Overview

Definition:
-Segment VIII hepatic resection involves the surgical removal of the right anterior superior section of the liver, often required for tumors or benign lesions
-Inflow and outflow control are critical techniques to minimize blood loss and ensure patient safety during this complex procedure.
Epidemiology:
-Primary liver tumors, metastatic disease, and benign conditions like adenomas or cysts are indications
-Segment VIII resections constitute a significant portion of major hepatic resections, particularly for lesions in the dome of the liver.
Clinical Significance:
-Accurate application of inflow and outflow control is paramount to reduce intraoperative hemorrhage, liver ischemia time, and subsequent complications such as post-hepatectomy liver failure (PHLF)
-Proficiency is essential for surgical trainees preparing for DNB and NEET SS examinations.

Indications

Specific Indications:
-Primary hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma confined to segment VIII
-Colorectal metastases or other secondary malignancies in segment VIII
-Benign tumors like adenomas or large hemangiomas causing symptoms or malignancy concern
-Congenital anomalies requiring resection.
Patient Selection:
-Adequate future liver remnant (FLR) is crucial, typically assessed by volumetric analysis and indocyanine green (ICG) retention test
-Patients with severe cirrhosis or impaired liver function may not be suitable candidates
-Multidisciplinary tumor board evaluation is recommended.
Contraindications:
-Extensive bilateral multifocal disease
-Major vascular invasion not amenable to resection
-Significant comorbidities limiting surgical tolerance
-Unacceptable FLR
-Advanced liver cirrhosis with decompensation.

Inflow Control Techniques

Principle: Temporary occlusion of blood supply to the liver (hepatic artery and portal vein) to reduce bleeding during parenchyma dissection.
Methods:
-Pringle maneuver: Temporary clamping of the hepatoduodenal ligament
-Selective inflow control: Occlusion of individual vessels supplying the liver segment to be resected
-Pharmacological methods: Vasoconstrictors to reduce portal venous pressure
-Total vascular exclusion: Temporary occlusion of hepatic artery, portal vein, and hepatic veins.
Duration And Monitoring:
-The Pringle maneuver is typically performed for periods of 15-20 minutes of occlusion followed by 5-10 minutes of reperfusion to prevent ischemic injury
-Liver function tests and arterial blood gas monitoring are essential
-Transabdominal ultrasound can assess liver viability.

Outflow Control Techniques

Principle: Managing venous drainage from the liver to prevent hemorrhage and manage congestion during resection, especially for segments with significant suprahepatic caval drainage.
Methods:
-Temporary caval clamping: For resections involving hepatic veins draining directly into the inferior vena cava
-Proximal and distal control of hepatic veins
-Resection with non-crushing vascular clamps applied to hepatic veins prior to dissection
-En bloc resection with suprahepatic vena cava
-Atriocaval shunt placement during complex liver transplant-related resections.
Considerations:
-Segment VIII often drains via short hepatic veins directly into the suprahepatic vena cava, necessitating careful attention to outflow control
-Injury to the suprahepatic vena cava can lead to significant bleeding and hemodynamic instability
-Knowledge of individual hepatic vein anatomy is key.

Surgical Procedure Steps

Preoperative Planning:
-Detailed imaging (CT, MRI with angiography) to delineate tumor extent, vascular anatomy, and biliary tree
-Volumetric analysis for FLR assessment
-Preoperative optimization of liver function and coagulation status.
Approach And Exposure:
-Standard laparotomy or laparoscopic approach
-Adequate exposure of the liver hilum and suprahepatic vena cava
-Identification and mobilization of the relevant vascular pedicles and hepatic veins.
Parenchymal Dissection:
-Using techniques like the Cavitron Ultrasonic Surgical Aspirator (CUSA), harmonic scalpel, or monopolar electrocautery
-Dissection is guided by anatomical landmarks and preoperative imaging
-Serial ligation of intrahepatic vessels and bile ducts
-Careful management of inflow and outflow control throughout dissection.
Closure And Drainage:
-Hemostasis achieved with meticulous attention to vascular and biliary structures
-Placement of drains for monitoring of bile leaks and bleeding
-Closure of abdominal incision.

Complications

Early Complications: Post-hepatectomy liver failure (PHLF), bleeding, bile leak (biloma), biliary stricture, intra-abdominal infection, hepatic artery thrombosis, portal vein thrombosis, sepsis.
Late Complications: Chronic liver dysfunction, incisional hernia, adhesions, recurrence of malignancy.
Prevention And Management:
-Meticulous surgical technique, accurate inflow/outflow control, adequate FLR, perioperative liver support (e.g., albumin, fluid management), early detection and prompt management of complications
-Prophylactic antibiotics and early mobilization.

Key Points

Exam Focus:
-Understanding the indications, contraindications, and stepwise execution of both inflow and outflow control techniques
-Recognition of potential complications and their management
-Importance of FLR assessment
-Familiarity with Pringle maneuver timing and rationale.
Clinical Pearls:
-Always anticipate and plan for bleeding
-Use a combination of inflow and outflow control when necessary
-Intraoperative ultrasound is invaluable for anatomical orientation
-Adequate decompression of the congested liver is crucial after outflow control.
Common Mistakes:
-Inadequate FLR assessment leading to PHLF
-Prolonged ischemia time during inflow occlusion
-Incomplete control of hepatic veins leading to massive hemorrhage
-Overlooking small biliary radicles during dissection
-Failure to monitor for bleeding or bile leak postoperatively.