Omentectomy: Surgical Perspectives and Metabolic Connections

The omentum, a fatty tissue in the abdominal cavity, plays a role in immune function, metabolism, and disease processes. Omentectomy, the surgical removal of part or all of this tissue, is performed for conditions such as cancer, infection, or metabolic research. Understanding its implications helps clarify both potential benefits and risks.

Anatomy And Function Of The Omentum

The omentum consists of two sections: the greater omentum and the lesser omentum. The greater omentum, a large apron-like fold of peritoneal tissue, extends from the stomach and drapes over the intestines, while the lesser omentum connects the stomach and liver. These structures contain adipose tissue interwoven with blood vessels, lymphatics, and connective tissue, acting as a dynamic interface between the digestive organs and the rest of the body.

Its extensive vascularization supports the transport of nutrients, hormones, and signaling molecules, helping modulate local tissue environments in response to injury or inflammation. The omentum also contains milky spots—clusters of specialized cells that aid in fluid absorption and molecular exchange within the peritoneal cavity. These features enable it to function beyond simple fat storage.

The omentum plays a protective role by adhering to damaged or inflamed tissues, limiting the spread of infections or perforations within the gastrointestinal tract. This adhesive property has been observed in clinical settings, where it naturally migrates to sites of injury, reinforcing compromised areas and promoting tissue repair. Surgeons sometimes use the omentum in reconstructive procedures to enhance healing.

Tissue Composition And Immune Role

Though primarily composed of adipose tissue, the omentum contains a specialized microenvironment enriched with immune-related structures. Its adipocytes are interspersed with stromal cells, fibroblasts, and an extensive network of blood and lymphatic vessels. Within this matrix, the omentum houses milky spots—lymphoid structures that facilitate interactions between macrophages, B cells, T cells, and dendritic cells. These milky spots enable the omentum to detect and respond to pathogens, foreign particles, and inflammatory stimuli within the peritoneal cavity.

Omental immune cells actively modulate inflammation and contribute to tissue repair. Macrophages within milky spots can shift between pro-inflammatory and anti-inflammatory states, depending on the conditions. This adaptability is evident in infections and post-surgical settings, where omental macrophages either enhance pathogen clearance or promote resolution of inflammation to prevent tissue damage. The omentum also produces cytokines and chemokines that influence systemic immune responses.

Another distinctive feature is its role in immune tolerance. Unlike lymph nodes, which often mount aggressive responses, the omentum promotes immune regulation. This has implications in conditions such as peritoneal carcinomatosis, where tumor cells exploit the omental environment to evade detection and establish metastatic sites. Studies suggest omental immune cells may suppress anti-tumor immunity, allowing malignant cells to proliferate. This has drawn interest in oncology, as targeting the omentum’s immune components could offer new therapeutic strategies.

Surgical Approaches In Omentectomy

Omentectomy can be performed using different techniques, depending on the condition, disease extent, and patient factors. Traditionally, an open approach is favored for cases requiring extensive tissue removal, such as advanced malignancies where complete resection is necessary. A midline laparotomy provides direct access to the abdominal cavity, allowing thorough inspection and dissection. While open surgery offers superior visibility, it involves longer recovery times and higher risks of complications such as adhesions or infections.

Minimally invasive techniques, including laparoscopic and robotic-assisted omentectomy, have gained traction due to reduced surgical trauma. Laparoscopic omentectomy involves small incisions through which specialized instruments and a camera are inserted, enabling precise excision with minimal disruption to surrounding tissues. This approach is particularly useful for early-stage malignancies, benign tumors, and metabolic research. Robotic-assisted surgery further refines this technique by providing enhanced dexterity and visualization, making it advantageous for complex resections.

The extent of omentectomy—partial or total—depends on the clinical indication. In cytoreductive surgery for ovarian or gastrointestinal cancers, a total omentectomy is often performed to eliminate potential sites of tumor dissemination. In contrast, a partial omentectomy may be sufficient for localized lesions or conditions where preserving some omental function is beneficial. Imaging techniques such as CT or MRI guide surgical planning, ensuring optimal outcomes.

Relationship To Metabolic Processes

The omentum’s involvement in metabolism stems from its distinct adipose composition and proximity to digestive organs. Unlike subcutaneous fat, which primarily stores energy, omental adipose tissue exhibits high metabolic activity, influencing lipid storage, insulin sensitivity, and systemic energy balance. Studies show omental fat has a greater density of blood vessels and a heightened capacity for lipolysis, allowing it to rapidly release fatty acids into circulation. This is linked to conditions such as insulin resistance, where excessive fatty acid flux contributes to impaired glucose uptake and increased hepatic glucose production.

Beyond lipid metabolism, the omentum produces adipokines such as leptin and adiponectin, which regulate appetite, inflammation, and insulin responsiveness. Leptin communicates with the hypothalamus to modulate hunger and energy expenditure, while adiponectin enhances insulin sensitivity and promotes fatty acid oxidation. Reductions in omental mass following surgery have been associated with changes in these hormone levels, potentially impacting metabolic homeostasis. Some studies have explored omentectomy as an adjunct to bariatric surgery, hypothesizing that removing this fat depot could enhance insulin sensitivity and reduce diabetes risk.

Differences In Partial Vs Total Omentectomy

The choice between partial and total omentectomy depends on pathology, disease extent, and potential metabolic consequences. While both procedures involve resecting omental tissue, the degree of removal influences recovery, immune function, and long-term physiological effects. Surgeons carefully weigh these factors, particularly in cases where preserving some omental function may be beneficial for peritoneal healing and fluid dynamics.

Partial omentectomy removes only a segment of the omentum, typically for localized disease or diagnostic purposes. This approach is used for isolated metastases, benign cysts, or select inflammatory conditions where complete excision is unnecessary. By preserving part of the omentum, surgeons retain its role in tissue repair and fluid homeostasis, potentially reducing post-operative complications such as adhesions or impaired healing. Some metabolic research suggests that leaving part of the omentum intact may help maintain adipokine signaling and metabolic stability.

A total omentectomy is often performed in oncologic surgery for cancers such as ovarian, gastric, or colorectal malignancies with a high risk of peritoneal spread. This procedure removes all omental tissue, reducing residual tumor burden and improving prognosis. However, eliminating the entire omentum may have broader physiological consequences, including alterations in lipid metabolism and immune responses. Some studies suggest total omentectomy affects insulin sensitivity and inflammatory markers post-surgery. While its benefits in cancer treatment are clear, ongoing research aims to better understand its long-term metabolic and immunologic effects.