hepatic injury takes the third place in abdominal injury and 80%90% of hepatic injuries are blunt ones . in 2013 , a study using ultrasonography to evaluate the intraperitoneal trauma showed that liver was the mostly affected organ and younger people were more vulnerable to hepatic and pancreatic injury . in 1994 , american association for surgery of trauma ( aast ) proposed the standard classification of hepatic trauma . according to the classification , level i - ii hepatic trauma is called minor hepatic trauma , accounting for 80%90% of all hepatic trauma . the hepatic trauma of level iii and above is called serious hepatic trauma , with the mortality of 10% , and if patients have multiple injuries , the mortality may be elevated to as high as 25% . serious hepatic trauma is always combined with parahepatic vena cava injury , with the mortality of above 50% . the clinical experience shows that early diagnosis , accurate assessment , active resistance to shock , optimal treatment plan and the organ function preservation are protective factors to reduce the mortality and enhance the treatment . patients have some typical clinical manifestations such as right upper abdominal pain ( sometimes with radiating pain to the right shoulder ) , nausea and vomiting , thirst , peritonitis , and hypovolemic shock . abdominal ultrasound can quickly assess intra - abdominal hemorrhage , suitable for hemodynamically instable patients , but limited by weak sensitivity and a high rate of misdiagnosis . therefore , abdominal ultrasound is usually used for the patients who could not tolerate ct scanning . ct is the most commonly used method for the diagnosis of intra - abdominal solid organ injury . for small occult liver damage , enhanced enhanced ct combined with ultrasound is regarded as the most valuable method to evaluate abdominal trauma.9 , 10 thanks for the development of modern imaging techniques , ct scanning can provide adequate information for definite diagnosis of liver injury or intra - abdominal hemorrhage.11 , 12 the most difficult and important aspect is the preliminary evaluation and early rescue . for hemodynamically instable patients , we should promptly determine the order of severity of hepatic trauma , and proceed with timely exploratory laparotomy and treatment . in the past , most scholars thought that non - operative therapy was only appropriate for level i - ii liver traumas , which were hemodynamically stable without signs of peritoneal irritation or other organ injuries . a study showed that non - operative therapy is effective for isolated liver trauma . with the development of conservative treatment in medical field , asfar et  al revealed that about 80% of blunt hepatic injuries can be treated by non - operative therapy , especially the hemodynamically stable patients . in china , non - operative strategy is widely used in clinic , especially for minor blunt hepatic trauma and liver capsule bleeding . the reasons for this change lie in the following aspects : ( 1 ) in about half of blunt liver trauma patients , the bleeding has been stopped before exploratory laparotomy ; ( 2 ) liver has the great capability of auto - hemostasis after injury ; ( 3 ) ct has been improved and minimally invasive surgery has been developed ; ( 4 ) medical treatment in intensive care unit is given . the study of about 40  000 liver injured patients from 405 trauma centers showed that the probability of operative therapy for successfully treated complicated liver trauma is lower than 40% , regardless of whether or not other organs are injured . this data indicated that non - operative therapy for complicated liver trauma is more successful than operative therapy , and the success rate of non - operative therapy is increasing . in cases of serious liver trauma ( levels iii and iv ) , non - operative therapy reduced the mortality to 23.5% . based on clinical experience , a substantial amount of evidences suggest that non - operative therapy has a great curative effect . norrman et  al reported that the curative ratio for non - operative therapy was 89% . besides the adults , non - operative therapy also presents beneficial outcome for children . for perforating liver injury , operation is the first choice ; for multiple organ injury , exploratory laparotomy could find the occult trauma . for blunt trauma patients who are hemodynamically stable , non - operative therapy could be adopted , with monitoring vital signs . in the absence of complicating factors , abdominal laparotomy is not dependent on the severity of hepatic trauma , as the success rate of non - operative therapy is 90% . for hepatic trauma patients , the doctors should pay close attention to the hemodynamic status . hemodynamic stability is the basis of non - operative therapy , i.e. , non - operative therapy depends upon the premise that the patients have no other injured organs , especially no intestinal damage . the monitoring system , angiography and endoscopic retrograde cholangiography are very important for hepatic trauma patients . doctors should be experienced in order to closely observe the patients and prepare for emergent operation in time . in the early stage , the doctors should accurately judge the severity of injury , monitor the patients ' vital signs and ensure hemodynamic changes timely . moreover , symptomatic treatment , nutritional support , and the maintenance of the