Intracorporeal Anastomosis in Laparoscopic Left Colectomy. Cohort Comparative Study

HYPOTHESIS Resection of the left colon / sigmoid with intracorporeal colorectal TT anastomosis is safe and not inferior to that performed extracorporeally. With the benefits of reduced intraoperative dissection, traction on the mesenteries, reduced vascular compromise of the anastomosis, a smaller incision size and being able to choose its location. Main Aim: The objective of this study is to demonstrate that colorectal mechanical end-to-end intracorporeal anastomosis is not inferior to extracorporeal approach in terms of anastomotic dehiscence. Secondary Aims: * To demonstrate the reproducibility of the colorectal mechanical end-to-end intracorporeal anastomosis technique in terms of reconversion, anastomotic dehiscence, organo-cavitary infection, and other postoperative complications. * To determine the benefits that the IC anastomosis technique can bring to patients with obesity. * To determine the benefits that the IC anastomosis technique can provide in terms of postoperative complications, hospital stay, and size of the accessory incision. * To determine the benefit of the application of indocyanine green to determine the point of resection and anastomosis. STUDY DESIGN Comparative, single-center, controlled non-inferiority cohort study of resection and mechanical end-to-end intracorporeal anastomosis in left colon, sigmoid, and upper rectum surgery (prospective cohort) versus the standard technique of extracorporeal laparoscopic surgery (retrospective cohort). SUBJECTS OF THE STUDY In group 1 or control (retrospective cohort): patients diagnosed with adenocarcinoma of the left colon, sigmoid or upper rectum who meet the inclusion criteria Operated on surgically by our unit, collected in our database, by laparoscopic oncological surgery applying the conventional extracorporeal anastomosis technique. In group 2 or case (prospective cohort): patients diagnosed with adenocarcinoma of the left colon, sigmoid or upper rectum, that meet the inclusion criteria, with an oncological surgical indication with a laparoscopic approach since July 2020, to which the resection and intracoporeal anastomosis technique will be applied.