Review of Colonic Anastomotic Leakage and Prevention Methods

Experimental models of high-risk bowel anastomosis in rats: A systematic review

BACKGROUND

Anastomotic leaks remain one of the most dreaded complications in gastrointestinal surgery causing significant morbidity, that negatively affect the patients' quality of life. Experimental studies play an important role in understanding the pathophysiological background of anastomotic healing and there are still many fields that require further investigation. Knowledge drawn from these studies can lead to interventions or techniques that can reduce the risk of anastomotic leak in patients with high-risk features. Despite the advances in experimental protocols and techniques, designing a high-quality study is still challenging for the investigators as there is a plethora of different models used.

AIM

To review current state of the art for experimental protocols in high-risk anastomosis in rats.

METHODS

This systematic review was performed according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. To identify eligible studies, a comprehensive literature search was performed in the electronic databases PubMed (MEDLINE) and Scopus, covering the period from conception until 18 October 2023.

RESULTS

From our search strategy 102 studies were included and were categorized based on the mechanism used to create a high-risk anastomosis. Methods of assessing anastomotic healing were extracted and were individually appraised.

CONCLUSION

Anastomotic healing studies have evolved over the last decades, but the findings are yet to be translated into human studies. There is a need for high-quality, well-designed studies that will help to the better understanding of the pathophysiology of anastomotic healing and the effects of various interventions.

Splenic flexure mobilization in left-sided colonic and rectal resections: A meta-analysis and meta-regression of factors associated with anastomotic leak and complications

AIM

Splenic flexure mobilization (SFM) is commonly performed during left-sided colon and rectal resections. The aim of the present systematic review was to assess the outcomes of SFM in left-sided colon and rectal resections and the risk factors for complications and anastomotic leak (AL).

METHOD

This study was a PRISMA-compliant systematic review. PubMed, Scopus and Web of Science were searched for studies that assessed the outcomes of sigmoid and rectal resections with or without SFM. The primary outcomes were AL and total complications, and the secondary outcomes were individual complications, operating time, conversion to open surgery, length of hospital stay (LOS) and pathological and oncological outcomes.

RESULTS

Nineteen studies including data on 81 116 patients (49.1% male) were reviewed. SFM was undertaken in 40.7% of patients. SFM was associated with a longer operating time (weighted mean difference 24.50, 95% CI 14.47-34.52, p < 0.0001) and higher odds of AL (OR 1.19, 95% CI 1.06-1.33, p = 0.002). Both groups had similar odds of total complications, splenic injury, anastomotic stricture, conversion to open surgery, (LOS), local recurrence, and overall survival. A secondary analysis of rectal cancer cases only showed similar outcomes for SFM and the control group.

CONCLUSIONS

SFM was associated with a longer operating time and higher odds of AL, yet a similar likelihood of total complications, splenic injury, anastomotic stricture, conversion to open surgery, LOS, local recurrence, and overall survival. These conclusions must be cautiously interpreted considering the numerous study limitations. SFM may have only been selectively undertaken in cases in which anastomotic tension was suspected. Therefore, the suboptimal anastomoses may have been the reason for SFM rather than the SFM being causative of the anastomotic insufficiencies.

A 3D printable tissue adhesive

Tissue adhesives are promising alternatives to sutures and staples for joining tissues, sealing defects, and immobilizing devices. However, existing adhesives mostly take the forms of glues or hydrogels, which offer limited versatility. We report a direct-ink-write 3D printable tissue adhesive which can be used to fabricate bioadhesive patches and devices with programmable architectures, unlocking new potential for application-specific designs. The adhesive is conformable and stretchable, achieves robust adhesion with wet tissues within seconds, and exhibits favorable biocompatibility. In vivo rat trachea and colon defect models demonstrate the fluid-tight tissue sealing capability of the printed patches, which maintained adhesion over 4 weeks. Moreover, incorporation of a blood-repelling hydrophobic matrix enables the printed patches to seal actively bleeding tissues. Beyond wound closure, the 3D printable adhesive has broad applicability across various tissue-interfacing devices, highlighted through representative proof-of-concept designs. Together, this platform offers a promising strategy toward developing advanced tissue adhesive technologies.

