Despite improvements in surgical approaches and perioperative care, anastomotic leak – a dire complication of colorectal surgery – still occurs, bringing with it increased morbidity, mortality, length of stay, and related costs. The consequences for patients with failed anastomoses have compelled colorectal surgeons to pursue materials and techniques to improve their outcomes.
Dr. Alessio Pigazzi
“A reduction in the anastomotic leak rate is extremely important when we talk about rectal cancer,” says Alessio Pigazzi, MD, PhD, Chief of Colorectal Surgery in the Department of Surgery at NewYork-Presbyterian/
In the November 23, 2021, issue of Clinics in Colon and Rectal Surgery, Dr. Pigazzi evaluates multiple techniques to reduce the rate of anastomotic leaks following colorectal surgery. Among these are sealants applied to the exterior of anastomoses, reinforcement of staple lines with bioabsorbable materials, omental flaps, and perfusion assessment with fluoroscopy.
Fibrin and Other Sealants
Fibrin-based sealants to reduce anastomotic leak have been studied for more than three decades. Comprised of a biologic polymer protein, fibrin clots are resistant to tension and compression but remain porous to cytokines and other proteins, and the polymer scaffold enables the passage of immune cells. Obtained from donated plasma, fibrin does not provoke an immune response when purified, making it a potential substance for wound healing. Alternate substances, such as platelet-rich plasma, cross-linking gelatins, and intestine submucosal wraps, have been found to yield higher bursting pressures in animal models.
Clinical studies of fibrin and other sealants have demonstrated varied results in other gastrointestinal anastomoses, but few human trials of fibrin glue for protection of colorectal anastomoses have been reported. To date, no robust clinical trials have demonstrated a benefit from liquid or gelatinous sealants around any gastrointestinal anastomoses.
Staple Line Reinforcements
Reinforcement of stapled anastomoses with bioabsorbable materials placed along the length of the staple line is another alternative approach to reduce anastomotic leak. The strengthening material is placed between opposing tissues and secured together with staples.
In GI surgery, the suggested benefit of buttressing the anastomosis is a reduction of leaks through better apposition of the stapled walls and added tensile strength to resist intraluminal pressures. However, investigations in a porcine model have shown conflicting results, with one study demonstrating no differences in burst pressures and another finding showing improved burst pressures with reinforcement.
The increased use of stapled anastomoses in clinical practice has facilitated easier incorporation of bioabsorbable buttressing materials, as studied in bariatric surgeries. In three large clinical trials of staple-line reinforcement in colorectal surgery, however, the usefulness of buttressing stapled colorectal anastomoses remains unclear.
Our colorectal surgeons have greatly reduced the rate of anastomotic leak, but a definitive solution is still to be reached. Our faculty have published widely in this area and we continue to explore techniques that can manage this most significant issue.
— Dr Alessio Pigazzi
Omental Flaps
A common clinical practice is the use of omental flaps, which involves wrapping a portion of well-vascularized omentum against an anastomosis. Investigations of omentoplasty, which is considered a relatively low-risk technique, in preventing colorectal anastomotic leaks are limited. Several studies have shown conflicting results, perhaps due to devascularization that can occur when fashioning an omentum to have sufficient length to reach the pelvis. While data appear to support the use of omental flaps for high-risk anastomoses, larger randomized trials evaluating this technique are needed to confirm the potential benefit.
Perfusion Assessment
Adequate perfusion has long been acknowledged as a critical component of successful anastomosis creation. The most direct assessment of perfusion is to evaluate bleeding after transection of the colon, along with an examination of the mucosa and serosa before performing the anastomosis. Perfusion assessment with fluorescent imaging – commonly using indocyanine green (ICG) – improves on the visual assessment to further reduce leaks. This technique is inexpensive and easily performed. Despite ensuring adequate perfusion, however, anastomotic leak continues to occur and further study with larger randomized trials is needed to confirm its benefit.
Intraluminal Sheaths
Small studies in the 1980s evaluated an endoscopically deployed, nonbiodegradable intraluminal sheath secured with Vicryl sutures to the proximal bowel, extending across the anastomosis and ending in the distal bowel. While the studies established the feasibility of this approach, larger trials did not ensue. Thirty years later, small pilot studies demonstrated the safety of deploying an endoluminal biodedgradable sheath as part of a circular stapled anastomosis. However, a subsequent trial involving 402 patients undergoing a colorectal anastomosis showed no difference in leak rates and the trial was ended early. Today, a large trial of a new device is underway to protect the anastomosis and diminish leak.
According to Dr. Pigazzi, the causes of anastomotic leak are multifactorial and require continued research in preclinical experiments on novel materials and methods to attempt to reduce the morbidity in colorectal surgery. “In our field, we are very much aware of the ongoing need to reduce anastomotic leak rates,” says Dr. Pigazzi. “We participate in clinical trials and conduct numerous bench and animal studies looking at anastomotic leak and factors that affect it, including the ability to discern and detect optimal oxygen delivery at the anastomosis. At NewYork-Presbyterian/
