Liver resection involves the removal of part(s) of the liver to remove tumours of the liver. Liver resections are classified broadly as anatomical or non-anatomical. Anatomically, the liver comprises eight segments, each of which has its own bile duct and its own branches of the hepatic artery and portal vein.
Anatomical hepatic resections are based on the segmental anatomy, dissecting along intersegmental planes to resect from one to six of the eight segments. A liver that is normal, apart from the tumours that one has to remove, has great reserve functional capacity, which allows liver surgeons to remove up to 60% of the liver safely. When the underlying liver is diseased, as in hepatic steatohepatitis (fatty liver), chronic hepatitis or liver cirrhosis, the reserve function may be significantly reduced, and in patients with such diseases, the surgeon will not be able to resect such large proportions of the liver. Patients with a chronically diseased liver have to be very carefully assessed to try to assess the functional reserve of the liver before deciding whether it is safe to do a liver resection and, if so, how many segments can be removed without the patient developing hepatic failure.
A unique feature of the liver is that it has the ability to regenerate. This means that after liver resection, the remnant liver returns within a few months to the same functional capacity that it had before the liver resection. This property can be exploited by liver surgeons to resect very extensive tumour involvement of the liver by doing two-stage resections. This means that some of the tumours are removed at the first operation, and the remaining tumours are removed at a second operation after regeneration has taken place. Another strategy employed in people requiring extensive resections where there is a risk of post-op liver failure is to occlude the portal veins supplying the segments to be removed prior to doing the resection. This diverts portal venous blood away from the segments containing the tumours to be removed and to the segments that it is planned to leave behind. The result of this is to cause atrophy (shrinkage) of the segments to be removed and hypertrophy (enlargement) of the segments to be retained.
Non-anatomical resections do not follow anatomical segmental planes and, provided blood supply to the rest of the segment involved is preserved, means that liver tissue and functional capacity away from the tumour is preserved.
Liver resection surgery is done for people with benign or malignant tumours of the liver.
Benign hepatic adenomas, which are rare, might need to be removed because some of them have a high risk of spontaneous rupture and haemorrhage and a small but significant risk of malignant transformation. The more common benign mass lesions, which are not true neoplasms are Cavernous Haemangiomas and Focal Nodular Hyperplasias. These very seldom cause problems and so seldom need to be removed. However, sometimes they become very large and exert compression effects on adjacent organs with resulting symptoms or complications, and in those cases, it may be necessary to remove them.
Malignant tumours are either primary or secondary (metastatic) tumours.
Primary malignant liver tumours include hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma and a few other rare types of tumours arising from cells native to the liver.
Secondary (metastatic) liver tumours are tumours that have spread to the liver from cancers of other organs.
The vast majority of secondary liver tumours for which liver resections are done are metastases from colorectal cancer because, in many people with colorectal cancer metastases, the metastases are confined to the liver. These patients can, thus, still be treated with curative intent.
Metastases from neuroendocrine tumours of the gastrointestinal tract and pancreas are also commonly amenable to surgical resection.
Metastases from cancers of organs other than colon and rectum and neuroendocrine tumours (non-colorectal, non-neuroendocrine) are occasionally amenable to surgical resection after a thorough search shows no evidence of extrahepatic metastases.
In principle, resection of metastases is done when the surgeons can safely remove all detectable metastases. However, in the case of neuroendocrine tumours, which have very different biological behaviour from other cancers and sometimes cause very disabling symptoms by virtue of excessive secretion of hormones, there is often good reason to do cytoreductive (debulking) surgery, where a large proportion of the tumours can be safely removed, even if it is not possible to remove all detectable tumours.
The most common form of primary liver cancer is hepatocellular carcinoma (HCC) which is most commonly found in patients who suffer from chronic liver disease and cirrhosis. Hepatic cirrhosis represents an end-stage liver disease that usually develops as a complication of chronic Hepatitis B or C viral hepatitis, alcoholic liver disease and steatohepatitis secondary to morbid obesity and diabetes mellitus. Liver resection is much more difficult and risky in these diseased livers, and there is a much greater risk of postoperative liver failure. These patients have to be very carefully assessed as to the most appropriate form of treatment. In some patients, the most appropriate treatment is a liver transplant because the transplant removes both cancer and the underlying diseased liver and replaces it with a healthy liver. If the patient has a reasonably good level of hepatic function and would tolerate a limited resection, a resection might be preferable to transplantation.
