Traumatic Retroperitoneal Hematoma Spreads Through the Interfascial Planes J Trauma. 2005;59:595– 608.

1. Traumatic Retroperitoneal
Hematoma Spreads Through the
Interfascial Planes
Volume 59(3), September 2005, pp 595-608

2. BACKGROUND
• In the early 1980s, Sheldon
introduced a treatment principle
founded on a location-based
classification of traumatic RH as
1. Central-medial (zone I) RH
2. Flank or perirenal (zone II) RH
3. Pelvic (zone III) RH
• Feliciano established
management strategies for
various kinds of traumatic RH by
sub-dividing the zones and by
focusing on vascular injuries

3. 1. Central-medial (zone I) RH
2. Flank or perirenal (zone II) RH
3. Pelvic (zone III) RH

4. • Traditionally, the retroperitoneal
space was believed to comprise
only 3 compartments:
1. Anterior pararenal space (APS)
2. Perirenal space (PRS)
3. Posterior pararenal space (PPS)
which are demarcated by 3 well-
defined fascias:
1. Anterior renal fascia
2. Posterior renal fascia
3. Lateroconal fascia

5. Traditional tricompartmental theory New concept of interfascial planes
anterior renal fascia
posterior renal fascia
lateroconal fascia
retromesenteric plane
retrorenal plane
lateroconal plane
1. anterior pararenal space (APS)
2. perirenal space (PRS)
3. posterior pararenal space (PPS)

6. retrorenal plane
retromesenteric plane
combined
interfascial
plane
Traditional tricompartmental theory New concept of interfascial planes

7. Spread of renal lesion by means of
perinephric bridging septa and
interfascial planes

8. Track of Perinephric Hematoma
An 80-year-old man suffered renal injury from a motorcycle
crash. Midlevel of a left renal CT scan shows extension
of the perinephric hematoma along the perinephric
bridging septa (dotted arrow), RMP (open arrow), and
RRP (open arrowhead).
Note that RH within the RMP
traverses the midline, anterior to
the aorta and inferior vena cava,
and that RH extends into the
LCP (closed arrowhead) by
means of the fascial trifurcation
(FT) (thin arrow). Perinephric
bridging septa provide the
conduit between the kidney and
interfascial planes.
This is considered Zone I +
Zone II RH and Type II-a RH.

9. PATIENTS AND METHODS
• Between January 1997 and December
2003, 594 trauma patients required
abdominal or pelvic CT scans for
evaluation of abdominal or pelvic
injury within 24 hours after admission
to Osaka Prefectural Senshu Critical
Care Medical Center, a Level I trauma
center in Japan.
• RH was diagnosed when a high-
attenuation (>30 hounsfield units)
retroperitoneal lesion was identified
on two or more consecutive CT
images. According to this criterion,
169 (28.5%) of the 594 patients had
traumatic RH.

10. Assessment of RH on CT Images
10 component parts of the
retroperitoneal space were identified:
• 3 compartments (APS, PRS, and PPS),
• 4 interfascial planes comprise
1. Retromesenteric plane (RMP)
2. Retrorenal plane (RRP)
3. Lateroconal plane (LCP)
4. Combined interfascial plane (CIP),
providing a route for the spread of
disease from the abdominal
retroperitoneum into the pelvis.
• 3 other extraperitoneal spaces are
1. Retrohepatic space (rhe)
2. Prevesical space (PV)
3. Presacral space (PS)

11. Massive RH Resulting from Renal Injury
A 53-year-old man suffered renal injury from an
industrial accident. (A) Midlevel of the left renal CT
scan reveals an enormous perinephric hematoma
displacing the left kidney, spreading into the RRP
(open arrowhead) and RMP (open arrow) by means
of the bridging septa (dotted arrows).
RH within the RMP spread
across the midline. RH with
a total volume of 2,248 mL
can be clearly subdivided in
to the PRS RMP, RRP, and
LCP (closed arrowhead)
components with
intermediate adipose
tissues. K, kidney.

