Case

A 75-year-old man presented to this hospital with abdominal pain. The patient described the sudden onset of: left lower quadrant pain nine-out-of-ten in severity, associated with multiple episodes of bilious vomiting. The patient had not had a bowel movement in 4 days. Physical examination was notable for tenderness to palpation and guarding in the left lower quadrant. Computed tomography of the abdomen and pelvis without contrast material was completed, and demonstrated a closed-loop bowel obstruction involving an ileal loop (Figs. 1, 2). The patient underwent an exploratory laparotomy, which confirmed an ischemic closed-loop obstruction. A small bowel resection was performed (Fig. 3), and the patient recovered uneventfully.

Fig. 1
figure 1

Axial, oblique coronal, and coronal images from computed tomography without intravenous or oral contrast material demonstrating adjacent dilated loops of small bowel in the left lower abdomen (asterisk) with proximal (solid arrow) and distal (dotted arrow) transition points, consistent with a closed-loop bowel obstruction. Wall thickening (arrowheads) and mesenteric congestion (m) suggest ischemia

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Fig. 2
figure 2

Sagittal oblique reformatted image demonstrating the closed-loop bowel obstruction (arrows)

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Fig. 3
figure 3

Single intraoperative photograph demonstrating a grossly ischemic small bowel with the closed-loop obstruction

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Discussion

A closed-loop obstruction is a mechanical obstruction in which a single segment of bowel is obstructed at two locations (Fig. 4) [1–4]. Adjacent segments may form a narrow pedicle, leading to rotation, twisting, and volvulus formation (Fig. 5) [2]. Such obstructions are most frequently caused by adhesions, and less commonly by herniations [2].

Fig. 4
figure 4

Schematic diagram demonstrating a single segment of bowel obstructed at two adjacent locations, consistent with a closed-loop obstruction

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Fig. 5
figure 5

Schematic diagram demonstrating the formation of a narrow pedicle leading to rotation, twisting, volvulus, and strangulation

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As demonstrated in this case, computed tomography frequently reveals a ‘C-shaped’ configuration of dilated, fluid-filled bowel with twisting mesenteric vessels converging toward the site of obstruction [3, 4]. A ‘beak sign’ or tapering of the bowel at the point of obstruction or a ‘whorl sign’ reflecting rotation of the bowel around a fixed obstruction may be observed [3, 4]. Signs of strangulation include lack of mural enhancement after contrast administration, mural thickening, surrounding mesenteric fluid, and pneumatosis intestinalis [5].

A closed-loop obstruction is a surgical emergency and requires urgent laparotomy.