Full text of DOI:10.1007/s005950070125

Surg Today (2000) 30:544–547
Herniation Through Both Winslow’s Foramen and a Lesser Omental
Defect: Report of a Case
Yoshihisa Saida, Jiro Nagao, Makoto Takase, Yasumitsu Noto, Shinya Kusachi, Yoshihiro Kajiwara,
and Yoshinobu Sumiyama
Third Department of Surgery, Toho University, School of Medicine, 2-17-6 Ohashi, Meguro-ku, Tokyo 153-8515, Japan
Abstract: The herniation of small bowel through Winslow’s
foramen is a rare type of internal hernia which can cause ileus;
however, a hernia traversing the lesser sac is even more un-
usual. To the best of our knowledge, only 25 cases of hernia-
tion through Winslow’s foramen and 10 cases of lesser sac
hernia have been reported in the Japanese literature. We
describe herein the case of a 33-year-old man who presented
to our hospital complaining of abdominal pain in whom a
plain abdominal radiograph revealed small bowel gas with air-
fluid levels, suggesting ileus. Following admission, an ileus
tube was inserted, but the intestinal shadow did not improve
and surgery was performed based on suspicion of an internal
hernia. Approximately 100cm of ileum was found to have
herniated through a defect in the lesser omentum after passing
through Winslow’s foramen. Since the herniated bowel was
viable, manual reduction without resection was performed.
The patient had a satisfactory postoperative course, and was
discharged on postoperative day 11. There are many unknown
aspects surrounding the etiology of Winslow’s foramen hernia
and lesser sac hernia, and although internal hernia is a rare
cause of ileus, its possibility should be kept in mind.
Case Report
A 33-year-old man was admitted to our hospital with a
3-day history of acute abdominal pain and nausea, the
cause of which was nonspecific. His family history was
unremarkable and he had never undergone surgery or
suffered abdominal trauma. The patient appeared well
nourished, being 167cm tall and weighing 58kg. His
temperature was 37.6°C, pulse 66bpm, and blood pres-
sure 160/99mmHg. The abdomen was slightly distended
and tender in the epigastral region, but Blumberg’s sign
and muscular defense were not observed.
Blood tests on the first day of hospitalization revealed
leukocytosis of 12000mm3 and a high C-reactive protein
of 8mg/dl. Significant dilation of the proximal small
bowel was evident on an abdominal plain radiograph
taken the same day. A computed tomography (CT) scan
showed obvious dilation of the small intestine but no
abnormality in the omental bursa.
Another abdominal radiograph taken after the inser-
tion of an ileus tube on the second day of hospitalization
showed a dilated proximal small bowel, niveau forma-
tion in the slightly lower portion of the mediastinum,
and gas in the distal small bowel in the right upper
abdomen (Fig. 1). Thereby, an ileus was diagnosed and
a preservative was administered before ileus tube inser-
tion; however, no movement of the ileus tube was ob-
served and the abdominal pain became more severe.
Furthermore, Blumberg’s sign and muscular defense
subsequently developed, and the leukocyte count in-
creased to 14800/mm3. Thus, the patient was transferred
to the department of surgery where an emergency lap-
arotomy was performed for a suspected internal hernia
or adhesive ileus. The intraoperative findings are shown
in Figs. 2 and 3. Through a midline incision, 600ml of
bloody ascites was drained, and dilated, edematous,
deep-red small intestine was observed. The small intes-
tine was found to have traversed the transverse colon
and entered Winslow’s foramen. Moreover, 100cm of
Key Words: internal hernia, hernia through Winslow’s fora-
men, lesser omental hernia
Introduction
A lesser omental traversing hernia, which is an ex-
tremely rare type of internal hernia, can cause strangu-
lated ileus. We report herein the first known case of
a lesser omental traversing hernia occurring with a
Winslow’s foraminal hernia. We also discuss the best
way of establishing a preoperative diagnosis and review
the available literature on these unusual types of hernia.
