Liver resectionMedical editor Bjørn Edwin MD
Oslo University Hospital
Bård Røsok MD
Oslo University Hospital
The liver is an organ which is richly vascularized and has a double blood supply. Arterial blood originates from the hepatic artery and venous blood from the large portal vein which drains blood from the bowels. The liver blood is drained via the three hepatic veins into the vena cava close to the right atrium of the heart. It is therefore important to know the course of these vascular structures when surgically dissecting the liver. The remaining liver tissue must have an intact venous outlet. The choice of operation method is decided after accurate assessment of the tumor's size and relation to these large blood vessels.
A liver resection can either be performed by a traditional open resection or by laparoscopy. Both methods allow for both wide, formal resections following anatomical structures such as blood vessels and biliary ducts, as well as smaller local (tissue-sparing) resections where the procedure is limited to removing the tumor with a minimum of surrounding healthy liver tissue.
At Oslo University Hospital, Rikshospitalet, most of the large resection procedures are performed as open surgery. This always applies when involvement of blood vessels requires vessel reconstruction. Laparoscopic surgery is recommended in most local resections, including lateral left-sided resection (segment 2/3) and in selected cases of wider, formal resections. Previous liver resections are not a contraindication for laparoscopic surgery.
Depending on the size of the liver and quality of the surrounding tissue, up to 80% of the liver can be resected. Regeneration of the liver occurs after a few months.
The liver is divided into 8 segments. The left lobe of the liver includes segments 2-4 while the right lobe includes segments 5-8. Segment 1 (caudate) overlies the inferior vena cava. The division between the two lobes is defined by the separation of the portal vein into the right and left portal veins. The falciform ligament defines the separation between left liver lobe segment 4 and segment 2/3.
A formal resection (anatomical resection/segmentectomy/lobectomy) is performed according to the liver's vascular and biliary anatomy. The traditional resections are defined as follows:
- Lateral left-sided resection: Removal of segment 2 and 3 (Resection of about 20% of the liver's volume)
- Formal left-sided resection: Removal of segment 2-4. (about 40% resection)
- Formal right-sided resection: segment 5-8 including the gallbladder are removed (about 60%)
- Extended right-sided resection: segment 5-8 plus all or parts of segment 4 are removed (up to 80% is removed, often after pre-treatment with portal vein embolization)
The tumor is removed with a margin of around 1 cm (local, non-anatomical resection/wedge resection). This may be difficult when the tumor is located close to large vessels. This method may be applicable for multiple small metastases (multiple wedge resections).
- Primary liver cancer
- Cancer in intrahepatic biliary ducts
- Liver metastasis
- Complete removal of cancerous tissue
Identifying the resection margin
Division of the liver capsule
- Ultrasound scalpel
- Harmonic Ace®
Dissect the parenchyma
- CUSA® (cavitron ultrasonic surgical aspirator)
- SonoSurge Aspirator®
Both of these are based on ultrasound.
Divide small vessels/biliary ducts
Divide larger vessels
- All open surgery is performed with the patient in the supine position.
- For laparoscopic surgery, the position of the patient depends on the location of the tumor. For lateral right-sided tumors, the patient lies on the left side with a 45° angle.
- The procedure is carried out under general anesthesia.
- For open surgery, a curved transverse incision is made on the right side of the abdomen and further extended in the midline up to the xiphoid process. Sometimes, the transverse incision must be extended over to the left subcostalregion forming a three-armed "star." For laparoscopic resections, 4 ports of about 1 cm are generally used. Location on the abdominal wall depends on the location of the tumor. Sometimes, 1-2 additional ports are needed.
- For formal resections, the blood vessels and the bile ducts are dissected and preferably divided at the point of the entrance and exit of the liver. This will reduce the blood loss during the procedure.
- The capsule is separated either with diathermy or with an ultrasound scalpel.
- The division of the liver tissue is identically performed for both local and formal resections. The principle is to identify and secure small blood vessels and bile ducts during the dissection. The liver tissue is divided by controlled crushing, either manually or mechanically with ultrasound equipment (CUSA® or SonoSurge Aspirator®), and blood vessels and bile ducts are ligated or stapled.
- In some cases, it is necessary to stop all blood supply to the liver due to bleeding from inflow blood vessels. This is done by the Pringle's maneuver where over the hepatoduodenal ligament is clamped with its large blood vessels (portal vein and hepatic arteries). The duration of this procedure is monitored. If prolonged clamping is needed, breaks are taken to provide the liver cells with oxygen.
- When the involved part is separated from the remaining liver, careful hemostasis of the resection margin is performed. During laparoscopic surgery, the specimen is placed in a bag which is retrieved by extending the laparoscopy ports incisions. For wider resections, the incision must be extending 6-8 cm while in most cases an incision up to 3-4 cm is sufficient.
- To avoid a hernia, all layers of the abdominal wall are approximated before the skin is closed. Sometimes, a self-absorbing intracuticular suture is used while other times a normal skin suture or metal staples are used.
- For open surgery, all patients receive an epidural (EDA). This provides good pain relief and allows for almost full mobilization from the first day after the operation.
- Rehabilitation occurs gradually during reduction of EDA. For laparoscopic surgery, EDA is not used. Despite this, the patient is often able to stand up a few hours after the operation and can start to eat and drink when they wish.
- The operation occurs right under the diaphragm. Right-sided atelectasis and pleural fluid are not uncommon. The patient is also susceptible to a lung infection.
- With an open technique, the patient has a subcostal incision which can influence/inhibit respiration.
- Damage to liver cells leads to increased breakdown of proteins which subsequently leads to increased formation of ammonia. The reduced number of liver cells may not be able to adequately convert ammonia to urea which can be excreted by the kidneys. This may lead to cerebral disturbance (encephalopathy) and the patient's mental state may be affected. The patient may also experience drowsiness, confusion, and even coma.
- Large liver resections prevent the liver from metabolizing medications as quickly as normal. Pain medication must therefore be adjusted/reduced and the patient's individual response to medication must be assessed carefully to identify the proper dosage.
- Fever, pain, increasing illness occurring a few days after the operation and may be sign of an abscess, either subphreneic or subhepatic.
The patient will have an outpatient follow-up with an abdominal CT scan after 3 months.