Most surgeons suggest the use of fecal diverting to address the high morbidity and mortality associated with anastomotic leakage (AL) in patients with high risk factors on AL who are undergoing low anterior resections(LAR). This exploratory study was conducted to evaluate the efficacy and safety of one kind of controllable tube ileostomy(CTI), which was designed to protect rectal anastomosis in patients with high risk factors on AL. Results of SCCI were compared to those of the loop ileostomy (LI) method.

In fact when we told the patients about the tube ileustomy's effect and risk, almost all the almost all of my patients like to choose tube ileustomy(I have study this method for long time and have good expeience, and my patients either choose tube ileostomy directly or let me do the choice.) So I gave all the patients who meet the requirenments all tube ileustomy and have no control group.

After low anterior resection(LAR), a double row of concentric purse-string sutures were placed in the ileum wall using 3-0 absorbable suture. The diameters of the purse-string rings were about 10 mm and 20 mm, respectively. The investigators then made a small incision within the inner purse-string and inserted the trachea cannula into the proximal end of the ileum. The inner purse-string suture then was tied, followed by the outer purse-string suture. The outer purse string should capsulate the inner purse string to prevent leakage. Normal saline was injected into the air bag until the ileum wall. The investigators will test the pressure of airbag, and control the pressure of airbag from 30-40cmHg. The investigators then pulled the cannula out through the abdominal wall. The incision site in the ileum was approximated to the inner abdominal wall and extraperitonized by fixing the mobilized ileum wall around the cannula to the inner abdominal wall. This was accomplished using 3-4 interrupted sutures.

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.

Inclusion Criteria:

• Rectal Tumor After Low Anterior Resection the Anastomosis Located extraperitoneal
• Patients Agreed to Undergo the tube ileostomy or loop ileostomy Procedure

Exclusion Criteria:

• Bowel Preparation is not Satisfied Before Operation
• Blood lose is more than 1500ml during operation
• Critical incident during operation
• The vagina or bladder is seriously damaged and the fix is not satisfied.