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757
Traumatic
Lumbar
Hernia:
CT Diagnosis
Scott H. Faro1 C. Dyeanne Racette2 James F. LalIy1 John S. Wills1 Amir Mansoory2
A lumbar hernia usually involves protrusion of extraperitoneal fat or bowel through an area of weakness in the posterolateral abdominal wall bounded superiorly by the 12th rib, inferiorly by the iliac crest, posteriorly by the erector spinae muscle, and anteriorly by the posterior border of the external oblique muscle. Most are due to an acquired nontraumatic or congenital cause. Acute blunt abdominal trauma is a rare cause of lumbar hernia; to our knowledge, the CT diagnosis of this variety has not been reported. Since 1985, approximately 850 patients have undergone emergent abdominal CT for evaluation of acute abdominal trauma at our hospital; in seven of these patients, a
traumatic
lumbar
hernia
was diagnosed
prospectively.
In three
patients,
CT showed
a
flank hematoma with herniatlon of bowel through the lumbar triangle. CT showed pelvic fractures in three other patients, accompanied by herniation of bowel in one patient,
herniation
of extraperitoneal
fat in another,
blood in the third. One patient had both a herniation of bowel. Acute traumatic lumbar hernia is a rare considered in patients with blunt abdominal hematomas and pelvic fractures. The hernia muscle layers are all well demonstrated on AJR
Received
June 23, 1989; accepted
after revision
October 19. 1989. ‘Department
of Radklogy,
The Medical Center
of Delaware, 4755 Stanton-Ogletown Rd., Newark, DE 19718. Address reprint requests to S. H. Faro. 2Department of Surgery, Ste. 128, Medical Arts Pavilion, 19713.
4745
0361 -803X/90/1 C American
Stanton-Ogletown
544-0757
Roentgen
Ray Society
Rd., Newark,
DE
and herniation flank
hematoma
of extraperitoneal and a pelvic
fat and
fracture
with
but significant abnormality that should be trauma, especially in those with large flank contents, associated injuries, and disrupted CT.
April 1990
154:757-759,
Lumbar hernias occur within the superior or inferior lumbar triangle. Both triangles are areas of relative weakness in the posterolateral abdominal wall. The superior lumbar (Grynfelt-Lesshaft) triangle is an inverted triangle that is bound by the 12th rib superiorly, the internal oblique muscle anteriorly, and the erector spinae muscle posteriorly. The latissimus dorsi musde forms the roof of the triangle, and the aponeurosis of the transversalis muscle forms the floor. The inferior lumbar (Petit’s) triangle is an upright triangle bordered inferiorly by the iliac crest, anteriorly by the external oblique muscle, and posteriorly by the latissimus dorsi muscle. Superficial fascia and skin constitute the roof of the triangle, and the lumbar fascia, internal oblique muscle, and aponeurosis of the transversalis muscle form the floor [1]. Lumbar hernias occur most often in the superior lumbar triangle; most are due to an acquired nontraumatic or congenital cause and less commonly are due to trauma. CT diagnosis of traumatic lumbar hernias associated with surgical flank incisions or iliac bone graft donor sites has been described; to our knowledge, however, there have been no reports of the CT diagnosis of lumbar hernia due to acute blunt abdominal trauma. We present our experience with the CT diagnosis of acute traumatic lumbar hernia in seven patients and describe the role of CT in the initial examination and follow-up of these patients. Materials
and
Methods
Since 1985, approximately Medical
Center
of
Delaware
850 patients for
evaluation
have undergone of
acute
emergent
abdominal
trauma.
abdominal In seven
CT at The of
these
FARO
758
ET AL.
AJR:154,
April 1990
Downloaded from www.ajronline.org by 152.7.0.100 on 10/28/15 from IP address 152.7.0.100. Copyright ARRS. For personal use only; all rights reserved
Fig. 1.-CT scan in a 32-year-old woman involved in an automobile accident reveals herniation of bowel through thinned transversus abdominis muscle (long straight arrow) and internal oblique muscle (short straight arrow). Hernia is covered by external oblique muscle (curved arrow). Arrowhead = right flank hematoma.
