Closed loop obstruction is a specific type of obstruction in which two points along the course of a bowel are obstructed at a single location thus forming a closed loop. Usually this is due to adhesions, a twist of the mesentery or internal herniation. In the large bowel it is known as a volvulus. In the small bowel it is simply known as small bowel closed loop obstruction. Let first start with a rather difficult case and then continue with some basic knowledge about closed loop obstruction.

So the most important question for you to answer is: Is there a closed loop obstruction? Because if there is, this patient is at risk for bowel infarction and surgery is the best option. When we have a patient in the ER with what appears to be a small bowel obstruction SBOthe most important thing we can do, besides making the diagnosis, is to identify the presence or absence of strangulation.

Strangulation is defined as obstruction associated with vascular compromise. The morbidity and mortality rate in the SBO-group is mainly due to bowel infarction and subsequent necrosis. This is most commonly caused by a closed loop obstruction. CT is the imaging procedure of choice in the evaluation of patients suspected of SBO. If we have a short closed loop oriented within the plane of imaging, we will see a U- or C-shaped loop of bowel.

Another important appearance of a closed loop obstruction is that of a radial array of dilated small bowel loops with the mesenteric vessels converging to a central point. This is almost always due to a small bowel volvulus. The findings of ischemia in closed loop obstruction are the same as in patients with other causes of mesenteric ischemia:.

mesenteric hernia radiology

The case on the left shows another patient with closed loop obstruction. Although there is good enhancement of the vessels there seems to be a lack of enhancement of the bowel wall. Other signs of ischemia in this case are mesenteric edema and bowel wall thickening. Infarcted bowel was found at operation. If the closed loop is longer and is oriented perpendicular to the plane of section, we will see a clump of bowel loops as shown in the case on the left.

Sometimes this is difficult to appreciate on just the axial images and coronal or sagittal reconstructions can be helpful. In this case there is also mesenteric edema and localised ascites in combination with dilated loops with wall thickening indicating strangulation and risk of infarction.

Bowel obstruction after gastric bypass - Victor Sai - Mesenteric Internal Hernia

CT is the imaging procedure of choise in patients who are suspected for bowel obstruction. When we examine these patients, we should not give oral contrast for following reasons:.

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In some of the patients with a closed loop obstruction a bowel obstruction is not suspected. In the case on the left positive oral contrast was given. Notice the constriction in the small bowel in figure B. Distal to the constriction in figure C we see a cluster of dilated small bowel loops not filled with oral contrast, indicating the closed loop. Only rarely contrast will pass the point of obstruction and enter the area of the closed loop.Transmesenteric Postoperative Hernia. Most commonly Roux-en-Y gastric bypass and liver transplantation.

Much more common when Roux loop is placed in retrocolic position. Onset usually months after original surgery. Left Axial graphic shows dilated small bowel herniating through a mesenteric defect. Note the peripheral position of the small bowelmedial displacement of the colonand the displaced mesenteric vessels.

Right Axial CECT in a patient with prior colonic resection shows a cluster of dilated small bowel in the left abdomen. These loops lie ventral to the transverse colonand the mesenteric vessels are distorted and congested. These findings are typical of a transmesenteric hernia.

Left Axial CECT in a patient with a history of prior abdominal surgery demonstrates multiple dilated, fecalized loops of small bowel in the left abdomen, in keeping with a small bowel obstruction. Right Coronal CECT in the same patient demonstrates that these bowel loops are clustered in the lateral aspect of the abdomen, directly abutting the abdominal wall, and displacing the colon. This constellation of findings is classic for a postoperative transmesenteric hernia.

mesenteric hernia radiology

Hernias after liver transplant can occur in transverse mesocolon more common or small bowel mesentery. Crowded and dilated small bowel loops in abnormal location often towards periphery of abdomen. Displacement of overlying omental fat of herniated bowel loop, with obstructed bowel loops directly contacting abdominal wall.

mesenteric hernia radiology

Colon displaced posteriorly and inferiorly most common or medially less common. Right or left displacement of main mesenteric trunk with stretching and tethering of more distal mesenteric vascular branches. Most often occurs in right hemiabdomen.

