Computed tomography findings of intersigmoid hernia

Abstract

Purpose: To evaluate the computed tomography findings of intersigmoid hernias.

Material and methods: Between April 2010 and March 2018, 7 patients who were surgically diagnosed with intersigmoid hernia in 3 institutions were enrolled in this study. Two radiologists evaluated imaging findings for the herniated small bowel, the distance between the occlusion point and bifurcation of the left common iliac artery, and the anatomic relationship with adjacent organs.

Results: All patients were male, and their mean age (standard deviation, range) was 61.0 (13.5, 36-85) years. The mean size of the bowel loops was 5.2 (1.3, 4.0-8.3) cm in the caudal direction, 3.6 (0.8, 2.5-5.1) cm in the lateral, and 3.4 (0.6, 2.5-4.7) cm in the anterior-posterior direction. The volume was 37.9 (27.8, 15.6-103.0) cm³ approximated by an ellipse, and 24.0 (17.7, 9.9-65.6) cm³ approximated by a truncated cone. The obstruction point was located 3.6 (0.6, 2.8-4.7) cm inferior to the bifurcation of the left common iliac artery. In all cases, the small bowel ran under the point at which the inferior mesenteric vessels bifurcated to the superior rectal vessels and the sigmoid vessels and formed a sac-like appearance between the left psoas muscle and the sigmoid colon. The ureter ran dorsal to the point of the bowel stenosis, and the left gonadal vein ran outside the small bowel loops.

Conclusions: All cases showed common imaging findings, which may be characteristic of men's intersigmoid hernia. In addition, the fossa's position was lower, and the size was larger than in the previous study, which may be a risk factor.

Keywords: internal hernia; intersigmoid fossa; intersigmoid hernia.

Figure 1

61-year-old man with intersigmoid hernia. A) Axial and (B) coronal contrast-enhanced computed tomography images show the small bowel loop in the left side of the pelvic space (asterisk). We measured the size of the loop in the lateral and anterior-posterior length at the axial plane and the caudal-cranial length at the coronal plane in each largest section (2-headed arrow)

Figure 2

68-year-old with intersigmoid hernia. Coronal contrast-enhanced computed tomography image shows the strangulated small bowel (arrow). The vertical distance between the bowel occlusion point and bifurcation of the left common iliac artery (asterisk) was measured (2-headed arrow)

Figure 3

85-year-old man with intersigmoid hernia. A-D) Contrast-enhanced computed tomography images in arterial phase from cranial to caudal section. B, C) Small bowel loop (white star) lies between the sigmoid colon and the left psoas muscle (LPM). D) The dilated bowel (black star) runs under the point at which the inferior mesenteric vessels bifurcated to the superior rectal vessels (SRV) and the sigmoid vessels (SV)

Figure 4

85-year-old man with intersigmoid hernia (same case as Figure 3). Contrast-enhanced computed tomography image in delayed phase shows that the left ureter runs dorsal to the point of the bowel stenosis (asterisk), and the left gonadal vein (LGV) runs lateral to the small bowel loop

Figure 5

62-year-old man with intersigmoid hernia. A) Volume rendering (VR) images were created by segmenting each organ in the contrast-enhanced computed tomography images using a 3D-slicer, which is a free, open-source software application for the visualization and analysis of medical image computing datasets. A Front view of the VR image shows the small bowel running under the point that the inferior mesenteric vessels bifurcated to the superior rectal vessels and the sigmoid vessels (yellow arrow). B) Caudal view of the VR image shows the left ureter running dorsally to the stenosis point. The left gonadal vein runs laterally at the small bowel loop (*)