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Swirl Sign
Swirl Sign Mohammad Jamal, MBChB(Hons), MEd, Olivier Court, MD, FRCSC, Jeffrey Barkun, MD, FRCSC McGill University Health Center, Montreal, Quebec
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A 46-year-old woman presented to the emergency department with severe diffuse abdominal pain associated with nausea and vomiting. Six years earlier she had an open Roux en Y gastric bypass. An abdominal CT showed likely internal herniation of a small bowel segment, with a swirl sign of the mesenteric vessels. At laparotomy the entire small bowel had herniated through Petersen’s defect, created by the Roux en Y anatomy,1 between the mesentery of the Roux limb and the transverse mesocolon. The mesentery of the herniated bowel had twisted 360 degrees counter-clockwise around the axis of the mesenteric vessels (A–F, arrows follow the superior mesenteric vein [SMV] as it rotates 360 degrees around the superior mesenteric artery [SMA]). The small bowel was grossly ischemic, and was not salvageable, a resection of the entire small bowel was done. The patient recovered, but was rendered TPN-dependent. In a study by Lockhart et al,2 18 CT scans for Roux-en-Y gastric bypass patients with a proven internal hernia at
© 2009 by the American College of Surgeons Published by Elsevier Inc.
surgery were reviewed by 3 radiologists for 7 known radiologic signs of internal hernia. They found the swirl sign to be the best single predictor of internal hernia. The sensitivity and specificity were 61% and 94% for the first reviewer, 78% and 89% for the second reviewer, and 83% and 67% for the third reviewer. A swirl sign on CT scan in a patient with abdominal pain should always raise the suspicion of an internal hernia.
REFERENCES 1. Koppman JS, Li C, Gandsas A. Small Bowel Obstruction after Laparoscopic Roux-En-Y Gastric Bypass: A Review of 9,527 Patients. Journal of the American College of Surgeons 2008;206(3): 571–584. 2. Lockhart ME, Tessler FN, Canon CL, et al. Internal hernia after gastric bypass: sensitivity and specificity of seven CT signs with surgical correlation and controls. Am J Roentgenol 2007;188: 745–750.
789
ISSN 1072-7515/09/$36.00 doi:10.1016/j.jamcollsurg.2009.05.031
A
B
C
D
E
F
A 46-year-old woman presented to the emergency department with severe diffuse abdominal pain associated with nausea and vomiting. Six years earlier she had an open Roux en Y gastric bypass. An abdominal CT showed likely internal herniation of a small bowel segment, with a swirl sign of the mesenteric vessels. At laparotomy the entire small bowel had herniated through Petersen’s defect, created by the Roux en Y anatomy,1 between the mesentery of the Roux limb and the transverse mesocolon. The mesentery of the herniated bowel had twisted 360 degrees counter-clockwise around the axis of the mesenteric vessels (A–F, arrows follow the superior mesenteric vein [SMV] as it rotates 360 degrees around the superior mesenteric artery [SMA]). The small bowel was grossly ischemic, and was not salvageable, a resection of the entire small bowel was done. The patient recovered, but was rendered TPN-dependent. In a study by Lockhart et al,2 18 CT scans for Roux-en-Y gastric bypass patients with a proven internal hernia at
© 2009 by the American College of Surgeons Published by Elsevier Inc.
surgery were reviewed by 3 radiologists for 7 known radiologic signs of internal hernia. They found the swirl sign to be the best single predictor of internal hernia. The sensitivity and specificity were 61% and 94% for the first reviewer, 78% and 89% for the second reviewer, and 83% and 67% for the third reviewer. A swirl sign on CT scan in a patient with abdominal pain should always raise the suspicion of an internal hernia.
REFERENCES 1. Koppman JS, Li C, Gandsas A. Small Bowel Obstruction after Laparoscopic Roux-En-Y Gastric Bypass: A Review of 9,527 Patients. Journal of the American College of Surgeons 2008;206(3): 571–584. 2. Lockhart ME, Tessler FN, Canon CL, et al. Internal hernia after gastric bypass: sensitivity and specificity of seven CT signs with surgical correlation and controls. Am J Roentgenol 2007;188: 745–750.
789
ISSN 1072-7515/09/$36.00 doi:10.1016/j.jamcollsurg.2009.05.031