Spontaneous internal hernia through a defect in the hepatogastric ligament.

Transomental internal hernias are a rare cause of intestinal obstruction and most commonly iatrogenic, resulting from previous surgical interventions, abdominal trauma or inflammation. Occasionally, they may occur spontaneously. We report the case of a 44-year-old healthy male admitted to the emergency room with acute abdominal pain and vomiting, consistent with intestinal obstruction. An internal hernia of small bowel in the lesser sac was suspected after performing a computed tomography (CT) scan and emergent laparotomy confirmed herniation of a jejunal loop through a defect in the hepatogastric ligament, resulting in strangulation and requiring enterectomy. The patient had a favourable outcome and was discharged a few days after surgery. Both radiologists and surgeons must be aware of rare internal hernia subtypes, to avoid delays in diagnosis and treatment. Abdominal CT is the first-line imaging of choice, providing useful diagnostic hallmarks. Nevertheless, surgical exploration is typically essential to confirm the diagnosis, identify the defect and assess bowel viability.

Introduction

An internal abdominal hernia is defined as the protrusion of a viscus through a normal or abnormal aperture within the peritoneal cavity [1]. The orifice can be either acquired, such as a postsurgical, traumatic, or post inflammatory, or congenital, including both normal apertures, such as the foramen of Winslow, and abnormal apertures arising from anomalies of internal rotation and peritoneal attachment [2].

The overall incidence of internal hernias is <1% and they account for 0.5%-5.8% of all cases of intestinal obstruction [2,3]. Subtypes described by Meyers [1] are based on their anatomic location of origin. The most common are paraduodenal (53%), pericecal (13%), through the foramen of Winslow (8%), transmesenteric and transmesocolic (8%), intersigmoid (6%) and retro-anastomotic (5%). With more surgical procedures being performed using a Roux loop, the number of transmesenteric, transmesocolic and retro-anastomotic internal hernias has been increasing. Additionally, the overall incidence of internal hernias is increasing due to the growing number of laparoscopic surgical procedures, where mesenteric defects may not be routinely closed [1].

Although the symptoms are typical of bowel obstruction, a specific diagnosis is difficult and can lead to delayed management with serious complications, such as bowel ischemia and necrosis. Mortality exceeds 50% in most series, if strangulation is present [2,4].

We report the case of an internal hernia through a defect in the hepatogastric ligament (the cranial portion or pars flaccida of the lesser omentum), presenting as small bowel obstruction and strangulation, in a patient with no previous trauma or surgical manipulation in the supramesocolic space.

Case report

A 42-year-old male was admitted to the emergency department with abdominal pain in the epigastric area, for the preceding 24 hours. The pain, whilst initially colicky, had become constant and increased in severity. This had been associated with bilious vomiting. The patient had no history of abdominal trauma or any known medical condition. His surgical history included an open appendectomy by Rocky-Davis incision, in his childhood.

On arrival, he was haemodynamically stable. His abdomen was mildly distended with epigastric tenderness. Laboratory tests were unremarkable except for leukocytosis (12.01 × 103/mL with 89.1% neutrophils) and mild C reactive protein elevation (2 mg/dL). A plain abdominal film demonstrated dilated small bowel loops with air-fluid levels in the epigastrium, suggesting internal obstruction (Fig. 1). Abdominal computed tomography (CT) revealed an unusual crowding of dilated and fluid-filled jejunal loops above the transverse mesocolon, between the left liver lobe and the lesser gastric curve, dropping below and behind the stomach, without significant dilatation of distal bowel loops (Figs. 2 and 3).

Fig. 1

Plain abdominal x-ray. Dilated small bowel loops with air-fluid levels in the epigastrium (black arrow).

Fig. 2

CT scan (1). Unusual crowding of dilated and fluid-filled jejunal loops (black star) between the left liver lobe and the lesser gastric curve, dropping below and behind the stomach (white arrow).

