Hepatic Lobectomy / Segmentectomy
What the Examiner Expects
Anatomic resection of liver parenchyma along segmental boundaries defined by the Couinaud classification. The examiner expects you to know the eight hepatic segments, the key vascular anatomy (portal vein bifurcation, three hepatic veins, hepatic artery anatomy including a replaced right hepatic artery from the SMA in ~15% of patients), and how to assess the future liver remnant (FLR). For colorectal liver metastases, resection is the only potentially curative treatment and offers 5-year survival of 40–50%. Parenchymal transection can be performed with CUSA, harmonic scalpel, or clamp-crush technique. The Pringle maneuver (clamping the hepatoduodenal ligament) controls portal inflow and can be applied intermittently (15 minutes on, 5 minutes off).
Key Examiner Focus Points
- Couinaud segmental anatomy: 8 segments based on portal and hepatic vein anatomy
- Future liver remnant (FLR) must be adequate: ≥ 20% (normal liver), ≥ 30% (chemo-treated), ≥ 40% (cirrhotic)
- Portal vein embolization (PVE) to hypertrophy the FLR if inadequate
- Pringle maneuver (hepatoduodenal ligament clamping) controls inflow hemorrhage
- Most common indication: colorectal liver metastases, HCC, cholangiocarcinoma
Common Curveballs
CT volumetry shows the FLR is only 18% after planned right hepatectomy
The FLR is inadequate. Perform right portal vein embolization (PVE) to induce compensatory hypertrophy of the left lobe. Reassess with volumetric CT in 4–6 weeks. Alternatively, consider ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) for faster hypertrophy, though it carries higher morbidity.
During right hepatectomy, you encounter a replaced right hepatic artery arising from the SMA
This variant is present in ~15% of patients. It runs posterior to the portal vein and pancreatic head. It must be identified preoperatively on CT angiography. During right hepatectomy, it will be ligated as part of the resection, but you must preserve it during left-sided procedures.
Postoperative liver failure after a major hepatectomy
Post-hepatectomy liver failure (rising bilirubin, coagulopathy, encephalopathy). Supportive care: glucose infusion, lactulose, correct coagulopathy. Assess portal pressures — portal hypertension from excessive resection causes small-for-size syndrome. Consider molecular adsorbent recirculating system (MARS) as a bridge. Liver transplant may be needed in extreme cases.