Higher anastomotic leakage (AL) rate is reported after ileosigmoid (ISA) or ileorectal anastomosis (IRA) in total or subtotal colectomy (TSC) compared to colonic or colorectal anastomosis. An AL reduction in these cases may improve short and long terms outcomes significantly. Current evidence remains insufficient to assess AL risk after TSC, based on single-center studies or small cases series. The investigators aim to analyse and identify potential risk factors to AL following TSC and ISA or IRA, both preoperative and intraoperative in order to prevent surgical complications.

The study is set up as a retrospective multicentre observational study. Inclusion criteria are patients (1) over 18 years old, (2) underwent restorative TSC with ISA or IRA anastomosis, (3) with/without loop ileostomy (4) between 2013-2019. Exclusion criteria are: (1) non-restorative TSC, (2) previous colorectal resection, (3) deferred anastomosis in trauma surgery and (4) other surgical resection in the same procedure.

AL will be defined as a defect of the integrity of the intestinal wall at the anastomotic site leading to a communication of the intra and extraluminal or a pelvic abscess adjacent to the anastomosis according to the definition set by de International Study Group of Rectal Cancer. AL requiring no active therapeutic intervention will be classified as Grade A. AL requiring active therapeutic intervention (antibiotics and percutaneous drainage) but manageable without relaparotomy will be classified as Grade B and AL requiring re-intervention were classified as Grade C.

Multivariable logistic regression model will be used in order to assess potential AL risk factors. p value <0,05 will be consider to indicate statistical significance.

Primary outcome is to assess potential risk factors to AL after restorative (ISA or IRA) TSC. Secondary outcomes are to identify risk factors to associated postoperative morbidity, mortality and re-admissions.

Data will be collected in each participating center enrolled in the study by the assigned principal investigator, confidentially and codified. Data will be sent to the study principal investigator. Database, patients code and email address will be provided at the study inclusion.

Ileorectal (IRA) or ileosigmoid anastomosis (ISA) following Total or Subtotal Colectomy (TSC) are frequently performed in inflammatory bowel disease (IBD) (Crohn´s disease, ulcerative colitis and indeterminate colitis), familiar adenomatous polyposis or colonic polyposis syndromes and colorectal cancer (CRC). TSC is less frequently performed in refractory constipation and ischemic colitis.

Anastomotic leakage (AL) is a significant complication associate with increased mortality, reoperation and derivative morbidity and is also related to poor long term outcomes in oncological resections. Although, the formation of IRA or ISA is anatomically easy to performed, pelvic dissection is not mandatory, there is no tension at the anastomosis and a blood supply is theoretically ensured, higher AL risk is reported after IRA or ISA (6.5-21%) compared to colonic or colorectal anastomosis with lower AL rate, mainly under 15%. Regardless of the indication, similar AL rates are seen after TSC in IBD (4-12%), polyposis (20%) and colon cancer (6-21%). Reducing AL rates might improve short, long term and functional outcomes after IRA or ISA There is not a wide evidence about determinants for AL following colectomy with IRA or ISA.

The impact of the anastomosis (ISA or ISA) on AL is controversial with no findings any in the most recent studies. Great number of studies have been published about risk factors for AL after colectomy, but the majority are focused in colorectal cancer patients. IRA or ISA results after TSC are mixed with other anastomosis sites and the reported results are hardly clear and conclusive.

For this reason, The investigators aim to assess potential risk factors to AL in restorative TSC, including every surgical main reason.

Inclusion Criteria:

• (1) over 18 years old
• (2) underwent restorative TSC with ISA or IRA anastomosis (emergent or elective)
• (3) with/without loop ileostomy
• (4) between 2013-2019

Exclusion Criteria:

• (1) non-restorative TSC
• (2) previous colorectal resection
• (3) deferred anastomosis in trauma surgery and
• (4) other surgical resection in the same procedure.

Patients underwent total or subtotal colectomy with primary anastomosis