Keywords
cecum - foramen of Winslow - herniation - laparoscopic surgery - lesser sac
Introduction
The foramen of Winslow is the omental communication between the greater and lesser
sac. An internal hernia through the foramen of Winslow is extremely rare, accounting
for <0.1% of abdominal hernias and 8% of internal hernias.[1] The majority of lesser sac hernias contain small bowel only, less commonly cecum
or omentum. Diagnostic delay is associated with high morbidity and mortality and accurate
radiological interpretation is invaluable to guide surgical intervention.[2] As such, the recognition of foramen of Winslow herniation on computed tomography
(CT) is paramount. We present a case of caecal herniation that was recognized early
and reversed within 48 hours of presentation, without the need for bowel resection.
Case Presentation
A 72-year-old female presented by ambulance to the emergency department with a 3-day
history of sudden onset abdominal pain and nausea. She was clinically diagnosed with
biliary colic following a similar episode 2 weeks prior. The pain started in the epigastric
region and radiated laterally across the abdomen, was exacerbated by eating and was
associated with belching and reduced appetite. Her bowels, previously opening daily,
had not opened for 72 hours and at presentation she was not passing flatus. Relevant
past medical history included total abdominal hysterectomy, borderline diet controlled
type II diabetes, and paroxysmal atrial fibrillation managed with apixaban. There
is a family history of gastric cancer on the paternal side. No recreational drug or
alcohol use. On examination, her abdomen was soft with mild epigastric tenderness,
negative Murphy’s sign. Bowel sounds were reduced, no palpable masses, inguinal or
femoral herniation. Digital rectal examination revealed an empty rectum. Clinical
observations were within normal range.
Differential diagnoses included postprandial pain secondary to biliary colic and peptic
ulcer disease.
Biochemical investigations revealed a mildly raised C-reactive protein. Hemoglobin,
leukocytes, urea, electrolytes, liver function tests, and amylase were all within
normal range. Arterial blood gas demonstrated a mild, uncompensated metabolic alkalosis
with pH 7.46 and HCO3
- 28.5, normal lactate. The patient proceeded to have an abdominal ultrasound whereby
the gallbladder was thoroughly examined and no evidence of calculi was visualized.
The common bile duct was of normal caliber.
A CT abdomen/pelvis was subsequently performed. The patient was imaged on a Siemens
Somatom Definition Flash 256 slice CT scanner manufactured by Siemens Healthineers
AG, Forchheim, Germany. Axial 1.5 mm sections were performed through the abdomen and
pelvis in the portovenous phase; 60 seconds postintravenous contrast injection using
automated dosimetry at 100 kV average 230 mAs. 200 mL intravenous Omnipaque 350 (iohexol)
manufactured by GE Healthcare Ireland Limited, Cork, Ireland was delivered at the
rate of 3 mL/s. SAFIRE (sinogram affirmed iterative reconstruction) raw data-based
iterative reconstruction was performed.
The caecal pole was found to be ectopically situated, lying adjacent to the lesser
curve of the stomach in the epigastric region suggestive of herniation through the
foramen of Winslow into the lesser sac ([Figs. 1]
[2A]
[B]). The proximal ascending colon and terminal ileum had also passed through the epiploic
foramen into the lesser sac ([Figs. 3]
[4]). [Fig. 5] is a schematic anatomical representation of caecal herniation through the foramen
of Winslow. No significant inflammatory changes were seen around the cecum and no
abnormal gas seen in the caecal wall.
Fig. 1 Coronal oblique reconstruction of 1.5 mm abdominal slices imaged in the portovenous
phase 60 seconds postintravenous iohexol contrast. The cecal pole is ectopically situated
adjacent to the lesser curve of the stomach in the epigastric region suggestive of
herniation into the lesser sac.
Fig. 2 (A) and (B) Axial oblique reconstructions demonstrating caecal, proximal ascending colon and
terminal ileum herniation through the epiploic foramen into the lesser sac. Astrix,
caecal pole; arrowheads, lesser curve of the stomach.
Fig. 3 Coronal oblique reconstruction of 1.5 mm abdominal slices imaged in the portovenous
phase 60 seconds postintravenous iohexol contrast. TI, terminal ileum; TC, transverse
colon.
Fig. 4 (A–F) Sagittal reconstruction of 1.5 mm abdominal slices imaged in the portovenous phase
60 seconds postintravenous iohexol contrast. Images demonstrate caecal, terminal ileum,
and proximal ascending colon herniation through the foramen of Winslow into the lesser
sac. TC, transverse colon; TI, terminal ileum; asterix, caecal pole; arrowheads, lesser
curve of the stomach.
Fig. 5 Schematic representation of caecal herniation through the foramen of Winslow. Image
Courtesy: Dr. Andrew Lowe.
The patient was taken to theater the following day, intraoperative findings confirmed
CT diagnosis that the terminal ileum and cecum had herniated through the foramen of
Winslow. The aperture through which the cecum had herniated was so tight that laparoscopic
reduction was not possible and the band was successfully reduced by open transverse
laparotomy. The anterior border comprised the common bile duct (CBD), hepatic artery
and hepatic vein, therefore the Hartmann’s pouch of the gallbladder was sutured to
the posterior abdominal wall following reduction. The right colon was completely free
of omentum, therefore sutured to the right abdominal wall to keep it in place. The
patient made a slow but steady recovery without complication and was discharged 9 days
later.
Discussion
The foramen of Winslow is the communication between the greater peritoneal cavity
and the lesser sac. The posterior border is formed by the inferior vena cava and the
anterior border by the hepatoduodenal ligament containing the CBD, hepatic artery
and portal vein. Inferiorly lies the duodenum and superiorly the caudate lobe of the
liver.
Herniation of the bowel through the foramen of Winslow is a rare condition, accounting
for <0.1% of abdominal herniation.[1] The majority of cases contain small bowel only, rarely there have been reports of
cecal, ascending and transverse colon,[3] gallbladder,[4] small bowel diverticulum[5] or Meckel’s diverticulum herniation through the lesser sac.[6] Risk factors for lesser sac herniation are thought to include an enlarged foramen
of Winslow, failed retroperitonealization of the right colon, a common intestinal
mesentery or long small bowel mesentery. Other factors include atrophic greater omentum
as in our case and sudden raised intra-abdominal pressure.
Presenting symptoms are nonspecific and can include both upper abdominal and chest
pain. Prompt diagnosis is important because of the risk of necrosis to the herniated
structures. Management involves urgent surgical reduction with bowel decompression
and resection of nonviable tissue, frequently open surgery will be required.[7]
[8]
Historically, patients presenting with typical abdominal pain were investigated with
explorative laparotomy, the diagnosis was made intraoperatively and often led to bowel
resection because of ischemia. Such diagnostic delay therefore resulted in high morbidity
and mortality.[2] CT is fast and accessible allowing earlier diagnosis and earlier surgical intervention,
even before the bowel becomes ischemic. Intervention ahead of bowel ischemia may possibly
negate the need for bowel resection in this patient group with a projected reduction
in morbidity and mortality.