Fig. 2.-CT
scan
in a 46-year-old
man who was an unrestrained driver in a motor vehicle accident shows bilateral lumbar hernias (arrows) and bilateral flank hematomas (arrowheads).
patients,
an inferior
patients included 21 to 78 years. reviewed,
with
lumbar
lumbar
specific
hernia,
hernia
was
diagnosed
prospectively.
The
two women and five men, whose ages ranged The hospital charts of the seven patients attention
associated
to
injuries,
mechanism
and
of injury,
surgical
from were
history
treatments.
of
All seven
patients were involved in motor vehicle accidents. Three patients were unrestrained during the accident, two were restrained, and whether the remaining two patients used seat belts is unknown. No history flank
of lumbar
hernia
was
were
the
hematomas
Three
other
physis
patients
diastasis,
present
suffered
one
with
in this
major
clinical
pelvic sacral
group
of patients.
findings
fractures,
in three one
fractures
and
with
bilateral
fractures, and the third with multiple comminuted The last patient had both a large flank hematoma fracture
of the
CT scans
1200SX
right
iliac
were
obtained
E-Z-Em, the CT
by
bolus
a rapid
(Conray,
with
Three these
drip
either
a Picker
Heights,
of the
Westbury,
IV contrast
infusion
of 75
had
during palpable,
underwent
Fig. 3.-CT
600SX
via
and 2 cm through sulfate 1 .2% w/w
nasogastric
was
given
iothalamate
MO), followed symptomatic
The
60%
meglumine
by approximately lumbar
exploratory
hernias.
laparotomy
50
remaining
four
patients
Two and
of sur-
had an elective had
nonpal-
pable, asymptomatic lumbar hernias. Two of these patients were treated conservatively (observation). A third patient initially was treated conservatively, and 6 weeks after the trauma a large abscess developed in the region of the lumbar hernia. This abscess was drained
surgically.
patient
small-bowel had emergent
lumbar
hernia
required
was
Enteroenteric
and
enterocutaneous
fistulas
that
resection developed subsequently. The fourth exploratory laparotomy after CT, but the small not
scan in a 78-year-old
man who was a restrained
driver in a
motor vehicle accident reveals herniation of bowel (long straight arrows) through torn layers (medial to lateral) of transversus abdominis, internal oblique, and external oblique muscles (short straight arrows). A right flank hematoma (arrowhead) and an avulsion fracture of right iliac crest (curved arrow) are also present
30
tube to all patients
after CT. The third patient
hernia.
or Picker
OH) with 1-cm-thick
scanning.
emergent
of the hernias lumbar
NY) material
ml of
St. Louis,
infusion
patients
patients
gical repair repair
Inc., scan.
Mallinckrodt,
ml by slow
symbone
pelvic fractures. and an avulsion
slices at intervals of 1 cm through the abdomen the pelvis. All patients received 450 ml of barium mm before
pubic pubic
crest.
CT scanner (Picker, Highland
(Readi-CAT,
Large patients.
repaired.
Results
In all seven patients, CT clearly showed a lumbar hernia(s), all of which involved the inferior lumbar triangle. Three of the seven patients with a traumatic lumbar hernia on CT had large flank hematomas as the major associated finding. The hematoma was on the same side as the lumbar hernia. In one patient, the CT scan showed a right lumbar hernia with bowel herniation through thinned transversus abdominis and internal oblique muscles (Fig. 1 ). A second patient had a small left lumbar hernia on CT, with bowel herniation. The third patient
had extensive bilateral flank hematomas and bilateral lumbar hernias with bowel herniation on CT (Fig. 2). The CT scan of a fourth patient showed both a right flank hematoma and an avulsion fracture of the right iliac crest, with herniation of bowel through a right lumbar hernia (Fig. 3). Pelvic fractures were the major associated injuries in the remaining three patients with lumbar hernias. One had herniation of extraperitoneal fat through a right lumbar hernia on CT. Another had free intraperitoneal fluid on CT (proved surgically to be hemoperitoneum) and a left lumbar hernia containing extraperitoneal fat and a similar fluid density, presumably blood. The CT scan obtained in the third patient at the time of admission showed a right lumbar hernia with herniation of bowel, probably colon (Fig. 4A). This patient was discharged in satisfactory condition but returned to the emergency room 2 weeks later with a fever and a palpable, fluctuant right flank mass. A CT scan at this time (6 weeks after the initial trauma) showed a large heterogeneous fluid collection with associated gas, representing an abscess in the region of the right lumbar hernia (Fig. 4B).
