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At laparoscopy, the colon was quite distended with distortion of the normal anatomy in the epigastrium by mass effect. There was herniation of the ascending colon into the lesser sac, displacing the stomach anteriorly and laterally. Two working 5-mm ports were placed. The patient was placed in reverse Trendelenburg position to further facilitate exposure. Using gentle, persistent traction and countertraction with atraumatic graspers, the colon was reduced from the lesser sac and out of the foramen of Winslow back into its normal anatomic position. After reduction, we noted that our patient had a mobile right colon, as well as a marginally enlarged foramen. The involved segment of colon was pink and viable. No attempt was made to close the defect (Figure 3). The patient was discharged home on postoperative day 2, and to date there has been no recurrence.

Previously, Van Daele and colleagues¹ reported what was believed to be the first documented laparoscopic reduction of a foramen of Winslow hernia. On review of the literature, it seems that Webb and Riordan² may have predated them with their case report of internal herniation of the cecum in 2009. Both groups discuss successful use of minimally invasive techniques for reduction of the hernia. In those cases, as in the one presented herein, the preoperative recognition of the possibility of an internal hernia made radiographically—specifically with CT—followed by prompt exploration afforded the best outcomes.

An internal hernia is a protrusion of a viscus from its normal position through a peritoneal or mesenteric orifice.³ It may be congenital or acquired. Internal hernias may be further subdivided, depending on their location, into paraduodenal, transmesenteric, pelvic, transomental, pericecal, and foramen of Winslow hernias.^3- 4 Internal hernias constitute 1% to 5% of all hernias, and foramen of Winslow hernias are estimated to make up about 8% of this select group.⁵

The foramen of Winslow forms a window between the greater and lesser sacs; however, herniation through this location is rare because the hepatic flexure and transverse colon, with its attached greater omentum, normally prevent bowel from migrating near the foramen.⁶ Historically, this has been an intraoperative diagnosis, with only a handful of cases being diagnosed preoperatively. Nevertheless, the routine use of ever-faster and higher-section CT scans in our emergency department are sure to change this, particularly when the following imaging clues are appreciated: (1) displacement of the stomach laterally and anteriorly, (2) gas in the lesser sac, (3) CT features of mesenteric fat and vessels posterior to the portal triad, or (4) a “bird's beak” pointing toward the foramen.⁷

The clinical symptoms of a foramen of Winslow hernia are nonspecific and can mimic seemingly benign abdominal complaints that further predispose these internal hernias to an insidiously higher mortality rate, likely due to delay in diagnosis. A laparoscopic approach is reasonable in a stable patient. Operative findings of bowel ischemia or gangrene should prompt one to strongly consider conversion to an open approach because the bowel's architecture will be less forgiving of the shearing forces required for reduction and the risk of perforation or injury to the portal structures increases. Finally, there have been no reports of recurrence, and closure of the defect has been associated with portal vein thrombosis and probably should not be attempted.^8- 9

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