Liver Injuries PDF

INDIVIDUAL ORGAN INJURY Liver The liver is the second most common organ injured in abdominal trauma after the spleen. Liver injuries are commonly associated with affection of other intra or extraabdominal organs. The ribs, pleura, lungs, colon...

INDIVIDUAL ORGAN INJURY Liver The liver is the second most common organ injured in abdominal trauma after the spleen. Liver injuries are commonly associated with affection of other intra or extraabdominal organs. The ribs, pleura, lungs, colon and spleen are common associations. The prognosis after treatment of liver injury largely depends on these associated injuries. The mortality of liver injury averages 15-20%. It gets worse if other major organs are injured. Aetiology Liver trauma can be divided into those inflicted by accidents which may be blunt and penetrating injuries; Blunt trauma occurs as a result of direct injury. The liver is a solid organ and compressive forces can easily burst the liver substance. The liver is usually compressed between the impacting object and the rib cage or vertebral column. Most injuries are relatively minor and can be managed non-operatively. Blunt injury produces contusion, laceration and avulsion injuries to the liver, often in association with splenic, mesenteric or renal injury. Blunt injuries are more common and have a higher mortality than penetrating injuries. Penetrating trauma is relatively common. Penetrating injuries, such as stab and gunshot wounds, are often associated with chest or pericardial involvement. Not all penetrating wounds require operative management and may stop bleeding spontaneously. Iatrogenic injury is increasing with the rising popularity of invasive investigations as percutaneous liver biopsy, and percutaneous transhepatic cholangiography (PTC). Spontaneous rupture of the liver is an extreme rarity that may happen with eclampsia or hepatic tumours. Pathology Type of injury In increasing seriousness the following types can be seen 1. Small subcapsular haematoma. 2. Small superficial tear or tears. 3. Large subcapsular or intrahepatic haematoma. 4. Large deep tear or tears. 5. Shattered liver parenchyma which may include a whole lobe. 6. Vascular injury, the most difficult to control is that of the main hepatic veins because of the difficult access. 1|Page Clinical features and diagnosis of liver injury Presence of intraperitoneal haemorrhage with history of trauma except in spontaneous cases. All lower chest and upper abdominal stab wounds should be suspect, especially if considerable blood volume replacement has been required. Severe crushing injuries to the lower chest or upper abdomen often combine rib fractures, haemothorax and damage to the spleen and/or liver. Abdominal pain, tenderness and rigidity due to parietal peritoneal irritation, by blood. Massive bleeding presents with the picture of haemorrhagic shock and minor bleeding is discovered by diagnostic peritoneal lavage (DPL), ultrasound or by CT scan, which are done in suspected cases. These tests are particularly useful in the unconscious patient as it is difficult to assess the abdomen. The injury may also be discovered with systematic exploration during laparotomy for penetrating abdominal trauma. FAST can diagnose free intraperitoneal fluid. Patients with free intraperitoneal fluid on FAST and haemodynamic instability, and patients with a penetrating wound, will require a laparotomy and/or thoracotomy once resuscitation is under way. Owing to the opportunity for massive ongoing blood loss and the rapid development of a coagulopathy, the patient should be directly transferred to the operating theatre while blood products are obtained and volume replacement is taking place. Patients who are haemodynamically stable should have a contrast enhanced CT scan of the chest and abdomen as the next step. This scan will demonstrate evidence of parenchymal damage to the liver or spleen, as well as associated traumatic injuries to their feeding vessels. Free fluid can also be clearly established. Initial management of liver injuries Penetrating The initial management is maintenance of airway patency, breathing and circulation (ABC) following the principles of advanced trauma life support (ATLS). Peripheral venous access is gained with two large-bore cannulae and blood sent for crossmatch of 10 units of blood, full blood count, urea and electrolytes, liver function tests, clotting screen, glucose and amylase. Initial volume replacement should be with blood. Arterial blood gases should be obtained and the patient intubated and ventilated if the gas exchange is inadequate. Intercostal chest drains should be inserted if associated pneumothorax or haemothorax is suspected. Once initial resuscitation has commenced, the patient should be transferred to the operating theatre, with further resuscitation performed on the operating table. The necessity for fresh frozen plasma and cryoprecipitate should be discussed with the blood transfusion service immediately the patient arrives in the hospital (often by activation of a major transfusion protocol), as these patients rapidly develop irreversible 2|Page  coagulopathies due to a lack of fibrinogen and clotting factors. Standard coagulation profiles are inadequate to evaluate this acute loss of clotting factors, and factors should be given empirically, aided by the results of thromboelastography (TEG), if available. A contrast CT prior to laparotomy should be considered if the patient is haemodynamically stable. Blunt trauma Patients who are haemodynamically unstable will require an immediate laparotomy. For the patient who is haemodynamically stable, imaging by CT should be performed to further evaluate the nature of the injury. It provides information on the liver injury itself, as well as on injuries to the adjoining major vascular and biliary structures. Injury in which there is a suggestion of a vascular component