Teaching Case

An 89-year-old patient presented with peri-umbilical and low abdominal pain for 4 days. The pain increased with motion. She had not eaten in two days and had vomited a lot over the course of the past few days. No fever was registered at clinical examination. CRP was 220 mg/L.

We can view the sac extension medial to the pubic tubercle on figure 1. This is pathognomic for an inguinal hernia [1]. Furthermore we can discern its location to the epigastric vessels. A lateral location means indirect hernia and medial location is direct hernia. Figure 2 provides a comprehensive axial view of the pathology with a clear view of a tubular structure in the hernial sac. This is the appendix descending downwards from its caecal origin (figure 3).

Appendicitis and groin hernias are frequent pathologies in acute abdominal pain. The combination of the two in De Garengeot or Amyand hernias is rare. Amyand hernias consist of an appendix located in an inguinal hernia (direct or indirect) (0.19% to 1.7% of all hernias) [2] and are more predominant in men (considering inguinal hernias are 12 times more frequent in men [3]). Children are also more prone (>3 times more frequent) due to the patency of the processus vaginalis [4]. An appendicitis located in an inguinal hernia is even rarer and occurs in only 0.07-0.13% of all hernias [2]. De Garengeot hernia is a femoral hernia with an appendix inside the sac and since the femoral canal is smaller, is a more difficult problem.

Since complications such as incarceration or strangulation are much more frequent in femoral hernia, careful differentiation between the two types is needed. Indeed 40% of femoral hernias present with incarceration or strangulation while lifetime risks of strangulation of the inguinal hernia are 0.272 and 0.034 for an 18- year-old man and 75-year-old man, respectively. [1].

The clinical presentation is vague and often difficult. Peritonitis signs are often not present since the inflammation is contained inside the hernia sac. [4] Leucocytosis can be seen in haematological investigation. Raised CRP can be a sign of inflammation but is not specific. Abscess or perforation are not frequent, but due to the sometimes delayed diagnosis can occur. [3]

CT remains the gold standard in the work-up and shows a tubular structure inside a hernia sac. Anatomically the distinction between inguinal and femoral hernias is its location compared to the inguinal ligament. This is often difficult to identify on CT and it is easier to differentiate based on femoral vein compression (more likely femoral hernia when <2/3 of the diameter of the unaffected side) and extension medial from the pubic tubercle (more likely inguinal hernia). [1]
Strangulation and perforation are key elements to look for.

Both laparoscopy and laparotomy have been used in treatment. If the appendix is not inflamed laparoscopy can be used safely to remove it from the sac. A mesh hernia repair can be used if the appendix was normal or was not removed. Otherwise risk of infection is too high (up to 29%). In such cases a Bassini's repair is performed. [4]

- An appendix in a hernia sac exists and poses a surgical difficulty.
- Differentiation between femoral and inguinal hernia is important!