Hernia usually not encapsulated or enveloped in sac unlike paraduodenal hernias. Mesenteric vessels appear engorged, crowded, or twisted. Thickened bowel wall and ascites, particularly in cases with bowel ischemia. Bowel loops do not appear contained in sac or have confining border. Varying degrees of small bowel obstruction SBO with discrete point of transition between dilated and nondilated bowel. Some degree of fixation, stasis, and delayed flow of contrast seen in herniated bowel.

Lateral films useful to demonstrate displacement of herniated bowel loops. Only gold members can continue reading.

Mesenteric volvulus in conjunction with an inguinal hernia in a female

Log In or Register to continue. Tags: Diagnostic Imaging Gastrointestinal.Visit appliedradiology. Internal hernias remain one of the most challenging and potentially frustrating diagnoses that face abdominal imagers.

Understanding the RYGB surgical approach and its appearance at postsurgical CT, as well as the types of postoperative internal hernia and their common imaging features can assist radiologists in making the diagnosis of postoperative internal hernia.

Gastric bypass surgery is now most commonly performed laparoscopically, and uses a combination of restrictive and malabsorptive components to result in patient weight loss. While most postoperative weight loss was originally thought to arise from early satiety resulting from the small gastric remnant, there is increasing realization that weight loss is related to a combination of factors, including complex changes in metabolism that are beyond the scope of this article.

The traditional RYGB surgical approach begins with fashioning a small gastric pouch using the gastric fundus, leaving the larger excluded stomach intact. The roux limb may be brought up over antecolic or through retrocolic the transverse colon mesentery Figure 1.

Finally, the biliopancreatic or afferent limb is anastomosed cm distal to the G-J anastomosis in side-to-side fashion the enteroenterostomy or J-J anastomosis. In the immediate postoperative period when an anastomotic leak is suspected, traditional fluoroscopy studies with water-soluble contrast agents are usually employed.

However, when possible, administering a small volume of oral contrast material immediately prior to the CT can facilitate identification of the roux limb. Both axial and reconstructed images readily depict the location of the J-J anastomosis, seen in the left mid-abdomen in normal postoperative patients arrows, Figures Use of intravenous contrast is preferred when possible, as it facilitates identification of mesenteric vasculature and highlights areas of decreased bowel wall perfusion in the setting of ischemia.

Patient signs and symptoms from internal hernias are nonspecific. While some hernias are completely asymptomatic, patient complaints often range from intermittent vague abdominal discomfort to vomiting and acute abdominal pain. Time to postoperative presentation of internal hernias is quite variable, occasionally occurring in the immediate postoperative period, but averaging months after surgery.

There are three main types of RYGB-associated postoperative internal hernias: transverse mesocolonic hernias, which extend through the transverse mesocolon; J-J hernias, which traverse through the small-bowel mesenteric defect near the enteroenterostomy; and Petersen hernias, which course through the potential space between the roux limb and the transverse mesocolon Figure 6.

While the transverse mesocolonic hernia is seen only in patients with a retrocolic roux limb, the other two hernias are seen in both the retro- and antecolic roux limb surgeries. While variable, most series suggest that trans-mesocolonic hernias are most common, particularly in patients with a retrocolic surgical approach Table 2.

Petersen hernias, although reportedly common in some small series, are likely least common overall. Variability in the incidence of the three subtypes of post-bariatric internal hernias over time likely relates in part to the evolving RYGB surgical approach.

Initial open RYGB procedures had a much lower incidence of postoperative hernias, attributable to fixation of bowel loops from adhesions associated with open surgical approaches.

Closed Loop in Small bowel obstruction

While internal hernias are challenging to identify, several key findings are suggestive of the diagnosis: dilated small-bowel loops may be pancreaticobiliary, roux, or distal loops ; displacement of the J-J anastomosis out of the left mid-abdomen; clustered small-bowel loops, often in the left upper quadrant but potentially anywhere in the abdomen ; swirling of the mesentery seen with associated torsion ; and convergence of bowel loops and vessels, potentially with associated mesenteric edema seen at the site of herniation.

Of these, swirling of the mesentery has been shown to be most sensitive in one series. In general, however, the more findings that are present, the more likely the diagnosis of internal hernia. Trans-mesocolonic hernia— Trans-mesocolonic hernias occur through the defect in the transverse mesocolon created for passage of the retrocolic roux limb.

