Introduction
Torsion of the omentum is a condition in which the organ twists on its long axis to such an extent that its vascularity is compromised. (See image below and Image 1.)
This is an example of primary torsion of the omentum. A normal-appearing omentum can be seen above the torsion point. The omentum below that point is edematous and congested.
Problem
Although omental torsion is rarely diagnosed preoperatively, knowledge of the entity is important to the surgeon because it mimics the common causes of acute surgical abdomen.
Frequency
Eitel first described omental torsion in 1899; since then, fewer than 250 cases have been reported.
Etiology
Torsion of the omentum may be primary or secondary. In primary torsion, a mobile segment of omentum rotates around a proximal fixed point in the absence of any associated intra-abdominal pathology. Although the precise cause is unknown, both predisposing and precipitating factors in the pathogenesis of the condition can be identified.
Factors that predispose a patient to torsion include anatomical variations of the omentum itself, eg, accessory omentum, bifid omentum, irregular accumulations of omental fat (in patients who are obese), and narrowed omentum pedicle. Any redundancy of omental veins may lead to kinking and twisting around the shorter and tenser arteries. The higher incidence of torsion on the right side of the omentum is related to the greater size and mobility of that side.
Precipitating factors are those causing displacement of the omentum, including trauma, violent exercise, and hyperperistalsis with resultant increased passive movement of the omentum.
Secondary torsion is more common than primary torsion and is associated with preexisting abdominal pathology, including cysts, tumors, foci of intra-abdominal inflammation, postsurgical wounds or scarring, and hernial sacs. Most cases of secondary torsion occur in patients with inguinal hernias.
Pathophysiology
The omentum twists around a pivotal point, usually in a clockwise direction. Venous return is compromised, and the distal omentum becomes congested and edematous. Resultant hemorrhagic extravasation creates a characteristic serosanguineous fluid in the peritoneal cavity.
As the torsion progresses, arterial occlusion leads to acute hemorrhagic infarction and eventual necrosis of the omentum occurs. Spontaneous derotation may be possible and may explain omental adhesions in the right lower quadrant, which are often found during laparotomy and have no clear cause.
Presentation
Torsion of the omentum is difficult to clinically diagnose preoperatively. Accurate preoperative diagnosis was reported in the range of 0.6-4.8%.
In a report from Greece, for example, a 14-year-old boy who was admitted to the hospital for acute appendicitis was found during surgery to be suffering from omental torsion on the long axis.1
Omental torsion usually occurs in adults (of either sex). The twisted portion of the omentum tends to be localized to a right-sided segment, thereby giving rise to the sudden onset of pain and signs of peritoneal irritation on the right side of the abdomen. The condition may be associated with nausea, vomiting, or low-grade fever. An abdominal mass may be palpable in half of the patients.
This right-sided acute pain and rebound tenderness is often mistaken for acute appendicitis, acute cholecystitis, or twisted ovarian cysts.
At laparotomy, the finding of free serosanguineous fluid in association with a normal appendix, gallbladder, or pelvic organs should alert the surgeon to the possibility of omental torsion.
More on Omental Torsion |
 Overview: Omental Torsion |
| Workup: Omental Torsion |
| Treatment: Omental Torsion |
| Follow-up: Omental Torsion |
| Multimedia: Omental Torsion |
| References |
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References
Efthimiou M, Kouritas VK, Fafoulakis F, et al. Primary omental torsion: report of two cases. Surg Today. 2009;39(1):64-7. [Medline].
Jeon YS, Lee JW, Cho SG. Is it from the mesentery or the omentum? MDCT features of various pathologic conditions in intraperitoneal fat planes. Surg Radiol Anat. Jan 2009;31(1):3-11. [Medline].
Costi R, Cecchini S, Randone B, et al. Laparoscopic diagnosis and treatment of primary torsion of the greater omentum. Surg Laparosc Endosc Percutan Tech. Feb 2008;18(1):102-5. [Medline].
Adams JT. Primary torsion of the omentum. Am J Surg. Jul 1973;126(1):102-5. [Medline].
Basson SE, Jones PA. Primary torsion of the omentum. Ann R Coll Surg Engl. Mar 1981;63(2):132-4. [Medline].
Beattie GC, Irwin ST. Torsion of an omental lipoma presenting as an emergency. Int J Clin Pract Suppl. Apr 2005;130-1. [Medline].
Lipsett PJ. Torsion of the greater omentum: report of 2 cases. Ann Surg. 1941;114:1026-34.
Mainzer RA, Simoes A. Primary idiopathic torsion of the omentum. Arch Surg. 1964;88:974-81.
Tompkins RK, Sparks FC. Primary torsion of the omentum: mimic of appendicitis. Am Surg. 1966;32:399-402.
Young TH, Lee HS, Tang HS. Primary torsion of the greater omentum. Int Surg. Apr-Jun 2004;89(2):72-5. [Medline].
Zager JS, Gadaleta D, De Noto G. Primary omental torsion in adults: a small series of cases. Contemp Surg. 1999;55(5):261-63.
Further Reading
Keywords
omental torsion, omentum, omental, omental infarction, volvulus of the omentum, twisted omentum, acute abdomen, accessory omentum, bifid omentum, omental fat, omentum pedicle
