Clinical review: Healing in gastrointestinal anastomoses, Part I

Magnamosis improves the healing of gastrojejunal anastomosis and down-regulates TGF-β1 and HIF-1α in rats

This study elucidated the unique pathological features of tissue healing by magnamosis and revealed the changes in landmark molecule expression levels related to collagen synthesis and tissue hypoxia. Forty-eight male Sprague-Dawley rats were divided into the magnamosis and suture anastomosis groups, and gastrojejunal anastomosis surgery was performed. Rats were dissected at 6, 24, and 48 h and 5, 6, 8, 10, and 12 days postoperatively. Hematoxylin, eosin, and Masson's trichrome staining were used to evaluate granulation tissue proliferation and collagen synthesis density at the anastomosis site. Immunohistochemistry was used to measure TGF-β1 and HIF-1α expression levels. Magnamosis significantly shortened the operation time, resulting in weaker postoperative abdominal adhesions (P < 0.0001). Histopathological results showed a significantly lower granulation area in the magnamosis group than in the suture anastomosis group (P = 0.0388), with no significant difference in the density of collagen synthesis (P = 0.3631). Immunohistochemistry results indicated that the magnamosis group had significantly lower proportions of TGF-β1-positive cells at 24 (P = 0.0052) and 48 h (P = 0.0385) postoperatively and HIF-1α-positive cells at 24 (P = 0.0402) and 48 h postoperatively (P = 0.0005). In a rat model of gastrojejunal anastomosis, magnamosis leads to improved tissue healing at the gastrojejunal anastomosis, associated with downregulated expression levels of TGF-β1 and HIF-1α.

Short cycles of remote ischemic preconditioning had no effect on tensile strength in small intestinal anastomoses: an experimental animal study

PURPOSE

This study aimed to investigate the effect of remote ischemic preconditioning (RIPC) on the healing of small intestinal anastomoses, evaluated by tensile strength and histologic wound healing on postoperative day 5.

METHODS

A total of 22 female pigs were randomized 1:1 into either an intervention or control group. The intervention group received 5 cycles of 3-minute ischemia followed by 3-minute reperfusion on the right forelimb. Two end-to-end anastomoses, a distal and a proximal, were created in the small intestine 30 and 60 min after RIPC, respectively. On postoperative day 5, the anastomoses were harvested and underwent a maximal anastomotic tensile strength (MATS) test (MATS 1-3) followed by histologic analyses.

RESULTS

MATS 1, when a tear became visible in the serosa, was significantly increased in the proximal anastomoses of the RIPC group compared with the control group (4.91 N vs 3.83 N; P = .005). No other significant differences were found when comparing these 2 groups.

CONCLUSION

Our study showed no convincing results of RIPC on intestinal anastomotic healing to recommend its use in a general clinical setting. Further animal studies on RIPC's effect after relative or absolute intestinal ischemia may be recommended.

Developments in the Use of Indocyanine Green (ICG) Fluorescence in Colorectal Surgery

Indocyanine Green (ICG) has significantly advanced minimally invasive surgery. It is widely recognized for its ability to visualize blood vessel patency in real-time across various surgical specialties. While its primary use in colorectal surgery is to evaluate anastomoses for leaks, numerous other applications have been documented in the literature. In this review, we aim to explore both established and emerging applications of ICG fluorescence in colorectal surgery, with the goal of improving patient outcomes. This includes preoperative tumor marking and the detection of metastatic disease. Some applications, such as lymphatic mapping, require further research to determine their impact on clinical practices. Conversely, others, like the intraoperative localizations of ureters, necessitate additional procedures and are not yet widely accepted by the surgical community. However, the development of alternative compounds could offer better solutions. Future research should focus on areas like quantitative ICG and protocol standardization in prospective multicenter studies.

