Page 196 - Medicine and Surgery
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                   192 Chapter 5: Hepatic, biliary and pancreatic systems


                                                                T-tube is sited into the opening, which is brought out
                                 Inferior vena cava
                                                                to the abdominal wall. The T-tube allows drainage of
                          Right lobe         Left lobe          bile and also allows a cholangiogram later. Alternatively,
                                                                common bile duct stones are removed at endoscopic ret-
                                                                rograde cholangiopancreatography (ERCP).
                                                                  Laparoscopic cholecystectomy requires three or four
                                                                cannulae inserted through the anterior abdominal wall,
                                               Caudate and      for visualisation and access with operative instruments.
                                               quadrate lobes
                                               (functionally part  The cystic duct and artery are clipped and dissected,
                                               of left hemi-liver)  while the gallbladder is held retracted.
                                                                  Open cholecystecomy often requires quite a long stay
                                Gallbladder  Hepatic artery and  in hospital, possibly a week or more, whereas laparo-
                                          portal vein           scopic cholecystectomy may be conducted as a day case.
                                                                  Complications include haemorrhage, respiratory
                   Figure 5.3 Anatomy of the liver.             problems and wound infection. Bile leakage and haem-
                                                                orrhage may require further surgery. Laparoscopic tech-
                     This means that right hepatectomy, left hepatectomy  nique reduces the incidence of respiratory problems and
                   and extended right hepatectomy (right lobe plus cau-  surgical site infection.
                   date and quadrate lobes) or individual segments may be
                   resected. The liver is first mobilised from its peritoneal
                   attachments. The appropriate vessels for the segment(s)  Disorders of the liver
                   are ligated and divided before the segment(s) are dis-
                   sectedawayfromtheremainderoftheliver.Carefuliden-  Introduction to the liver and
                   tification and ligation of biliary ducts and smaller vessels  liver disease
                   is required to reduce blood loss and therefore morbidity
                   and mortality. Drainage is required postoperatively, to  Introduction to the liver
                   prevent bile from pooling intra-abdominally.
                                                                The liver is divided into two lobes, left and right (which
                                                                includes the caudate). It has two blood supplies: 25% of
                   Cholecystectomy
                                                                its blood originates from the hepatic artery (oxygenated)
                   Surgical removal of the gallbladder and associated stones  and 75% originates from the portal vein that drains the
                   in the biliary tract may be by open surgery or laparo-  gastrointestinal tract and spleen. This blood is therefore
                   scopic surgery.                              relatively low in oxygen, but rich in glucose, lipids and
                     Cholecystectomy may be indicated for symptomatic  amino acids.
                   gallstones. Cholecystectomy is also considered in  The functions of the liver are carried out by the hepa-
                   younger patients with asymptomatic gallstones in or-  tocytes, which have a special architectural arrangement.
                   der to prevent complications such as acute pancreatitis.  Blood enters the liver through the portal tracts, which
                   Carcinoma of the gallbladder is treated by wider resec-  contain the triad of hepatic artery, portal vein and bile
                   tion, including neighbouring segments of the liver and  duct. It then filters from the edges of the lobule to the
                   regional lymph nodes.                        central (efferent) vein. The lobule is classically used to
                     Open cholecystectomy is usually performed through  describe the histology of the liver (see Fig. 5.4a) but the
                   aright subcostal (Kocher) incision or by a paramedian  acinus forms the functional unit (see Fig. 5.4b).
                   or midline incision. Cholangiography may be used to  The hepatocytes in zone 1 of the acinus receive well-
                   visualise the duct system. The gallbladder is removed  oxygenated blood from the portal triads, whereas the
                   with ligation and division of the cystic duct and artery.  hepatocytes in zone 3 receive poorly-oxygenated blood
                   If stones have been found, the common bile duct may  and are therefore more vulnerable to damage when the
                   be opened longitudinally and the stones removed. A  blood supply is compromised.
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