Bio-Inspired Self-Healing, Shear-Thinning, and Adhesive Gallic Acid-Conjugated Chitosan/Carbon Black Composite Hydrogels as Suture Support Materials

The occurrence of leakage from anastomotic sites is a significant issue given its potential undesirable complications. The management of anastomotic leakage after gastrointestinal surgery is particularly crucial because it is directly associated with mortality and morbidity in patients. If adhesive materials could be used to support suturing in surgical procedures, many complications caused by leakage from the anastomosis sites could be prevented. In this study, we have developed self-healing, shear-thinning, tissue-adhesive, carbon-black-containing, gallic acid-conjugated chitosan (CB/Chi-gallol) hydrogels as sealing materials to be used with suturing. The addition of CB into Chi-gallol solution resulted in the formation of a crosslinked hydrogel with instantaneous solidification. In addition, these CB/Chi-gallol hydrogels showed enhancement of the elastic modulus (G') values with increased CB concentration. Furthermore, these hydrogels exhibited excellent self-healing, shear-thinning, and tissue-adhesive properties. Notably, the hydrogels successfully sealed the incision site with suturing, resulting in a significant increase in the bursting pressure. The proposed self-healing and adhesive hydrogels are potentially useful in versatile biomedical applications, particularly as suture support materials for surgical procedures.

Anastomotic leak in colorectal cancer surgery: Contribution of gut microbiota and prediction approaches

AIM

To monitor prospectively the occurrence of colorectal anastomotic leakage (CAL) in patients with colon cancer undergoing resectional surgery, characterizing the microbiota in both faeces and mucosal biopsies of anastomosis. In a second stage, we investigated the ability to predict CAL using machine learning models based on clinical data and microbiota composition.

METHOD

A total of 111 patients were included, from whom a faecal sample was obtained, as well as biopsy samples from proximal and distal sites in the healthy margins of the tumour piece. The microorganisms present in the samples were investigated using microbial culture and 16S rDNA massive sequencing. Collagenase and protease production was determined, as well as the presence of genes responsible for expressing enzymes with these activities. Machine learning analyses were developed using clinical and microbiological data.

RESULTS

The incidence of CAL was 9.0%, and CAL was associated with collagenase/protease-producing Enterococcus. Significant differences were found in the microbiota composition of proximal and distal biopsy samples, but not in faecal samples, among patients who developed CAL. Clinical predictors of CAL were 5-day C-reactive protein and heart disease, whereas 3-day C-reactive protein and diabetes were negative predictors.

CONCLUSION

Biopsy samples from surgical margins, rather than faecal samples, are the most appropriate samples for exploring the contribution of the intestinal microbiota to CAL. Enterococci are only enriched in the anastomosis after surgery, and their collagenases and proteases are involved in the degradation of the anastomotic scar.

'4-Check' protocol for intraoperative anastomotic assessment during transanal total mesorectal excision: retrospective cohort study

BACKGROUND

Anastomotic leakage is a major complication following rectal cancer surgery. The primary aim of this study was to investigate the efficacy of a protocol based on a quadruple intraoperative anastomotic assessment (4-Check) during transanal total mesorectal excision (TaTME).

METHODS

Patients who underwent TaTME for rectal cancer with primary anastomosis were reviewed and divided into two groups: before (pre-4-Check: April 2015 - April 2019) and after the implementation of the 4-Check protocol (May 2019 - May 2022). This protocol consisted of a multimodal anastomotic integrity assessment, including indocyanine green-evaluation of colonic stump and intraluminal anastomosis perfusion, a reverse air leak test and anastomotic doughnuts assessment. The primary outcome was incidence of clinical and/or radiological anastomotic leakage. The secondary outcome included intraoperative anastomosis defects and repairs and 30-day complication rate. Propensity score matching and multivariable analyses were performed.