Discussion
Less than 300 cases of lumbar hernia have been described literature [1 ]. Most of these hernias are due to an acquired nontraumatic or congenital cause [1 ]. The remaining lumbar hernias are due to trauma [1 ,2]. Recent studies have in the
Downloaded from www.ajronline.org by 152.7.0.100 on 10/28/15 from IP address 152.7.0.100. Copyright ARRS. For personal use only; all rights reserved
AJR:154,
April 1990
CT
OF TRAUMATIC
LUMBAR
HERNIA
759
Fig. 4.-CT scans in a 21-year-old man involved in a motor vehicle accident. It was not known if he was wearing a seat belt. A, CT scan just above right iliac crest after trauma reveals herniation of bowel in posterolateral abdominal wall (arrow). B, Second CT scan 6 weeks after trauma shows a large heterogeneous fluid collection with associated gas (arrow), representing an abscess, in right posterolateral flank.
reported lumbar hernias resulting from direct surgical trauma and occurring postoperatively at the sites of flank incisions and iliac crest bone graft donor sites [2-4]. Acute blunt abdominal trauma is a rare but significant cause of lumbar hernia. To our knowledge, the CT diagnosis has not been described before. The major clinical findings in our patients were large flank hematomas and pelvic fractures. These associated injuries were diagnosed accurately with CT. Three of the seven patients had palpable, symptomatic flank masses resulting from trauma. The differential diagnoses included flank hematoma and/or lumbar hernia. CT was able to show the presence of these abnormalities as well as show the anatomy of the adjacent muscle layers; furthermore, the contents of the hernia were well shown by this imaging technique. Lumbar hernias, which have a natural history of a gradual increase in size over time [1 ],can result in significant morbidity, ranging from chronic lower back pain to bowel strangulation [5]. Bowel incarceration occurs in approximately 25% of these hernias, and strangulation may occur in 1 0%. Two of our seven patients had significant morbidity related to the hernia. One patient continued to have a palpable, symptomatic lumbar hernia and underwent elective surgical repair. A second patient developed a large flank abscess in the region of the lumbar hernia that required surgical drainage. This abscess presumably was due to microperforation of herniated
bowel. The CT diagnosis of lumbar hernia was of value in the management of these patients. The majority of lumbar hernias have been diagnosed on physical examination; only recently has CT become a major diagnostic technique. CT allows the diagnosis of asymptomatic, nonpalpable lumbar hernias. We believe that these hernias can be monitored clinically until symptoms develop and that all symptomatic lumbar hernias should undergo repair. CT is also beneficial in the follow-up of asymptomatic patients who develop flank pain or a palpable flank mass after the initial trauma. ACKNOWLEDGMENTS
We thank Karen McFadden with the preparation raphy.
