Para-duodenal hernia: a report of five cases and review of literature

Background Para-duodenal hernia (PDH) represents rare clinical entities based on few literatures. Case presentation We report five cases of Para-duodenal hernia, all occurring in male patients ranging from 34 to 75 years of age. The patients had varied manifestations presenting with abdominal pain with or without vomiting and nausea and with or without signs of intestinal obstruction. CT images showed cluster of dilated bowel segments with displaced mesenteric vessels at hernial orifice. Laparoscopic surgical approach was adopted, and the patients were discharged about a week later without further complications. Conclusion We hope to raise awareness about the management of this rare clinical entity and the benefits of CT imaging and laparoscopic surgery as standard approaches.


Background
Para-duodenal hernias (PDH) have traditionally been considered the most frequent type of congenital internal hernia [1]. Left para-duodenal hernia (hernia of Lanzert) is about three times more common than the right counterpart (Waldayer's hernia) [2]. Left para-duodenal hernia (LPDH) is a congenital defect with an occurrence of approximately 2% of the population. It is posterior to the inferior mesenteric vein and left branches of middle colic artery and is situated to the left of the fourth part of the duodenum. It arises from the fossa of Landzert [3][4][5]. The fossa to the left of the fourth part of the duodenum is the area where the small bowel loops (usually jejunum) prolapse through and into the left portion of the transverse mesocolon. The herniated small bowel loops may therefore become trapped within the mesenteric sac [5,6]. The initial rotation of the midgut behind and then left to the superior mesenteric artery and comes to lie in the left side of the abdomen behind the mesentery of the descending colon leads to development of LPDH [7]. The right para-duodenal hernia (RPDH) occurs when the small bowel herniates through a defect in the first part of the jejunal mesentery in the so called Waldeyer's fossa. At autopsy, the Waldeyer's fossa was found in about 1% of the population [8]. The malrotation of the midgut and failure of fusion of mesentery to parietal peritoneum create a hernial defect called RPDH. PDH can lead to bowel obstruction, ischemia, and perforation with a high mortality [6]. Clinical diagnosis of PDH is a challenge as symptoms are entirely non-specific. They usually affect males more than females (3:1) [9,10]. Most patients are diagnosed between the 4th and 6th decades of life and the mean age of diagnosis is 38.5 years [2]; for our case series all were males. 75% of mesocolic hernias occur on the left side and 25% on the right side with middle mesocolic hernia being very rare [11]. In medical literature, para-duodenal hernias causing intestinal obstruction are few and report no evidence of long lasting postoperative ileus after surgery. We report herein five cases of PDH and their management based on a review of literatures.

Case 1
A 68-year-old man complained left middle abdominal pain for 10 days. The pain was paroxysmal without nausea and vomiting. It got worse after meals. He has a past medical history of chronic gastritis treated with regular proton pump inhibitor. He had laparoscopic cholecystectomy 2 years ago. The results of complete blood count, serum and urine amylase were within normal limit. Endoscopy showed chronic gastritis with bile reflux. His abdominal CT scan showed that a part of small intestine and its mesentery were folded together on the left side of the abdomen (Fig. 1). The patient was diagnosed with abdominal internal hernia and laparoscopic surgery was done. During the surgery, a soft mass of 5 cm in diameter was found within the transverse mesocolon. It was later found to be that 60 cm of the small intestine, which was trapped through a defect in the transverse mesocolon. The defect was 2 cm in diameter on the left side of the ascending part of duodenum ( Fig. 2) within the mesocolon. The entrapped intestinal loop was reduced, and the defect was repaired. He was diagnosed with left paraduodenal hernia and was discharged on 7th post-operative day. No abnormal presentation was found during follow-up. (Table 1).

Case 2
A 34-year-old man complained about left upper abdominal pain for 24 h. The pain was paroxysmal accompanied with vomiting. His abdominal CT scan showed a fold, at the left upper abdomen, consisting of small intestine coiled with mesentery ( Fig. 3). Subsequent laparoscopy found a loop of jejunum was entrapped in the left side of mesocolon through a defect on the left side of the ascending part of duodenum. After the reduction of the small intestine, the hernia orifice was opened large enough to prevent further herniation (Fig. 4). Post-operative recovery was uneventful, and the patient was discharged on 7th post-operative day. No abnormalities were found during follow-up so far. (Table 1).