Reprint requests to: Y. Saida
(Received for publication on May 6, 1999; accepted on Jan. 7,
2000)

Y. Saida et al.: Winslow’s Foraminal and Lesser Omental Hernia
545
Fig. 3. Intraoperative findings, showing an internal hernia of
about 100cm of small intestine that had extruded through
Winslow’s foramen and an abnormal defect in the lesser
omentum (arrows)
Table 1. Causes of ileus in patients without any surgical
history (Third Department of Surgery, Toho University:
1988–1997)
Causes
Number (%)
Colorectal cancer
External hernia
Colonic volvulus
Internal hernia
Small intestinal tumor
Adhesion
Inflammatory stenosis
Foreign body
Others
54 (46)
26 (22)
12 (10)
5 (4)
Fig. 1. Radiograph done after the insertion of an ileus tube.
This image shows dilated proximal small bowel and niveau
formation in the slightly caudal portion of the mediastinum.
Gas was evident in the distal small bowel in the right upper
abdomen
5 (4)
5 (4)
4 (3)
3 (3)
4 (3)
Total
118
tum was sutured; however, Winslow’s foramen was not
sutured. Because the strangulated intestine was viable,
bowel resection was not necessary and no other ab-
dominal abnormalities were discovered.
Postoperatively, the intestinal paralysis resolved and
the patient was discharged from hospital 11 days after
his operation. He has experienced no further symptoms
in the subsequent 5 months.
Discussion
Fig. 2. Intraoperative findings, showing an abnormal defect in
the lesser omentum of the stomach
Internal hernias are uncommon and account for only
0.5% of all operations for ileus.1 In our department, 118
cases of ileus occurring in patients with no history of
surgery have been recorded. These were predominantly
due to colorectal cancer (46%) and an internal hernia
was found in only 5 cases (4%) (Table 1). Ikeuchi et al.
reported that internal hernias were mostly comprised of
ileum that had herniated through an abnormal defect in
the lesser omentum was outside the omental sac, caus-
ing an ileus. The herniated intestine was able to be
manually repositioned, and the hole in the lesser omen-

546
Y. Saida et al.: Winslow’s Foraminal and Lesser Omental Hernia
mesenteric hernias (56%), paraduodenal hernias, and
omental traversing hernias, whereas foraminal hernias
and lesser omental traversing hernias accounted for
only 4.6% and 0.8% of cases, respectively.2 In fact, to
the best of our knowledge a foraminal hernia occurring
in association with a lesser omental traversing hernia
has never before been reported in the medical litera-
ture, and the present case should therefore be regarded
as exceedingly unique. In Japan, 24 cases of Winslow’s
foraminal hernia have been reported,3–6 for which there
appears to be no common causative factor. Of these 24
patients, 14 (58%) were male and 11 female, and their
ages ranged from 8 to 84 years. The herniated organ was
the small intestine in 84% (21 patients), and the colon
or gallbladder in the rest. The possible causes of forami-
nal hernia include anatomical abnormalities such as
a dilated Winslow’s foramen, incomplete fixation of
the cecum or ascending colon, an unusually long
mesenteriolum, an irregularly short transverse mesoco-
lon, omental atrophy, hepatomegalia in the right lobe,
and a choanoid foramen resulting from adhesions.
However, in our patient, the Winslow’s foramen was
normal and no anatomical abnormality, apart from the
defect in the lesser omentum, was noted. Thus, a
Winslow’s foraminal hernia should be suspected if ra-
diographs show an air-distended small intestine in an
extreme cranial position in the upper abdomen.3,5,7 It
has been proposed that a CT scan might feasibly pro-
duce accurate images of the impacted and dilated small
bowel in the lesser omental sac;8,9 however, making a
diagnosis noninvasively in our patient proved difficult
because of the unusual herniated course of the small
intestine and the normal location of the small intestine
after reherniation through the defect of the lesser
omentum. Radiography done following the insertion of
an ileus tube might show a strangulated small intestine
in the omental bursa, because the normally distal side of
the ileum is found in cases of Winslow’s foraminal her-
nia in an extreme cranial position. The most appropri-
ate treatment of Winslow’s foraminal hernia depends
on the condition of the herniated intestine. If intestinal
necrosis is evident, bowel resection is indicated, but if it
is not, then repositioning the intestine without suturing
the Winslow’s foramen is sufficient.10 There have been
no reports of the recurrence of Winslow’s foraminal
hernia, and postoperative mortality is less than 5% in
Europe and America11 and 0% in Japan.
