Internal Hernia in Pregnant Woman after Roux-en-Y Gastric Bypass Surgery

Abstract

Laparoscopic Roux-en-Y gastric bypass has become the most common obesity surgery procedure worldwide over the last two decades. Many patients undergoing the procedure are women of reproductive age. This carries a risk for developing gastric bypass-related complications during pregnancy. One of the potentially serious risks is an internal hernia. We present a patient in the third trimester of pregnancy with an internal hernia following a laparoscopic Roux-en-Y gastric bypass for morbid obesity. We discuss the importance of computed tomography (CT) in the diagnosis of an internal hernia and review key CT findings including compression of the superior mesenteric vein, which proved to be crucial in diagnosing the internal hernia in this patient.

Keywords: CT scan; Gastric bypass; Roux-en-Y gastric bypass; SMV beaking sign; SMV compression; internal hernia; pregnancy; swirl sign.

Figure 1

37-year-old pregnant woman with an internal hernia. Findings: Upright abdominal radiograph shows slightly dilated loops of the small bowel in the epigastric region with few air-fluid levels (arrow). The gravid uterus can be seen.

Figure 2

37-year-old pregnant woman with a small-bowel obstruction secondary to an internal hernia. Findings: Axial contrast-enhanced CT image of the abdomen in the portal venous phase demonstrates dilated small bowel loops in the left upper abdominal quadrant combined with a small bowel feces sign (arrows). There is an abrupt small bowel caliber change and obstruction adjacent to the level of jejuno-jejunal anastomosis (arrow head). Technique: Axial CT (Siemen’s SOMATOM Definition AS 128-slice), 388 mAs, 100 kV, 3 mm slice thickness, 120 ml Omnipaque, DLP 745.5 mGycm

Figure 3

37-year-old pregnant woman with an internal hernia. Findings: Axial contrast-enhanced CT series (a, b, c) of the abdomen in the portal venous phase following the course of the superior mesenteric vein craniocaudally. Slices demonstrate the gradual compression of the superior mesenteric vein (black dashed circles), with complete obstruction of the SMV on the last slice. Technique: Axial CT (Siemen’s SOMATOM Definition AS 128-slice), 388 mAs, 100 kV, 3 mm slice thickness, 120 ml Omnipaque, DLP 745.5 mGycm

Figure 4

37-year-old pregnant woman with an internal hernia. Findings: Coronal reconstructed contrast-enhanced CT images (a) of the abdomen in the portal venous phase demonstrate the compression of the main stem of the superior mesenteric vein (arrow), also described in the literature as the SMV "beaking" sign (b magnified). Technique: Coronal reconstructed CT (Siemen’s SOMATOM Definition AS 128-slice), 388 mAs, 100 kV, 3 mm slice thickness, 120 ml Omnipaque, DLP 745.5 mGycm

Figure 5

37-year-old pregnant woman with an internal hernia. Findings: Axial contrast-enhanced CT image of the abdomen in the portal venous phase demonstrates the engorgement of the mesenteric veins (arrow heads), most likely due to the obstruction of the superior mesenteric vein. Note the increase in the density of mesenteric fat due to mesenteric edema and free intraperitoneal fluid (white arrows). Technique: Axial CT (Siemen’s SOMATOM Definition AS 128-slice), 388 mAs, 100 kV, 3 mm slice thickness, 120 ml Omnipaque, DLP 745.5 mGycm