New classification of Amyand’s hernia, our experience: a retrospective observational study with a literature review

Abstract

Purpose

Amyand’s hernia (AH) is the name given to the type of hernia in which the appendix is found in a hernial sac. We aimed to share our clinical experience with a literature review for AH.

Methods

A total of 1,774 inguinal hernias and 13 AH cases were repaired in our clinic between 2009 and 2020. In addition, detailed clinical features about AH were extracted by including unpublished data of 165 cases, which were gathered from the extensive literature on childhood AHs using PubMed, Web of Science, and Cochrane databases.

Results

The rate of AH was 0.73% in all inguinal hernias; this rate was 8.6% for incarcerated hernias. The average age was 5.74 ± 7.27 months for AH. Our AH cases were seen in males and on the right side. AH is seen in 97.3% of males according to a review of 69 articles. The average age was 16.78 ± 30.46 months. One hundred sixty-five of the AH cases were on the right (88.7%). The main symptoms were swelling or redness in the inguinal region, pain, fever, and vomiting, along with patients presenting septic or with stercoral fistula.

Conclusion

If the appendix is normal and easily reduced, high ligation is sufficient. In cases where reduction is difficult and/or the appendix is inflamed, appendectomy and hospitalization should be performed.

INTRODUCTION

Amyand’s hernia (AH) is the name given to the type of hernia in which the appendix is found in a hernial sac and was first described by Claudius Amyand in 1,735 with a case involving a perforated appendix included in the hernial sac. AH cases make up 1% of groin hernias, while appendicitis developing in the hernial sac makes up 0.1% of appendicitis cases [1,2]. In AH cases, patients may present with findings such as swelling in the inguinal region, acute scrotum, and strangulated hernia, and preoperative diagnosis is generally impossible. The sliding of the appendix within the hernial sac may feel like a thickened cord or a second cord during physical examinations or produce testicle-like findings. Also, in delayed inflammation cases, the patient may present with redness, swelling, or pain in the groin and scrotum. Extremely delayed cases may present with stercoral fistula in the scrotal or inguinal region [1,3,4,5].

Most of the publications in the literature are presentations of single cases. There are a limited number of publications that give information about AH which are original publications from clinics or literature reviews that include multiple patients. This study aims to compile all the information on AH by collecting our clinical AH experience and all the cases in the literature that relate to childhood.

METHODS

The study protocol was approved by the Institutional Ethics Committee of Our University (No. 21/3/2022; 216). This study was performed in accordance with the Declaration of Helsinki and written informed consent was waived due to its retrospective nature.

All inguinal hernia cases admitted to our clinic between January 2009 and March 2020 were retrospectively scanned. Of the total 1,774 inguinal hernias repaired in our clinic within the given timeframe, 151 of them were incarcerated, and AH was identified in 13. All patients were diagnosed with AH intraoperatively. Preoperative ultrasonography (USG) was performed in only 1 patient, and it was determined that there was a bowel loop in the inguinal canal, but the appendix could not be evaluated. In addition, detailed clinical features about AH were extracted by including unpublished data of 165 cases, which searched the extensive literature for childhood AHs using PubMed, Web of Science, and Cochrane databases [6].

RESULTS

The appendix was found in the sac in 13 of the 1,774 patients who were operated on for inguinal hernias between 2009 and 2020. While the AH rate in our clinic was 0.73%, the AH rate in strangulated hernias was 8.6%. All patients were male and the hernias were on the right side. The average age was 5.74 ± 7.27 months (range, 48 days–2.5 years). While all cases were done with the open method, an appendectomy was performed on 4 patients because the appendix was hyperemic in 2 patients and dissection of the appendix from the sac was difficult in 2 patients. The appendix was pushed into the abdomen in 9 cases. Two cases were reported as lymphoid hyperplasia while 2 were evaluated as normal (Table 1).

Table 1. Our Amyand’s hernia patients (all of male sex) and characteristics.

Sixty-nine publications presenting AH were screened. In these publications, the rate of incarceration was similar for boys and girls. However, of the cases where sex was disclosed 180 were male (97.3%) while 5 were female (2.7%). Sex was not stated in 13 cases. The average age of the cases was 16.78 ± 30.46 months (range, 4 days–16 years). Of the 137 cases where age was disclosed, 91 were younger than 1 year (66.4%), 43 were 1–10 years-old, and 3 were older than 10 years. Of the 198 AH cases, 165 case were on the right (88.7%), 21 on the left (11.3%), and in 12 cases the side was not stated. An appendectomy was performed in 103 cases, 2 of which were inverted. Out of the 51 cases sent to pathology, 13 were normal, 33 were acute, and 5 were reported as perforated. Of the 39 appendectomy cases not sent to pathology, perioperative findings showed 2 normal, 16 acute, and 7 gangrenous cases. Clinical and histopathological appendicitis was observed in 83.3% of cases where appendectomy was performed, while this rate was 37.8% for all cases [6] (Table 2).

Table 2. Literature review for Amyand’s hernia.

USG, ultrasonography; UTI, urinary tract infection; ASD, atrial septal defect; CMV, cytomegalovirus.

Not all publications included postoperative follow-up, and in the publications that did include this information, 4 reported wound infection; and in general, there were no complications [7,8,9,10].

In 1 case where the appendix was pushed back into the abdomen, the patient was operated on a second time 2 days after the first operation due to fever and distension, and ischemia of the appendix was found in the patient [11].

