Bilateral traumatic lumbar hernias with injuries of the right renal pelvis and ureteropelvic junction (UPJ)
Multidetector (16-slice) CT images of the abdomen were obtained
with both renal corticomedullary- and excretory-phase acquisitions.
Early corticomedullary-phase images revealed bilateral traumatic
lumbar hernias and minimal right-sided retroperitoneal fluid or
hemorrhage (Figure 1), while the excretory-phase images revealed
extravasation of contrast material near the right renal hilum
(Figure 2). Scanning performed 7 hours later showed progressive
urinary contrast extravasation into the retroperitoneum and the
right lumbar hernia (Figure 3).
Emergent surgical exploration of the abdomen was performed to
address the abdominal wall and UPJ injuries, in addition to other
injuries. The attempted UPJ repair was unsuccessful, and,
ultimately, a right nephrectomy was necessary. Herniated bowel and
peritoneal fat were reduced, and the retroperitoneum was repaired.
The abdominal wall musculature was macerated at the injured sites,
and acute repair of their attachments was impossible. Following
initial recovery and discharge, the patient returned 4 months later
with a bulging right flank mass. Repeat CT scans of the abdomen
revealed recurrent bilateral lumbar hernias containing bowel and
intraperitoneal fat (Figure 4) that necessitated definitive repair
of the abdominal wall defects.
Traumatic lumbar hernias are uncommon injuries that typically
result from high-speed motor vehicular trauma. The proposed
mechanism of injury involves transmission of force from a seatbelt
to the abdomen during sudden deceleration. The resulting increase
in intrabdominal pressure exerts sufficient force to rupture the
abdominal wall musculature at a point of weakness.1,2
Injury typically occurs at either the superior lumbar
(Grynfeltt-Lesshaft) triangle, which is bordered by the 12th rib
superiorly, erector spinae muscle posteriorly, and internal oblique
muscle anteriorly; or the inferior lumbar (Petit's) triangle, which
is bordered by the iliac crest inferiorly, external oblique muscle
anteriorly, and latissimus dorsi muscle posteriorly.3
However, the injury may occur at other locations. Early recognition
is important, since without surgical repair, the hernia can
enlarge, thereby increasing long-term morbidity. An index of
suspicion is necessary, since the high incidence of other
intra-abdominal injuries may distract the radiologist from the
Renal collecting system injuries are often unsuspected or
initially overlooked. This can sometimes be the result of
inadequate renal imaging, as major renal pelvic injuries may not be
evident on routine medullary- or corticomedullary-phase
imaging.6 As in this case, evidence of excreted urinary
contrast extra-vasation on delayed (renal-excretory) phase imaging
is often necessary for the diagnosis. While urine extravasation is
not necessarily an indication for surgery, it is nonetheless
important to recognize, since a delay in diagnosis can lead to
increased morbidity due to urinoma formation, increased rate of
nephrectomy, and longer hospital stays.7 The importance
of delayed-phase imaging is not limited to evaluation of the
urinary tract, since other injuries, such as slow active
hemorrhage, may manifest only on delayed-phase images. For this
reason, renal excretory-phase images are routinely acquired during
initial CT evaluation of all high-impact, blunt abdominal trauma
patients at the Shock Trauma Center.
Traumatic lumbar hernias are uncommon injuries that are
typically associated with other intra-abdominal injuries that may
garner greater immediate attention from the radiologist and trauma
surgeon. Similarly, UPJ injuries may be easily overlooked, with
delayed contrast-enhanced CT imaging improving sensitivity for this
and other injuries. Since early repair reduces the morbidity
associated with both injuries, a high index of suspicion should be
maintained when assessing patients with signs of high-energy blunt
trauma to the abdomen.
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- Balkan M, Kozak O, Gulec B, et al. Traumatic lumbar hernia due
to seat belt injury: Case report. J Trauma. 1999; 47:154-155.
- McCarthy MC, Lemmon GW. Traumatic lumbar hernia: A seat belt
injury. J Trauma. 1996; 40:121-122.
- Shanmuganathan K, Killeen KL. Imaging of abdominal trauma. In:
Mirvis SE, Shanmuganathan K, eds. Imaging in Trauma and Critical
Care. 2nd ed. Philadelphia, PA: Saunders; 2003:369-481.
- Killeen KL, Girard S, DeMeo JH, et al. Using CT to diagnose
traumatic lumbar hernia. AJR Am J Roentgenol.
- Barden BE, Maull KI. Traumatic lumbar hernia.South Med J.
- Mulligan J, Cagiannos I, Collins JP, Millward SF. Ureteropelvic
junction disruption secondary to blunt trauma: Excretory phase
imaging (delayed films) should help prevent a missed diagnosis.J
- Harris AC, Zwirewich CV, Lyburn ID, et al. CT findings in blunt
renal trauma. RadioGraphics. 2001;21(Spec No):S201-S214.
Bilateral traumatic lumbar hernias with injuries of the right renal pelvis and ureteropelvic junction (UPJ).
April 20, 2006