RESULTS

Of 186 patients, 160 were selected: 86 patients in the pre-4-Check and 74 in the 4-Check group. After propensity score matching, there was no difference in postoperative anastomotic leakage (pre-4-Check versus 4-Check: 11.1 per cent versus 7.4 per cent; P = 0.50). However, in the 4-Check group, the intraoperative detection of defects and repairs was significantly increased (P = 0.03), and the number of complications was reduced (pre-4-Check versus 4-Check: 33.3 per cent versus 9.3 per cent, P = 0.004). Multivariable analyses confirmed that the use of the 4-Check protocol, the detection of anastomotic defects and increased albumin levels were associated with a reduced number of complications.

CONCLUSION

The 4-Check protocol allowed the intraoperative detection and repair of anastomotic defects. Anastomotic leakage rates were not reduced; however, 30-day complication rates were lower after implementation of this protocol.

Effect of Chitosan on Rheological, Mechanical, and Adhesive Properties of Pectin-Calcium Gel

In the present study, chitosan was included in the pectin ionotropic gel to improve its mechanical and bioadhesive properties. Pectin-chitosan gels P-Ch0, P-Ch1, P-Ch2, and P-Ch3 of chitosan weight fractions of 0.00, 0.25, 0.50, and 0.75 were prepared and characterized by dynamic rheological tests, penetration tests, and serosal adhesion ex vivo assays. The storage modulus (G') and loss modulus (G″) values, gel hardness, and elasticity of P-Ch1 were significantly higher than those of P-Ch0 gel. However, a further increase in the content of chitosan in the gel significantly reduced these parameters. The inclusion of chitosan into the pectin gel led to a decrease in weight and an increase in hardness during incubation in Hanks' solution at pH 5.0, 7.4, and 8.0. The adhesion of P-Ch1 and P-Ch2 to rat intestinal serosa ex vivo was 1.3 and 1.7 times stronger, whereas that of P-Ch3 was similar to that of a P-Ch0 gel. Pre-incubation in Hanks' solution at pH 5.0 and 7.4 reduced the adhesivity of gels; however, the adhesivity of P-Ch1 and P-Ch2 exceeded that of P-Ch0 and P-Ch3. Thus, serosal adhesion combined with higher mechanical stability in a wide pH range appeared to be advantages of the inclusion of chitosan into pectin gel.

Advances in Hydrogel Adhesives for Gastrointestinal Wound Closure and Repair

Millions of individuals undergo gastrointestinal (GI) tract surgeries each year with common postoperative complications including bleeding, perforation, anastomotic leakage, and infection. Today, techniques such as suturing and stapling seal internal wounds, and electrocoagulation stops bleeding. These methods induce secondary damage to the tissue and can be technically difficult to perform depending on the wound site location. To overcome these challenges and to further advance wound closure, hydrogel adhesives are being investigated to specifically target GI tract wounds because of their atraumatic nature, fluid-tight sealing capability, favorable wound healing properties, and facile application. However, challenges remain that limit their use, such as weak underwater adhesive strength, slow gelation, and/or acidic degradation. In this review, we summarize recent advances in hydrogel adhesives to treat various GI tract wounds, with a focus on novel material designs and compositions to combat the environment-specific challenges of GI injury. We conclude with a discussion of potential opportunities from both research and clinical perspectives.

Role of Damage-Associated Molecular Patterns (DAMPS) in the Postoperative Period after Colorectal Surgery

Anastomotic leakage (AL) is a defect of the intestinal wall at the anastomotic site and is one of the most severe complications in colorectal surgery. Previous studies have shown that the immune system response plays a significant role in the development of AL. In recent years, DAMPs (damage-associated molecular patterns) have been identified as cellular compounds with the ability to activate the immune system. The NLRP3 inflammasome plays an important role in the inflammatory responses which are mediated by DAMPs such as ATP, HSP proteins or uric acid crystals, when found in extracellular environments. Recent publications suggest that systemic concentration of DAMPs in patients with colorectal surgery may determine the inflammatory process and have a role in the occurrence of AL and other post-surgery complications. This review provides valuable knowledge about the current evidence supporting this hypothesis and highlights the possible role of these compounds in postoperative processes, which could open a new path to explore new strategies to prevent possible post-surgical complications.