12. CT scan at the level of the upper pole of the left kidney
shows RH extension into the RRP (open arrowhead) by
means of bridging septa (dotted arrow) behind the left
kidney. Sp, spleen. (C) Below the promontory, RH
extended into the retroperitoneum of the lesser pelvis and
presacral space (PS) by means of the CIP (hatched
arrowhead). Note that RH in the presacral space is clearly
distinguished from hemoperitoneum (HP) in the Douglas
pouch.

13. Delayed scans at the level of the lower pole of the left
kidney and at a slightly lower level reveal thickened
perinephric bridging septa (dotted arrow) and the
expanded RMP (open arrow) and RRP (open
arrowhead) stained with contrast medium. Note that
RRP lies apposed to the psoas muscle. This is
considered Zone I + Zone II + Zone III RH and Type
II-b RH.

14. RESULTS
• The study population included
169 patients with traumatic RH:
• One or more injuries of
retroperitoneal organs or major
vessels were immediately
identified in 70 patients (38.7%):
renal injury (n = 52), adrenal
injury (n = 12), pancreatic or
duodenal injury (n = 7), liver
injury in the bare area (n = 5),
and vascular injury (n = 9). In 86
patients (50.9%), RH was
attributed to pelvic fracture.

15. • There was a high incidence of
intraperitoneal organ injury to the
liver (n = 42), spleen (n = 20), or
intestine (n = 12). Head or facial injury
(n = 80), chest injury (n = 88), and
fracture of the extremities (n = 101)
were common associated injuries.
• Shock was present in 112 (66.3%)
patients at admission. Because of
multiple injuries, the mean Injury
Severity Score was 29.8 ± 14.5, much
higher than the score (18.6 ± 15.6) of
all trauma patients admitted to our
institute during the same period.

16. • 51 patients (30.2%) were treated
nonoperatively, most of whom
underwent transfusion.
• 61 patients (36.1%) were treated by
emergent laparotomy, and 26 (15.4%)
of these underwent retroperitoneal
exploration.
• 51 patients (30.2%) underwent TAE,
C-clamp, or external fixation of the
pelvic ring without laparotomy.
• 6 patients died before aggressive
treatment could be undertaken.

17. • There were 39 deaths among the 169
patients, yielding an overall mortality
rate of 23.1%; the overall mortality rate
of contemporary traumatic patients was
only 10.9% in our institute.
• In 27 study patients (16.0%),
uncontrolled hemorrhage from multiple
locations, including RH, was the major
cause of death.
• 4 died as a result of exsanguination
apart from RH and 5 died as a result of
severe head injury. The remaining 3
patients died as a result of complicated
multiple organ dysfunction 40.0 ± 16.5
days after admission.

18. Distribution of total volume of RH
and mortality rate by volume

20. • RH volume, need for surgical exploration,
and patient mortality were significantly
higher in the broadly defined Zone I RH
patients (patients with RH in Zone I, in
Zone I + Zone II , and Zone I + Zone II +
Zone III than in any other group of
patients, reconfirming the importance of
the conventional Zone I RH classification.
• However, of the 73 patients with broadly
defined Zone I RH, 40 (54.8%) did not
undergo laparotomy and 17 (23.3%)
survived with only conservative
treatment.
• Major vascular injuries were identified in
only 6 of the 73 patients.

21. Our interpretation of the relation between the PPS and
the RRP it is neither the PPS nor the PRS but the RRP
that lies immediately adjacent to the psoas muscle or
QLM.

