You are in: eMedicine Specialties > General Surgery > Abdomen Omental TorsionArticle Last Updated: Sep 6, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 8
  Author: Alan A Saber, MD, Chief, Minimally Invasive Surgery and Bariatric Surgery, Department of Surgery, Assistant Professor, Michigan State University Alan A Saber is a member of the following medical societies: American College of Surgeons, American Society for Bariatric Surgery, and American Society for Gastrointestinal Endoscopy Coauthor(s): Raymond D LaRaja, MD, Chairman, Program Director, Clinical Professor, Department of Surgery, Cabrini Medical Center, Mount Sinai School of Medicine Editors: Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Amy L Friedman, MD, Professor of Surgery, Director of Transplantation, State University of New York Upstate Medical University College of Medicine, Syracuse; Michael E Zevitz, MD, Assistant Professor of Medicine, Finch University of the Health Sciences, The Chicago Medical School; Consulting Staff, Private Practice; John Geibel, MD, DSc, MA, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital Author and Editor Disclosure Synonyms and related keywords: volvulus of the omentum, twisted omentum, acute abdomen, accessory omentum, bifid omentum, omental fat, omentum pedicle, violent exercise, hyperperistalsis, inguinal hernias, abdominal mass, laparotomy, laparoscopy, laparoscopic appendectomy, appendicitis, cholecystitis, twisted ovarian cysts INTRODUCTIONSection 2 of 8
  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. ProblemAlthough 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. FrequencyEitel first described omental torsion in 1899; since then, fewer than 250 cases have been reported. EtiologyTorsion 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. PathophysiologyThe 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. ClinicalTorsion of the omentum is difficult to clinically diagnose preoperatively. Accurate preoperative diagnosis was reported in the range of 0.6-4.8%. 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. WORKUPSection 3 of 8
Lab Studies
Imaging Studies
Diagnostic Procedures
Histologic FindingsAcute hemorrhagic infarct and fat necrosis TREATMENTSection 4 of 8
Surgical therapyTorsion of the omentum is usually discovered during laparotomy or laparoscopy for an acute abdomen. Consider omental torsion if preoperatively diagnosed acute appendicitis is not found and if the gallbladder and ovaries reveal no disease. In addition, the presence of serosanguineous fluid in the peritoneal cavity mandates inspection of the omentum to exclude torsion. Treatment consists of resection of the affected portion of the omentum. Correct any disease process associated with secondary torsion. Preoperative detailsPreoperative differential diagnosis includes acute appendicitis, acute cholecystitis, and twisted ovarian cysts. Intraoperative detailsAn incision centered over the site of maximal tenderness facilitates the operative diagnosis and eases resection of the infarcted omentum. When a healthy appendix is found, search for the cause of the abdominal pain.
OUTCOME AND PROGNOSISSection 5 of 8
Postoperative recovery is usually rapid, and morbidity is minimal. If left untreated, the natural process of omental torsion is necrosis and fibrosis. FUTURE AND CONTROVERSIESSection 6 of 8
With the advent of diagnostic laparoscopy and the increased demand for laparoscopic appendectomy, omental torsion may become a more frequently recognized clinical entity. MULTIMEDIASection 7 of 8
REFERENCESSection 8 of 8
Article Last Updated: Sep 6, 2007 | ||||||||||||
