**4. Postoperative complications of colorectal anastomoses and their prevention**

#### **4.1 Anastomotic leakage**

Anastomotic leak (AL) is a common problem in colorectal surgery, and its prevalence has remained steady in recent years.

The use of an intra-abdominal drain or mechanical bowel preparation to prevent AL has been shown to be ineffective and should be avoided.

The function of oral antibiotic preparation regimens should be explained and compared to other routes of administration, such as intravenous or enema, according to a study conducted by Meyer and coauthors [5].

Parallel to this, preoperative antibiotherapy should target pathogens that induce collagenase, as defined by the microbiome study.

Fluorescence angiography may minimize AL even further, resulting in major intraoperative improvements in surgical strategies.

Fluorescence angiography can be used more often.

There have been studies, such as the one by Gained and coauthors [6], that looked at the literature's connection between colorectal cancer recurrence, microbiome, and anastomotic leakage, and among the findings, one can find the aspect according to which the numerous mechanisms by which environmental factors act on the microbiome to alter its composition and function, with the net effect of adversely affecting oncological outcomes following surgery, are well documented and increasing.

Diet, antibiotic use, the procedures used to prepare the colon for surgery, and the physiological discomfort of the procedure are all examples of environmental causes.

Furthermore, using next-generation sequencing technologies to investigate the intestinal microbiome has the ability to affect cancer outcomes following colon

#### *The Problem of the Colorectal Anastomosis DOI: http://dx.doi.org/10.5772/intechopen.100302*

resection. In a systematic review that targeted the endoscopic management of early postoperative complications, a literature search was performed by Clifford and coauthors [7] for published full text articles using the PubMed, Cochrane, and Scopus databases using the search criteria string "colorectal anastomotic ("leak" or "bleed")," "endoscopy," and "endoscopic management." Endoscopic therapy in the management of stable patients with colorectal anastomotic leaks appears safe and is associated with the high rates of technical performance in selected patients, according to a review of 89 papers.

The most suitable method, patient selection, and considering the practical and long-term consequences of this approach remain challenging.

To fully assess the function of these novel strategies, further data from large prospective cohort studies are needed.

Shalaby and coauthors [8] conducted another systematic review on endoluminal vacuum-assisted therapy as a salvage treatment for rectal anastomotic leakage and found the following findings among 476 articles identified, 17 studies reporting on 276 patients:

The weighted mean success rate was 853% (95% confidence interval [CI]: 801–905), with a median time from the start of EVT to full healing of 47 (range 40–105) days.

The weighted mean rate of stoma reversal was 759% (646–872%) across the studies.

After EVT, twenty-five patients (91%) needed additional interventions. Thirty-eight patients (138%) experienced complications as a result of the procedure.

The weighted mean complication rate was 111% (60–162%) across all tests.

Preoperative radiotherapy, the absence of a diverting stoma, complications, and male sex were all found to be significantly associated with failure.

According to the findings of the study, EVT is linked to a high rate of full healing of anastomotic leakage and stoma reversal.

In appropriately selected patients with anastomotic leakage, it is a viable choice.

Colorectal cancer surgery is thought to involve "high tie" and "low tie" of the inferior mesenteric artery (IMA).

However, the blood supply of the anastomosis is closely linked to the ligation stage, which can increase the leakage rate, and it is unclear which technique confers a lower anastomotic leakage rate (AL) and survival advantage.

The aim of the literature review, as stated by Yang and coauthors [9], was to compare the efficacy and impact of IMA high ligation versus IMA low ligation on anastomotic leakage, lymph node yield rates, and 5-year survival.

Finally, after reviewing studies from 1990 to 2017, researchers came to the conclusion that neither the high-tie nor the low-tie approach has any data in terms of anastomotic leakage, harvested lymph nodes, or 5-year survival rates.

More RCT is needed.

A study conducted by Simianu and coauthors [10] looked at the recency effect, which means that people place disproportionate emphasis on events that occurred recently when making decisions, but the magnitude of this influence on surgeons' decisions is uncertain.

The use of preventative leak testing before and after colorectal operations with anastomotic leaks is examined in this study to see whether there is a recency effect in surgeons.

A prospective cohort of adult patients (aged 18 years) undergoing elective colorectal surgery at Washington State hospitals participating in the Surgical Care and Outcomes Assessment Program was used to develop the materials and methods (2006–2013).

The key outcome measure was the difference in leak monitoring between 6 months before and 6 months after an anastomotic leak.

A leak rate of 2.6% (n = 124) was found in 4854 elective colorectal operations performed by 282 surgeons at 44 hospitals.

The anastomosis was not checked in 40 leaks (32%), which were spread through 25 surgeons.

While the small sample size restricted the ability to detect an overall difference in leak testing use, 9 (36%) of the 25 surgeons increased their leak testing by 5% or more after leaks in cases where the anastomosis was not checked.

The above facts led to the conclusion that only one-third of qualified surgeons demonstrated the recency effect.

Understanding the degree to which the recency effect influences clinical decisions may be useful in developing quality management strategies that involve clinician's behavior change.

Wang and colleagues [11] contrasted many aspects of robot-assisted versus laparoscopic surgery for rectal cancer by reviewing 20 studies with a total of 5496 patients, divided into a robot-assisted surgery group (*n* = 2168, 39.4%) and a laparoscopic surgery group (*n* = 3328, 60.6%).

Longer operating period (OR: 0.48, 95% CI: 0.14, 0.82), lower conversion to open surgery rate (OR: 0.55, 95% CI: 0.44, 0.69), shorter LOS (Length Of Stay) (OR: −0.15, 95% CI: −0.30, 0.00), faster bowel function recovery (OR: −0.38, 95%

**Figure 10.** *Dehiscence at the level of the anastomosis.*

**Figure 11.** *Methylene blue test.*

#### *The Problem of the Colorectal Anastomosis DOI: http://dx.doi.org/10.5772/intechopen.100302*

CI: −0.74, −0.02), and lower postoperative complications were all correlated with the robot-assisted surgery community (OR: 0.79, 95% CI: 0.65, 0.97).

There were no substantial differences between groups in EBL, anastomosis leak rate, or oncological outcomes such as the number of lymph nodes removed, the DRM, or the PCRM (**Figures 10** and **11**).
