Dr. Kelsey Lena is an Emergency Medicine Resident and Drs. Michael Avery and Joshua Davis are Surgery Residents at Carolinas Medical Center in Charlotte, NC. They are interested in medical education. With the guidance of Drs. Kyle Cunningham and Michael Gibbs, they aim to help augment our understanding of emergent abdominal imaging. Follow along with the EMGuideWire.com team as they post these monthly educational, self-guided radiology slides. This month also offers additional expert guidance by Dr. Brent Matthews This month’s topics include: Parastomal hernia Obstruction Incarcerated inguinal hernia Abdominal wall abscess secondary to infected mesh framework

1. Adult Abdominal Imaging Case Studies
Michael Avery, DO, Joshua Davis, MD, Kelsey Lena, MD,
Brent Matthews, MD
Departments of Surgery & Emergency Medicine
Carolinas Medical Center & Levine Children’s Hospital
Kyle Cunningham, MD & Michael Gibbs MD - Faculty Editors
Abdominal Imaging Mastery Project
May 2021

2. Disclosures
▪ This ongoing abdominal imaging interpretation series is proudly co-
sponsored by the Emergency Medicine & Surgery Residency Programs
at Carolinas Medical Center.
▪ The goal is to promote widespread interpretation mastery.
▪ There is no personal health information [PHI] within, and ages have been
changed to protect patient confidentiality.

3. Process
▪ Many are providing cases and these slides are shared with all contributors.
▪ Contributors from many Carolinas Medical Center departments, and now…
Brazil, Chile and Tanzania.
▪ Cases submitted this month will be distributed next month.
▪ When reviewing the presentation, the 1st slide will show an image without
identifiers and the 2nd slide will reveal the diagnosis.

4. It’s All About The Anatomy!

5. Systematic Approach to Abdominal CTs
● Aorta Down - follow the flow of blood!
○ Thoracic Aorta → Abdominal Aorta → Bifurcation → Iliac a.
● Veins Up - again, follow the flow!
○ Femoral v. → IVC → Right Atrium
● Solid Organs Down
○ Heart → Spleen → Pancreas → Liver → Gallbladder → Adrenal
→ Kidney/Ureters → Bladder
● Rectum Up
○ Rectum → Sigmoid → Transverse → Cecum → Appendix
● Esophagus Down
○ Esophagus → Stomach → Small bowel

6. Systematic Approach to Abdominal CTs
● Abdominal Wall/Soft Tissue Up
○ Free air, abscesses, hernias
● Retroperitoneum Down
○ Hematoma, masses
● GU Up
○ Masses
● Tissue Specific Windows
○ Lung
○ Bone
● Don’t Forget To Look At Multiple Planes
○ Axial, sagittal, coronal

7. CASE #1:
A 70-year-old female
with a history of
abdominoperineal
resection with VRAM
flap reconstruction
and a right-sided end
colostomy, presents to
the ED with several
days of decreased
ostomy output and 6-
12 hours of abdominal
pain. The physical
exam demonstrated a
firm bulge by the
stoma. CT imaging is
obtained.
Diagnosis?
CBD
SMV
SMA
duodenum
Portal vein
CBD and PD

8. CBD
SMV
SMA
duodenum
Portal vein
CBD and PD
Fecalization of small bowel contents Decompressed distal loop of
the small bowel
Transverse colon
Sigmoid colon end colostomy
CASE #1:
The patient’s CT scan
demonstrated a
parastomal hernia
with a mechanical
obstruction. The
hernia was not
reducible. Ultimately,
the patient went to the
operating room for
parastomal hernia
repair.
Note: The patient end
colostomy was right-
sided as the VRAM
flap was harvested
from the left side.

9. Parastomal Hernias

10. • The incidence of parastomal hernias varies and are highest for end-
colostomies; estimated to occur in 4-48% of patients undergoing this
procedure.
• Risk factors: obesity, wound infection, and conditions causing
increased abdominal pressure (COPD, ascites, chronic constipation).
• Indications for operative fixation include symptoms of obstruction or
bowel strangulation, refractory appliance leakage.
• Our patient underwent a Sugarbaker repair with mesh placement (see
diagram next slide).
Parastomal Hernias

12. • Upon the construction of an end-colostomy, the use of prophylactic,
synthetic non-absorbable mesh is strongly recommended to avoid the
subsequent development of a parastomal hernia.
• Suture repair of a parastomal hernia not recommended for elective repair.
• The use of mesh is recommended, safe, and infrequently associated with
infection.
• In laparoscopic repair a Sugarbaker mesh technique is superior to a
Keyhole technique; showing fewer recurrences.
Summary Of Guideline Recommendations

14. CASE #2:
A 21-year-old male with
no significant medical
history presented to the
ED with 24 hours of
increasing left groin and
scrotal swelling. Physical
examination reveals in
enlarged, tender left hemi-
scrotum, with overlying
skin erythema.
Diagnosis?