should be reimaged, as there is a significant risk of the development of subsequent ischaemia, false aneurysms, arteriovenous fistulae or haemobiliary fistula. It is advised that all patients should be rescanned prior to discharge. Most patients with blunt liver injury who are haemodynamically stable can be managed conservatively. A subcapsular or intrahepatic haematoma requires no specific intervention and should be allowed to resolve spontaneously. The indication for discontinuing conservative treatment is the development of haemodynamic instability, evidence of ongoing blood loss despite correction of any underlying coagulopathy and the development of signs of generalised peritonitis. Interventional radiology has an important role in management of liver trauma and embolization to control hepatic artery bleeding is safe and effective in a stable patient with no evidence of hollow viscus perforation. The surgical approach to liver trauma Treatment for both liver and spleen 1. Patients who are haemodynamically stable with no evidence of peritonitis, are treated conservatively by repeated examination and CT. 2. Patients who are haemodynamically unstable, have peritonitis or deteriorate under conservative treatment will need laparotomy. Good access is vital. A 8rooftop9 incision with midline extension to the xiphisternum and retraction of the costal margins gives excellent access to the liver and spleen. Compression of the liver with packs and correction of coagulopathy, if present, will control most of the active bleeding. If bleeding persists, further control by Pringle maneuver. A stab incision in the liver can be sutured with a fine absorbable monofilament suture. Lacerations to the hepatic artery should be identified and repaired with 6/0 Prolene suture. If unavoidable, the hepatic artery may be ligated, although parenchymal necrosis and abscess formation will result in some individuals. 3|Page  Bleeding points should be controlled locally when possible, and such patients if required, subsequently undergo subsequent angioembolisation. If there has been direct damage to the hepatic artery, it can be tied off. Damage to the portal vein must be repaired, as tying off the portal vein carries a greater than 50% mortality rate. If it is not technically feasible to repair the vein at the time of surgery, it should be shunted by veno-venous bypass using cannulae in the femoral vein via a long saphenous cut-down, with the blood returned using a roller pump to the superior vena cava (SVC) via an internal jugular line and the patient referred to a specialist centre. Venous return is provided by the venovenous bypass. Warm ischaemia of the liver is tolerated for up to 45 minutes, allowing sufficient time in a blood-free field for repair of injuries to the IVC or hepatic veins. A closed suction drainage system must be left in situ following hepatic surgery. Finally, the liver can be definitively packed, restoring the anatomy as closely as possible. Placing omentum into cracks in the liver is not recommended. Portal vein injuries should be repaired with 5/0 Prolene. Inflow occlusion facilitates suturing of lacerations and vessels. If bleeding persists despite inflow occlusion, consider major hepatic vein or IVC injuries, and also look for abberant arteries to the liver. Deceleration injuries often produce lacerations of the liver parenchyma adjacent to the anchoring ligaments of the liver. These may be amenable to suture with an absorbable monofilament suture. Again, inflow occlusion may facilitate this suturing and, if necessary, the sutures can be buttressed to prevent them cutting through the liver parenchyma. With more severe deceleration injuries, a portion of the liver may be avulsed. These injuries are more complex as they are associated with a devitalised portion of the liver and, often, major injuries to the hepatic veins and IVC. Diffuse parenchymal injuries should be treated by packing the liver to achieve haemostasis. Care should be taken to avoid overzealous packing, as this may produce pressure necrosis of the liver parenchyma or abdominal compartment syndrome. Crush injuries to the liver often result in large parenchymal haematomas and diffuse capsular lacerations. Suturing is usually ineffective, and perihepatic packing, is the most useful method of providing haemostasis, to be removed after 48 hours, antibiotic cover is advisable. Translobar penetrating injuries are particularly challenging because the extent of the injury cannot be fully visualized. Options include intraparenchymal tamponade with a Foley catheter or balloon occlusion. If tamponade is successful with either modality, the balloon is left inflated for 24 to 48 hours followed by sequential deflation and removal at a second laparotomy. Hepatotomy with ligation of individual bleeders occasionally may be required; however, division of the overlying viable hepatic tissue may cause considerable blood loss in the coagulopathic patient. Finally, angioembolization is an effective 4|Page  adjunct in any of these scenarios and should be considered early in the course of treatment. Several centers have reported patients with devastating hepatic injuries or necrosis of the entire liver who have undergone successful hepatic transplantation. Clearly this is dramatic therapy, and the patient must have all other injuries delineated, particularly those of the central nervous system, and have an excellent chance of survival excluding the hepatic injury. Principles of surgical management in short: 1. Adequate exposure by a longitudinal incision that can be extended to the chest in case of need. 2. Thorough systematic exploration of the abdomen is required to assess the liver affection and to detect other intra-abdominal injuries. 