OMENTALIZATION, THE PLACEMENT of omentum around organs or within cavities to improve vascularization or drainage, has been used in a variety of abdominal, thoracic, oncologic, and reconstructive surgical procedures.1-3 The omentum has an extensive supply of blood and lymphatic vessels, providing a rich source of inflammatory and immunogenic cells—including neutrophils, T and B lymphocytes, mast cells, and macrophages—that stimulate healing and help prevent and resolve infection.2 The omentum's large surface area also aids in lymphatic drainage and bacteria and particulate matter absorption.3 Additionally, angiogenic factors released from the omentum encourage neovascularization and activation of macrophages, mast cells, and lymphocytes from local tissues.2,4-6
Omentalization is most commonly used to seal intestinal anastomotic sites (see the intestinal anastomosis article).4 Wrapping suture lines with omentum reduces the risk of leakage after end-to-end anastomoses. By adhering to the surgical site, omentum rapidly seals the incision, fills dead space, and provides an environment conducive to healing.6,7 For these reasons, omentalization is also useful for covering enterotomy, gastrotomy, and cystotomy incisions, particularly when the blood supply or tissue health is questionable, and for sealing around feeding tubes exiting the gastrointestinal (GI) tract.
The omentum can be used as a physiologic drain for prostatic, paranephric, pancreatic, and hepatic cysts; prostatic and uterine stump abscesses; and necrotic neoplastic sublumbar lymph nodes.2,4,5,8,9 In refractory cases of chylothorax or pleuritis, an omental flap can be brought through a diaphragmatic incision and sutured to the mediastinum to increase absorption of effusion.1,10
Using omental pedicle grafts to aid in the reconstruction of delayed or infected skin wounds is ideal because of the omentum's many functional characteristics that promote healing. Nonhealing axillary wounds in cats can be covered with a subcutaneously tunneled, extended omental graft and then closed with skin flaps.6 Additionally, a mesh skin graft can be placed directly over a subcutaneous bed lined with an omental flap to provide the graft with a novel blood supply and to encourage its survival.11
TECHNIQUE FOR OMENTALIZATION OF GI SURGERY SITES
An omental patch can be applied to any portion of the GI tract. Distal regions, such as the lower descending colon or rectum, may be reached by developing an omental pedicle extension.4,12 For general perioperative considerations when performing this procedure, including diagnostic testing, patient monitoring, and postoperative support, please see the symposium introduction.
To create an omental patch, tack the omentum over the GI incision site by using multiple simple interrupted sutures of rapidly absorbable monofilament suture. For end-to-end anastomotic sites, suture two portions of the caudal omental fold (the junction of the ventral and dorsal leaves) or the distal edge of an extended flap to either side of the incision line so that each covers half of the circumference of the anastomosis site (Figures 1-4).
To create an omental pedicle extension, exteriorize the omentum and spleen from the abdomen. Retract the dorsal leaf13 of the omentum cranially to expose its pancreatic attachments, and sharply transect them. Ligate or cauterize vessels as they are encountered. Then extend the dorsal leaf caudally, unfolding the omentum and doubling its length. This length is usually sufficient for all abdominal procedures. To achieve full extension, incise the flap in an inverted L-shape on its left side, just caudal to the gastrosplenic ligament.12 The incision should extend one-half to two-thirds the length of the omental width. Continue the incision caudally alongside the omental vessels for up to two-thirds of its length.