Herniation of the hepatic flexure through the foramen of Winslow, and a review of literature describing the minimally invasive technique

Abstract

Foramen of Winslow hernias is a rare and challenging diagnosis as signs and symptoms are usually non-specific. CT imaging has become the method of choice in diagnosing such conditions preoperatively. Traditionally managed via laparotomy, there has been an increase in the use of the minimally invasive technique in recent times, though experience remains sparse. This is a case of a 73-year-old woman with hepatic flexure herniation through the foramen of Winslow who was managed by the traditional laparotomy approach. A review of the literature was performed to learn key techniques in the use of laparoscopy to manage future cases.

Background

Internal hernias are a rare entity, accounting for 0.5%–1% of acute mechanical bowel obstructions.^1–3 Among these are lesser sac hernias which can be classified based on the anatomical location of their defect. These involves defects through the transverse mesocolon, greater omentum, lesser omentum, with most common type through the foramen of Winslow, accounting for 8% of all internal hernias.^1–6 The foramen of Winslow is a natural peritoneal orifice that allows communication between the greater peritoneal cavity and lesser sac. However, it usually remains closed due to intra-abdominal pressure.^{7 8} The viscera most commonly involved are the small bowel (63%), ascending colon and caecum (30%), and transverse colon (7%).^{2 5 8} Cases of gallbladder, greater omentum, small bowel diverticulum and Meckel’s diverticulum have also been reported.2 4 5 8–11

Since the first case of herniation through the foramen of Winslow reported by Bladin in 1834, there have been about 200 cases reported.2 4 5 7 8 10 11 Clinical diagnosis is often difficult with non-specific symptoms, and mild peritoneal signs due to pathology located in the lesser sac. The use of CT has increased the rate of preoperative diagnosis, and has reduced the historic mortality from approximately 50% to 5%.⁴

Treatment of foramen of Winslow hernia involves reducing the herniated viscera, and resecting if there are evidence of perforation or necrosis. This was traditionally performed via laparotomy; however, in recent times, there have been a number of cases managed laparoscopically though experience remained limited.

We report here a case of hepatic flexure herniation through the foramen of Winslow. A review of published reports was done in order to highlight the considerations and learn the techniques described for a laparoscopic repair.

Case presentation

A 73-year-old woman presented to the emergency department with sudden onset severe crampy right upper quadrant and epigastric pain. The pain radiates into her lower chest with no associated nausea, vomiting or shortness of breath. She describes a feeling of fullness earlier in the day, with seven episodes of loose bowel movement. Her medical history was significant for hypertension, hypercholesterolaemia and gastro-oesophageal reflux disease. She had previously undergone a hysterectomy via a pfannestiel incision.

On presentation, the patient was haemodynamically stable and apyrexial. There was no abdominal distention, but mild tenderness over the epigastric region on palpation with no guarding or signs of peritoneal irritation. Tinkling bowel sounds were present.

Investigations

Blood work including troponin and C reactive protein was unremarkable except for a lactate of 3.5. ECG demonstrated normal sinus rhythm.

CT with intravenous contrast portovenous protocol was performed. It demonstrated that the caecum and ascending colon were not located in the right abdomen, but were displaced cranially. The ascending colon has herniated into the upper abdomen medial to the hepatic flexure, sitting between the caudate lobe of the liver and inferior vena cava, almost circumferentially surrounding the portal vein with associated periportal oedema (figure 1).

Figure 1.

CT demonstrating the absence of caecum and ascending colon in right abdomen, with bowel located between left lobe of liver and lesser curvature of stomach. There is a narrow transition point at site of herniation through the foramen of Winslow.

Treatment

The patient underwent an urgent exploratory laparotomy through a midline incision which confirmed the presence of a foramen of Winslow hernia. The mid ascending colon to transverse hepatic flexure was involved and this was reduced using light traction. There was no evidence of perforation or ischaemia. She was found to have a completely mobile ascending colon lacking lateral folds and the decision was made to perform a right hemicolectomy to prevent a recurrence or caecal volvulus. The foramen of Winslow was not closed.

Outcome and follow-up

The postoperative course was uneventful and diet slowly upgraded. She was discharged 4 days post operatively in good health.

Patient was followed up in the outpatient clinics 6 weeks post operatively and has recovered well. She did not report recurrence or obstructive symptoms.

Discussion

The foramen of Winslow allows communication between the lesser sac and greater peritoneal cavity. It is approximately 3 cm and admits one to two fingers.¹² The foramen is bounded superiorly by the peritoneum of the caudate lobe, inferiorly by first part of the duodenum, anteriorly by the hepatoduodenal ligament and posteriorly by the inferior vena cava.^{7 13} The anterior boundary formed as by the hepatoduodenal ligament is of importance as it contains the portal vein, common bile duct and hepatic artery.¹¹

Foramen of Winslow hernia tend to occur most frequently from the third to sixth decade, with increased prevalence in men.^{5 6 10} Various factors have been identified to predispose patients to such a hernia: an abnormally large foramen of greater than 3 cm2 7 8 10–12; long hypermobile small bowel mesentery2 7 10 11; persistence of ascending colon mesocolon2 7 8 11; non-retroperinteal right colon7 8 11 12; large right hepatic lobe2 7 10 11; gastrohepatic ligament defects^{8 14}; greater omentum atrophy; and bowel malrotations.^{8 11}

