WSES classification and guidelines for liver trauma
General Emergency and Trauma Surgery Department, Papa Giovanni XXIII
Hospital, Piazza OMS
WSES classification and guidelines for liver trauma
Federico Coccolini 0
Ernest E. Moore
Fikri M. Abu-Zidan
Marco Ceresoli 0
Giulia Montori 0
Frederick A. Moore
Luca Ansaloni 0
0 General Emergency and Trauma Surgery Department, Papa Giovanni XXIII Hospital , Piazza OMS 1, 24127 Bergamo , Italy
The severity of liver injuries has been universally classified according to the American Association for the Surgery of Trauma (AAST) grading scale. In determining the optimal treatment strategy, however, the haemodynamic status and associated injuries should be considered. Thus the management of liver trauma is ultimately based on the anatomy of the injury and the physiology of the patient. This paper presents the World Society of Emergency Surgery (WSES) classification of liver trauma and the management Guidelines.
Liver trauma; Minor; Moderate; Severe; Classification; Guidelines; Surgery; Hemorrage; Operative management; Non-operative management
The severity of liver injuries is universally classified
according to the American Association for the Surgery of
Trauma (AAST) grading scale (Table 1) . The
majority of patients admitted for liver injuries have grade I, II
or III and are successfully treated with nonoperative
management (NOM). In contrast, almost two-thirds of
grade IV or V injuries require laparotomy (operative
management, OM) . However in many cases there is
no correlation between AAST grade and patient
physiologic status. Moreover the management of liver trauma
has markedly changed through the last three decades
with a significant improvement in outcomes, especially
in blunt trauma, due to improvements in diagnostic and
therapeutic tools [3–5]. In determining the optimal
treatment strategy, the AAST classification should be
supplemented by hemodynamic status and associated
injuries. The anatomical description of liver lesions is
fundamental in the management algorithm but not
definitive. In fact, in clinical practice the decision whether
patients need to be managed operatively or undergo
NOM is based mainly on the clinical conditions and the
associated injuries, and less on the AAST liver injury
grade. Moreover, in some situations patients conditions
lead to an emergent transfer to the operating room (OR)
without the opportunity to define the grade of liver lesions
before the surgical exploration; thus confirming the
primary importance of the patient’s overall clinical condition.
Utimately, the management of trauma requires an
assessment of the anatomical injury and its physiologic effects.
This paper aims to present the World Society of
Emergency Surgery (WSES) classification of liver trauma and the
treatment Guidelines, following the WSES position paper
emerged from the Second WSES World Congress .
As stated in the position paper, WSES includes
surgeons from around the globe. This Classification and
Guidelines statement aims to direct the management of
liver trauma, acknowledging that there are acceptable
alternative management options. In reality, not all trauma
surgeons work in the same conditions and have the
same facilities and technologies available .
The discussion of the present guidelines started in 2011
during the WSES World Congress in Bergamo (Italy).
From that first discussion, through the Delphi process
came the published position paper . A group of
experts in the field coordinated by a central coordinator
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Table 1 AAST Liver Trauma Classification
Capsular tear <1 cm parenchymal depth
Haematoma Subcapsular 10–50 % surface area; intraprenchymal,
<10 cm diameter
1–3 cm parenchymal depth, <10 cm in length
Haematoma Subcapsular >50 % surface area or expanding,
ruptured subcapsular or parenchymal haematoma.
Intraprenchymal haematoma >10 cm
>3 cm parenchymal depth
Parenchymal disruption 25–75 % of hepatic lobe
Juxtavenous hepatic injuries i.e. retrohepatic vena
cava/centrl major hepatic veins
Advance one grade for multiple injuries up to grade III
AAST liver injury scale (1994 revision)
was contacted to express their evidence-based opinion
on several issues about the liver trauma management
differentiated into blunt and penetrating trauma and
evaluating the conservative and operative management
The central coordinator assembled the different
answers derived from the first round and drafted the first
version that was subsequently revised by each member
of the expert group separately in the second round. The
definitive version about which the agreement was
reached consisted in the position paper published in
In July 2013 the position paper was discussed during
the WSES World Congress in Jerusalem (Israel) and
then a subsequent round of consultation among a group
of experts evaluated the associated WSES classification
and the new evidence based improvements. Once
reached the agreement between the first experts group,
another round among a larger experts group lead to the
present form of the WSES classification and guidelines
of liver trauma to which all the experts agreed. Levels of
evidence have been evaluated in agreement with the
The WSES position paper suggested dividing hepatic
traumatic lesions into minor (grade I, II), moderate
(grade III) and major/severe (grade IV, V, VI) . This
classification has not previously been clearly defined by
the literature. Frequently low-grade AAST lesions (i.e.
grade I-III) are considered as minor or moderate and
treated with NOM [7, 8]. However some patients with
high-grade lesions (i.e. grade IV-V laceration with
parenchymal disruption involving more than 75 % of the
hepatic lobe or more than 3 Couinaud segments within a
single lobe) may be hemodynamically stable and
successfully treated nonoperatively . On the other
hand, “minor” lesions associated with hemodynamic
instability often must be treated with OM. This
demonstrates that the classification of liver injuries into minor
and major must consider not only the anatomic AAST
classification but more importantly, the hemodynamic
status and the associated injuries.