Thus, herniated bowel loops typically reside in the left upper quadrant, sometimes causing mass effect on the gastric remnant. Although only occurring in patients with retrocolic RYGB surgeries, as noted previously, these hernias account for a large proportion of internal hernias in RYGB patients.

The relatively small aperture associated with this type of hernia is thought to explain the high risk of torsion and ischemia. Figures 7 and 8.

Internal Hernias in the Era of Multidetector CT: Correlation of Imaging and Surgical Findings

J-J hernia— J-J hernias enteroenterostomy or trans-mesenteric hernias occur when bowel loops traverse the repaired mesenteric defect at the site of the jejunal to jejunal anastomosis. For antecolic RYGB, these likely represent the most common type of internal hernia. While bowel loops may traverse left-to-right or right-to-left, most commonly the herniated bowel resides in the right upper quadrant. Although displacement of the J-J anastomosis out of the left mid-abdomen may be seen with any internal hernia, it has been our anecdotal experience that this is more common with J-J hernias.

Figures Petersen hernia— The Petersen hernia probably represents the least common RYGB-associated hernia, created when bowel loops move into the potential space between the transverse mesocolon and the antecolic or retrocolic roux loop.

Petersen hernias may occur alone or, in patients with a retrocolic bypass, in combination with trans-mesocolonic hernias.Clinical diagnosis of internal hernias is challenging because of their nonspecific signs and symptoms. Many types of internal hernias have been defined: paraduodenal, small bowel mesentery-related, greater omentum-related, lesser sac, transverse mesocolon-related, pericecal, sigmoid mesocolon-related, falciform ligament, pelvic internal, and Roux-en-Y anastomosis-related.

An internal hernia is a surgical emergency that can develop into intestinal strangulation and ischemia. Accurate preoperative diagnosis is crucial for appropriate management. Multidetector computed tomography CTwith its thin-section axial images, high-quality multiplanar reformations, and three-dimensional images, currently plays an essential role in preoperative diagnosis of internal hernias.

The diagnostic approach to internal hernias at multidetector CT includes detecting an intestinal closed loop, identifying the hernia orifice, and analyzing abnormal displacement of surrounding structures and key vessels around the hernia orifice and hernia sac. At each step, multidetector CT can depict pathognomonic findings.

A saclike appearance suggests an intestinal closed loop in several types of internal hernias. Convergence, engorgement, and twisting of mesenteric vessels in the hernia orifice can be seen clearly at multidetector CT, especially with use of multiplanar reformations. For definitive diagnosis of an internal hernia, analysis of displacement of anatomic landmarks around the hernia orifice is particularly important, and thin-section images provide the required information.

Detailed knowledge of the anatomy, etiology, and imaging landmarks of the various hernia types is also necessary. Familiarity with the appearances of internal hernias at multidetector CT allows accurate and specific preoperative diagnosis.

Abstract Clinical diagnosis of internal hernias is challenging because of their nonspecific signs and symptoms. Publication types Comparative Study.Uludag et al. Non-enhanced CT, axial plane of abdomen and pelvis.

Venous phase, CT coronal reformatted image of abdomen and pelvis. Venous phase, sagittal reformatted image of abdomen and pelvis. Home Advanced Search Case Connected authors. Show more Show less. Clinical History. A year-old female patient presented with complaint of swelling in left inguinal region for past 10 years. Sudden onset pain in lower abdomen for 2 days. Clinically no tenderness and no redness over the swelling.

No history of constipation or previous surgery.

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Clinically a femoral hernia was suspected. Imaging Findings. Non-enhanced CT scan of the abdomen and pelvis revealed a 8. It was located in the left anterior peroneal cavity. The pseudo-mass seemed to herniate through the left inguinal canal, up to the groin. The femoral canals on both sides and right inguinal canal appeared clear. On enhanced CT examination, the bowel walls appeared normal with no signs of ischaemia or herniation. No ascites or lymphadenopathy was noted.

Inguinal hernias: - Indirect inguinal hernia occurs through inguinal canal extending into scrotal sac or anterior peroneal cavity. It is lateral to inferior epigastric vessels. Usually it occurs due to the failure of obliteration of processus vaginalis [1] - Direct inguinal hernia occurs due to an acquired defect in transversalis fascia of Hesselbach triangle.