patient 's water and electrolyte balance are necessary to promote the healing of viscus organs , meanwhile the doctors should also pay attention to the protection of viscus function . in china , it is believed that non - operative therapy applied for level iii hepatic trauma should be very prudent . due to a lack of advanced medical techniques , most primary hospitals do not have adequate monitoring capacity , good icu guardianship or liver specialists in medical team , and follow - up treatment options , especially after non - operative therapy fails . therefore , for liver trauma , especially for serious and complicated liver trauma , surgeons should select the optimal treatment method according to the patient 's condition and the medical conditions of the hospital and in the end , if possible , they should broaden the indication criteria for operative therapy as required . if the patients are hemodynamic unstable , they should be operated upon promptly . for perforating liver wounds , operative therapy is the first choice , and for multiple organ damage , exploratory laparotomy can locate and repair occult trauma . for blunt trauma patients , who are hemodynamic stable , non - operative therapy may be suitable , with close monitoring and appropriate preparation for operation . the aim of operation is to ascertain the traumatic condition , stop any bleeding , prevent bile leakage , remove the devitalized tissues and give adequate drainage . for the patients who need surgical treatment , mors in tabula  or during the first 24  h after injury and 6.9% of deaths occurred during the hospitalization . if the patients have absolute surgical indications , the surgery should be performed as soon as possible . stopping bleeding is the key to treat hepatic trauma because it can influence the mortality of the hepatic trauma patients . in addition , thorough debridement and adequate drainage could reduce the decomposition products of necrotic tissue and prevent the formation of abdominal abscesses . surgeons should choose the most appropriate scheme according the result of surgical exploration and the wound condition . operation methods include single pure suture , deep mattress suture , debridement , anatomical hepatectomy , hepatic arterial ligation , gauze packing , liver coated mesh method , etc . damage control is the principle for operative treatment since it may save time , which is beneficial for those patients transferred to other trauma centers , or requiring further treatment . deep mattress suture is appropriate for contusion and laceration of the liver in which the cleft is deep , including the placement of hemostatic gauze and omentum majus into the liver tissue defect . this is suitable for level iii injury , and even some cases of level iv injury . debridement should be performed based on the anatomical structure of the liver , in order to completely remove any necrotic tissues , ligature the damaged vessels and bile ducts , and retain the normal liver tissue to the greatest extent . this is routinely performed because debridement is focused upon the injured part of the liver , unlike anatomical hepatectomy . the anatomical hepatectomy requires excellent technical skill and a prolonged operation time , and is thus rarely used clinically . the peripheral hepatic gauze is effective to control bleeding for level iii liver trauma , even for levels iv and v liver trauma . nicol et  al found that the increased tamponade time was not associated with increased the morbidity of complications such as sepsis and bile leakage . the secondary operation should be performed 48  h after the condition becomes stable and the hypotension , hypothermia , acidosis and blood coagulation disorders should be corrected . in addition , surgeons should pay attention to excessive filling of the vena cava or renal vein caused by tamponade , which may lead to abdominal compartment syndrome . the filling parts could get effective drainage in order to reduce the risk of infection . mesh wrapping is to use absorbable synthetic mesh to pack the damaged area of the liver or the entire organ , to achieve hemostasis by compression . this method is suitable for extensive damage to the liver parenchyma or star - shaped liver laceration , which has vitality and is connected with hepatic pedicle . normally continuous hemorrhage results from the rupture of liver parenchyma or the damage of major blood vessels . to treat serious hepatic trauma such as levels iii and iv injuries if the patients present no hemodynamic instability , acidosis or blood coagulation disorders , stage i operation is advisable . during the operation , surgeons should expose operation vision quickly and achieve hemostasis , and the key to treat the complicated liver trauma is to control hemorrhage . when the surgeon is unable to find the exact origin of bleeding , he should avoid suturing hemostasis or hepatic lobectomy blindly . if the tip is still bleeding , it suggests that the bleeding comes from the main hepatic vein or inferior vena cave . these liver traumas are very intractable and the mortality is very high . in theory , surgeons could dissociate and control the inferior vena cave and repair the venous directly , but in fact it is very difficult to get enough time to dissociate the blood vessel . therefore , it is advisable to control bleeding with gauze and stabilize the conditions for the secondary phase