22. Extent of RRP identified with CT scanning.
(A) A 41-year-old woman was shot in the
abdomen. CT scan shows that the RRP
(open arrowhead) seems to terminate at
the lateral edge of the QLM and divides
the PPS from the PRS. Note gases in the
PRS caused by the gunshot injury. This is
considered Zone II RH and Type II-a RH.
Open arrow, RMP; closed arrowhead, LCP;
thin arrow, fascial trifurcation.
(B) A 35-year-old
man suffered renal
injury from a motor
vehicle crash. CT
scan shows that
the RRP seems to
terminate at the
lateral face of the
psoas muscle.
This is considered
Zone I + Zone II
RH and Type II-a
RH.

23. Percentage distribution
of RH and partial volume
of RH by component.
• The largest volume
(61 ± 96 mL) and
percentage
distribution (66.1%)
occurred in the CIP.
• RH in interfascial
planes accounted for
78.1% of the total RH
volume.

24. Extension of RH from
pancreatic injury. A 45-year-
old man was kicked in the
abdomen. (A) CT scan
obtained at level of the
pancreatic uncinate process
shows a large hematoma
with extravasation from the
pancreaticoduodenal artery
(hatched arrow) pressing on
the inferior vena cava. Du,
duodenum; P, pancreas. (B)
CT scan obtained below the
kidney shows RH spreading
along either side of the RMP
(open arrow). This is
considered Zone I + Zone II
RH and Type I-a RH.

25. Extension of RH from pelvic fracture.
A 63-year-old man was hit by a
dump truck. (A) CT scan at level of
the anterior superior iliac spine
shows pelvic fracture and RH in the
PV and CIP (hatched arrowhead).

26. (B and C) RH ascended within the CIP
(hatched arrowhead) near the left kidney.
This is considered Zone II + Zone III RH and
Type III-b RH.

27. • In patients with great vessel
injuries, because the artery or
inferior vena cava is located in
the RRP or CIP, bleeding in the
planes spread uninhibitedly
upward and downward within
interfascial planes.

29. Extension of RH from aortic injury. A 68-year-old man
was involved in a motor vehicle collision. (A) CT
scan at level of the fourth lumbar vertebra shows
aortic injury with an enormous RH and massive
extravasation of contrast medium (short arrows).
RH within the CIP (hatched arrowhead) extends
into the LCP (closed arrowhead) and contralateral
CIP. (B) CT scan at the level of the right renal hilus
shows ascending extension of RH into the RRP
(open arrowhead), RMP (open arrow), and PRS by
means of bridging septa in retrograde fashion. (C)
CT scan at the level of the acetabulum shows RH
extension into the presacral space. HP,
hemoperitoneum. Note that this 1,508-mL RH is
confined to interfascial planes and the PRS. The
abdominal aorta was repaired, but the patient died
as a result of multiple hemorrahages complicated
with coagulopathy. This is considered Zone I +
Zone II + Zone III RH and Type IV-b RH.

30. Extension of RH from lumbar artery injury. A
62-year-old man fell from a height of 8 m.
(A) Midlevel right renal CT scan shows
massive RH in the RMP (open arrow), LCP
(closed arrowhead), and RRP (open
arrowhead) surrounding the right kidney.
There is neither perirenal hematoma nor
thickened perirenal bridging septa. (B) CT
scan at the level of the third lumbar
vertebra shows continuity of the massive
RH (1,356 mL). Note extravasations from
both sides of the lumbar arteries (short
arrows) that were misidentified as fractures
in the transverse process of the lumbar
vertebra. Emergent laparotomy with
retroperitoneal exploration revealed that
bleeding was derived from a psoas injury.
Despite bilateral TAE for the third and
fourth lumbar arteries, he died as a result
of uncontrollable hemorrhage from multiple
areas complicated with coagulopathy. Note
hematoma escaping from the lateral edge
of the QLM. (checkmark sign, curved
dotted arrows). This is considered Zone I +
Zone II + Zone III RH and Type IV-b RH with
checkmark sign. (C) Schematic diagrams of
the checkmark sign. Hematoma intrudes
into another potential space among the
PPS, QLM, and transversalis fascia,
forming the checkmark sign (curved dotted
arrow).

