: Eitel, in 1899 first described
primary omental torsion as a rare entity as a cause acute abdominal pain 1.
Since then, around 300 cases have been reported worldwide 1.
Omental torsion can be classified as “primary” and “secondary”
or as “unipolar” and “bipolar”.
Primary or idiopathic torsion occurs spontaneously
without any underlying pathology and is seen less commonly. The predisposing
factors for development of primary omental torsion include anatomic variations
of omentum, obesity and variations in arrangement of omental blood vessels.
There are conditions which may precipitate primary omental torsion in an
otherwise normal omentum. These include trauma, hyperperistalsis and acute
changes in body position 1, 2.
Secondary omental torsion is more common and is
found to be associated with an underlying abdominal affection. Most commonly it
is seen in association inguinal hernias. Other conditions are omental cysts and
tumours, previous abdominal surgeries, inflammatory diseases of abdomen and
conditions that increase abdominal pressure 1.
In unipolar omental torsion the proximal end of
omentum is fixed but distal end remains free. In bipolar omental torsion both
ends of omentum are fixed 2. Primary or idiopathic omental torsion is always
unipolar but secondary omental torsion can develop both as unipolar or bipolar
Clinical presentation of right sided omental torsion
mimics acute appendicitis with a similar triad of pain, vomiting and
temperature. The patient typically presents with a first time episode of
constant, non-radiating pain in right lower quadrant which is gradually
increasing in severity. It may be associated nausea and vomiting also 1. Half
of the patients develop low grade fever and leukocytosis 3. The course of
illness is generally prolonged as the patient is systemically less sick as
compared to acute appendicitis. In some cases spontaneous resolution takes
place and such patients may again present with another episode of torsion at a
Clinical examination shows localized peritonitis.
Large omental torsions may present as abdominal lumps as was seen in our
Differential diagnosis in right sided omental
torsion includes acute appendicitis, acute cholecystitis and twisted ovarian
cyst in females. Left sided omental torsion is very uncommon and differential
diagnosis includes sigmoid diverticulitis and epiploic appendagitis 1.
In radiology, ultrasonography shows complex mass
with a mixture of solid and hypoechoic zones and free fluid in the peritoneal
cavity. Although not very specific but it
may help to rule out other more common conditions like acute appendicitis and
cholecystitis. In contrast, CT scan has got high sensitivity for detecting an
omental mass. The ‘whirl’ sign is the classical sign of omental torsion. It
consists of an ill defined omental/fatty mass with strands of twisted blood
vessels whirling around a central vascular pedicle. The specificity of CT scan
is low in detecting omental torsion because similar pattern is also seen in fat
containing neoplasm, internal hernia containing omentocoele, epiploic
appendagitis and panniculitis 4.
selected cases, where the patient is stable and willing and diagnosis certain,
conservative treatment may be offered and recovery is expected in two weeks 4.
But if the conservative trial fails it may result in formation of
intra-abdominal abscess which may increase the abdominal pain, hospital stay
and cost of treatment.
laparoscopy has now become the diagnostic and therapeutic tool of choice in the
management of omental torsion because low morbidity, rapid
recovery and good aesthetic results that it offers. While doing diagnostic laparoscopy if one comes across a
normal looking appendix and gall bladder along with haemorrhagic/serosanguinous
free fluid in the peritoneal cavity Fig. 1a, possibility of omental torsion
should also be kept in mind and should be actively looked for. It is suggested
that appendicectomy should be done in the same sitting to avoid diagnostic
dilemma in future.