of treatment . in recent years , surgeons have developed new surgical methods to treat hepatic trauma , such as laparoscopic exploration , hepatic artery embolization and liver transplantation . the laparoscopic exploration is widely used for hepatic trauma patients , with advantages of damage control , clear vision , simple operation and high safety . with the development of interventional surgery , hepatic artery embolization is found to be an effective way to treat hepatic trauma patients , both adults and children , regardless of hemodynamic stability.26 , 27 , 28 some surgeons used transarterial microchip embolization to treat children who suffered from liver artery injury , and obtained beneficial results . transcutaneous contrast - enhanced ultrasound - guided injection of hemostatic agents was compared with traditional surgery treatment for liver , spleen and kidney trauma , presenting better outcomes . for the patients with large - area comminuted liver damage and some cases of levels iii and iv hepatic trauma , liver transplant is their last resort , however , because of the lack of liver source for transplantation and high cost , it has not been widely applied . in 1983 , stone et  al proposed a theory of damage control surgery . in 1993 , rotendo et  al formalized the concept and the treatment specification of damage control surgery . operative treatment may bring damages to patients , if combined with primary trauma , it may lead to a double - attack . the focus of damage control surgery is the reduction of the adverse impact on patients . at present , damage control surgery is widely recognized , but it has strict indications : firstly , surgeons should act according to the traumatic condition of patients ; secondly , the patients with serious combined injuries are preferred ; thirdly , the patients present with hemodynamic instability , clotting disorders and low temperature . the most important purpose of damage control surgery is to rapidly control the hemorrhage , shorten operation time and avoid complex surgery . before effective resuscitation , the surgeons should repair liver vasculature to avoid the risk of low blood pressure , acidosis and clotting disorders . for a large area of comminuted liver rupture with uncontrollable bleeding , surgeons should stop the bleeding by stuffing gauzes around the liver and clear necrotic tissues as soon as possible . after hypothermia , acidosis and blood coagulation a majority of scholars , both in china and abroad , believe that the second phase of surgery should be 3672  h after the patient becomes medically stable.10 , 34 concurrently , surgeons should be aware that this procedure may bring high risk of complications such as wound infection , abdominal abscess , wound dehiscence , even abdominal compartment syndrome . due to severe hepatic trauma caused by extensive damage to the liver tissues , ischemic necrosis may cause a few complications such as bleeding , biliary fistula , abdominal abscess cyst formation . the drainage is necessary in such cases , i.e. , the surgeons routinely set double tubes around the liver section and under the diaphragm area . after operation , sustained low pressure suction for 48  h is suggested , together with washing if necessary , to guarantee unobstructed drainage and prevent postoperative wound infection . if the patient suffers from late - onset bleeding with hemodynamic stability , vascular embolization should be performed to pinpoint the vascular damage and embolize the artery . postoperative cholestasis or peripheral hepatic abscess can be treated by percutaneous puncture drainage , either under the ultrasound or ct - guided . the patients with large cysts usually have clinical manifestations including right upper distension , dull pain , fever and increased bilirubin level , but wbc count shows no obvious change . biliary fistula can be treated by endoscopic retrograde cholangiopancreatography and endoscopic sphincterotomy , achieving satisfactory results . batur et  al reported a possibility of hepatic artery pseudoaneurysm , which should be paid attention to in clinic . at present , hepatic trauma is mainly managed by non - operative therapy in clinic . serious hepatic trauma patients whose effective liquid recovery is still accompanied by hemodynamic instability require surgical intervention . the basic principle of operation is to control the trauma and choose the optimal operative method according to the general condition informed by surgical exploration . meanwhile , surgeons ' experiences and technical skill have great influence on the prognosis of the patients .
liver is one of the organs with the highest injury rate , and in recent decades , the guidelines for the treatment of liver trauma have changed considerably . now , there is a growing consensus that the most important step is diagnosis and depending upon the degree of severity , non - operative therapy is the main treatment method for hepatic trauma if conditions permit . for serious hepatic trauma patients such as those with hemodynamic instability 
 , they should be operated upon as soon as possible . 
 regardless of the surgical options , doctors should control damage to patients and try to prevent complications . 
 new therapies such as hepatic artery embolization and liver transplantation have been more and more used for the treatment of serious hepatic damage in clinics .