Why is an ultra-low anterior resection (ULAR) requiring a diverting ileostomy?

From the Guidelines

Ultra-low anterior resection (LAR) often requires a diverting ileostomy to protect the distal colorectal or coloanal anastomosis from leakage during the healing process, as the risk of anastomotic leakage can be as high as 10-20% without diversion 1. The primary reason for this approach is to reduce the risk of severe complications, including pelvic sepsis, peritonitis, and even death, associated with anastomotic leakage in ultra-LAR procedures. Some of the key risk factors that make diversion particularly important include:

• Anastomoses less than 5 cm from the anal verge
• Male patients with narrow pelvises
• Preoperative radiation therapy
• Poor nutritional status
• Technical difficulties during surgery The diverting ileostomy is typically reversed after 8-12 weeks, once the anastomosis has healed adequately, which is usually confirmed by a contrast study 1. However, recent evidence suggests that early closure of the diverting ileostomy, within 2 weeks, may be safe and feasible, with lower incidence of postoperative small bowel obstruction, stoma-related complications, and better functional outcomes, despite a relatively higher surgical site infection rate compared with late closure 1. The experts’ panel suggests that in selected elderly fit patients, early (within 2 weeks) closure of ileostomy after rectal resection should be performed, as it is related to lower incidence of postoperative complications and better functional outcomes 1. It is essential to weigh the risks and benefits of diverting ileostomy and its timing of closure on an individual basis, considering factors such as patient age, comorbidities, and overall health status. While the ileostomy adds another surgical procedure and potential complications like dehydration and electrolyte imbalances, these risks are generally considered acceptable compared to the potentially catastrophic consequences of anastomotic leakage in the pelvis. In real-life clinical practice, the decision to perform a diverting ileostomy and its timing of closure should be made on a case-by-case basis, taking into account the latest evidence and individual patient factors.

From the Research

Ultra Low Anterior Resection (LAR) and Diverting Ileostomy

• The use of diverting ileostomy in ultra low anterior resection (LAR) is a topic of discussion among surgeons, with some studies suggesting its benefits in reducing the risk of anastomotic leakage and others highlighting its potential complications 2, 3, 4, 5, 6.
• A study published in 2022 found that the creation of a diverting ileostomy did not prevent anastomotic leakage, but may reduce the need for further surgery due to septic complications in the early postoperative period 2.
• Another study from 2013 reported that a diverting stoma decreased the rate of immediate anastomosis-related complications, but also had a non-negligible rate of complications associated with its creation and reversal 3.

Indications for Diverting Ileostomy

• The indications for a diverting stoma in LAR for rectal cancer are not well established, but some studies suggest that it may be beneficial for patients with a high risk of anastomotic leakage, such as those with a very low anastomosis or those who have undergone preoperative chemoradiation therapy 4, 6.
• A study from 2011 recommended a diverting stoma for anastomoses within 5.0 cm of the anal verge and strongly recommended it for very low anastomoses within 2.0 cm 6.
• Another study from 2020 found that diverting ileostomy was associated with a lower rate of anastomotic leakage requiring surgical intervention, especially in male patients with malnutrition 5.

Complications of Diverting Ileostomy

• The creation and closure of a diverting ileostomy are associated with severe complications, including anastomotic leakage, wound infection, and bowel obstruction 2, 3, 5.
• A study from 2020 reported a diverting ileostomy construction-related morbidity of 9.7% and a stoma closure-related morbidity of 9.1% 5.
• Another study from 2013 found that 12% of patients in the diverting stoma group had complications either in making or reversing the stoma 3.