It is medial to inferior epigastric vessels. Usually it is more common in middle-aged men [2] 2. Femoral hernia occurs through the femoral canal medial to the femoral vein.

Bowel or fat in hernia sac can be demonstrated. Stranding of fat suggest the possibility of incarceration. There may be proximal bowel dilatation from obstruction [3]. Bowel wall thickening, extraluminal fluid, severe fat stranding and engorged mesenteric vessels suggest strangulation [4]. Mesenteric volvulus is defined as the twisting of mesentery along its axis.

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It may be primary, without an associated underlying cause, or secondary to a congenital or acquired condition, as in inguinal hernia seen in our case. The presence of long mobile mesentery and dietary factors may contribute to the volvulus [1, 2].

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Ultrasound and CT are useful modalities for diagnosis [2]. Once the diagnosis is made, prompt surgical intervention is required to either lyse adhesions, dextorse the bowel, or formally resect and anastomose the bowel if it is found to be ischaemic. Differential Diagnosis List.

Mesenteric volvulus in conjunction with a left-sided inguinal hernia in an elderly woman. Final Diagnosis.Abdominal and Pelvic Hernias.

General Considerations. Groin pelvic hernias. Indirect inguinal hernia. There is a large inguinal scrotal hernia white arrow containing a dilated loop of small bowel red arrow. Ventral abdominal wall hernias. Umbilical Hernia. Mesenteric fat white arrow and bowel orange arrow protrude through the abdominal wall at the umbilicus. The hernia has caused a small bowel obstruction with dilated loops of small bowel seen red arrows There is also ascites present A. Spigelian Hernia. A loop of small bowel has herniated through the lateral edge of the rectus muscle at the semilunar line white arrow and produced a mechanical small bowel obstruction.

Obturator hernia. A loop of small bowel has herniated between the pectineus and obturator muscles white arrow. Clinical Findings. Imaging Findings.

Differential Diagnosis. Ventral umbilical hernia. Almost completely well-circumscribed, soft tissue mass blue arrows overlies umbilicus demonstrating incomplete rim sign white arrow where hernia is attached to body. Hernia contains fat, but appears dense because it is an additive density superimposed on the normal soft tissues of the abdomen.

For more information, click on the link if you see this icon For this same photo without the annotations, click here. Paraumbilical hernia Adults Occurs adjacent to site of umbilicus Superior to umbilicus called epigastric more common Inferior to umbilicus called hypogastric Occur along the linea alba Usually contain fat Richter hernia Involves only anti-mesenteric side of bowel entering hernia Usually no obstructive symptoms Can occur with any of the abdominal hernias Incisional hernia Breakdown in fascia closing prior abdominal surgery More common with obesity, wound infection and smokers Usually occur within first few months after surgery Can be quite large and are frequently incarcerated Spigelian hernia Lateral edge of rectus muscle at semilunar line Inferior and lateral to umbilicus Rare Over age 50 Spigelian Hernia.The most common presentation is an acute obstruction of small bowel loops that develops through normal or abnormal apertures.

Internal hernias not infrequently self-resolve, making imaging at the time of symptomatology vital. The orifice that the small bowel herniates through is usually a pre-existing anatomic structure, such as foraminarecesses, and fossae e.

Pathologic defects of the mesentery and visceral peritoneum, such as from congenital maldevelopment of the mesenteries, and surgery also create potential internal herniation orifices.

In contemporary practice, virtually all patients undergo CT, which is the gold standard imaging modality for assessment of bowel obstruction and suspected internal hernias. Traditionally barium studies were performed and may still on occasion be used in niche circumstances. Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Updating… Please wait. Unable to process the form.

Transmesenteric and Transmesocolic Hernias

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mesenteric hernia radiology

Log in Sign up. Articles Cases Courses Quiz. About Blog Go ad-free. On this page:. Quiz questions. Review of internal hernias: radiographic and clinical findings. Edit article Share article View revision history Report problem with Article. URL of Article.

Article information. System: Gastrointestinal. Tags: general surgeryemergency medicinegeneral surgery. Case 1: foramen of Winslow internal hernia Case 1: foramen of Winslow internal hernia. Case 2: intersigmoid hernia Case 2: intersigmoid hernia.