EP554 - Short Gastric Division and Postoperative Ileus: Lessons from Omental Flaps in Pelvic Cancer Surgery

Purpose/Background: Omental flap creation or omentoplasty is a versatile tool used across multiple surgical disciplines. Specifically, within colorectal surgery, omental flaps have been used to fill dead space and/or create a biologic barrier between critical structures and compromised tissue such as residual tumor beds, irradiated tissue, and fistula repair sites. However, data on postoperative morbidity—particularly ileus—remain limited. This study evaluates outcomes associated with omental flap use in complex oncologic abdominopelvic surgeries, with a focus on technique-specific complications.

Methods/Interventions: We retrospectively analyzed data from 130 patients treated through our Complex Abdominal and Pelvic Surgery (CAPS) Program between June 2019 and June 2024. Patients who underwent omental flap creation were compared to those who did not. Demographics, surgical complexity, and 30-day complications were reviewed. Statistical analyses included the Wilcoxon Rank Sum to compare continuous variables and Chi-square or Fisher’s exact test to compare categorical data. The primary outcome was postoperative ileus; secondary outcomes included length of stay and operative time.

Results/Outcomes: Of 130 patients, 61 (46.9%) underwent omental flap creation. Baseline demographics were similar between groups. Indications included malignancy (62%) and benign conditions such as fistula, chronic leaks, mesh erosion, and trauma (38%). Flap technique varied: 74% involved a formal flap based on the gastroepiploic artery with division of the short gastrics, while 26% were mobilized off the colon only. Over half (51%) underwent additional flap reconstruction (e.g., vertical rectus myocutaneous or unilateral/bilateral gracilis flaps), range 1-3. Omental flaps were used to secure the intraoperative brachytherapy seed implant mesh in three patients, simultaneously providing separation from organs at risk in our series.

Omental flap patients had a higher 30-day ileus rate (44% vs. 27%, p=0.05). Ileus rates were highest when short gastrics were divided, regardless of approach: 50% in robotic cases (2/4) and 53% in open cases (22/41) (p = 1.0). In contrast, Ileus rates were clinically but not statistically higher among the open/colon-only patients (21% (3/14)) compared to the robotic/colon-only (0.0% (0/2)) (p = 1.0).Operative duration did not differ by presence of ileus (median 547 vs. 500 minutes, p=0.35), but ileus was associated with significantly longer length of stay (median 17 vs. 10 days, p< 0.001).

The rate of wound complications was similar between the omental flap and non-omental flap group: wound infection (5% vs. 3%, p=1.0), deep fluid collection requiring drainage (19% vs. 16.9%, p=1.0), dehiscence (7% vs. 3%, p=0.68). There was no significant difference in post-operative bleeding requiring blood transfusion between both groups (2% vs. 0% respectively, p=1.0).

Conclusion/Discussion: Omental flaps are an important tool in the armamentarium for extirpative surgery as they can be used for a wide range of surgical problems and contribute relatively minimal morbidity. However, division of the short gastric vessels may increase the risk of postoperative ileus. This risk appears lower with colon-only mobilization, particularly via robotic approach. Further prospective studies are warranted to investigate this conclusion further.