Liver resection is usually done by open surgery, via a large incision through the abdominal wall below the right rib margin. In some cases, the liver resection can be done laparoscopically using a minimally invasive technique through ports inserted into the abdomen through several small incisions. Whichever technique is used, it is performed under general anaesthetic.
In most liver resections, the liver has to be extensively mobilized off the abdominal wall and diaphragm to get good access and to control the vascular inflow and outflow.
In some cases, the blood supply to the segments to be resected is interrupted prior to starting the dissection through the liver tissue, while the blood supply to those segments that are to remain continues during the dissection. In other cases, the blood supply to the entire liver is clamped (Pringle manoeuver), intermittently or continuously, during the dissection through the liver tissue.
There are different techniques used for a dissection through the liver tissue. Dr Stapleton uses a combination of CUSA (Cavitron ultrasound aspirator), Ligasure (Medtronic ®), a form of bipolar electrocautery and Argon beam coagulator. Major vascular/biliary pedicles supplying the segments to be removed usually divided with surgical stapling devices that staple the pedicles on either side of a blade that cuts between the staple lines. Intrahepatic blood vessels that are too large to seal with the Ligasure device are clipped with locking plastic clips or clamped, and suture ligated. With these techniques, devices and intimate knowledge of hepatic segmental anatomy, most liver resections are completed without the need for blood transfusion. However, if a large hepatic vein is injured during the operation, a lot of blood can be lost very rapidly, so it is routine to have blood available for transfusion in case of such rapid haemorrhage.
Patients will have an epidural catheter, a nasogastric tube and various drips and monitoring equipment inserted by the anaesthetist. The epidural usually affords good control of abdominal pain after liver resection surgery. Most people spend four days in ICU. The epidural catheter is usually removed on the fourth day, after which abdominal pain is controlled with a combination of pain-killing drugs administered transdermally, intravenously, sublingually and orally. After any major abdominal surgery, the stomach and intestines do not contract normally for a few days, so it is necessary to keep the stomach decompressed with a tube inserted through the nostril into the stomach and food will be administered intravenously through a central venous catheter. Oral feeding is introduced when bowel motility returns, and it is safe to remove the nasogastric tube.
After any major surgery, there is a risk of serious and not so serious complications developing, so Dr Stapleton and an intensive care physician will keep a very vigilant watch over the patient in the days following surgery. Post-op complications may be directly related to the execution of the operation and complications related to the general stress of surgery. The most common complications directly related to the surgery on the liver include: 1) a bile leak, with or without associated infection; 2) liver failure; 3) right pleural effusion and 4) wound infection. Major intra-operative bleeding requiring blood transfusion does occasionally occur, but major postoperative bleeding is very uncommon. Complications related to the general stress of surgery that occasionally occurs include deep venous thromboses, pulmonary emboli, myocardial infarction, lung collapse and pneumonia and strokes.
Full recovery will take four to eight weeks after the surgery. For the first 2-3 weeks after discharge from hospital patients gradually regain strength, energy and appetite. Dr Stapleton usually sees patients for a check-up two weeks after discharge from the hospital.
After recovery from the surgery, there is a good chance that it will be necessary to have adjuvant chemotherapy to lower the chances of developing recurrent cancer. Dr Stapleton participates in meetings of multidisciplinary teams for discussion of optimal management of colorectal and neuroendocrine tumours. These teams are made up of surgeons, radiation oncologists, radiologists, histopathologists and nuclear medicine physicians.
After completing treatment for malignant tumours, we recommend regular, active follow-up with blood tests and imaging aimed at early detection of possible recurrences of the tumours. This is because if recurrent tumours are detected early, they are more likely to be amenable to further treatment with curative intent or for meaningful palliation. Generally, Dr Stapleton and the oncologist see the patient alternately at three-month intervals for the first few years after the surgery.