Omental torsion

　　Omental torsion can be divided into primary and secondary types. Primary torsion is rare, has no obvious cause, may be related to anatomical variations, and is unipolar, that is, a fixed point, which can be complete or incomplete. Secondary torsion is often caused by omental and intra-abdominal lesions, such as tumors, inflammatory foci, or even adhesion to the hernial sac, which is slightly more common than primary torsion and is often bipolar, that is, there are two fixed points.

　　6. Anatomical factors

　　5. The omentum has a high degree of mobility. The omentum is divided into three types according to its lower margin: the upper abdominal type, where the free margin is above the umbilicus, accounts for (13.70±1.86)%, the middle abdominal type, where it reaches the umbilicus and the anterior superior iliac spine, accounts for (46.36±2.60)%, and the lower abdominal type, where the free margin is below the line connecting the two anterior superior iliac spines, accounts for (39.4±2.64)%. The lower abdominal type has a longer lower margin and a greater degree of mobility, so it is more prone to torsion.

　　4. Anatomical variations of the omentum: The right part of the omentum is thicker and longer, some omentums protrude in a lingual shape, some omentums are enlarged with a long pedicle, and there are also accessory omentum and bifurcated omentum, etc.

　　3. Omentum during pregnancy: Due to the enlargement of the uterus, the small intestine and omentum are elevated, and the omentum has varying degrees of coiling.

　　Second, pathological factors

      The omentum vein dilates, the distribution of omental fat in obese patients is uneven, and the adhesion of the omentum caused by intra-abdominal inflammatory lesions, oblique hernia, and postoperative adhesion of the omentum, omental cysts, omental teratoma, omental vascular lipoma, and postoperative torsion of the omentum wrapped around the transplanted spleen lobe, and so on.

　　Third, kinematic factors

      Continuous intense activity and sudden changes in body position can all cause torsion of the greater omentum, especially in the pathological condition of the greater omentum. The greater omentum itself cannot move, but the peristalsis of the gastrointestinal tract can act on the greater omentum. After a sudden change in body position, not only does the greater omentum itself flip, but the peristalsis of the gastrointestinal tract is also a factor causing its torsion. Most people are right-handed, and omental torsion occurs more frequently on the right side. The main reasons not only include the greater omentum being larger and more active on the right side, but also the uneven force of the movement of the lower limbs, which drives the bilateral lumbar muscle groups to act on the abdominal intestinal tract and greater omentum. The result of unbalanced and reverse action is also a cause of omental torsion, and it is also a clockwise torsion.

　　Torsional onset is relatively acute, may resolve, and can recur later. Mild cases may only cause edema and venous congestion in the distal omental tissue. Severe cases can cause circulatory disorders, with the greater omentum presenting purple-black infarctive hemorrhage and necrosis. There is a small amount of blood-containing exudate in the peritoneal cavity, with varying sizes of infarction, with larger ones having a diameter of 20cm or more. The omental segment with torsional infarction can gradually form fibrotic mass-like substances, and even may fall off to become free floating objects in the peritoneal cavity.It can be accompanied by gastrointestinal symptoms, such as nausea and vomiting. The body temperature is usually not high or only slightly elevated, and in a few cases, it is of moderate degree. The longer the duration of the lesion, the higher the body temperature..

      Omental torsion is a rare disease, commonly occurring in middle-aged individuals, with twice as many men as women. Although the greater omentum in children is not fully developed and is shorter, torsion can also occur. Abdominal pain is the main symptom of omental torsion, most often occurring in the right lower quadrant, presenting as a dull or bloated pain. Initially, it may be tolerable, but it gradually becomes persistent pain with intermittent exacerbations. According to statistics, 80% of patients with right lower quadrant pain, and 10% with right upper quadrant pain. About half of the patients experience nausea and vomiting. Fever may be accompanied if there is an infarction.

　　Regardless of primary or secondary, patients usually seek medical attention for abdominal pain in the early stage, which is often a subacute process. However, about half of the patients experience sudden onset of abdominal pain, which is persistent and gradually intensifies. The pain starts from the umbilical area and then spreads to the entire abdomen. In the early stage, it is often limited to the right lower quadrant of the abdomen, and activity can exacerbate the pain, while rest usually does not alleviate it. The pain does not ease with changes in body position, which is due to the traction of the root of the greater omentum in the early stage, stimulation of the autonomic nerves, and is manifested as不定性 pain around the umbilicus or under the xiphoid process. When the greater omentum becomes ischemic and necrotic, the pain becomes fixed at the site of torsion, and a mass can be felt in the abdomen, but most cannot be felt. There is no mobile dullness when percussed, bowel sounds are normal or decreased, and in a few cases, bowel sounds are hyperactive.

　　Omental torsion refers to the rotation of the greater omentum around its longitudinal axis, leading to torsion of the greater omentum and causing circulatory disturbances in its blood supply. For some individuals with obesity and uneven distribution of omental fat, those with adhesions of the greater omentum caused by intra-abdominal inflammatory lesions, as well as those with adhesions of the greater omentum after abdominal surgery and those who suddenly change body positions after sustained剧烈 movement, the prevention of omental torsion is of utmost importance. During the acute attack phase, it is not suitable to eat or drink, and it is necessary to seek timely medical attention from a regular hospital's surgery department and receive targeted treatment.

　　Most cases of mesenteric torsion are counterclockwise, and the torsion can reach several weeks. Routine blood tests show normal white blood cells or slightly increased moderate rise. After mesenteric torsion, there may be hemorrhagic effusion in the abdominal cavity, so diagnostic peritoneal puncture has special diagnostic value. CT and MRI scans show that the mesentery containing fibrous strands and fat radiates to the site of torsion, but both sensitivity and specificity are not high. Ultrasound or color Doppler ultrasound can show irregular masses with unclear boundaries in the abdominal cavity, while the gallbladder, pancreas, ovary, appendix, and other organs are normal. Therefore, ultrasound can be used as the first-line auxiliary examination for suspected mesenteric torsion, but the diagnosis rate is not high due to limitations in diagnostic technology.

　　Patients with mesenteric torsion should eat foods with mild flavors and properties, foods that improve gastrointestinal motility, and high-fiber foods. Spicy and刺激性 foods, as well as fried and rough foods, and dry, difficult-to-digest foods should be avoided. Diet should be followed according to the doctor's guidance.

　　Once diagnosed with mesenteric torsion, the twisted mesentery should be surgically removed immediately. The excision range should include the part with secondary venous thrombosis, which is about 2-3 cm above the torsion site. Early consultation, simple surgery, and definite efficacy. If treatment is delayed, serious consequences may occur. The mesentery in children is shorter, usually above the umbilical plane. During pregnancy, the mesentery is also often above the umbilical plane. Clinical diagnosis and differential diagnosis are difficult when the mesentery twists. According to the above principles, it is even more important to be careful. When there are indications for laparotomy, timely surgical exploration should be performed to carry out diagnosis and treatment simultaneously to avoid delaying the condition and increasing the patient's suffering. Especially for those with migratory right lower abdominal pain, but with clinical manifestations that are different from acute appendicitis, the incision should be made along the outer margin of the right rectus muscle. If the inflammation of the appendix or the degree of inflammation of appendicitis does not correspond to its clinical manifestations during surgery, the organs and tissues in the abdominal cavity should be explored. In addition to exploring the distal ileum, attention should be paid to exploring the mesentery.