Ulcerative Colitis (UC) is a chronic Inflammatory Bowel Disease (IBD) characterized by a multifactorial etiology, a variable involvement of large bowel, and a relapsing-remitting course.

In order to keep the disease in a "quiescent" status and to prevent relapses, a significative percentage of UC patients will remain on long-term drug therapy. However, long-term immunosuppressant therapy is not free of risks and complications: in fact, these therapies have an impact on both healthcare system resources and patients' quality of life; more, there are even concerns regarding the side effects of long-term immunosuppressant therapy.

Over the past 20 years, a considerable amount of evidence was produced to support the immunomodulatory role of the appendix in the development and course of UC: there is a strong inverse relationship between previous appendectomy and development of the UC. One of the proposed theories to justify this link is that the appendix could act as a reservoir for commensal bacteria that can be secreted into the colon, affecting its microbiome and immunological response; another theory describes the appendix as the "priming site" for the cytokine production and the immunological cascade that may trigger inflammation in colon and rectum.

The idea of this study moves from these assumptions: the investigators aim to evaluate the impact of appendectomy in patients with UC who are candidates to the treatment with biologics (Anti TNF-a), because of conventional therapies failure. To further reduce any ethical problems and significantly lower any surgical morbidity, investigators will restrict the study population to only patients with active left-sided colitis, so that the surgery for appendectomy will take place on a non-inflamed cecum.

By undertaking this study, the investigators hope to a) learn more about the role of appendix and the impact of appendectomy in the clinical history of Ulcerative Colitis; b) demonstrate that laparoscopic appendectomy, a relatively simple surgical procedure that can also be performed in day-surgery with a very low expected complication rate, is a treatment that is superior to biological therapy, avoiding patients starting a chronic, long-lasting therapy, with the consequent risk of immunosuppression, and with possible higher costs for the health system in the long term.