15. Inguinal hernia
defect
Hernia extending into
inguinal canal and scrotum
Sigmoid colon and omentum
entrapped in hernia sac
CASE #2:
A 21-year-old male with
no significant medical
history presented to the
ED with 24 hours of
increasing left groin and
scrotal swelling.
Diagnosis?
Incarcerated left inguinal
hernia with colon and
omentum entrapped in the
hernia sac.

16. Hernia Types:
Inguinal:
• Above the inguinal ligament
• Direct and indirect
Femoral:
• Below the inguinal ligament
Epidemiology:
• The lifetime risk is 27% in men and 3%
in women. Femoral hernias are more
common in women.
• Indirect hernias twice as common as
direct hernias.
• A family history increases the risk 8-
fold.

19. Inguinal Hernias
• Protrusion of abdominal cavity contents through the inguinal canal:
-Present with swelling and/or pain in the groin
-7:1 male-to-female ratio
• Divided into two categories based on anatomy:
-Indirect
-Hernia lateral to inferior epigastric vessels
-Males: anterior to the spermatic cord; females: follows the round ligament
-Direct
-Hernia medial to the inferior epigastric vessels
• Complications: incarceration, strangulation, bowel obstruction

20. Sliding Inguinal
Hernia
• A sliding hernia is a protrusion
through an abdominal wall of a
retroperitoneal organ. The
frequency of sliding hernias is
estimated at 6-8% of all elective
inguinal hernia repairs.
• The sliding inguinal hernia is a
rare finding. The risk of injury
of the sliding organ in minimal.
If a tension free technique is
used, the risk of recurrence is
similar to that of patients with
non-sliding inguinal hernia.

21. CASE #3:
A 62-year-old female
with a past medical
history of ventral hernia
repair with mesh
presented to the ED
with abdominal pain
and vomiting. Physical
examination reveals
abdominal tenderness
and erythema at the site
of the prior hernia
repair. Due to concern
for acute kidney injury,
a CT abdomen/pelvis
without contrast was
obtained.
Diagnosis?

22. Significant gas containing density
fluid collection in the right anterior
abdominal wall
Inferior to the abscess is a
right lower quadrant
abdominal wall hernia
containing distended loops
of small bowel
CASE #3:
A 62-year-old female
with a past medical
history of ventral hernia
repair with mesh
presented to the ED
with abdominal pain
and vomiting.
Diagnosis?
Abdominal wall
abscess.
The patient was taken
to the operating room
where 3 liters of
purulent material was
drained, and an infected
mesh was identified and
excised.

23. Abdominal Wall Abscess
• Purulent skin and soft tissue infection
• Clinical features include surrounding erythema, fluctuance, and/or a
tender nodular region with surrounding induration
• Soft tissue ultrasound can differentiate between between abscess
and cellulitis:
-Cellulitis: cobblestoning
-Abscess: cobblestoning + fluid collection with “swirl”
• CT imaging can be obtained if there is concern for a subsequent
abscess communicating with the intra-abdominal cavity

24. Abdominal
Wall Abscess
Treatment
• Bedside incision and drainage:
-Abscesses < 5 cm in diameter
-Packing for immunocompromised or diabetic patient
-Loop drainage with vessel ties or a Penrose drain as an alternative
• Formal surgical incision and drainage with subsequent wash-out
performed on patients with larger anterior abdominal wall abscesses
• Antibiotic coverage: MRSA (vancomycin or Bactrim) + Gram negatives
(piperacillin tazobactam)

25. • Analysis demonstrated that the lowest surgical site infection (SSI) rate belonged to non-smokers with BMI < 24.2 kg/m2
(1.9%), and the highest SSI to smokers with BMI > 42.3 kg/m2 (12%).
• Between the values above, there was a stepwise increase in SSI rate as BMI increased, while smoking added additional risk
in each group.
• Immunosuppressive drugs use, urgent repair, and postoperative surgical site infection are predictive of mesh infection.
• Risk factors of prosthesis explantation are PTFE mesh, onlay mesh position, and associated enterotomy in the same
procedure.

26. Summary Of Diagnoses This Month
● Parastomal hernia with mechanical obstruction
● Incarcerated inguinal hernia
● Abdominal wall abscess secondary to infected mesh framework

27. See You Next Month!