Appendix: “an appendage to a twelve-meter gut or a storehouse for microbiota”?

Abstract

Acute appendicitis is the most common surgical pathology in paediatric practice. Surgical interventions in children with acute and complicated appendicitis are performed when urgently indicated at various stages of the disease. Laparoscopic appendectomy has become the current “gold standard” for providing emergency surgery care to children. Improvements in surgical techniques and post-operative protocols have reduced complications in children to 5–7%. The current discussion topics include the issues of argumentation of “incidental appendectomies” to be performed in minimal macroscopic changes in the vermiform appendix in children with nonspecific mesenteric lymphadenitis, intestinal indigitation, appendiceal lithiasis, justifications for indications and timing for surgical interventions in chronic appendicitis. The appendix has long been considered an “unnecessary” organ, just vestigial structures left over in the process of human evolution. Over the past two centuries, much work has been done to study the appendix. The structure of the vermiform appendix is unique. It has a narrow lumen, abundant mucosa-associated lymphoid tissue and valuable microbial composition. It has recently been hypothesized that the appendix has immunomodulatory functions and serves as a “safe house” for the microbiota, providing commensal bacteria that may restore the gut after infections or antibiotic therapy. Some studies suggest that removal of the appendix increases the risk of inflammatory bowel disease, including ulcerative colitis. However, mechanisms underlying such causal relationship remain unclear. This article considers current knowledge when addressing the appendix microbiome and the relationship between the appendix and ulcerative colitis.