5.1. Literature Search

A literature search was done from 1986 until 2024 on PubMed. We searched with the titles and abstract (tiab) function with Omentum AND Infarction, Omentum torsion. We initially found 9883 articles, we then excluded the duplicates and uploaded to RAYYAN and we included patients of all ages, gender and diagnosis of omental infarction and omental torsion. We excluded omental infarction from a hernia and epiploic appendagitis. This exclusion was done as omental infarct secondary to hernia is usually managed by operative repair and epiploic appendagitis should be managed conservatively. From this initial search, we found only 126 articles. We further searched for Grey literature from Google Scholars and references of the literature that has a literature review and other published articles. We further found 220 articles. We then further excluded the duplicates and then, we extracted data which are summarised in (supporting information). We excluded 32 articles from the analysis because they were either not accessible, not archived or the journals were disbanded.

We found a total of 479 cases from 236 articles. The condition showed a higher prevalence in males with a 2:1 ratio. There were three times more adults over 18 years old who presented with omental infarction. Not all patients were investigated with bloods or scans. Out of 368 (76.8%) that had blood investigation, 179 patients had normal white cell count and 189 patients with raised white cell count. There were 130 (27.1%) patients tested with CRP and 104 (80%) of them were raised. Three hundred and forty nine (72.9%) patients were not investigated with CRP. CT scans were done to 245 (51.1%) patients and was considered the most reliable diagnostic tool, followed by ultrasound that was done in 209 (43.6%) cases. While 153 cases were initially managed conservatively, 32 required surgical intervention due to treatment failure. Overall, surgical management was performed in 358 cases, including those that failed conservative management. Intraoperative findings frequently revealed omental torsion with necrosis, serosanguineous fluid and mesenteric lymphadenopathy, which was histologically confirmed with inflammation, venous congestion and thrombosis. Omental torsion was diagnosed in 220 patients (45.9%); in this group, 194 (88.2%) patients were treated surgically, 21 (9.5%) underwent surgery after failed conservative management and only five (2.3%) were successfully treated conservatively. Out of 32 patients who failed conservative treatment, 65.6% of them were diagnosed as omental torsion. The collated data extracted from the articles provided clinical decisions made by clinicians globally. These decisions were carefully represented as a flowchart for the management of omental infarction and omental torsion (Figure 4).

Clinically all patients reported in this search presented symptoms like acute appendicitis as well as biliary colic which was then investigated with abdominal ultrasound. This increases the diagnostic difficulties without imaging. Where centres did not use imaging such as CT scan or ultrasound scan because of local policies, they would often find a normal appendix or gall bladder and would perform omentectomy with or without taking the appendix out. Ultrasound will usually show a negative finding of the two common working diagnoses which helps clinicians to decide for CT scans [3, 6, 7]. CT will then provide a definitive diagnosis of omental infarction with radiological findings of fat stranding and or whirl sign as demonstrated in Figures 1 and 2 [3, 7, 8]. Omental torsion could additionally be diagnosed when pedicle sign is present [9–12]. With the definitive diagnosis, the decision to operate becomes unclear as there is no consensus between clinicians whether to operate or not [2–4]. Many patients have been successfully treated with conservative management which shifts the attention away from operative management [13, 14]. This, however, is not the case as some patients fail conservative management, and their intractable abdominal pain resolves with surgical resection of the omentum [2, 4, 15].

Conservative management should always be considered as up to 23.6% of cases reported from our literature search suggests that it is successful. Although a large majority of 76.4% of cases were successfully managed with surgical resection, the authors believe most surgeons globally opt to operate instead of a conservative approach. What was found to be interesting were the 32 patients that failed conservative management. About two-thirds of these patients have torted omentum (Table 1). Some cases of omental infarction even reported the omentum to be twisted up to 18 times [9]. In which case, it would be sensible to decide for surgery to remove the torted tissue causing ischaemia and intractable abdominal pain. Among those diagnosed with omental infarction without torsion, almost half of them were successfully treated conservatively. These patients presented with omental infarction for the first time (Table 1). Within this group, only 4.2% experienced failed conservative management which is reassuring considering the high success rate with conservative management. In our hospital, because our population of patients usually stay more than 2 h of commuting distance, our consultants have decided that surgery will provide a definitive management for our patient. The role of minimally invasive surgery can also benefit patients undergoing surgery for omental infarction in terms of scaring, postoperative pain management and days of hospital stay. Many cases from our literature search has performed them, but were not analysed as there were missing data from the reported cases. From the literature, most if not all patients were discharged within the same day of operation which includes both open and laparoscopic approach.

The clinical features of omental infarction are often similar to many causes of acute abdomen which makes it challenging to diagnose clinically. Although omental infarction is considered to be a rare cause of abdominal pain, a total of 479 cases were collated and it is probably under-reported in the literature.