The Advanced Trauma Life Support (ATLS) definition
considers as “unstable” the patient with: blood pressure
<90 mmHg and heart rate >120 bpm, with evidence of
skin vasoconstriction (cool, clammy, decreased capillary
refill), altered level of consciousness and/or shortness of
The WSES Classification divides Hepatic Injuries into
– Minor (WSES grade I).
– Moderate (WSES grade II).
– Severe (WSES grade III and IV).
The classification considers either the AAST
classification either the hemodynamic status and the associated
lesions (Table 2).
Minor hepatic injuries:
Moderate hepatic injuries:
Severe hepatic injuries:
Basing on the present classification WSES indicates a
management algorithm explained in Fig. 1.
Recommendations for non operative management (NOM)
in blunt liver trauma (BLT)
Blunt trauma patients with hemodynamic stability
and absence of other internal injuries requiring
surgery, should undergo an initial attempt of
NOM irrespective of injury grade (GoR 2 A).
Table 2 WSES Liver Trauma Classification
(SW Stab Wound, GSW Gun Shot Wound; OM: Operative Management; NOM: Non Operative Management; *NOM should only be attempted in centers capable of
a precise diagnosis of the severity of liver injuries and capable of intensive management (close clinical observation and haemodynamic monitoring in a high
dependency/intensive care environment, including serial clinical examination and laboratory assay, with immediate access to diagnostics, interventional radiology and
surgery and immediately available access to blood and blood products; # wound exploration near the inferior costal margin should be avoided if not strictly necessary
because of the high risk to damage the intercostal vessels)
NOM is contraindicated in the setting of
hemodynamic instability or peritonitis (GoR 2 A).
NOM of moderate or severe liver injuries should be
considered only in an environment that provides
capability for patient intensive monitoring, angiography,
an immediately available OR and immediate access to
blood and blood product (GoR 2 A).
In patients being considered for NOM, CT-scan with
intravenous contrast should be performed to define the
anatomic liver injury and identify associated injuries
(GoR 2 A).
Angiography with embolization may be considered the
first-line intervention in patients with hemodynamic
stability and arterial blush on CT-scan (GoR 2 B).
Fig. 1 Liver Trauma Management Algorithm. (SW Stab Wound, GSW Gun Shot Wound; *NOM should only be attempted in centers capable of a
precise diagnosis of the severity of liver injuries and capable of intensive management (close clinical observation and haemodynamic monitoring
in a high dependency/intensive care environment, including serial clinical examination and laboratory assay, with immediate access to diagnostics,
interventional radiology and surgery and immediately available access to blood and blood products; # wound exploration near the inferior costal
margin should be avoided if not strictly necessary because of the high risk to damage the intercostal vessels; @ extremely selected patients
hemodynamically stable with evisceration and/or impalement and/or diffuse peritonitis with the certainty of an exclusive and isolated abdominal
lesion could be considered as candidate to be directly taken to the operating room without contrast enanched CT-scan)
In hemodynamically stable blunt trauma patients without
other associated injuries requiring OM, NOM is considered
the standard of care [10–12]. In case of hemodynamic
instability or peritonitis NOM is contraindicated [7, 11, 13].
The requirements to attempt NOM of moderate and
severe injuries are the capability to make a diagnosis of
the severity of liver injuries, and to provide intensive
management (continuous clinical monitoring, serial
hemoglobin monitoring, and around-the-clock
availability of CT-scan, angiography, OR, and blood and blood
products) [14–19]. No evidence exists at present to
define the optimal monitoring type and duration.
In patients with ongoing resuscitative needs, the
angioembolization is considered as an “extension” of
resuscitation. However with the aim to reduce the need for
transfusions and surgery, angioembolization can be
applied safely but generally only in selected centers [13, 20,
21]. If required it can be safely repeated. Positive results
associated with its early use have been published [22, 23].
In blunt hepatic trauma, particularly after high-grade
injury, complications occur in 12–14 % of patients [13, 24].
