Amyand’s Hernia: A Case Report
Amyand’s hernia is a rare and atypical hernia characterized by the herniation of the appendix into the inguinal sac. This hernia may be present without symptoms until inflammation of the appendix leads to incarceration, strangulation, necrosis, perforation or rupture. Early symptoms include tenderness and inguinal swelling which may be misdiagnosed as a strangulated hernia. This condition can be difficult to diagnose clinically. Ultrasound and Computed Tomography may aid in diagnosis. This article presents a rare case of Amyand’s hernia followed by a discussion of the epidemiology, diagnosis, imaging details and treatment options for this condition.
A 47-year-old male was admitted to a trauma service with history of a ground level fall at work. Computed tomography (CT) showed bilateral inguinal hernias with small bowel obstruction. A normal appearing appendix was noted extending into the right inguinal canal. The patient was initially managed non-operatively, but was subsequently taken for exploratory laparotomy due to failure of conservative management. Operatively, there was chronic scarring and adhesion formation in the right lower quadrant, presumably from chronic incarceration within the right inguinal hernia. Lysis of adhesions was performed around the cicatrix of the distal ileum just proximal to ileo-cecal valve. On the left, sigmoid colon was reduced from the left inguinal hernia.
The rare presence of the appendix in an inguinal hernia sac is known as Amyand’s hernia [1-6]. This condition was first described and treated in 1735 by Claudius Amyand [1-5, 7-9]. It is most often found incidentally during hernia repair surgery .
Amyand’s hernia accounts for between 0.4 and 1% of all inguinal hernias, and appendicitis in conjunction with Amyand’s hernia accounts for 0.1% of all cases of appendicitis [3, 4]. 11% occur in patients with Meckel’s diverticulum  and is three times more common in the pediatric population, due to the patency of the processus vaginalis . In the pediatric population, the prevalence is 1% and occurs more often in males than females [2, 3]. Amyand’s hernia typically presents on the right side. This is likely due to the normal anatomic position of the appendix [4, 7]. Although it is rare, left sided Amyand’s hernias do occur and have thought to be the result of a mobile or floppy cecum, intestinal malrotation or situs inversus [1-3, 10].
The pathophysiology of Amyand’s hernia is uncertain, though theories proposed include an accidental herniation of the appendix, a congenital laxity of the right colon or some factor of both . Michalinos et al. points to a congenital factor, noting that Amyand’s hernia has been seen in neonates and a set of premature twins .
It is also unclear if there is a causal relationship between the herniation of the appendix and the appendicitis. Most investigators believe inflammatory swelling may lead to incarceration and subsequent impaired blood supply and bacterial overgrowth .
The appendix may remain in the hernia sac without symptoms throughout a patient’s lifetime . When symptoms do appear, they mimic an incarcerated hernia including crampy and episodic pain . On physical examination there is tenderness and swelling in the inguinal or inguinoscrotal region [1, 3]. A mass-like appearance in the inguinal region may exist . Rarely necrotizing fasciitis complicates Amyand’s hernia .
It is clinically difficult to differentiate Amyand’s hernia from an inguinal hernia due to their similar presentations. Imaging tests such as ultrasound (US) and computed tomography (CT) aid in distinguishing the pathologies [1, 2]. US is the initial diagnostic modality of choice in the pediatric population . US shows a blind-ended tubular structure with thickened walls in connection with the cecum inside the hernia sac. CT allows direct visualization of the appendix inside the inguinal canal .
Controversy exists regarding the best treatment for Amyand’s hernia. Traditionally, appendectomy with simultaneous hernioplasty has been performed. The traditional appendectomy has been performed prophylactically in order to prevent repeat herniation and possible future irritation, which may lead to appendicitis. The incidence of appendicitis is greater with Amyand’s hernia than with the routine position of the appendix [1, 2, 3]. More recent sources claim that there is no additional benefit to a prophylactic appendectomy and advocate surgery only in the setting of inflammation, perforation or gangrene [1, 3].The degree of infection, inflammation, and perforation determine whether mesh repair is used. Recurrent herniation is also a reason to perform mesh repair . When Amyand’s Hernia is treated appropriately, the morbidity and mortality match the typical inguinal hernia .
Amyand’s hernia is a rare hernia that is difficult to diagnose clinically. CT and US are particularly helpful in making an accurate diagnosis. Because there is no additional benefit to prophylactic surgery, surgeons should evaluate the state of the appendix before proceeding with an appendectomy, hernioplasty and mesh installation.
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