Inclusion Criteria:  Previous bariatric surgery; Age:> 18 <65 years; Compensated comorbidities; Official surgical informed consent with Covid-19 addendum in case the state of emergency continues. Revisional bariatric procedures approved by: SICOB (Italian Society of Obesity Surgery), EAES (European Association for Endoscopic Surgery) and IFSO (International Federation for Obesity Surgery), including: Roux-en-Y gastric bypass, sleeve gastrectomy or repeated sleeve gastrectomy, biliopancreatic diversion, duodenal switch, duodenal-jejunal bypass, one-anastomosis gastric bypass, single anastomosis duodeno-ileal bypass (SAID), performed exclusively laparoscopically.  Routine performance expected during the clinical study, as inclusion criteria:  obtaining the informed consent for participating in the clinical study; delivery of the privacy, information and data treatment forms; online data collection form's compilation (CRF); collection of specific Italian Society of Obesity Surgery (SICOB) informed consent for revisional bariatric surgery, COVID-19 regional questionnaire and SICOB's addendum for bariatric surgery during COVID-19 (attachment 6); emission of patients' letter of discharge, indicating the telephone interview after 7 and 15 days and the first outpatient check-up after 30 days; information letter for the general practitioner (see attachment 7);  Exclusion Criteria:  no compliance to the inclusion criteria; other revisional bariatric procedures than ones approved;