RESUMEN
BACKGROUND: Transanal endoscopic microsurgery (TEM) is a minimally invasive procedure with low morbidity. The definition of risk factors for postoperative complications would help to identify the patients likely to require more care and surveillance in an ambulatory or 1-day surgery (A-OdS) program. The main endpoints are overall 30-day morbidity and relevant morbidity. The secondary objectives are to detect risk factors for complications, rehospitalization, and the time of occurrence of the postoperative complications, and to describe the adverse effects following hospitalization that the A-OdS program would avoid. METHODS: This is an observational study of consecutive patients undergoing TEM between June 2004 and December 2016. Overall and relevant morbidity based on the Clavien-Dindo (Cl-D) classification were recorded, as were demographic, preoperative, surgical, and pathology variables. Univariate and multivariate analyses of the risk factors were carried out. RESULTS: Six hundred and ninety patients underwent surgery, of whom 639 were included in the study. Overall morbidity rate was 151/639 patients (23.6%); the clinically relevant morbidity rate was 36/639 (Cl-D > II) (5.6%) and mortality 2/639 (0.3%). The most frequent complication was rectal bleeding, recorded in 16.9% (108/639 patients) and grade I in 86/108 patients (78. 9%). The period with the greatest risk of complications was the first 2 days. The rehospitalization rate after 48 h was 7%. The risk factors for complications were as follows: tumor size > 6 cm (OR 3.2, 95% CI 1.3-7.8), anti-platelet medication (OR 2.3, 95% CI 1.1-5.1), and surgeon's experience < 150 procedures (OR 2.0, 95% CI 1-4.1). CONCLUSIONS: TEM is a safe procedure. The low rates of morbidity, re-hospitalization, and postoperative complications in the first 2 days after surgery make the procedure suitable for A-OdS.