Liver resection

Principles

• It is possible to remove any single segment with jeopardising blood supply or biliary or venous drainage to the rest of the liver, but sometimes it is easier to remove more than just the involved segment
• Most blood loss comes from hepatic veins - operate with a low central venous pressure (central line, mild Trendelenburg, fluid restriction, and venodilators if necessary, aiming central venous pressure <5mmHg)
• To decrease mortality, minimise blood loss, amount of normal liver resected, and maximise function of remnant liver
• Carefully plan with FLR (Future Liver Remnant) in mind and optimise it if required
  1. Quantify expected remnant
     • Volumetric CT or MRI
     • Some centres perform functional nuclear medicine study - technetium-99m-labelled mebrofenin hepatobiliary scintigraphy
  2. Assess liver quality
     • Worse regeneration in cirrhosis, steatosis, obesity, diabetes, age > 65, sepsis, prior chemotherapy
  3. Compare against minimum required to avoid post-op liver failure (POLF)
     • In normal healthy liver, 80% can be resected without increasing risk of PHLF
     • Safe FLR in mild CLD (fibrosis but no cirrhosis) is 30-35%; in C-P A cirrhosis safe FLR is 40%
     • If C-P B/C or MELD > 10-12 and portal HTN, even a small resection can result in PHLF, and advanced cirrhosis is therefore a contraindication. There is also a constant risk of further HCC in the remnant. These patients would theoretically need a transplant.
  4. Optimise FLR if necessary
     • Portal Vein Embolisation
       • Best first choice
       • FLR increases 40-60% in 6 weeks - risk of disease progression while waiting
     • 90Y radioembolisation
       • Low risk
       • FLR increases 30% in 6 weeks
       • Possible reduced risk of progression during that period due to anti-tumour effect
     • Portal vein ligation
       • Low-moderate risk
       • FLR increases 30-43% in 6 weeks
       • Main operation may be harder due to porta scarring
     • ALPPS (associating liver partition and portal vein ligation)
       • PV and hepatic arterial segmental ligation
       • Higher morbidity and mortality
       • Again, two operations, might be harder second time
       • Fastest growth (up to 80% in a week)
       • Can be considered if other techniques have not been sufficient
• Strategies to avoid PHLF
  • Limited pringle maneuvre/intermittent clamping
  • Meticulous surgical technique to avoid blood loss
  • Avoid prolonged operation
  • Plan and optimise FLR from the start
• Anatomical resections are much more likely to have negative margins in malignant disease than wedge resection

Operative preparation:

• Resection devices
  • Clamp-crush
  • Ultrasonic shears
  • Cavitron Ultrasonic Surgical Aspirator (CUSA)
  • Hydrojet
  • Bipolar devices
• X-match and cell-saver
• Correct coagulopathy
• Central line and arterial access
• DVT prophylaxis
• Warming
• Trendelenburg position
• Should be anatomic resection of portal territories (sectionectomy/segmentectomy/subsegmentectomy), since HCC spreads via PV tributaries
• Location of lesions w/r/t main hepatic vessels and biliary tree is important
• CP score (periop mortality of 5%, 30% and 80% respectively)
• 2cm margins get better survival and recurrence rate than 1cm margins

Wedge resection

• Transverse RUQ incision
• Thompson
• Control hilar structures with loop
• Check abdomen, palpate whole liver
• Mark the lines of parenchymal transection on the liver capsule with diathermy
• Divide parenchyma using method of your choice, controlling vessels or ducts as required
• Remove tumour
• Carefully check for any exposed vessels or ducts
• Don't usually drain

Anatomical resection

• Mobilisation of liver to be resected
  • Division of right or left triangular ligaments and falciform
  • May require mobilisation off IVC with careful control of retrohepatic caval venous branches
• Dissection of inflow and outflow structures
• Inflow control and division (portal vein, hepatic artery, bile duct)
  • Can be suture ligated or divided with vascular staplers
  • Bile duct should be divided within the liver substance in case there are anatomic abnormalities affecting the other side's drainage
• Outflow control and division(hepatic veins)
  • Typically extra-hepatic with a stapler
• Parenchymal transection using preferred technique (see above)
  • Preserve liver remnant of adequate size with intact inflow, biliary drainage and venous outflow

Complications (overall morbidity 45%)

• Mortality (5% or less in experienced centres)
  • Risk related to blood loss, amount of normal liver resected, and condition of the liver itself)
• Bleeding
  • Median blood loss 600mL in one large review
• Prolonged hospital stay
  • Median stay 8 days
• Bile leak (10-20%; higher in complex resections with reconstruction)
• Hepatic dysfunction
  • Minimal risk if reduction in parenchyma <50%
  • Defined as impairment in the liver's ability to maintain its synthetic, excretory, and detoxifying functions as characterised by increased INR and high bilirubin on or after day 5
  • Main risk factor is underlying liver disease and inadequate FLR
  • Management is supportive
  • Mortality as high as 70%