In 19 out of 20 cases where the patient had previously been confirmed to have an inguinal hernia by family or doctors but had not undergone surgery, the patient underwent emergency interventions due to incarceration during follow-up. The average age of these patients was 22.10 ± 22.22 months and follow-up time was 20.18 ± 22.37 months. The other patient underwent elective surgery and an AH was found on the left, and a right Littre hernia was identified. The hernia was reported as extending into the scrotum in 36 patients. The cecum was also found in the hernia sac next to the appendix in 33 patients (16.6%), and in 10 of these cases, the ileum was also in the sac. Thirteen patients were reported as having a sliding hernia [6] (Table 2).

In addition to the main symptoms of AH such as swelling or redness in the groin area, pain, fever, and vomiting, there were also patients who presented with septic conditions or stercoral fistula. In the screening, epididymo-orchitis was considered before AH in 6 patients (3.0%) aged 5–42 days [12,13,14,15,16,17]. Four patients (2.0%) aged 10 days, 26 days, 28 days, and 10 months were first considered for a diagnosis of testicular torsion [8,18,19,20].

Of the 21 AH cases on the left, all were found in males. The cecum was in the sac in 12 cases, of which 4 also had the ileum in the sac, and no information was reported for 9 of these cases. Ninety-five patients underwent open surgery, and 11 underwent laparoscopic surgery, while no information was provided about the operation procedure for 92 patients [6] (Table 2).

DISCUSSION

Inguinal hernia, the incidence of which varies between 0.8% and 4.4% in the pediatric age group, is the disease that most frequently requires surgery in this age group [21,22]. AH make up 1% of all hernias, and appendicitis in AH makes up 0.1% of all appendicitis cases [2]. According to this screening, AH is found in males 97.3% of the time and on the right in 88.7% of cases. This is in line with our clinical experiences in which all cases were on the right side and in male patients. This may be due to low numbers.

While the reason for appendicitis developing in AH is not entirely known, some authors have stated possible reasons such as circulation problems due to incarceration, the appendix being open to trauma when it settles in the inguinal region, especially during reduction, contraction of the abdominal muscles, and circulatory abnormalities due to increased intraabdominal pressure [1,23]. Since AH is an incarcerated inguinal hernia and most AH cases (66.4%) are seen in patients under the age of 1 year, and when we consider that the average age in our batch is 5.74 months, the operation should be performed at an earlier stage because these cases are more prone to incarceration. This is why when swelling or a cord-like structure is identified in the inguinal region of a patient under the age of 1 year, even though the number of patients receiving preoperative diagnoses using USG and exhibiting findings similar to the acute scrotum is 2, at least a differential diagnosis should be performed with USG and elective surgery should be performed to lower the risk of incarceration and emergency surgical intervention [12,15]. The 3 late cases presenting with fistula in the scrotum and inguinal region should also be kept in mind clinically [3,4,5].

Generally, cases are taken into surgery without a preoperative diagnosis (91.4%) and receive a diagnosis of AH during surgery. Today, the use of ultrasound makes it at least more likely to diagnose AH preoperatively. In 1 patient in our batch, preoperative USG detected the intestinal contents but could not visualize the appendix. In the cases in the literature where appendicitis diagnoses were delivered preoperatively using USG, the appendix was seen preoperatively, and an incompressible lumen was observed for diagnosing appendicitis [9,12,15,24,25,26,27,28].

In classic AH, the appendix is included in the hernial sac. In the literature, it has been stated that in the presence of patent processus vaginalis, the persistent fibrous band between the appendix and the testicle may cause the appendix to be directed to the inguinal canal and cause this type of hernia [2]. In our opinion, the openness of the inner ring or processus vaginalis and the 30% of the appendix being pelvic and mobile in premature and young children explain why the appendix moves into the hernia sac and develops into AH. The fact that the inner ring or processus vaginalis was open in premature and young children and the majority of patients were premature or young children both in the literature and in our batch supports this view [29].

Even though there are no left-sided AH cases in our batch due to the low number of cases, left-sided AH makes up 11.3% of cases in the literature. The relation between the testicle and the appendix is not as obvious in left AH. The fact that 60% of hernias are typically on the right explains the right-sided involvement of AH [30].

Considering cases where the appendix is retrocecal or subserosal, in 4 cases in our batch (30.8%) and in 16.6% of cases in the literature, the cecum and ileum were included in the hernial sac. This is why cases in which intestinal organs such as the cecum are included in the hernial sac in AH cases disprove this hypothesis. Also, in 57.1% of cases in the literature, the cecum was included in the hernial sac in left-sided AH cases, which also excludes AH occurrence related to this band. In almost all these cases where left AH was diagnosed, pathologies such as mobile cecum, malrotation, or situs inversus were also found. Thus, AH cases that include intestines apart from the appendix should typically be classified as incarcerated inguinal hernias. The appendix is in the inguinal sac because the cecum is in the sac. The cecum is not in the sac because the appendix is in the inguinal sac. The clinical findings described by Lossonaf and Basson with a 1–4 grading do not explain the symptoms of these patients. Also, the hernia described by Amyand that would later be named after him only included the appendix in the hernial sac [31]. Thus, in the classification of AH in children, we are of the opinion that a modified Gazi classification would be more appropriate (Table 3).

Table 3. Classification of Amyand’s hernia for children with Gazi modification.

In cases where the appendix is normal and easily reduced, only high ligation is sufficient, whereas in cases where reduction is difficult and/or the appendix is inflamed, appendectomy, reduction, and hospitalization should be performed for patient safety.