and Suzie McCormick for their help of this paper and Douglas Bugel for the photog-
REFERENCES 1 . Swartz WT. Lumbar hernia. In: Nyhus LM, Condon RE, eds. Hernia, 2nd ed. Philadelphia: Lippincott, 1978:409-426 2. Baker ME, Weinerth JL, Andriani RT, Cohan RH, Dunnick NR. Lumbar hernia: diagnosis by CT. AJR 1987;148:565-567 3. Kane VG, Silverstein GS. CT demonstration of hernia through an iliac crest defect. J Comput Assist Tomogr 1986;10:432-434 4. Lawdahl RB, Moss CN, Van Dyke JA. Inferior lumbar (Petit’s) hemia. AJR 1986;147:744-745 5. Florer RE, Kiriluk L. Petit’s triangle hernia, incarcerated: two case reports. Am Surg 1971;37:527-530
757
Traumatic
Lumbar
Hernia:
CT Diagnosis
Scott H. Faro1 C. Dyeanne Racette2 James F. LalIy1 John S. Wills1 Amir Mansoory2
A lumbar hernia usually involves protrusion of extraperitoneal fat or bowel through an area of weakness in the posterolateral abdominal wall bounded superiorly by the 12th rib, inferiorly by the iliac crest, posteriorly by the erector spinae muscle, and anteriorly by the posterior border of the external oblique muscle. Most are due to an acquired nontraumatic or congenital cause. Acute blunt abdominal trauma is a rare cause of lumbar hernia; to our knowledge, the CT diagnosis of this variety has not been reported. Since 1985, approximately 850 patients have undergone emergent abdominal CT for evaluation of acute abdominal trauma at our hospital; in seven of these patients, a
traumatic
lumbar
hernia
was diagnosed
prospectively.
In three
patients,
CT showed
a
flank hematoma with herniatlon of bowel through the lumbar triangle. CT showed pelvic fractures in three other patients, accompanied by herniation of bowel in one patient,
herniation
of extraperitoneal
fat in another,
blood in the third. One patient had both a herniation of bowel. Acute traumatic lumbar hernia is a rare considered in patients with blunt abdominal hematomas and pelvic fractures. The hernia muscle layers are all well demonstrated on AJR
Received
June 23, 1989; accepted
after revision
October 19. 1989. ‘Department
of Radklogy,
The Medical Center
of Delaware, 4755 Stanton-Ogletown Rd., Newark, DE 19718. Address reprint requests to S. H. Faro. 2Department of Surgery, Ste. 128, Medical Arts Pavilion, 19713.
4745
0361 -803X/90/1 C American
Stanton-Ogletown
544-0757
Roentgen
Ray Society
Rd., Newark,
DE
and herniation flank
hematoma
of extraperitoneal and a pelvic
fat and
fracture
with
but significant abnormality that should be trauma, especially in those with large flank contents, associated injuries, and disrupted CT.
April 1990
154:757-759,
Lumbar hernias occur within the superior or inferior lumbar triangle. Both triangles are areas of relative weakness in the posterolateral abdominal wall. The superior lumbar (Grynfelt-Lesshaft) triangle is an inverted triangle that is bound by the 12th rib superiorly, the internal oblique muscle anteriorly, and the erector spinae muscle posteriorly. The latissimus dorsi musde forms the roof of the triangle, and the aponeurosis of the transversalis muscle forms the floor. The inferior lumbar (Petit’s) triangle is an upright triangle bordered inferiorly by the iliac crest, anteriorly by the external oblique muscle, and posteriorly by the latissimus dorsi muscle. Superficial fascia and skin constitute the roof of the triangle, and the lumbar fascia, internal oblique muscle, and aponeurosis of the transversalis muscle form the floor [1]. Lumbar hernias occur most often in the superior lumbar triangle; most are due to an acquired nontraumatic or congenital cause and less commonly are due to trauma. CT diagnosis of traumatic lumbar hernias associated with surgical flank incisions or iliac bone graft donor sites has been described; to our knowledge, however, there have been no reports of the CT diagnosis of lumbar hernia due to acute blunt abdominal trauma. We present our experience with the CT diagnosis of acute traumatic lumbar hernia in seven patients and describe the role of CT in the initial examination and follow-up of these patients. Materials
and
Methods
Since 1985, approximately Medical
Center
of
Delaware
850 patients for
evaluation
have undergone of
acute
emergent
abdominal
trauma.
abdominal In seven
CT at The of
these
FARO
758
ET AL.
AJR:154,
April 1990
Downloaded from www.ajronline.org by 152.7.0.100 on 10/28/15 from IP address 152.7.0.100. Copyright ARRS. For personal use only; all rights reserved
Fig. 1.-CT scan in a 32-year-old woman involved in an automobile accident reveals herniation of bowel through thinned transversus abdominis muscle (long straight arrow) and internal oblique muscle (short straight arrow). Hernia is covered by external oblique muscle (curved arrow). Arrowhead = right flank hematoma.