Diagnostic tools for complications after NOM include:
clinical examination, blood tests, ultrasound and CT-scan.
Although routine follow-up with CT-scan is not
necessary, [2, 13, 24] in the presence of abnormal inflammatory
response, abdominal pain, fever, jaundice or drop of
hemoglobin level, CT-scan is recommended .
Bleeding, abdominal compartment syndrome, infections
(abscesses and other infections), biliary complications (bile
leak, hemobilia, bilioma, biliary peritonitis, biliary fistula)
and liver necrosis are the most frequent complications
associated with NOM [14, 24]. Ultrasound is useful in the
assessment of bile leak/biloma in grade IV-V injuries,
especially with a central laceration.
Re-bleeding or secondary hemorrhage are frequent (as in
the rupture of a subcapsular hematoma or a
pseudoaneurysm) [13, 24]. In the majority of cases (69 %), “late”
bleeding can be treated non-operatively [13, 24].
Posttraumatic hepatic artery pseudo-aneurysms are rare and they
can usually be managed with selective embolization [6, 25].
Biliary complications can occur in 30 % of cases.
Endoscopic retrograde cholangio-pancreatography (ERCP) and
eventual stenting, percutaneous drainage and surgical
intervention (open or laparoscopic) are all effective ways
to manage biliary complications . In presence of
intrahepatic bilio-venous fistula (frequent associated
with bilemia) ERCP represents an effective tool .
CT-scan or ultrasound-guided drainage are both
effective in managing peri-hepatic abscesses (incidence 0–7 %)
[13, 22, 24]. In presence of necrosis and devascularization
of hepatic segments surgical management would be
indicated [6, 24]. Hemobilia is uncommon and frequently
associated with pseudo-aneurysm [2, 6, 24]. In hemodynamically
stable and non-septic patients embolization is safe and
could be considered as the first approach; otherwise surgical
management is mandatory [6, 24].
Lastly, the liver compartment syndrome is rare and has
been described in some case reports as a consequence of
large sub-capsular hematomas. Decompression by
percutaneous drainage or by laparoscopy has been described
No standard follow-up and monitoring protocol exist
to evaluate patients with NOM liver injuries . Serial
clinical evaluation and hemoglobin measurement are
considered the pillars in evaluating patients undergone
to NOM . Abdominal ultrasound could help in
managing non-operatively managed liver trauma patients.
NOM in penetrating liver trauma could be considered
only in case of hemodynamic stability and absence of:
peritonitis, significant free air, localized thickened
bowel wall, evisceration, impalement (GoR 2 A).
NOM in penetrating liver trauma should be
considered only in an environment that provides
capability for patient intensive monitoring, angiography,
an immediately available OR and immediate access to
blood and blood product (GoR 2 A).
CT-scan with intravenous contrast should be always
performed to identify penetrating liver injuries suitable
for NOM (GoR 2 A).
Serial clinical evaluations (physical exams and
laboratory testing) must be performed to detect a
change in clinical status during NOM (GoR 2 A).
Angioembolisation is to be considered in case of
arterial bleeding in a hemodynamic stable patient
without other indication for OM (GoR 2 A).
Severe head and spinal cord injuries should be
considered as relative indications for OM, given the
inability to reliably evaluate the clinical status (GoR 2A).
The most recent published trials demonstrate a high
success rate for NOM in 50 % of stab wounds (SW) in
the anterior abdomen and in about 85 % in the posterior
abdomen [6, 28]. The same concept has also been applied
to gunshot wounds (GSWs) [29, 30]. However, a
distinction should be made between low and high-energy
penetrating trauma in deciding either for OM or NOM. In
case of low energy, both SW and GSW, NOM can be
safely applied. High energy GSW and other ballistic
injuries are less amenable to NOM because of the high-energy
transfer, and in 90 % of cases an OM is required [6, 31,
32]. Of note, a 25 % non-therapeutic laparotomy rate is
reported in abdominal GSWs . This confirms that in
selective cases NOM could be pursued either in GSWs.
Clinical trials report a high success rate of NOM in
penetrating liver injuries (69 to 100 %) [29, 30, 32–37].
Absolute requirements for NOM are: hemodynamic
stability, absence of peritonitis, and an evaluable abdomen
. Evisceration and impalement are other indications
for OM [30, 32, 34]. Current guidelines suggest that
hemodynamically stable patients presenting with
evisceration and/or impalement and/or diffuse peritonitis should
be considered candidates to be directly taken to the OR
without CT-scan . These findings are particularly
important in cases of gunshot injuries. Other suggested
predictive criteria of NOM failure in abdominal GSWs
according to Navsaria et al. are: associated head and spinal
cord injuries (that preclude regular clinical examination)
and significant reduction in hemoglobin requiring more
than 2–4 units of blood transfusion in 24 h [6, 29].