The present case of an internal hernia occurring due
to an abnormal defect of the lesser omentum is the tenth
to be documented in Japan12–20 (Table 2). The incidence
by sex was identical, and the majority of patients were
aged between 19 and 34 years old. Strangulated intes-
tines were seen in all patients, involving the ileum in
most. The cause was unclear in the majority of patients,
although congenital abnormality21 and trauma22 were

Y. Saida et al.: Winslow’s Foraminal and Lesser Omental Hernia
547
7. Hatashi Y, Iguma T, Gotou Y, Uchiyama M (1985) Two cases of
internal herniation through the foramen of Winslow (in Japa-
nese). Rinsho Geka (J Clin Surg) 40:1767–1769
both reported. The fact that 4 of the 10 cases were
complicated with a greater omental foraminal hernia
suggests the presence of congenital abnormalities. Un-
fortunately, establishing a preoperative diagnosis is dif-
ficult, although one report of a foraminal hernia being
diagnosed by CT scan21 has been reported. All cases in
Japan have thus far been diagnosed intraoperatively
after suspicion of an acute abdomen or ileus; therefore,
the possibility of an internal hernia should be consid-
ered during surgery for ileus. The procedure for treating
hernias traversing the lesser omentum is nearly identi-
cal to that for treating Winslow’s foraminal henrias. In
all except the report by Kikuchi et al.,18 suturing of the
defects was described and no postoperative complica-
tions or deaths were reported. Therefore, appropriate
surgical treatment for hernias through Winslow’s fora-
men and defects of the lesser omentum can result in an
entirely satisfactory outcome.
In conclusion, the case report presented herein de-
scribed a Winslow’s foraminal hernia complicated by a
lesser omental traversing hernia. Both types of hernia
are rare, and their causes are uncertain. Because estab-
lishing a preoperative diagnosis is difficult, surgeons
must be mindful of the possibility of an internal hernia
when treating ileus in a patient without any history of
abdominal surgery.
8. Shimizu M, Ohshima Y, Watanabe R, Matsui K, Miyauchi K,
Nishi Y, Morise M, Egashira K, Nakamura H, Kayama H (1991)
A case of hernia through the foramen of Winslow (in Japanese).
Nihon Kyukyu Igakukaizasshi (J Jpn Assoc Acute Med) 2:377
9. Yoshida K, Hirano T, Kusano H, Nishida T, Hisamatu T, Shimizu
T, Nakagoshi T, Miura T, Tomita M (1992) Herniation through
the foramen of Winslow (in Japanese). Fukubu Kyukyu-
shinryouno Shinpo (Prog Acute Abdom Med) 12:569–573
10. Tran TL, Pitt PC (1989) Hernia through the foramen of Winslow.
A report of two cases with emphasis on plain film interpretation.
Clin Radiol 40:264–266
11. Richardson JB, Anastopoulos HA (1981) Hernia through the
foramen of Winslow. MD State Med J 30:56–59
12. Yamazaki Y, Isohashi T, Ookawa H, Takahashi K (1967) Two
cases of intestinal obstruction due to a hernia traversing the lesser
sac (in Japanese). J Jpn Surg Soc 68:303
13. Fukagawa H, Taniguchi T, Watanabe M, Hanaya Y, Yokoyama S,
Yokoyama I, Arai T, Yamada Y, Saitou T (1982) A case of
internal hernia caused by abdominal foramen of the lesser omen-
tum (in Japanese). Rinsho Geka (J Clin Surg) 37:1287–1289
14. Suenaga T, Baba K, Toshinaga R (1987) A case of internal hernia
through the defect of the greater and lesser omentum (in Japa-
nese). Nihon Shoukakigeka Gakkaizasshi (Jpn J Gastrol Surg)
20:486
15. Horikoshi M, Nakamura S, Fujii T, Asanuma K, Ishii N (1988)
Two cases of internal hernia (in Japanese). Nihondaigaku
Igakukaizasshi (J Nihon Univ Med Assoc) 47:94
16. Yasuda S, Inatsugi N, Sakurai T, Nakamura H, Hashimoto T,
Shiratori T (1989) A case of intestinal obstruction due to a hernia
traversing the lesser sac. Jpn J Surg 19:70–73
17. Tagami K, Kuroe K, Numano M, Tabamura K, Watanabe A
(1990) A case of internal hernia through the defect of the greater
and lesser omentum (in Japanese). Nihon Shoukakigeka
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