In the CTI group, the tube will be removed after 3-4 weeks. If anastomotic leakage occurred, the investigators will test the airbag pressure and keep the pressure during 30-40cmHg. Because with time went on, the ileum will dilated , the airbag pressure will go down, then the feces may go through the airbag plane and flow into colon and the tube ileostomy will lose its defunctioning effect.When the investigators control the airbag pressure, we can control the defunctioning effect of tube stomy. So it is called controllable tube ileostomy. The investigators will keep the tube until the anastomotic leakage was cured.