The Colorectal Anastomosis: A Timeless Challenge

Colorectal anastomosis is a sophisticated problem that demands an elaborate discussion and an elegant solution. "Those who forget the past are condemned to repeat it." George Santayana, Life of Reason , 1905.

Trans-Anastomotic Drainage Tube Placement After Hand-Sewn Anastomosis in Patients Undergoing Intersphincteric Resection for Low Rectal Cancer: An Alternative Drainage Method

Anastomotic leakage (AL) is a common complication after intersphincteric resection (ISR). It significantly reduces quality of life and causes great distress to patients. Although traditional drainage (e.g., anal and pelvic catheters) may reduce the impact of AL to some extent, their role in reducing the incidence of AL remains controversial. In this study, we developed a novel drainage technique involving the placement of drainage tubes through the gap between sutures during handsewn anastomosis, to reduce the occurrence of anastomotic leakage. We retrospectively analyzed 34 consecutive patients who underwent intersphincteric resection requiring handsewn anastomosis between February 1, 2017, and January 1, 2021. Patients were classified into the trans-anastomotic drainage tube group (TADT, n = 14) and the non-TADT group (n = 20) based on whether trans-anastomotic tube placement was performed. The incidence of postoperative complications, such as AL, was compared between the two groups, and anal function of patients at 1-year post-ISR was evaluated. Six cases of AL occurred in the non-TADT group, while none occurred in the TADT group; this difference was statistically significant (p=0.031). The TADT group also had a shorter hospital stay (p=0.007). There were no other significant intergroup differences in operation time, blood loss, pain score, anastomotic stenosis, intestinal obstruction, or incidence of wound infection. In the 30 patients (88.2%) evaluated for anal function, there were no significant intergroup differences in stool frequency, urgency, daytime/nocturnal soiling, Wexner incontinence score, or Kirwan grading. Taken together, trans-anastomotic tube placement is a novel drainage method that may reduce AL after ISR requiring handsewn anastomosis and without adversely affecting anal function.

Comprehensive testing of colorectal anastomosis: results of prospective observational cohort study

BACKGROUND

Anastomotic leakage remains one of the most threatening complications in colorectal surgery. Intraoperative testing of anastomosis may reduce the postoperative anastomotic leakage rates. This study aimed to investigate a novel comprehensive intraoperative colorectal anastomosis testing technique to detect the failure of the anastomosis construction and to reduce the risk of postoperative leak.

METHODS

This multi-centre prospective cohort pilot study included 60 patients who underwent colorectal resection with an anastomosis at or below 15 cm from the anal verge. Comprehensive trimodal testing consisted of indocyanine green fluorescence angiography, tension testing, air-leak, and methylene blue leak tests to evaluate the perfusion, tension, and mechanical integrity of the anastomosis.

RESULTS

Ten (16.7%) patients developed an anastomotic leakage. Trimodal test was positive in 16 (26.6%) patients and the operative plan was changed for all of them. Diverting ileostomy was performed in 14 (87.5%) patients. However, two (12.5%) patients still developed clinically significant anastomotic leakage (Grade B). Forty-four (73.4%) patients had a negative trimodal test, preventive ileostomy was performed in 19 (43.2%), and five (11.4%) patients had clinically significant anastomotic leakage (Grade B and C).

CONCLUSION

Trimodal testing identifies anastomoses with initial technical failure where reinforcement of anastomosis or diversion can lead to an acceptable rate of anastomotic leakage. Identification of well-performed anastomosis could allow a reduction of ileostomy rate by two-fold. However, anastomotic leakage rate remains high in technically well-performed anastomoses.

