Management of Anastomotic Leak

Introduction

Although significant improvements in oncologic outcomes after surgery for colorectal cancer have been achieved, the issue of anastomotic leaks remains a challenge. In fact, an anastomotic leak is one of the most serious complications of any restorative colon or rectal resection. Leaks account for a quarter of all postoperative deaths after colorectal surgery and up to one third of all deaths after low anterior resection. In addition to mortality, anastomotic leaks are associated with increased morbidity and decreased quality of life because of the rate of permanent ostomy (up to 72%), the need for additional surgeries, and the functional consequences of the related sepsis. In the literature, the major focus has been on the causes of anastomotic leaks, with little attention given to their management. The mortality rate has not changed in the past three decades despite significant improvements in critical care, and our knowledge of factors contributing to leaks unfortunately has not resulted in effective leak prevention. Anastomotic leaks traditionally have been thought to be due to problems with technique, yet the rate of leaks has remained unchanged despite the introduction of the surgical stapler. If leaks were the result of technical error, surgeons would be the best predictors of these events. However, studies have shown that a surgeon’s own judgment in predicting the risk of a leak is very poor. Given that anastomotic leaks remain both inevitable and unpredictable, the only way that postoperative outcomes can be improved is through early detection and better management when they do occur.

What Defines a Leak?

Despite the constant rate of anastomotic leaks, little consensus exists among surgeons about how to manage the problem. Much of this lack of consensus could be due to variation in how an anastomotic leak is defined. The definition of an anastomotic leak used in this chapter will be consistent with the definition put forth by the International Study Group of Rectal Cancer. An anastomotic leak is defined as a defect of the intestinal wall at the anastomotic site leading to a communication between the intra- and extraluminal compartments. This communication can be confirmed radiographically, endoscopically, or intraoperatively. Anastomotic leaks can be symptomatic (clinical) or asymptomatic (subclinical). Clinical leaks generally cause symptoms of pelvic discomfort and signs of sepsis and can be identified endoscopically or with imaging. Subclinical leaks may only be identified at a follow-up endoscopy, prior to stoma closure, or during surveillance for cancer risk.

Principles of Management

The goals of any leak management strategy should be preservation of the anastomosis, minimal morbidity and mortality, and maintenance of quality of life. These goals can best be achieved through early diagnosis, control of sepsis, and use of interventions that do not increase the risk of a permanent stoma.

Early Diagnosis

Mortality rates have been shown to increase from 0 to 18% if an anastomotic leak is recognized after the fifth postoperative day. A delay of 2½ days in definitive intervention for a recognized leak increased the mortality by 15%. A leak that is present from the time of the operation is difficult to diagnose early in the postoperative period because signs and symptoms take time to appear, especially if a diverting ostomy is present or the patient has a prolonged ileus. Symptomatic leaks are typically diagnosed between 7 and 12 days after surgery. Asymptomatic leaks can be diagnosed months later, especially if the leak is through a portion of the anastomosis that is not in the direct fecal stream (e.g., the blind end of a side-to-end anastomosis). Overall, up to 42% of leaks are diagnosed after the patient is discharged. An anastomotic leak can cause a variety of nonspecific cardiovascular, pulmonary, and gastrointestinal (GI) symptoms. Signs and symptoms, such as fever and leukocytosis, are usually indicative of a postoperative infectious complication and rarely reach predictive values while the patient is still in the hospital. Peritonitis is unlikely in patients if their anastomosis is either extraperitoneal or covered by a proximal stoma. Drains placed at surgery can provide early clues to the presence of a leak but can just as easily be misleading. Goligher examined data from a large series of patients, all of whom underwent a postoperative contrast enema after undergoing colorectal anastomoses, and found a 30% leak rate. The study was performed prior to the introduction of stapling techniques but still serves to encourage a high index of suspicion for a leak after a colorectal anastomosis.

Imaging

Computerized tomography (CT), CT with rectal contrast material (CT-RC), and a gentle water-soluble contrast enema (WSCE) are the preferred techniques for diagnosing a leak but can fail to diagnose it at the vital early stage. CT-RC has proved to be more sensitive in identifying anastomotic leaks than WSCE and also permits accurate identification of any abscess that may be amenable to percutaneous drainage. Contrast material can be injected down the distal limb of the ostomy to prevent further disunion of the anastomosis by injection through the rectum.

CRP Levels

C-reactive protein (CRP) appears to be a very promising marker for anastomotic leaks. CRP levels remain elevated beyond the third day postoperatively in all patients who have had leaks. We have noticed that the absolute value is less important than the trend. Postoperative CRP levels increase on postoperative days 1 and 2 but begin to decrease on postoperative day 3 and onward in the vast majority of patients who do not have a leak. If CRP levels are not declining by postoperative day 4 or 5, further investigation may be warranted. However, there is no level 1 evidence to prove that postoperative serum CRP levels accurately diagnose a leak. They are another piece of evidence that guides the clinician and adds minimal cost to the care of the patient.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here