Fig. 2.-CT
scan
in a 46-year-old
man who was an unrestrained driver in a motor vehicle accident shows bilateral lumbar hernias (arrows) and bilateral flank hematomas (arrowheads).
patients,
an inferior
patients included 21 to 78 years. reviewed,
with
lumbar
lumbar
specific
hernia,
hernia
was
diagnosed
prospectively.
The
two women and five men, whose ages ranged The hospital charts of the seven patients attention
associated
to
injuries,
mechanism
and
of injury,
surgical
from were
history
treatments.
of
All seven
patients were involved in motor vehicle accidents. Three patients were unrestrained during the accident, two were restrained, and whether the remaining two patients used seat belts is unknown. No history flank
of lumbar
hernia
was
were
the
hematomas
Three
other
physis
patients
diastasis,
present
suffered
one
with
in this
major
clinical
pelvic sacral
group
of patients.
findings
fractures,
in three one
fractures
and
with
bilateral
fractures, and the third with multiple comminuted The last patient had both a large flank hematoma fracture
of the
CT scans
1200SX
right
iliac
were
obtained
E-Z-Em, the CT
by
bolus
a rapid
(Conray,
with
Three these
drip
either
a Picker
Heights,
of the
Westbury,
IV contrast
infusion
of 75
had
during palpable,
underwent
Fig. 3.-CT
600SX
via
and 2 cm through sulfate 1 .2% w/w
nasogastric
was
given
iothalamate
MO), followed symptomatic
The
60%
meglumine
by approximately lumbar
exploratory
hernias.
laparotomy
50
remaining
four
patients
Two and
of sur-
had an elective had
nonpal-
pable, asymptomatic lumbar hernias. Two of these patients were treated conservatively (observation). A third patient initially was treated conservatively, and 6 weeks after the trauma a large abscess developed in the region of the lumbar hernia. This abscess was drained
surgically.
patient
small-bowel had emergent
lumbar
hernia
required
was
Enteroenteric
and
enterocutaneous
fistulas
that
resection developed subsequently. The fourth exploratory laparotomy after CT, but the small not
scan in a 78-year-old
man who was a restrained
driver in a
motor vehicle accident reveals herniation of bowel (long straight arrows) through torn layers (medial to lateral) of transversus abdominis, internal oblique, and external oblique muscles (short straight arrows). A right flank hematoma (arrowhead) and an avulsion fracture of right iliac crest (curved arrow) are also present
30
tube to all patients
after CT. The third patient
hernia.
or Picker
OH) with 1-cm-thick
scanning.
emergent
of the hernias lumbar
NY) material
ml of
St. Louis,
infusion
patients
patients
gical repair repair
Inc., scan.
Mallinckrodt,
ml by slow
symbone
pelvic fractures. and an avulsion
slices at intervals of 1 cm through the abdomen the pelvis. All patients received 450 ml of barium mm before
pubic pubic
crest.
CT scanner (Picker, Highland
(Readi-CAT,
Large patients.
repaired.
Results
In all seven patients, CT clearly showed a lumbar hernia(s), all of which involved the inferior lumbar triangle. Three of the seven patients with a traumatic lumbar hernia on CT had large flank hematomas as the major associated finding. The hematoma was on the same side as the lumbar hernia. In one patient, the CT scan showed a right lumbar hernia with bowel herniation through thinned transversus abdominis and internal oblique muscles (Fig. 1 ). A second patient had a small left lumbar hernia on CT, with bowel herniation. The third patient
had extensive bilateral flank hematomas and bilateral lumbar hernias with bowel herniation on CT (Fig. 2). The CT scan of a fourth patient showed both a right flank hematoma and an avulsion fracture of the right iliac crest, with herniation of bowel through a right lumbar hernia (Fig. 3). Pelvic fractures were the major associated injuries in the remaining three patients with lumbar hernias. One had herniation of extraperitoneal fat through a right lumbar hernia on CT. Another had free intraperitoneal fluid on CT (proved surgically to be hemoperitoneum) and a left lumbar hernia containing extraperitoneal fat and a similar fluid density, presumably blood. The CT scan obtained in the third patient at the time of admission showed a right lumbar hernia with herniation of bowel, probably colon (Fig. 4A). This patient was discharged in satisfactory condition but returned to the emergency room 2 weeks later with a fever and a palpable, fluctuant right flank mass. A CT scan at this time (6 weeks after the initial trauma) showed a large heterogeneous fluid collection with associated gas, representing an abscess in the region of the right lumbar hernia (Fig. 4B).
