Subcutaneous Closed-Suction Drainage Affects Surgical Wounds Healing in Lower Gastrointestinal Open Surgery: a Randomized Controlled Study

Inclusion Criteria: * aged 18-85 years old, male or female * all patients underwent lower gastrointestinal surgery: the digestive tract below Treitz ligament was called lower gastrointestinal tract, including jejunum, ileum, ileocecal part and colorectal * open surgery (instead of laparoscopic) required * willing participated in clinical verification and signed informed consent. Exclusion Criteria: * laparoscopic surgery * upper gastrointestinal surgery (esophagus, stomach, duodenum and hepatobiliary pancreas) * simple appendectomy / total appendectomy * hernia surgery and intestinal obstruction surgery without intestinal resection * infection of incision site before operation * pregnant women * expected death within 1 month after operation.