drainage of the remnant liver
Major or extended hepatectomies are often required for tumors involving the hepatic veins at the
hepatocaval junction. The risk of congestion ischemia must be assessed to plan the proper type of liver
resection for these lesions. Intraoperative color-Doppler ultrasound (described for the first time by Sano
et al. ) is crucial to verify venous congestion of the remanent liver, owing to concomitant and reversible
[10]
hepatic vein clamping. If the remnant liver does not find alternative vein drainage (e.g., veno-venous shunts
or accessory veins), the parenchyma will develop a variable and inconstant area that is not perfused or is
[11]
congested along the cut surface . This condition should be prevented to avoid postoperative morbidity
[12]
(bile leakage and bleeding) and poor long-term outcomes . As recently shown, persistent imbalance of
inflammatory cytokines caused by ischemic residual liver leads to altered immunological states. This
condition facilitates tumor progression and affects oncology results after partial resection for hepatocellular
carcinoma and colorectal liver metastases .
[13]

CONCLUSION
IOUS is an essential tool for laparoscopic anatomic and non-anatomic liver surgery. Ultrasound liver map
technique allows real-time planning and direction during laparoscopic liver resections.

Video comments
Video 1
The video [Supplementary Video 1] displays a 75-year-old woman with left colon adenocarcinoma and
seven liver metastases (LMs). First, she underwent chemotherapy with six cycles of oxaliplatin-based
therapy. She obtained a partial response and then underwent a procedure according to the “liver first”
strategy. She underwent preoperative staging with CT-Scan and magnetic resonance imaging. Both
highlighted six LMs: 15 mm in Sg3 infiltrating the left hepatic vein (LHV), 20 mm in Sg4a adhering to the
middle hepatic vein (MHV), the larger about 22 mm in Sg7-8d in a tight connection with a portal pedicle of
Sg7 (P7) and the right hepatic vein (RHV), 10-mm in Sg6, 11-mm in the Spiegel lobe (SL). Finally, in the
caudate lobe (CL), one LM (known at diagnosis) was no longer detectable (disappeared liver metastasis,
DLM).

IOUS verified the location and vascular contacts of all LMs and discovered a DLM (5 mm) in the CL. First,
we performed right liver mobilization to obtain extrahepatic control of the right hepatic vein. The RHV was
clamped, and color-Doppler LUS flow analysis was performed. Hepatofugal inflow was found in venous
occlusive segment 8 lateral (Sg8l). Finally, LUS facilitated planning for six resections: the first including
Sg4a, Sg8, and Sg7 with the RHV preserved, the second for three lesions in Sg8l with MHV, the third for the
SL, the fourth, fifth and sixth were subsegmentectomies and atypical resections of Sg3, Sg6, and CL,
respectively. Inflow and outflow were controlled.

Regarding the vascular approach, to isolate P7 on the back liver surface, an LUS-guided pedicle-first
approach was carried out. To dissect the MHV and RHV, the cranio-caudal method was used, and the LM
in Sg4a was freed from the MHV. At the end of the procedure, all hepatic veins were exposed on the
resected liver slice. We calculated a blood loss of about 400 cc. Transection and intermitting clamping times
were 298 and 203 min, respectively. The postoperative period was uneventful, and the patient was