MA. JELLALI*, N. EZZAAIRI, S. EZZINE, A.ZRIG, W. MNARI, M. MAATOUK, W. HARZALLAH, R. SALEM, M....
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MA. JELLALI*, N. EZZAAIRI, S. EZZINE, A.ZRIG, W. MNARI, M. MAATOUK, W. HARZALLAH, R. SALEM, M. Toffahi, H.SAAD, M. GOLLI. CT FINDINGS IN BLUNT RENAL TRAUMA: A STUDY ABOUT 66 CASES Radiology service, FB Hospital, Rue 1st June, 5000 Monastir, Tunisia. UR13
MA. JELLALI*, N. EZZAAIRI, S. EZZINE, A.ZRIG, W. MNARI, M. MAATOUK, W. HARZALLAH, R. SALEM, M. Toffahi, H.SAAD, M. GOLLI. CT FINDINGS IN BLUNT RENAL TRAUMA:
MA. JELLALI*, N. EZZAAIRI, S. EZZINE, A.ZRIG, W. MNARI, M.
MAATOUK, W. HARZALLAH, R. SALEM, M. Toffahi, H.SAAD, M. GOLLI. CT
FINDINGS IN BLUNT RENAL TRAUMA: A STUDY ABOUT 66 CASES Radiology
service, FB Hospital, Rue 1st June, 5000 Monastir, Tunisia.
UR13
Slide 2
INTRODUCTION : Blunt trauma of the kidney remains a hot topic
because of its high frequency. Renal injury is observed in about
10% of cases of abdominal injury. However, the majority (80%90%) of
renal injuries are attributable to blunt trauma, while the rest are
due to penetrating renal injuries. Both kidneys are at equal
disposition for injury.
Slide 3
Renal injuries from blunt trauma usually occur as a consequence
of a direct blow to the flank or from rapid deceleration. A direct
blow crushes the kidney, causing a laceration or lacerations of the
renal parenchyma and resulting in a subcapsular, intrarenal or
perinephric haematoma. A deceleration injury causes an acute
tension on the renal pedicle, resulting in the laceration of the
renal vein or artery, an intimal tear in the vessel causing
thrombosis or laceration, or an avulsion of the ureteropelvic
junction (UPJ).
Slide 4
All subsets of renal trauma require a high index of clinical
awareness and prompt evaluation and management. With the
advancement in radiologic imaging modalities and the ready
availability of computed tomography, the approach to renal injuries
has changed over time, requiring diligent attention to recent
literature. Namely, the tolerance for nonoperative or expectant
management has increased, even in the most seriously injured
kidneys, replacing the past tendency toward aggressive
renorrhaphy.
Slide 5
OBJECTIVES: The objective of this study is to review the
specific diagnosis of blunt trauma of the kidney with emphasis on
the contribution of the Computed Tomography (CT) and especially to
define the current position of conservative treatment.
Slide 6
MATERIALS AND METHODS: The characteristics of this disease were
reviewed from a retrospective study of 66 kidney injuries collected
in the urology department of EPS F. Bourguiba in Monastir for a
period of 15 years. The assessment of the lesions was based
primally on CT.
Slide 7
RESULTS: Patients were predominantly male with a mean age of 25
years. The causes were largely dominated by road accidents (41%).
The clinical presentation was dominated by low back pain (77%) and
haematuria (59%). The trauma was associated with abdominal visceral
injury for 17 patients.
Slide 8
Was used the classification of Federle and our patients were as
follows: 28 cases stage I, 17 cases stage II, 18 cases stage III,
and 3 cases stage IV. Four patients underwent emergency surgery for
uncontrollable hemorrhage (intraabdominal lesions associated).
Forty three patients (65%) with minor trauma(stage I and II)
underwent non operative conservative treatment. Ten patients (15%)
underwent delayed five of them had a total nephrectomy.
Slide 9
RENAL CONTUSION SUBCAPSULAR HAEMATOMA GRADE I
Slide 10
LEFT RENAL LACERATION THROUGH THE CORTEX WITHOUT EXTENDING THE
MEDULLA GRADE II
Slide 11
GRADE III LACERATION OF THE LEFT KIDNEY WITH AN HEPATIC
CONTUSION GRADE III LACERATION OF THE LEFT KIDNEY WITH AN HEPATIC
CONTUSION GRADE IV LACERATION EXTENDING THE COLLECTING SYSTEM GRADE
IV LACERATION EXTENDING THE COLLECTING SYSTEM
Slide 12
GRADE IV
Slide 13
RELEVANT ANATOMY: In most instances, the kidneys are paired
retroperitoneal structures. They lie against the psoas muscles. The
superior aspect of the kidneys is somewhat protected by the lower
ribs. However, the lower poles are inferior to the 12th ribs. The
parenchyma of the kidney has a segmental arterial supply. This
anatomic arrangement becomes important in the management of renal
lacerations.
Slide 14
Blunt injuries tend to fracture along the planes between the
segmental vessels, while penetrating injuries cross the segmental
vessels. Numerous anatomic variations exist, including pelvic
kidneys; horseshoe kidneys; and multiple renal arterial, venous,
and ureteral duplications.
Slide 15
EPIDEMIOLOGY: The frequency of renal injury somewhat depends on
the patient population being considered. Renal trauma accounts for
approximately 3% of all trauma admissions and as many as 10% of
patients who sustain abdominal trauma.
Slide 16
PRESENTATION: The diagnosis of renal injury begins with a high
index of clinical awareness. The mechanism of injury provides the
framework for the clinical assessment. Particular attention should
be paid to complaints of flank or abdominal pain. Urinalysis, both
gross and, if necessary, microscopic, should be performed in
patients who are thought to have renal trauma. Based on these
initial measures, radiographic or operative investigation may
follow.