Intracorporeal versus Extracorporeal Anastomosis for Laparoscopic Right Hemicolectomy: Short-Term Outcomes

Laparoscopic right hemicolectomy represents an effective therapeutic approach for right colon cancer (RCC). The primary aim of this study was to evaluate bowel function recovery, length of hospital stay, operative time, and the number of general and anastomosis-related postoperative complications from intracorporeal anastomosis (ICA) vs. extracorporeal anastomosis (ECA); the secondary outcome was the number of lymph nodes retrieved. This observational study was conducted on 108 patients who underwent right hemicolectomy for RCC; after surgical resection, 64 patients underwent ICA and 44 underwent ECA. The operative time was slightly longer in the ICA group than in the ECA group, even though the difference was not significant (199.31 ± 48.90 min vs. 183.64 ± 35.80 min; p = 0.109). The length of hospital stay (7.53 ± 1.91 days vs. 8.77 ± 3.66 days; p = 0.036) and bowel function recovery (2.21 ± 1.01 days vs. 3.45 ± 1.82 days; p < 0.0001) were significantly lower in the ICA group. There were no significant differences in postoperative complications (12% in ICA group vs. 9% in ECA group), wound infection (6% in ICA group vs. 7% in ECA group), or anastomotic leakage (6% in ICA group vs. 9% in ECA group). We did not observe a significant difference between the two groups in the number of lymph nodes collected (19.46 ± 7.06 in ICA group vs. 22.68 ± 8.79 in ECA group; p = 0.086). ICA following laparoscopic right hemicolectomy, compared to ECA, could lead to a significant improvement in bowel function recovery and a reduction in the length of hospital stay in RCC patients.

Preoperative white blood cell count predicts anastomotic leakage in patients with left-sided colorectal cancer

To determine whether preoperative white blood cell (WBC) counts reflect risk of anastomotic leak (AL) for patients with colorectal cancer (CRC), we retrospectively examined data from records of 208 consecutive patients who had undergone resections for left-sided CRC, including their clinicopathological parameters and preoperative laboratory data. The diagnostic value of WBC count for AL was evaluated and compared with those of neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, lymphocyte-monocyte ratio and platelet count × C-reactive protein level multiplier (P-CRP) value; optimal cut-off values were derived from receiver operating characteristic curves. AL was observed in 11 of the 208 patients (5.3%). Compared with the no-AL group, the AL group had a significantly higher mean WBC count and smoking rate. In multivariate analysis, WBC count and smoking were independent risk factors for AL. Compared with the other tested inflammatory indicators, the cut-off value for WBC (6,200/μL) had the highest sensitivity (81.8%) and negative predictive value (98.4%), as well as the lowest likelihood ratio (0.289). Preoperative WBC count could therefore be a convenient predictor of AL in patients with left-sided CRC.

State-of-the-art surgery for sigmoid diverticulitis

Background

In the last two decades, there has been a Copernican revolution in the decision-making for the treatment of Diverticular Disease.

Purpose

This article provides a report on the state-of-the-art of surgery for sigmoid diverticulitis.

Conclusion

Acute diverticulitis is the most common reason for colonic resection after cancer; in the last decade, the indication for surgical resection has become more and more infrequent also in emergency. Currently, emergency surgery is seldom indicated, mostly for severe abdominal infective complications. Nowadays, uncomplicated diverticulitis is the most frequent presentation of diverticular disease and it is usually approached with a conservative medical treatment. Non-Operative Management may be considered also for complicated diverticulitis with abdominal abscess. At present, there is consensus among experts that the hemodynamic response to the initial fluid resuscitation should guide the emergency surgical approach to patients with severe sepsis or septic shock. In hemodynamically stable patients, a laparoscopic approach is the first choice, and surgeons with advanced laparoscopic skills report advantages in terms of lower postoperative complication rates. At the moment, the so-called Hartmann’s procedure is only indicated in severe generalized peritonitis with metabolic derangement or in severely ill patients. Some authors suggested laparoscopic peritoneal lavage as a bridge to surgery or also as a definitive treatment without colonic resection in selected patients. In case of hemodynamic instability not responding to fluid resuscitation, an initial damage control surgery seems to be more attractive than a Hartmann’s procedure, and it is associated with a high rate of primary anastomosis.