Giant left paraduodenal hernia

Abstract

Left paraduodenal hernia (LPDH) is a retrocolic internal hernia of congenital origin that develops through the fossa of Landzert, and extends into the descending mesocolon and left portion of the transverse mesocolon. It carries significant overall risk of mortality, yet delay in diagnosis is not unusual due to subtle and elusive features. Familiarisation with the embryological and anatomical features of this rare hernia is essential for surgical management. This is especially important with respect to vascular anatomy as major mesenteric vessels form intimate relationships with the ventral rim and anterior portion of the hernia. As an illustrative case, we describe our experience with a striking example of LPDH, particularly focusing on the inherent diagnostic challenges and associated critical vascular anatomy. We advocate the role of diagnostic laparoscopy; however caution that decision to safely proceed with laparoscopic repair must occur only with confident identification of the vascular anatomy involved.

Figure 1

Axial CT slices taken during the most recent symptomatic episode prior to surgical intervention. Several pathognomonic radiological features of left paraduodenal hernia (LPDH) are visible. ⁽5 13⁾ A large sac-like mass of clustered small bowel loops can be seen in the left abdomen with a well-circumscribed lateral convex border (A, dotted line). The inferior mesenteric vein runs at the anteromedial border of the hernia, a hallmark of LPDH. There is crowding and congestion of mesenteric vessels (A, arrow). A characteristic ‘whirl’ pattern of engorged mesenteric vessels is present (B, arrow). A transition zone of partial obstruction can be seen at the site of the efferent distal ileum exiting the hernia neck (C, arrow). At this site, a double-layered wall of peritoneal fold is also visible (superior duodenal plica), representing the ventral free edge of the hernia.

Figure 2

Coronal volume rendering CT of the abdomen. A large sac-like mass of clustered small bowel loops can be seen in the left side of the abdomen. This structure is between the pancreas and the stomach (solid arrows). Engorged and crowded vessels are running towards the centre of the mass from the superomedial rim of the hernia mass, which represents the site of the fossa of Landzert (double-headed arrow).

Figure 3

Laparoscopic view of left paraduodenal hernia with laparoscopic instrument probing the fossa of Landzert (A). Small bowel herniates through the cavernous fossa posteriorly and downward towards the left iliac fossa (B). The ventral surface of the hernia (descending mesocolon) was tented to the lateral abdominal wall peritoneum by dense adhesions (A, top right). Relevant vascular anatomy is indicated in (A) by dotted lines (IMV, inferior mesenteric vein; LCA, left colic artery; LCV, left colic vein).

Figure 4

Appearance following complete reduction of herniated bowel content. Gentle manual traction was applied to enlarge the hernia orifice and facilitate reduction (A). The inferior apex of the hernia orifice is visible at the root of small bowel mesentery (arrow). A small, well-demarcated segment of acutely ischaemic small bowel was observed following reduction of hernia content (B).