Year : 2006 | Volume
: 16 | Issue : 3 | Page : 371--372
Para duodenal hernia
V Mathur, P Parakh, M Tiwari, A Bhandari, P Pareek, H Chaturvedi
MD B - 109, Sethi Colony, Jaipur - 302004, India
MD B - 109, Sethi Colony, Jaipur - 302004
|How to cite this article:|
Mathur V, Parakh P, Tiwari M, Bhandari A, Pareek P, Chaturvedi H. Para duodenal hernia.Indian J Radiol Imaging 2006;16:371-372
|How to cite this URL:|
Mathur V, Parakh P, Tiwari M, Bhandari A, Pareek P, Chaturvedi H. Para duodenal hernia. Indian J Radiol Imaging [serial online] 2006 [cited 2020 Aug 13 ];16:371-372
Available from: http://www.ijri.org/text.asp?2006/16/3/371/29021
Internal hernias are important but under diagnosed entities. Clinical symptoms may be intermittent and nonspecific and usually include some degree of nausea, distension and abdominal pain. Therefore, imaging studies play an important role in the diagnosis and timely management of these cases. More than half of all internal hernias are paraduodenal. We are reviewing the clinical and radiologic features of paraduodenal hernia and are highlighting useful radiographic and CT criteria to assist in the diagnosis. To the best of our knowledge this will be the first case report in the Indian literature
MATERIAL AND METHODS
A thirty-five year old man presented with pain in the epigastrium. The symptoms were made worse by eating and standing and were relieved by fasting and assuming a recumbent position. The clinical suspicion was that of chronic pancreatitis or small bowel obstruction. CT scan of the abdomen was done by giving 2% Trazogastro (750ml) orally. Both plain as well as intravenous contrast enhanced scans were obtained on 16 slice Multislice scanner (GE Light speed 16).
Transverse CT scan through the upper abdomen showed a sac like mass of jejunal loops in the left upper quadrant interposed between the pancreas and stomach crossing the midline and indenting the posterior wall of the stomach. [Figure 1]a and b
Contrast enhanced CT scan shows almost the same findings as plain CT abdomen with mass effect and indentation of the posterior wall of the stomach. [Figure 2]
On the basis of these findings a diagnosis of paraduodenal hernia was made which was proven subsequently on surgical exploration.
Para duodenal fossa is the confluent zone of descending mesocolon, transverse mesocolon and small bowel mesentery. Depending on the position of the duodenum and the orientation of the opening of the paraduodenal fossa, either left or right paraduodenal hernias can result. Paraduodenal hernias are usually left sided and are believed to occur due to a congenital defect in the descending mesocolon . The small bowel may invaginate into this space, the fossa of Landzert, which lies to the left of the fourth portion of the duodenum. The herniated small bowel loops may become trapped within this mesenteric sac
Clinical findings in patients with paraduodenal hernias vary from mild intermittent gastrointestinal complaints to acute intestinal obstruction with volvulus and infarction. A paraduodenal hernia can be demonstrated by an upper gastrointestinal series performed during a period of acute symptoms, because examination during an asymptomatic interval may fail to show the hernia or merely demonstrate nonspecific dilatation, stasis, and edematous mucosal folds. Even at surgery, a paraduodenal hernia may not be evident, either because of spontaneous resolution of the hernia or inadvertent operative reduction due to traction on small bowel loops. In addition, the extent of potential space in a peritoneal fossa seen at exploratory laparotomy is generally not evident from the relatively small size of the orifice of the fossa.