Clinical diagnostic advances in intestinal anastomotic techniques: Hand suturing, stapling, and compression devices

The development of intestinal anastomosis techniques, including hand suturing, stapling, and compression anastomoses, has been a significant advancement in surgical practice. These methods aim to prevent leakage and minimize tissue fibrosis, which can lead to stricture formation. The healing process involves various phases: hemostasis and inflammation, proliferation, and remodeling. Mechanical staplers and sutures can cause inflammation and fibrosis due to the release of profibrotic chemokines. Compression anastomosis devices, including those made of nickel-titanium alloy, offer a minimally invasive option for various surgical challenges and have shown safety and efficacy. However, despite advancements, anastomotic techniques are evaluated based on leakage risk, with complications being a primary concern. Newer devices like Magnamosis use magnetic rings for compression anastomosis, demonstrating greater strength and patency compared to stapling. Magnetic technology is also being explored for other medical treatments. While there are promising results, particularly in animal models, the real-world application in humans is limited, and further research is needed to assess their safety and practicality.

Preoperative beta blockers and other drugs in relation to anastomotic leakage after anterior resection for rectal cancer

AIM

Previous research has indicated that preoperative beta blocker therapy is associated with a decreased risk of complications after surgery for rectal cancer. This is thought to arise because of the anti-inflammatory activity of the drug. These results need to be reproduced and analyses extended to other drugs with such properties, as this information might be useful in clinical decision-making. The main aim of this work was to replicate previous findings of beta blocker use as a prognostic marker for postoperative leakage. We also investigated whether drug exposure might induce anastomotic leaks.

METHOD

This is a retrospective multicentre cohort study, comprising 1126 patients who underwent anterior resection for rectal cancer between 2014 and 2018. The use of any preoperative beta blocker was treated as the primary exposure, while anastomotic leakage within 12 months of surgery was the outcome. Secondary exposures comprised angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, statins and metformin. Using multivariable regression, we performed a replication analysis with a predictive aim for beta blockers only, while adjustment for confounding was done in more causally oriented analyses for all drugs. We estimated incidence rate ratio (IRR) and relative risk (RR) with 95% confidence intervals (CIs).

RESULTS

Anastomotic leakage occurred in 20.6% of patients. Preoperative beta blockers were used by 22.7% of the cohort, while the leak distribution was almost identical between exposure groups. In the main replication analysis, no association could be detected (IRR 0.95, 95% CI 0.68-1.33). In the causally oriented analyses, only metformin affected the risk of leakage (RR 1.59, 95% Cl 1.31-1.92).

CONCLUSION

While previous research has suggested that preoperative beta blocker use could be prognostic of anastomotic leakage, this study could not detect any such association. On the contrary, our results indicate that preoperative beta blocker use neither predicts nor causes anastomotic leakage after anterior resection for rectal cancer.

Early postoperative endoscopy for predicting anastomotic leakage after minimally invasive esophagectomy: A large-volume retrospective study

BACKGROUND

Anastomotic leakage is one of the most severe adverse events of minimally invasive esophagectomy for esophageal cancer. Early postoperative endoscopy is considered to be the most objective means to diagnose anastomotic leakage, but its safety is questioned by clinicians. This study aimed to evaluate the safety and effectiveness of early postoperative endoscopy in predicting anastomotic leakage.

METHODS

Patients who underwent minimally invasive esophagectomy (from January 2017 to June 2021) in our center were identified and divided into early postoperative endoscopy and control groups according to whether they underwent early postoperative endoscopy within 72 hours after surgery. Propensity score matching was used to balance baseline characteristics. The incidence of postoperative adverse events was compared between the 2 groups, risk variables for anastomotic leakage were identified using logistic regression, and abnormal endoscopic findings related to anastomotic leakage occurrence were explored.