Slide 17
DISCUSSION: Given the high rate of renal loss and the improved
results with expectant treatment, the decision to perform immediate
surgery must be weighed carefully. In decision making process,
accurate assessment of the extent of injury is invaluable.
Intravenous urography (IVU) was previously the imaging modality of
choice in the investigation of renal injuries.
Slide 18
However, it has been noted that IVU fails to detect and
accurately stage some types of renal injuries. Ultrasonography (US)
has also been found to be very useful in the early evaluation of
renal trauma, especially in the emergency room, as well as for
detecting haemoperitoneum. However, US may also miss some types of
renal injuries. Computed tomography (CT) is currently the imaging
modality of choice in the evaluation of blunt renal injury.
Slide 19
It can provide the exact delineation and staging of the extent
of the renal injuries, and is superior to IVU, US and angiography.
However, CT needs to be performed in multiple phases for a complete
assessment of renal injuries. In certain cases, a delayed CT may
need to be repeated after 23 days in order to detect ureteropelvic
injuries and other complications.
Slide 20
Use of CT staging of renal trauma is sufficiently accurate to
allow the majority of the patients with major renal injuries to be
treated expectantly and to avoid unnecessary exploration with its
high risk of renal loss. Unless immediate exploratory laparotomy is
indicated because of associated injuries or shock, most major renal
injuries can be managed by non-surgical treatment with delayed
intervention as needed.
Slide 21
The indications for renal imaging in trauma patients include:
gross haematuria, microscopic haematuria with shock (systolic blood
pressure [SBP] < 90 mmHg), microscopic haematuria with flank
bruising, lower rib and lumbar spine transverse process fractures,
penetrating trauma, and a child with blunt trauma and haematuria
(> 50 red bloods cells/high power field).
Slide 22
CT SCANNING PROTOCOL IN RENAL TRAUMA: For a complete assessment
of renal injuries, CT is performed in multiple phases. It is
usually done as part of the CT abdomen and pelvis protocol for
abdominal injuries. The corticomedullary phase is performed from
the dome of the diaphragm to the pelvis, approximately 60 seconds
after an intravenous injection of nonionic iodinated contrast media
(iohexol 300 mg I/ml) at 2 mg/kg via the antecubital vein.
Slide 23
This phase would identify any renal contusion, laceration,
perinephric haematoma and arterial injury. Other associated
injuries to the liver, spleen, pancreas and intraperitoneal
haemorrhage could also be assessed. However, collecting system
injuries may be missed if an excretory phase is not performed. The
excretory phase is then obtained about 35 minutes later, which
include both the kidneys and the urinary bladder. This is important
in detecting urine extravastion which would indicate collecting
system, ureteropelvic or bladder injuries.
Slide 24
The timing of the excretory phase may be delayed until more
than 1020 minutes so as to allow more urine extravasation to be
visualised. In haemodynamically unstable patients, or patients with
Category II or higher injuries, CT of the abdomen may need to be
performed 23 days later to detect delayed complications, such as
urinoma, infected urinoma or expanding haematoma, which may require
intervention. All these multiphasic imagings of the renal system
allow for appropriate and complete assessment of the renal
injuries.
Slide 25
CT CLASSIFICATION OF RENAL TRAUMA: There are several
classifications of renal injuries, based on either imaging or
surgery. Federle Classification is a widely used imaging-based
grading system (Table I),while the American Association for the
Surgery of Trauma (AAST) renal injury severity scale is a commonly
used urological surgical staging in renal trauma (Table II).
However, considerable overlapping is observed in both
classifications.
Slide 26
Staging is important as it guides surgeons and radiologists in
the management of the patient, although it is not absolute and
needs to be tailored for individual patients. Out of the 66 cases
that we have identified, 28 (42%) cases were in Category I (minor
injury), 17 (25%) were in Category II (major injury), 18 (27%) were
in Category III (catastrophic injury) and 3 cases (0.5%) were in
Category IV (ureteropelvic junction injury).
Slide 27
Table I. Federle Classification (imaging-based) Category Type
Injury I Minor injury Renal contusion; intrarenal and subcapsular
haematoma; minor laceration with limited perinephric haematoma
without extension in the collecting system or medulla; small
subsegmental cortical infarct II Major injury Major renal
laceration through the cortex extending to the medulla or
collecting system with or without urine extravasation; segmental
renal infarct III Catastrophic injury Multiple renal lacerations;
vascular injury involving the renal pedicle IV Ureteropelvic injury
Avulsion (complete transaction); laceration (incomplete tear)
Slide 28
Table II. The American Association for the Surgery of Trauma
(AAST) renal injury severity scale: Grade Type Description I
Contusion Microscopic or gross haematuria; urological studies
normal Haematoma Subcapsular; not expanding with no parenchymal
laceration II Haematoma Not expanding perirenal haematoma confirmed
to be renal retroperitoneum Laceration < 1.0 cm parenchymal
depth of renal cortex with no urinary extravasation III Laceration
> 1.0 cm parenchymal depth of renal cortex with no collecting
system rupture or urinary extravasation IV Laceration Parenchymal
laceration extending through renal cortex, medulla and collecting
system Vascular Main renal artery or vein injury with contained
haemorrhage V Laceration Completely shattered kidney Vascular
Avulsion of renal hilum which devascularises kidney
Slide 29
Graphical representation of the American Association of
Surgeons in Trauma grading system Graphical representation of the
American Association of Surgeons in Trauma grading system
Slide 30
CONCLUSION: Contrast- enhanced CT is readily available in
emergency departments and can quickly and accurately depict renal
injuries as well as associated injuries to other abdominal or
retroperitoneal organs. It can provide essential anatomic and
physiologic information required to determine management of
injuries sustained during blunt abdominal trauma.