The small intestine generally fills the lower half of the abdomen, extending laterally into each flank, where it is bounded by the colon, and downward into the true pelvis. The jejunum mainly occupies the left side of the abdomen and the ileum the right. Dilated loops of jejunum or ileum extending beyond the midline are strong presumptive signs of the signs of the presence of an internal hernia, torsion or adhesions. In both types of paraduodenal hernia, the principal radiographic finding is that of displaced, bunched loops of small bowel that appear to be confined in a sac . When partial obstruction occurs, dilatation and delay in transit time can be noted. In the more common left paraduodenal hernia, small bowel loops pass into the paraduodenal fossa posteriorly and into the left mesocolon, producing dilated loops of small bowel clustered in the left upper quadrant of the abdomen lateral to the fourth portion of the duodenum The junction of the duodenum and jejunum has a low paramedian position. The duodenum is dilated and the jejunal loops are situated on the right side of the abdomen, extending into the right transverse mesocolon. In both types of paraduodenal hernia, the transverse colon tends to be depressed inferiorly by the mass.
Repeated episodes of paraduodenal herniation can increase the size of the defect and lead to adhesions between the intestinal loops or between the trapped bowel and hernial sac. This process can result in obstruction or circulatory compromise. Therefore, even a small paraduodenal hernia is potentially dangerous and is usually considered to be an operable condition.
The most commonly seen signs of paraduodenal hernias are clustering of small bowel loops, a sac like mass with encapsulation at or above the ligament of Treitz, duodenojejunal junction depression, mass effect on the posterior stomach wall, engorgement and crowding of the mesenteric vessels with frequent right displacement of the main mesenteric trunk and depression of the transverse colon. . Left sided paraduodenal hernias have a characteristic appearance of a cluster of dilated small bowel loops seemingly encased in a sac and lying between the pancreatic body and/or tail and the stomach to the left of ligament of Treitz. There is usually a mass effect causing displacement of posterior wall of stomach, duodenojejunal flexure (inferiorly) and transverse colon (inferiorly) . The mesenteric vessels that supply the herniated small bowel segments are crowded together at the entrance of the hernial sac and the vessels are often engorged. On CT, left sided paraduodenal hernias appear as encapsulated bowel loop displacing the inferior mesenteric vein anterolaterally. The inferior mesenteric vein is the landmark of the right margin of the descending mesocolon. Angiography has proved helpful, in few cases, in demonstrating displacement or twisting of blood vessels. 
The right-sided paraduodenal hernias occur through mesentericoparietal fossa of Waldeyer. On CT encapsulated bowel loops are seen displacing the right colic vein anteriorly. The right colic vein is the landmark of the left margin of ascending mesocolon. Other CT signs are looping of small bowel behind superior mesenteric vessels below the transverse portion of duodenum. Para duodenal hernias occurring on the right side are associated with incomplete intestinal rotation. There is absence of normal horizontal duodenum with superior mesenteric vein located ventral and to the left of superior mesenteric artery. The right-sided paraduodenal hernias are complicated by partial or complete obstruction in about 50% of cases.
The internal hernia should always be held in due consideration at the moment of diagnosis because the consequent mortality due to complications such as intestinal gangrene is rather high . Reduction of herniated viscera can be simple, by gentle traction or difficult, requiring dilatation of the hernial orifice and /or opening of the sac.
We are highly thankful to Mr.Vergese and John, the Senior CT technicians of Vardhman Imaging Center, SDMH, Jaipur for their assistance and help during the study.
|1||Parsons P B, Para duodenal hernias. AJR Am J Roentgenol. 1953; 69: 2.563-589.|
|2||Passas V, Karavias D, Grilias D, Birbas A. Computed Tomography of left paraduodenal hernia. J Comput Assist Tomogr 1986; 10: 542-543.|
|3||Arye B, Michael PF, Forrest D, Internal hernia: Clinical and imaging findings in 17 patients with emphasis on CT criteria. Radiology 2001; 218: 68-74.|
|4||Warshauer DM, Mauro MA. CT diagnosis of paraduodenal hernia. Gastrointest Radiol 1992; 17: 13-15.|
|5||Meyers MA. Para duodenal hernias: Radio logic and arteriographic diagnosis. Radiology 1970; 95: 29-37.|
|6||Nardi M, Perrone A, D'amico G, Basti M. Internal hernias: Description of two cases. Minerva Chir. 1994 Sep; 49 (9): 849-51.|