Discussion

The first person to describe a case of appendiceal duplication was Picoli in 1892. Its prevalence worldwide is 0.004% to 0.009% [3]. In a worldwide search of scientific literature, most references to appendiceal duplication are found in case reports, indicating the rarity of this condition. In 1936, Cave proposed a classification system based on their anatomical location [4], and in 1963, Wallbridge revised this classification, and the modified Cave-Wallbridge classification was created [2]. Minor modifications were made until 1993 when Biermann suggested the following classification, which is used today:
Our case presented a B2 type appendiceal duplication, which is the most common type. According to a study by Nageswaran et al. [6], there are no associated congenital abnormalities in this type of duplication; concealed duplication is confirmed only intraoperatively.
Type B2 duplication is the most common variation of anatomy and the most difficult to identify. Difficulty in identification is because the appendix that arises from the convergence of the taenia is retrocaecal and out of sight. Moreover, if an inflamed, anteriorly placed appendix is found, the retrocaecal space is not usually explored. It is considered that approximately 37% of patients with duplication present with inflammation of both appendices at the time of operation; therefore, they may not recover postoperatively as expected. If signs of inflammation are present along the right paracolic gutter when the surgeon identifies an anteriorly placed appendix, careful examination of the caecal pole and retrocaecal space should be subsequently performed.
Some extremely rare cases are described, such as ’the triple appendix’ [7], which cannot include the existing types. In 1986, Alvarado [1] suggested a clinical diagnostic tool which considers the patient’s signs and symptoms as well as some laboratory values. It is used for stratifying the risk of appendicitis being present (Table 1). A score of 5 or 6 is compatible with the diagnosis of acute appendicitis; a score of 7 or 8 indicates probable appendicitis; and a score of 9 or 10 indicates a very probable appendicitis. The Alvarado score is considered to have high sensitivity and low specificity; therefore, it is useful in “catching” appendicitis. However, the score is less effective for stratifying the risk of appendicitis in children [8]. After some years, this score was modified for patients 3-18 years old, and the Paediatric Appendicitis Score was created and implemented.