Retroanastomotic hernia after gastrojejunostomy: US and CT findings with an emphasis on the whirl sign

Retroanastomotic hernia after Moynihan’s gastroenterostomy

Retroanastomotic hernias after gastroenterostomies-either antecolic or retrocolic-are extremely rare but are associated with high mortality rates due to delayed identification which precludes immediate surgical reduction. In this report, we present a 77-year-old man with retroanastomotic herniation of the efferent loop segments that occurred 14 years after a Moynihan’s gastroenterostomy.

Internal hernias after abdominal surgeries: MDCT features

As less-invasive treatments for small bowel obstruction, such as laparoscopic surgery or small incision therapy, have become common, there is a growing demand for preoperative assessment of the cause and location of the small bowel obstruction. Thus, the role of computed tomography (CT) in the evaluation of small bowel obstruction is expanding. CT imaging of internal hernias (IHs) has been extensively described and is well established; however, CT imaging of IH after abdominal surgeries is not well recognized because of their anatomical complexity. The aims of this pictorial review are (1) to evaluate the causes of internal IHs in relation to previous abdominal surgery (e.g., IH associated with Roux-en-Y reconstruction, Billroth II reconstruction, peritoneal adhesive band, perineal hernia, and IH after gynecological procedures), (2) to demonstrate the spectrum of imaging findings on multidetector CT (MDCT), and (3) explain the key features for CT diagnosis of IHs related to previous surgical procedures, with emphasis on the multi-planar reformation (MPR) image. We also demonstrate the dynamic changes in the progression of mesenteric strangulation revealed by CT. Understanding the imaging appearance on MDCT can help radiologists guide therapy for patients with a small bowel obstruction after abdominal surgery.

Trapped on the "whirl": diagnostic sign on emergency CT

The "whirl sign" is an uncommon finding on emergency CT. However, it is easy to overlook if not kept in mind. Its recognition is of capital importance, being most of its causes potentially lethal. Surgical treatment is also mandatory when signs of complication are found. The whirl sign is usually found associated to midgut, cecal and sigmoid volvulus, small-bowel volvulus and closed-loop obstructions, and post-surgical mesenteric windows (including retroanastomotic hernias). CT is an optimal imaging technique to depict the so-called sign and associated CT features suggesting complication (circumferential wall thickening, pneumatosis intestinalis, pneumoperitoneum, mesenteric fat stranding, free intraperitoneal fluid, mesenteric haziness). Radiologists must be able to recognize the whirl sign and seek associated findings that strongly support the diagnosis of a spectrum of entities, some of them lethal if no treatment is established.