The Omentum Is Your FriendThe Omentum Is Your Friend05-05-2009surgicalinsightsBy Phil Zeltzman, DVM, Dipl. ACVS We’ve all heard it: “The omentum is a surgeon’s best friend.” It is “the abdominal policeman” and “the forgotten organ.” So how can we use it to our advantage in surgery? In the Abdomen The omentum is mostly used in the abdominal cavity. After a gastrotomy, the omentum can be loosely sutured near the incision, effectively creating an omentopexy. . After an enterotomy or enterectomy, the intestine can be wrapped in omentum. Sutures are not even necessary. Omental wrapping, or augmentation, should be done after lavage has been performed. . Similarly, the bladder can be covered with omentum after a cystotomy. Used in this fashion, the omentum promotes vascularization. It brings fibroblasts to the surgical site and enhances healing. The omentum also can help reconstruct the abdominal wall. For example, it can be used between nylon mesh and the skin. The omentum may contain and fight septic peritonitis. It can be used to control mild hemorrhage from the liver or the spleen, as it has hemostatic properties. It can be beneficial to wrap feeding tubes (gastrostomy and enterostomy), as well as cystostomy tubes, with omentum to provide a seal. It is vital, however, not to consider the omentum a substitute for appropriate suturing or ligating technique. Likewise, it will not magically revive a nonviable segment of intestine. After all, the omentum is your friend, not your savior. Physiological Drain A lengthening procedure of the omentum in an 11-year-old male cat with chylothorax. Courtesy of Dr. Phil Zeltzman Thanks to its vascularization, both venous and lymphatic, the omentum can act as a natural or physiological drain. It can help absorb fluids from a variety of locations. For example, a prostatic cyst or abscess can be omentalized. The omentum will promote local angiogenesis and lymphatic drainage, which will help drain the cyst or the abscess. This is clearly a more elegant technique than an older procedure that involved marsupialization or placement of multiple Penrose drains, which exited through the skin. Postoperative care is easier, the rate of complications is lower, and therefore both patient and owners are better off. Similarly, a pyometra stump can be omentalized. In the thorax, the omentum can absorb chyle in a patient with chylothorax. After it is fed through an incision in the diaphragm, the lymphatic network of the omentum absorbs chyle. When a Denver shunt is used in a chylothorax patient, the concept is to redirect the chyle from the thorax into the abdomen. There, it is absorbed by the omentum. Omentalizing the thorax directly, through a tunnel in the diaphragm, is thought to achieve the same result without the use of a synthetic drain. The omentum acts, again, as a physiological drain. While this technique is no panacea, it can complement other techniques in the treatment of chylothorax, a difficult disease to treat. Other Clinical Uses The omentum is an incredibly versatile tool for the surgeon. Used “as is” or after a lengthening procedure, it has a place in other locations: The thorax, to patch the esophagus or the trachea, or to help reconstruct the thoracic wall. The omentum is fed through an incision in the diaphragm. Alternatively, it can be fed through a tunnel in the abdominal wall, a subcutaneous tunnel and an intercostal space as needed. . The axilla, inguinal area, limbs, head and neck can be reached by omentum, which helps with wound healing. Again, the thin membrane is fed through a tunnel under the skin. The omentum can stimulate the formation of granulation tissue. Even chronic or non-healing wounds, once dealt with appropriately, can heal. Omentum also has been used as a non-vascularized free flap to enhance healing of tendon lacerations in dogs. Surely, if we don’t wrap or suture the omentum, the body will spontaneously do it for us. The best proof is the adhesions we see after a second laparotomy. Five Golden Rules While working with the omentum, the surgeon should treat it with the utmost respect. Five golden rules apply: Handle it with caution. It is thin, fragile and tears easily. It shouldn’t be twisted because the vascular supply needs to be preserved. There should be no tension. There should be no crushing injury when it is fed through a tunnel (diaphragmatic or subcutaneous). It should be kept moist at all times using warm, sterile saline. A Quick Review The main part of the greater omentum attaches ventrally to the greater curvature of the stomach and dorsally to the spleen and the pancreas. From there, it extends caudally to cover the abdominal organs. The omentum contains varying degrees of fat, depending on the patient’s body condition score. The omentum has a rich vascular and lymphatic network. It also is rich in “milky spots,” which are a source of white blood cells. They participate in the defense mechanism of the peritoneal cavity. Diseases of Omentum The omentum can be involved in various disease processes. Omental adhesions to organs are common. For example, splenic masses are often covered with such adhesions. They should be carefully ligated before splenectomy is performed. One form of intra-abdominal metastasis is called carcinomatosis, a condition where small cancerous masses are found along the peritoneum, the mesentery or the omentum. As long as it is healthy, the omentum can be used in many simple abdominal procedures. You may want to consider using it during your next bladder, gastric or intestinal surgery. And you can proudly say you performed an omentopexy. <HOME> Dr. Phil Zeltzman is a small-animal board-certified surgeon at Valley Central Veterinary Referral Center in Whitehall, Pa.
