Diagnosing internal herniation after laparoscopic Roux-en-Y gastric bypass: usefulness of systematically reviewing CT scans using ten signs

Abstract

• Computed tomography is useful to diagnose internal herniation(IH) after gastric bypass surgery • Ten signs are described to improve CT diagnosis of IH • Systematically reviewing CT scans improves specificity • There is no difference in experience levels when using these ten signs.

Structured CT reporting improves accuracy in diagnosing internal herniation after laparoscopic Roux-en-Y gastric bypass

“…Our findings confirm the assumptions of previous studies, that also found that structured reporting using CT signs improved accuracy [14,16]. However, these previous studies performed blind reading of the CT scans retrospectively and compared them with the original report.…”

“…Most noteworthy, the sensitivity of the swirl sign decreased compared to most previous studies with a comparable increased specificity. However, the accuracy is comparable to a previous study into the ten CT signs, 89.7% compared to 86.5-91.4% [14]. The accuracy of small bowel obstruction, clustered loops, right-sided anastomosis, and enlarged nodes decreased compared to this previous retrospective study.…”

“…All data were entered into a computerised spreadsheet (Excel; Microsoft) and were analysed with Statistical Package for Social Sciences 21.0 (SPSS Inc.). Patient characteristics are listed as mean (± SD) or median (interquartile range (IQR) [14] (25th-75th percentile)), depending on the normality of the distribution. Continuous data were compared with the independent sample t test or Mann-Whitney test for not normally distributed data.…”

“…Part of the control group (1475 patients, undergoing gastric bypass surgery between 2011 and 2015) was previously reported in a study into the use of CT scans in case of suspicion of internal herniation and in a study into the accuracy of CT signs [14,15].…”

“…Recently, a study was performed into the accuracy of ten CT signs: (1) swirled appearance of mesenteric fat or vessels at the root of the mesentery (swirl sign), (2) dilated small-bowel loops with air-fluid levels as a sign of small-bowel obstruction, (3) clustered loops of small bowel, (4) mushroom shape of the herniated mesenteric root with protrusion of bowel between the superior mesenteric artery (SMA) and its branches (mushroom sign), (5) tubular or round shape of distal mesenteric fat closely surrounded by bowel loops (hurricane eye sign), (6) small bowel other than the duodenum passing posterior to the SMA, (7) right-sided location of the distal jejunal anastomosis, (8) the presence of enlarged mesenteric nodes as a secondary sign of lymphatic obstruction from mesenteric torsion (enlarged nodes), (9) tapering of mesenteric veins with subsequent engorgement (venous congestion, also referred to as beak sign), and (10) haziness of the mesenteric fat as a sign of mesenteric oedema (see Fig. 1) [14]. Structured reporting using these CT signs improved the specificity.…”