Discussion
Less than 300 cases of lumbar hernia have been described literature [1 ]. Most of these hernias are due to an acquired nontraumatic or congenital cause [1 ]. The remaining lumbar hernias are due to trauma [1 ,2]. Recent studies have in the
Downloaded from www.ajronline.org by 152.7.0.100 on 10/28/15 from IP address 152.7.0.100. Copyright ARRS. For personal use only; all rights reserved
AJR:154,
April 1990
CT
OF TRAUMATIC
LUMBAR
HERNIA
759
Fig. 4.-CT scans in a 21-year-old man involved in a motor vehicle accident. It was not known if he was wearing a seat belt. A, CT scan just above right iliac crest after trauma reveals herniation of bowel in posterolateral abdominal wall (arrow). B, Second CT scan 6 weeks after trauma shows a large heterogeneous fluid collection with associated gas (arrow), representing an abscess, in right posterolateral flank.
reported lumbar hernias resulting from direct surgical trauma and occurring postoperatively at the sites of flank incisions and iliac crest bone graft donor sites [2-4]. Acute blunt abdominal trauma is a rare but significant cause of lumbar hernia. To our knowledge, the CT diagnosis has not been described before. The major clinical findings in our patients were large flank hematomas and pelvic fractures. These associated injuries were diagnosed accurately with CT. Three of the seven patients had palpable, symptomatic flank masses resulting from trauma. The differential diagnoses included flank hematoma and/or lumbar hernia. CT was able to show the presence of these abnormalities as well as show the anatomy of the adjacent muscle layers; furthermore, the contents of the hernia were well shown by this imaging technique. Lumbar hernias, which have a natural history of a gradual increase in size over time [1 ],can result in significant morbidity, ranging from chronic lower back pain to bowel strangulation [5]. Bowel incarceration occurs in approximately 25% of these hernias, and strangulation may occur in 1 0%. Two of our seven patients had significant morbidity related to the hernia. One patient continued to have a palpable, symptomatic lumbar hernia and underwent elective surgical repair. A second patient developed a large flank abscess in the region of the lumbar hernia that required surgical drainage. This abscess presumably was due to microperforation of herniated
bowel. The CT diagnosis of lumbar hernia was of value in the management of these patients. The majority of lumbar hernias have been diagnosed on physical examination; only recently has CT become a major diagnostic technique. CT allows the diagnosis of asymptomatic, nonpalpable lumbar hernias. We believe that these hernias can be monitored clinically until symptoms develop and that all symptomatic lumbar hernias should undergo repair. CT is also beneficial in the follow-up of asymptomatic patients who develop flank pain or a palpable flank mass after the initial trauma. ACKNOWLEDGMENTS
We thank Karen McFadden with the preparation raphy.
and Suzie McCormick for their help of this paper and Douglas Bugel for the photog-
REFERENCES 1 . Swartz WT. Lumbar hernia. In: Nyhus LM, Condon RE, eds. Hernia, 2nd ed. Philadelphia: Lippincott, 1978:409-426 2. Baker ME, Weinerth JL, Andriani RT, Cohan RH, Dunnick NR. Lumbar hernia: diagnosis by CT. AJR 1987;148:565-567 3. Kane VG, Silverstein GS. CT demonstration of hernia through an iliac crest defect. J Comput Assist Tomogr 1986;10:432-434 4. Lawdahl RB, Moss CN, Van Dyke JA. Inferior lumbar (Petit’s) hemia. AJR 1986;147:744-745 5. Florer RE, Kiriluk L. Petit’s triangle hernia, incarcerated: two case reports. Am Surg 1971;37:527-530