3. Priority is for arrest of bleeding. As mentioned before, most small liver tears are found to have stopped bleeding by the time the abdomen is explored, and these tears deserve no treatment Preliminary control of brisk liver haemorrhage can be attained by a combination of temporarily packing the bleeding area, and the application of Pringle's manoeuvre to occlude the hepatic artery and the portal vein for a period up to 20 minutes. The lessened rate of bleeding allows the surgeon to visualize and ligate the injured vessels. 4. Whenever possible suturing liver tears should be avoided because it is likely to leave a space for accumulation of haematoma that may infect or communicate with intrahepatic bile ducts. It is, however, resorted to if control of bleeding vessels is not possible in deep tears. Tying sutures over pedicled omentum helps haemostasis. Deep transverse mattress sutures using special liver needles is recommended. 5. A haematoma is explored to ligate the damaged vessels and ducts, and to excise the dead tissues. It is then left open for drainage. 6. A lobe that is shattered beyond salvage is treated by excision of this lobe. 7. Firm packing of inaccessible and difficult bleeding areas, e.g., the hepatic veins, may be the only method for temporary arrest of bleeding. The patient is transferred to a specialized centre where the pack is removed in the operating theatre, and the injury is dealt with. 8. Multiple intraperitoneal drains are always placed to guard against collections of blood and bile. Prophylactic antibiotics are prescribed. Consequences 1. The main danger of such injuries is bleeding, and this should be the main concern of the surgeon. Most liver injuries stop bleeding by the time they are explored, but some of them cause death from blood loss. 2. A liver haematoma sometimes communicates with a torn bile duct allowing blood to trickle down the biliary passages to gastrointestinal tract producing what is known 'haematobilia', 5|Page Other complications of liver trauma Abscesses especially after penetrating trauma. Treatment is with systemic antibiotics and aspiration under ultrasound guidance once the necrotic tissue has liquefied. Bile collections require aspiration under ultrasound guidance or percutaneous insertion of a pigtail drain. The site of origin of a biliary fistula should be determined by endoscopic or percutaneous cholangiography, and biliary decompression achieved by nasobiliary or percutaneous transhepatic drainage or stent insertion. If this fails to control the fistula, the affected portion of the liver may require resection. Late vascular complications include hepatic artery aneurysm and arteriovenous (precipitating acute heart failure if between the hepatic artery and hepatic vein and acute portal hypertension if arterioportal) or arteriobiliary fistulae (resulting in often painful haemobilia). These are best treated nonsurgically by a specialist hepatobiliary interventional radiologist. The feeding vessel can be embolised transarterially. Hepatic failure may occur following extensive liver trauma. This will usually reverse with conservative supportive treatment if the blood supply and biliary drainage of the liver are intact. Long-term outcome of liver trauma The capacity of the liver to recover from extensive trauma is remarkable, and parenchymal regeneration occurs rapidly. Late complications are rare, but the development of biliary strictures many years after recovery from liver trauma has been reported. The treatment depends on the mode of presentation and the extent and site of stricturing. A segmental or lobar stricture, associated with atrophy of the corresponding area of liver parenchyma and compensatory hypertrophy of the other liver lobe, may be treated expectantly. A dominant extrahepatic bile duct stricture associated with obstructive jaundice may be treated initially with endobiliary balloon dilatation or stenting, but will usually require surgical correction using a Roux-en-Y hepatodochojejunostomy. Important points to remember regarding liver injuries Suspect liver injuries in patients with fractures of the right lower ribs. Minor liver injuries can be treated conservatively. Pringle's maneuver is useful for temporary control of hepatic bleeding during the operation. Perithepatic packing is very useful as a last resort to stop bleeding in serious hepatic injuries. 6|Page  Biliary injuries Aetiology Injuries to the gallbladder and extrahepatic biliary tree are rare. They occur as a result of blunt or penetrating abdominal trauma and occur mainly from penetrating trauma, often in association with injuries to other structures that lie in close proximity. The common bile duct can be repaired over a T-tube or drained and referred to appropriate care as part of damage control, or even ligated. Pathology Types of bile duct injuries include leaks, transection, occlusion (ligation or stricture), or a combination. The majority of bile duct injuries are iatrogenic, most commonly following laparoscopic cholecystectomy, with an incidence of 0.3– 2%. Clinical Findings Iatrogenic injury is perhaps more frequent than external trauma. The physical signs are those of an acute abdomen. Patients usually present with abdominal pain that may be diffused or localized. Nausea, anorexia, and abdominal distention due to ileus may also be seen. Clinically apparent ascites and bile peritonitis are less common. Fever is often absent. Investigations Laboratory evaluation typically reveals leukocytosis and nonspecific liver function test abnormalities. Initial imaging studies should involve abdominal ultrasound to assess for fluid collections or abnormalities in the biliary tree such as focal dilation, and radionuclide biliary scintigraphy to assess for ongoing leakage. Technetium-99m–labeled hepatoiminodiacetic acid derivative (HIDA) scanning is most accurate, approaching 100%. Treatment Management depends on the location and extent of the biliary and associated injury. In the stable patient a transected bile duct is best repaired by a Roux-en-Y choledochojejunostomy. 7|Page