Do We Really Know Why Colorectal Anastomoses Leak?

Abstract

In this review, we examine the major known risk factors and technical considerations that have been implicated as factors in leakage. Although surgical technique has evolved over the past several decades with the advent of newer surgical staplers, laparoscopy, and robotics, we have not witnessed a decrease in the incidence of colorectal anastomotic leaks suggesting that the fundamental pathogenesis of anastomotic leak remains unknown. Among the factors contributing to anastomotic healing, intestinal bacteria remains largely overlooked even though compelling evidence exist that intraluminal microbes could play a major role in pathogenesis of anastomotic leak. Further investigation focusing on intestinal microbes could be one such avenue for uncovering the elusive cause of colorectal anastomotic leak.

Are gut bacteria associated with the development of anastomotic leaks?

“…The fact that this knowledge has not found its way into clinical practice might have to do with the fact that most surgeons are convinced that AL is caused by poor surgical technique either leaving gaps, traumatizing intestinal tissue, causing poor blood supply or tension on the suture line [27]. Even though, the evidence for these mechanical factors is neither really that convincing nor particularly conclusive [24], the idea that AL always has a mechanical cause triggered many investigations searching for the perfect anastomotic technique [27,30]. Two arguments support the mechanical hypothesis, namely that experienced surgeons have a lower rate of AL since they are technically better and that those anastomoses which leak within the first 48 hours after surgery unsually do so for technical reasons [27].…”

“…Even though, the evidence for these mechanical factors is neither really that convincing nor particularly conclusive [24], the idea that AL always has a mechanical cause triggered many investigations searching for the perfect anastomotic technique [27,30]. Two arguments support the mechanical hypothesis, namely that experienced surgeons have a lower rate of AL since they are technically better and that those anastomoses which leak within the first 48 hours after surgery unsually do so for technical reasons [27]. On the other hand, even a perfectly fashioned anastomosis in a young and otherwise healthy patient treated in a high-volume department by the most experienced surgeon can leak [27], and unfortunately, far too many perfectly fashioned anastomoses do leak.…”

Fluorescent test accurately predicts leak of ischemic colon anastomosis in rats

“…This can be explained by its high incidence and negative impact on the health of the patient (increased morbidity and mortality rates, length of hospital stay, risk of permanent ostoma, poor prognosis in cancer patients, damage on quality of life) and on the socioeconomic status of the population (increased health costs and workplace absence) 25 . So far, there is no technique or cost-effective method for predicting the occurrence of colorectal anastomotic dehiscence 2,3,26 . Clinical parameters, such as intestine color, the presence of peristalsis, mesenteric pulse, active bleeding have historically demonstrated low accuracy to assess the viability of ischemic bowel 12 .…”

“…Ongoing advances in terms of perioperative care and surgical techniques have provided better results in the surgical treatment of patients with colorectal diseases. However, the rate of complications after colorectal surgeries is still high -around 30% -, and anastomotic dehiscence remains a relevant unsolved problem [2][3][4][5] . There is a general consensus on the key role of blood supply, mainly at the bowel margins, for the proper healing of intestinal anastomosis.…”

“…Clinical tests to predict the occurrence of anastomotic dehiscence have very low accuracy, with a failure rate up to 60% 4,[7][8][9] . Several studies have been conducted to find an objective and reliable method of intraoperative evaluation of intestinal blood supply in the last four decades 2,3,7,[10][11][12][13][14] . To present date, no method has been accepted as the standard for this matter, however fluorescence tests have gained some attention [16][17][18][19][20][21][22] .…”