Diagnosis of necrotic and non-necrotic small bowel strangulation: The importance of intestinal congestion.

Background: Despite the prevalence of laparoscopic techniques in abdominal surgeries today, bowel obstruction remains a potentially serious complication. Small bowel strangulation (SBS), in particular, is a critical condition that can lead to patient mortality. However, the prognosis for SBS is favorable if surgery is performed before the onset of necrosis. Non-necrotic SBS is a reversible condition in which blood flow can be restored by relieving the strangulation. The purpose of this study was to identify sensitive and specific contrast-enhanced computed tomography (CT) findings that are useful for diagnosis of both non-necrotic and necrotic SBS. Methods: We included patients diagnosed with SBS and simple bowel obstruction (SBO) who underwent contrast-enhanced CT followed by surgery from 2006 to 2023. Two gastrointestinal surgeons independently assessed the images retrospectively. Results: Eighty SBO and 141 SBS patients were included. Eighty-seven had non-necrotic SBS and 54 had necrotic SBS. Mesenteric edema was most frequently observed in both necrotic and non-necrotic SBS cases followed by abnormal bowel wall thickening. These two findings were observed significantly less frequently in SBO. Bowel hypo-enhancement is identified in only about half of the non-necrotic SBS cases, and it was detected at significantly higher rates in necrotic SBS compared to non-necrotic. Conclusion: Mesenteric edema and abnormal bowel wall thickening are sensitive and specific signs of both non-necrotic and necrotic SBS. These two findings indicate mesenteric and bowel congestion. Detecting intestinal congestion can lead to an accurate diagnosis of SBS, particularly in case of non-necrotic SBS, where bowel hypo-enhancement may sometimes be absent.