31. Extension of RH from inferior vena cava
injury. A 14-year-old boy was
involved in a motorcycle crash. CT
scan at the midlevel of the left
kidney shows an enormous RH
(1,484 mL) with massive
extravasation from the inferior vena
cava (short arrows) and right renal
laceration. Extravasion from the
inferior vena cava intruded directly
into the RMP (open arrow) and RRP
(open arrowhead) and spreading
into the LCP (closed arrowhead),
whereas RH in the PRS seemed to
derive from the renal laceration. The
checkmark sign is also visible
(curved dotted arrow). He died as a
result of massive hemorrhage
complicated with coagulopathy
during retroperitoneal exploration.
This is also considered Zone I +
Zone II + Zone III RH and Type IV-b
RH with the checkmark sign.

32. New Classification of RH
• Each RH was first classified by the
component where bleeding originated:
– Type I derived from the APS or RMP
– Type II from the PRS, LCP, Rhe, or PPS
above the pelvis
– Type III from the pelvis
– Type IV from the RRP or CIP
• Each type was subdivided according to
the degree of extension into subtype
– “a” if the RH never exceeded the
promontory or
– “b” if the RH spread beyond the
promontory.

34. • Ten of 13 patients with Type I RH
underwent surgical repair of an
injured organ or vessels.
• Renal or adrenal injury consisted
mostly of Type II RH, which occurred
in 43 of 51 patients. Most of these 43
patients were treated conservatively.
It is noteworthy that 4 of these
patients underwent TAE into the
adrenal artery or capsular artery and 7
underwent nephrectomy, which in
retrospect was considered
unnecessary in 3 patients, and was
ineffective in 3 other patients with
renal vein injury.

35. • No patient with Type III RH underwent laparotomy
with retroperitoneal exploration for hemostasis,
but TAE, C-clamp, or external fixation was often
applied.
• Unfortunately, we could not save many patients
with Type IV RH. This type of RH, which resulted
not only from great vessel injuries but also from
psoas injury, had an unexpectedly high mortality
rate (62.1%) despite aggressive therapy, including
retroperitoneal exploration in 8 patients and TAE
in 12. In particular, the checkmark sign, indicated
an extremely poor prognosis. Patients with Type
IV-b had the highest mortality rate; 13 of the 15
patients with the checkmark sign and and only 2 of
the 12 without the checkmark sign died as a result
of uncontrollable hemorrhage. Of the 12 patients
with other types of RH who died as a result of
uncontrollable hemorrhage, 6 manifested a clear
checkmark sign.

37. DISCUSSION
• RH was identified in interfascial
planes in most cases in this study
(88.8%) and the partial volume of RH
in interfascial planes accounted for
78.1% of the total volume. It is no
exaggeration to say that interfascial
planes are the base and center of RH.
• We suspected that the tri-
compartmental theory was
inappropriate for classification of
traumatic RH because it was
impossible to assign the major part of
the RH located within interfascial
planes, as shown in this study, to any
of the three compartments.

38. This Classification Also Indicated
The Appropriate Treatment Policy
1. Type I RH requires emergent
retroperitoneal exploration, which
also affords a good prognosis.
2. Type II RH is treatable with
conservative therapy unless renal
vein injury is complicated.
3. Type III RH requires TAE, C-clamp,
or external fixation but no
laparotomy for RH hemostasis.
4. Treatment of Type IV RH is still
challenging and requires further
investigation.

39. • Traditional RH management
strategies have recommended that all
Zone I hematomas discovered at
laparotomy should be explored
because of the high possibility of
major vascular or visceral injury.
• In this study, RH involving the Zone I
area required retroperitoneal
exploration more frequently (30.1%)
and had a higher rate (27.4%) of
mortality caused by uncontrollable
hemorrhage in comparison with RH
that did not invade Zone I, reaffirming
the value of conventional strategies.