Patients would usually present with upper abdominal pain, typically in the epigastric region, radiating to left hypochondrium, left shoulder or back.2 6–8 11 This may be accompanied by symptoms of acute bowel obstructions, and are relieved by bending forward or lying with trunk flexion as such position widens the foramen.^{2 8} Excessive herniation of viscera could also compress the hepatoduodenal ligament, causing obstructive jaundice, acute pancreatitis and Zahn’s liver infarct.9 12 13 15 16

Clinically diagnosing such pathologies is difficult, and radiological studies are key to early diagnosis so as to avoid strangulation. Abdominal plain films might reveal various findings. There could be lateral displacement of stomach with gas-filled loops of bowel sitting medially or along the lesser curvature with associated degree of small bowel obstruction.2 8–10 17 Herniation of the ascending colon is suggested by the absence of faecal material and gas in the right abdomen, with the presence of gas medial to the stomach. Various papers have suggested the use of water-soluble contrast and barium enema to aid diagnosis. It would reveal the displacement of the stomach and compression of the duodenum; and in cases of colon herniation, contrast in the lesser sac with compression of the colon by the foramen of Winslow, and opacification of the terminal ileum in the right upper quadrant.5 6 8 9 14 18

The use of CT has now instead been the radiographic modality of choice and has various key findings. Such signs include: air fluid collection in the lesser sac, specifically between the pancreas and stomach, anterior to the inferior vena cava and posterior to liver hilum, with a beak pointing towards the foramen of Winslow; the absence of ascending colon in right abdomen; evidence of intestinal obstruction with stretching of mesenteric vessels between inferior vena cava and liver hilum; and displacement of stomach anterior laterally.5–8 10 11 17 Another unusual but helpful CT finding described is the circumferential hypodensity ‘halo sign’ around the portal vein caused by lymphatic engorgement secondary to compression by the herniated viscera. This compression of the portal vein has also been described the ‘narrow portal vein’ sign.¹³

Foramen of Winslow hernias was usually managed with a laparotomy.³ However, since the first laparoscopic approach was described in 2010 by Van Daele et al,² there have been an increasing number of case reports describing the minimally invasive technique.

The patient should be placed in a reverse Trendelenburg lithotomy position.¹⁰ Four ports are usually used, with the 12 mm optical port in the supraumbilical position, and the 5 mm working ports in the epigastric and left lateral position. Positioning of the third 5 mm port has been variable but is usually in the right lateral or left hypochondrium.1 4 7 10 11 Due to the expected presence of dilated bowel loops, the use of the Veress needle access is discouraged, preferring the optical trocar or open Hasson technique.¹⁰

The presence of a foramen of Winslow hernia and the involving viscera should first be identified. Gentle traction of the gallbladder and liver would allow for good exposure of the portal triad and foramen.⁷ This is followed by an attempted reduction of the herniated viscera by way of gentle traction. Atraumatic graspers should be used to handle the mesentery, omentum or mesoappendix rather than bowel; and traction applied to the healthy distal collapsed limb.^{1 10} Opposing traction can be applied using gauze-protected graspers.⁴

When simple traction fails to reduce the herniated viscera, decompression of the dilated bowel could be performed.^{4 10} A purse string suture should first be prepared around the puncture site.⁴ A Veress needle then be introduced through the abdominal wall and into the bowel, with its contents aspirated until satisfactorily decompressed.^{4 10} On removal of the needle, the purse string suture should be concomitantly tightened to prevent the leakage of bowel contents.⁴ The reduced viscera should be inspected, and resection performed if there are evidence of perforation or ischaemia. Alternatively, the Kocher manoeuvre could be performed to aid reduction of hernia.⁴

There is no standardised treatment to prevent recurrence of foramen of Winslow hernias. However, there have not been any reported cases of a recurrence.^{5 7} In cases where the right colon has herniated due to the lack of anatomical fixation, caecopexy using non-absorbable sutures to the lateral wall is usually performed.^{5 8 11} It should be noted that there is a recurrence rate of up to 30% in cases of caecal volvulus managed by caecopexy.¹⁹ Closure of a large defect in the foramen of Winslow could be performed, but with extreme care due to the risk of injury to the porta hepatis and portal vein thrombosis.5 8 11 17 The foramen can be closed by suturing the peritoneum next to the porta hepatis, down to the retroperitoeum just next to the inferior vena cava.⁷ Alternatively, the omentum could be harvested and fixed to the anterior stomach to pack the foramen.^{4 10}

Learning points.

• Foreman of Winslow hernia is a rare and challenging diagnosis. Symptoms are non-specific and blood work might be unremarkable.

• CT remains the imaging modality of choice, with various key features indicating a foramen of Winslow hernia.

• The minimally invasive approach is a safe and feasible alternative which should be considered as it would lead to improved patient recovery and outcomes.

• Key considerations and techniques for the minimally invasive approach are described above.