Fig. 3

CT scan (2). Dilated and fluid-filled jejunal loops (black star) above the transverse mesocolon, between the left liver lobe and the lesser gastric curve, behind the stomach (white arrow, right) and internally to the second portion of the duodenum (white arrow, left).

The patient proceeded to supra-umbilical laparotomy and an internal hernia causing small bowel obstruction was evident. Around 20 cm of jejunum passed through a ∼2 cm defect in the hepatogastric ligament, resulting in a nonviable segment that required resection (Figs. 4 and 5). There was no peritoneal contamination of enteric or purulent content. A primary enteral anastomosis was fashioned and the hepatogastric and mesenteric defects were closed with absorbable sutures.

Fig. 4

Operative findings (1). Jejunal herniation through a defect in the pars flaccida of the lesser omentum (arrow), between the liver (white star) and the lesser curvature of the stomach (black star).

Fig. 5

Operative findings (2). Nonviable jejunal segment requiring resection (arrows).

The postoperative course was uneventful, with the patient resuming a normal diet and regaining normal bowel functions. He was discharged on the fifth postoperative day.

Discussion

Transomental hernias through the greater or lesser omentum are rare, accounting for approximately 1%-4% of all internal hernias [3]. They have been generally reported in patients over 50-years old [5] and are mostly acquired, resulting from surgical interventions (Roux-Y gastric bypass, liver transplantation, small bowel or colon resection), abdominal trauma or peritoneal inflammation [6], [7], [8]. Internal hernias within the lesser sac may occur from various directions, namely, through the foramen of Winslow or through defects in the transverse mesocolon or lesser omentum. A case of herniation through the pars flaccida of the lesser omentum (or hepatogastric ligament) following laparoscopic fundoplication was recently reported [9]. To our knowledge, there are no reported cases of spontaneous herniation through this site, such as the one we describe. Senile atrophy has been hypothesized as an etiological factor; yet our patient was relatively young. An alternative explanation could be a process of peritonitis in childhood, leading to his only previous surgery – an appendectomy. Still, this does not seem exceedingly likely, due to the distance between the appendiceal area and the lesser omentum.

Compared with other types of internal hernias, patients present more frequently with strangulation of the small bowel [10], thus radiologists and gastrointestinal surgeons must have a high index of suspicion to prevent delays in diagnosis and treatment. Of note, laboratory tests may not always be significantly altered, even in the presence of bowel ischemia. Abdominal CT is the first-line imaging of choice. In the differential diagnosis of radiographic findings of intestinal obstruction or unusual appearing grouping of bowel loops, “some type of internal hernia” is often loosely entertained without a precise appreciation of types and distinctive findings. However, with an awareness of the underlying anatomic features and of the dynamics of intestinal entrapment, the correct diagnosis can be made in most instances. The most useful diagnostic hallmarks include the following: (1) abnormal location and disturbed arrangement of the small intestine, (2) sacculation and crowding of several small bowel loops owing to encapsulation within the hernial sac, (3) segmental dilation and prolonged stasis within the herniated loops and (4) mesenteric vessel swirling or crowding [1].

Nevertheless, in most cases, a definitive diagnosis is established intraoperatively [11]. Surgical treatment consists in careful reduction of the herniated small bowel segment. If irreversible ischemia or perforation is found, resection is required. Additionally, the omental defect should be repaired to prevent recurrent herniation.

Conclusion

Opportune surgical exploration based on high clinical suspicion and hallmark radiologic findings can reduce the risk of postoperative complications and mortality, in patients with rare internal hernia subtypes, such as the one described in this report.

Learning points

Transomental hernias are a rare subtype of internal hernia and frequently present with small bowel strangulation.

There must be a high index of suspicion to prevent delays in diagnosis and treatment.

Abdominal CT is the first-line imaging of choice, providing useful diagnostic hallmarks.

Surgical exploration is needed to confirm the diagnosis and assess bowel viability.