40. • Exploration of all Zone I RH is not
always necessary, and indication for
exploration is assessed by
determining the bleeding source and
extension by means of interfascial
planes, as we did.
• Type I RH, derived from the APS or
the RMP, should always be explored
because of the high possibility of
major vascular or visceral injury.

41. • We detected 113 RHs intruding into
the broadly defined Zone II area. The
original bleeding derived from renal or
adrenal injury in only 43 (38.1%) of
113 cases and from flank injury in 3
cases (1.8%) because RH in the PRS;
LCP; PPS; or the lateral part of the
RMP, PPR, or CIP was considered
Zone II RH. Hemorrhage from the PRS,
LCP, Rhe, or suprapelvic PPS should
be considered Type II RH.

42. • Among the 43 cases of RH derived
from the PRS, only 4 required
effective retroperitoneal exploration
for hemostasis. 3 patients died
because of renal vein injury, with
extravasation clearly apparent on CT
scans. This low mortality rate
supports use of the conservative
treatment advocated in conventional
strategies.

43. • Type III RH corresponds to
conventional broadly defined Zone III
RH, usually requiring no
retroperitoneal exploration.
• The fact that the source of pelvic
bleeding has been identified as
predominantly a bone or vein in the
PPS serves as the basis for a recent
strategy for initial management of
unstable pelvic fracture, prioritizing
pelvic bony stability with a C-clamp or
external fixation over TAE.

44. • Type III-b RH ascended beyond the
promontory by means of the CIP and
sometimes spread all the way up to the
diaphragm. In such patients, the
bleeding source could be located in the
CIP in the pelvis; thus, angiography and
TAE should be performed along with
pelvic stabilization with a C-clamp or
external fixation because external
fixation cannot generate enough
pressure to stop arterial bleeding.
Gauze packing is often performed in the
PS or PV, a part of interfascial planes,
suggesting that pelvic packing can
serve to tampon interfascial planes.

45. • Because of the high mortality rate, we
have distinguished Type IV RH,
bleeding from the RRP or CIP, from
broadly defined Zone I RH. The RRP and
CIP contain great vessels and lie just
above the psoas muscles.
• Vessel injuries or psoas disruption
could induce direct bleeding into
interfascial planes without interference
from the compartments, which are
expected to have a tamponade effect in
other types of RH, and the hemorrhage
could spread rapidly throughout the
expansile interfascial planes, leading to
a high likelihood of mortality.

46. • If extravasations from great vessels
are detected in contrast-enhanced CT
scanning, the patient must undergo
emergent laparotomy and
retroperitoneal exploration.
• Angiography and TAE have recently
been shown to be safe and effective
modalities for evaluating and
controlling lumbar artery hemorrhage.
• In our study, many patients with
psoas injury died as a result of
exsanguination after apparent
coagulopathy despite aggressive
application of TAE.

47. • The checkmark sign was
frequently detected among
nonsurvivors.
• The checkmark sign must be
considered a predictor of
uncontrollable massive RH.

48. CONCLUSION
• The major portion of RH exists within
the interfascial planes, not in the three
compartments, and that RH extends
by means of interfascial planes and
bridging.
• We formulated an RH management
strategy by classifying RH into four
types according to the original
location and the extension.
• Type IV-b RH with the checkmark sign
have the worst prognosis.

49. DISCUSSION
Dr. Felix D. Battistella:
Do your findings,
which are based on
CT scan
appearance of
retroperitoneal
hematoma, alter
current treatment
recommendations
for retroperitoneal
hematomas
discovered during
laparotomy?
Dr. Kazuo Ishikawa
Our findings do not
change the treatment
strategies of Dr.
Sheldon and Dr.
Feliciano. In fact, we
treat patients with
retroperitoneal
hematoma according
to their principles.
We must determine
the real bleeding
source, by means of
the concept of
interfascial planes,
to exactly apply their
strategies.