In SWs the role of CT scan has been questioned [28, 34].
Local wound exploration (LWE) is considered accurate in
determining the depth of penetration; sometimes in little
wounds it would be necessary to enlarge a little the
incision [6, 30]. However, wound exploration near the inferior
costal margin should be avoided if not strictly necessary
because of the high risk to damage the intercostal vessels.
Emergency laparotomy has been reported to be necessary
even in some cases with negative CT-scan . CT-scan
may be necessary in obese patients and when the wound
tract is long, tangential and difficult to determine the
trajectory [6, 34].
In NOM of GSWs the CT-scan can help in
determining the trajectory. However not all authors consider it
mandatory [29, 31]. Velmahos et al. reported a CT-scan
specificity of 96 % and a sensitivity of 90.5 % for GSWs
requiring laparotomy . The gold standard to decide
for OM or NOM remains the serial clinical examination
NOM is contraindicated in case of CT-scan detection
of free intra- or retro-peritoneal air, free intra-peritoneal
fluid in the absence of solid organ injury, localized bowel
wall thickening, bullet tract close to hollow viscus with
surrounding hematoma  and in high energy
penetrating trauma. In NOM strict clinical and hemoglobin
evaluation should be done (every 4–6 h for at least
48 h); once stabilized the patient could be transferred to
the ward [28, 29, 34].
There is considerable variation in local CT-scan
imaging practices, and no uniform standard exists.
Variations are dependent on imaging hardware, radiation
exposure, contrast dose, and image sequences, among
other factors. For example, image acquisition may occur
in a triphasic fashion (non-contrast, arterial, and portal
venous phases), or as a single phase following a split
bolus contrast injection, providing a mixed arterial and
portal venous phase. These variables have not been
standardized across centers, or in the literature, and require
expert radiologist consideration and manipulation for
optimal diagnostic yield, and are dependent on the study
Even in penetrating liver trauma, the
angioembolization is considered as an “extension” of resuscitation in
those patients presenting with ongoing resuscitative
needs. However angioembolization can be applied safely
only in selected centers [13, 20, 21]. If required it can be
The main reluctance of surgeons to employ NOM in
penetrating trauma is related to the fear of missing other
abdominal lesions, especially hollow viscus perforation
[6, 33]. Published data clearly showed that in patients
without peritonitis on admission, no increase in
mortality rates with missed hollow viscus perforation has been
reported . On the other hand, non-therapeutic
laparotomy has been demonstrated to increase the
complication rate . Nevertheless OM in
penetrating liver injuries has a higher liver-related
complication rate (50–52 %) than in blunt ones [6, 33].
Concomitant severe head injuries
The otimal management of concomitant severe head
and liver injuries is debated. In patients with severe head
injuries hypotension may be deleterious, and OM could
be suggested as safer [24, 36]. Recently, a large cohort of
1106 non-operatively managed low-energy gunshot liver
injuries, has been published by Navsaria et al. . The
presence of concomitant liver and severe head injuries
has been considered one of the main exclusion criteria
to NOM. Authors stated that: “Hemodynamically stable
patients with unreliable clinical examinations (head and/
or high spinal cord injury) must also undergo an urgent
exploratory laparotomy”. Another paper analyzing 63
patients by Navsaria et al. suggested as predictive criteria
for NOM failure in abdominal low-energy GSWs is the
association with head and spinal cord injuries precluding
meaningful clinical examination .
Follow-up after successful NOM
Clear and definitive direction for post-injury follow-up
and normal activity resumption in those patients who
experienced NOM haven’t been published yet. General
recommendations are to resume usual activity after 3–4
months in patients with an uncomplicated hospital
course. This derives from the observation that the
majority of liver lesions heal in almost 4 months [10, 24]. If
the CT-scan follow-up (in grade III-V lesions) has shown
significant healing normal activity can be resumed even
after 1 month .
Patients should to be counseled not to remain alone
for long periods and to return to the hospital
immediately if they experience increasing abdominal pain,
lightheadedness, nausea or vomiting [6, 10].
Recommendations for operative management (OM) in
liver trauma (blunt and penetrating)
Patients should undergo OM in liver trauma (blunt
and penetrating) in case of hemodynamic instability,
concomitant internal organs injury requiring surgery,
evisceration, impalement (GoR 2 A).
Primary surgical intention should be to control the
hemorrhage, to control bile leak and to institute an
intensive resuscitation as soon as possible (GoR 2 B).