Case 3
A 68-year-old man complained about upper abdominal pain for 2 days. The pain was paroxysmal accompanied with vomiting. He was diagnosed with chronic gastritis 2 months ago and was treated with medications without any relief. His abdominal CT imaging showed part of the small intestine was folded (Figs. 5, 6). He underwent paraduodenal hernioplasty via laparoscopy. Surgery consisted of reduction of intestinal loops in the hernial sac and subsequent repair of the defect (Fig. 7). The length of the folded intestine was found to be 100 cm and the hernia was on the left side of mesocolon. He was discharged on 7th post-operative day and had no complications during follow-up so far. (Table 1).

Case 4
A 75-year-old man complained about abdominal distention and pain for 13 h. The pain was paraumbilical accompanied with nausea and vomiting. His abdominal CT imaging showed that the jejunum was folded at the left abdomen (Figs. 8,9). He was diagnosed with left paraduodenal hernia and laparoscopy was carried out. During the surgery, reduction of the entrapped jejunal loops from the hernial sac was attempted but failed due to severe adhesion with surrounding organs. It was then converted to open enterolysis. The defect of the mesocolon was found on the right side of the ascending duodenum and was repaired eventually with interrupted sutures (Fig. 10). After the surgery, the patient still felt occasional distension after meals, but no acute episode of obstruction has ever occurred. He was discharged two  (Table 1).

Case 5
A 40-year-old man complained about right abdominal pain for 11 h. The pain occurred suddenly without triggering factors. It was mild and intermittent. He has a history of laparoscopic cholecystectomy for one year. His abdominal X-ray showed a mass in the right upper quadrant of abdomen (Fig. 11). CT scan showed that a part of small intestine and its mesentery were folded together at the right abdomen (Figs. 12, 13). A diagnosis of right paraduodenal hernia was made. The patient underwent laparoscopic surgery during which the entrapped intestinal loop was reduced from a defect in the first part of the jejunal mesentery. He was discharged on 9th post-operative day. No other abnormal presentation was found during follow-up so far. (Table 1).

Discussion & conclusion
PDH also known as mesocolic hernias are congenital and derive from embryonary peritoneal anomalies and associated abnormal intestinal rotation [12]. These   patients usually present with chronic abdominal pain and vomiting with or without signs of intestinal obstruction [9]. There is an associated risk of strangulation and intestinal infarction for more than 50% over the course of a lifetime, making it necessary to investigate radiological signs of hypoperfusion and intestinal ischemia [13]. The high rate of mortality associated with these complications make early identification indispensable and justifies the role of abdominal CT in the early pre-operative diagnosis of paraduodenal hernia. Multislice computer tomography (CT) offers high resolution and multiplanar images which may be very demonstrative and characteristic providing a precise and early diagnosis, useful for surgical treatment planning [6,12]. In typical CT images, PDH shows a cluster of dilated bowel segments with engorged and displaced mesenteric vessels at the hernial orifice [14]. Early surgical intervention is essential to avoid future complications because patients with PDH have a 20-50% mortality for acute presentations [15,16]. A literature search was performed to identify the rare cases of paraduodenal hernia treated with laparoscopic approach. Only 28 case reports were published between January 1998, in which Uernatsu et al. [17]. first described the minimally invasive treatment of this surgical emergency, and November 2015. The several advantages of laparoscopic approach, deduced  after analysing data in previous cases, were: decrease in post-operative pain, reduced morbidity, early food resumption (1.33 average, 1-3), shorter hospital stay (3.60 average, range 1-10). These benefits occurred regardless of type of intervention (elective or emergency), type of repair (closure of hernial defect with continuous or interrupted suture, enlargement of defect or resection of the sac) and type of material used (adsorbable or not adsorbable, monofilament or poly-filament) [9,10,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. We opted for laparoscopic approach for all our five patients who shared same benefits as described by other authors. Therefore, based on our experience and current literatures, we believe that laparoscopic approach is the optimum treatment strategy for patients with paraduodenal hernia, especially in health centres with strong experience of advanced laparoscopic surgery. Patients with or without small bowel obstruction and   hemodynamically stable are suitable to enjoy the benefits of laparoscopic approach. Computed tomography remains the gold standard of imaging modality for early diagnosis of this clinical entity. However, the limitation of our report is that the number of cases is small and hence, a concrete conclusion can only be drawn based on our experience so far.