Major hepatic resections should be avoided at first,
and considered subsequently (delayed fashion) only in
case of large devitalized liver portions and in centers
with the necessary expertise (GoR 3 B).
Angioembolisation is a useful tool in case of persistent
arterial bleeding (GoR 2 A).
As exsanguination represents the leading cause of
death in liver injuries OM decision mainly depends on
hemodynamic status and associated injuries .
In those cases where no major bleeding are present at
the laparotomy, the bleeding may be controlled by
compression alone or with electrocautery, bipolar devices,
argon beam coagulation, topical hemostatic agents, or
omental packing [6, 8, 24, 40, 41].
In presence of major haemorrhage more aggressive
procedures can be necessary. These include first of all
hepatic manual compression and hepatic packing,
ligation of vessels in the wound, hepatic debridement,
balloon tamponade, shunting procedures, or hepatic
vascular isolation. It is important to provide concomitant
intraoperative intensive resuscitation aiming to reverse
the lethal triad [6, 8, 41].
Temporary abdominal closure can be safely considered
in all those patients when the risk of developing
abdominal compartment syndrome is high and when a second
look after patient’s hemodynamic stabilization is needed
[8, 40, 41].
Anatomic hepatic resection can be considered as a
surgical option [2, 42, 43]. In unstable patients and
during damage control surgery a non-anatomic resection is
safer and easier [6, 8, 24, 44]. For staged liver resection,
either anatomic either non-anatomic ones can be safely
made with stapling device in experienced hands .
If despite the fundamental initial maneuvers (hepatic
packing, Pringle maneuver) the bleeding persists and
evident lesion to a hepatic artery is found, an attempt to
control it should be made. If repair is not possible a
selective hepatic artery ligation can be considered as a
viable option. In case of right or common hepatic artery
ligation, cholecystectomy should be performed to avoid
gallbladder necrosis [44, 45]. Post-operative
angioembolization is a viable option, when possible, allowing
hemorrhage control while reducing the complications
[6, 8, 24, 46]. After artery ligation, in fact, the risk of
hepatic necrosis, biloma and abscesses increases .
Portal vein injuries should be repaired primarily. The
portal vein ligation should be avoided because liver
necrosis or massive bowel edema may occur. Liver Packing
and a second look or liver resection are preferable to
portal ligation [6, 44].
In those cases where Pringle maneuver or arterial
control fails, and the bleeding persists from behind the liver,
a retro-hepatic caval or hepatic vein injury could be
present [6, 46]. Three therapeutic options exist: 1)
tamponade with hepatic packing, 2) direct repair (with or
without vascular isolation), and 3) lobar resection .
Liver packing is the most successful method of managing
severe venous injuries [6, 24, 47–49]. Direct venous repair
is problematic in non-experienced hands, with a high
mortality rate [6, 24].
When hepatic vascular exclusion is necessary, different
types of shunting procedures have been described, most
of them anecdotally. The veno-veno bypass (femoral
vein to axillary or jugular vein by pass) or the use of
fenestrated stent grafts are the most frequent type of shunt
used by surgeons familiar with their use [8, 24, 44, 50].
The atrio-caval shunt bypasses the retro-hepatic cava blood
through the right atrium using a chest tube put into the
inferior cava vein. Mortality rates in such a complicated
situations are high . Liver exclusion is generally poorly
tolerated in the unstable patient with major blood loss .
In the emergency, in cases of liver avulsion or total
crush injury, when a total hepatic resection must be
done, hepatic transplantation has been described .
The exact role of post-operative angio-embolization is
still not well defined [51–55]. Two principal indications
have been proposed: 1) after primary operative hemostasis
in stable or stabilized patients, with an evidence at
contrast enhanced CT-scan of active bleeding, and 2)
as adjunctive hemostatic control in patients with
uncontrolled suspected arterial bleeding despite emergency
laparotomy [6, 56].
The management of trauma poses in definitive the
attention in treating also the physiology and decision can be
more effective when both anatomy of injury and its
physiological effects are combined.
AAST: American Association for Surgery for Trauma; ATLS: Advanced Trauma
Life Support; BLT: Blunt liver trauma; DCS: Damage Control Surgery;
ERCP: Endoscopic retrograde cholangio-pancreatography; GSW: Gunshot
wound; NOM: Non-Operative Management; OM: Operative Management;
OR: Operating Room; SW: Stab wounds; WSES: World Society of Emergency
FC, FaCa, EM, RI, WB, AP, RC, SR, YK, FM AZ, MC, GM, MS, DW, GF, NN, FAM,
NZ, LA, manuscript conception and draft critically revised the manuscript
and contribute with important scientific knowledge giving the final approval.
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