RESULTS

A total of 436 patients were enrolled, of whom 134 underwent early postoperative endoscopy. One hundred and thirty-two pairs were matched by propensity score matching, and baseline characteristics were well-balanced. Both before and after propensity score matching, early postoperative endoscopy did not increase the incidence of postoperative adverse events (chyle leak, hypoproteinemia, pneumonia, etc) and in-hospital mortality. Notably, the incidence of anastomotic leakage (9.8% vs 22.7%) and the length of mean postoperative hospital stay (17.6 vs 20.9 days) was significantly decreased in the early postoperative endoscopy group. Finally, based on the findings under early postoperative endoscopy, we found that gastric graft ischemia is related to a higher incidence of anastomotic leakage (P = .023).

CONCLUSION

Early postoperative endoscopy does not increase postoperative adverse events after minimally invasive esophagectomy and may guide early prediction and intervention strategies for anastomotic leakage in patients undergoing minimally invasive esophagectomy.

Poly-ϵ-caprolactone scaffold as staple-line reinforcement of rectal anastomosis: an experimental piglet study

PURPOSE

Rectal anastomoses have a persisting high incidence of anastomotic leakage. This study aimed to assess whether the use of a poly-ϵ-caprolactone (PCL) scaffold as reinforcement of a circular stapled rectal anastomosis could increase tensile strength and improve healing compared to a control in a piglet model.

METHOD

Twenty weaned female piglets received a stapled rectal anastomosis and were randomised to either reinforcement with PCL scaffold (intervention) or no reinforcement (control). On postoperative day five the anastomosis was subjected to a tensile strength test followed by a histological examination to evaluate the wound healing according to the Verhofstad scoring.

RESULTS

The tensile strength test showed no significant difference between the two groups, but histological evaluation revealed significant impaired wound healing in the intervention group.

CONCLUSION

The incorporation of a PCL scaffold into a circular stapled rectal anastomosis did not increase anastomotic tensile strength in piglets and indicated an impaired histologically assessed wound healing.

Effect of transanal drainage tube on prevention of anastomotic leakage after anterior rectal cancer surgery taking indwelling time into consideration: a systematic review and meta-analysis

Background

Placement of an indwelling transanal drainage tube (TDT) to prevent anastomotic leakage (AL) after anterior rectal cancer surgery has become a routine choice for surgeons in the recent years. However, the specific indwelling time of the TDT has not been explored. We performed this meta-analysis and considered the indwelling time a critical factor in re-analyzing the effectiveness of TDT placement in prevention of AL after anterior rectal cancer surgery.

Methods

Randomized controlled trials (RCTs) and cohort studies which evaluated the effectiveness of TDT in prevention of AL after rectal cancer surgery and considered the indwelling time of TDT were identified using a predesigned search strategy in databases up to November 2022. This meta-analysis was performed to estimate the pooled AL rates (Overall and different AL grades) and reoperation rates at different TDT indwelling times and stoma statuses.

Results

Three RCTs and 15 cohort studies including 2381 cases with TDT and 2494 cases without TDT were considered eligible for inclusion. Our meta-analysis showed that the indwelling time of TDT for ≥5-days was associated with a significant reduction (TDT vs. Non-TDT) in overall AL (OR=0.46,95% CI 0.34-0.60, p<0.01), grade A+B AL (OR=0.64, 95% CI 0.42-0.97, p=0.03), grade C AL (OR=0.35, 95% CI 0.24-0.53, p<0.01), overall reoperation rate (OR=0.36, 95%CI 0.24-0.53, p<0.01) and that in patients without a prophylactic diverting stoma (DS) (OR=0.24, 95%CI 0.14-0.41, p<0.01). There were no statistically significant differences in any of the abovementioned indicators (p>0.05) when the indwelling time of TDT was less than 5 days.

Conclusion

Extending the postoperative indwelling time of TDT to 5 days may reduce the overall AL and the need for reoperation in patients without a prophylactic DS.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023407451, identifier CRD42023407451.

A Comparative Study Between the Early and Late Enteral Nutrition After Gastrointestinal Anastomosis Operations

INTRODUCTION

Intestinal anastomosis is a surgical procedure crucial for restoring the integrity of the digestive system and finds widespread application in addressing diverse gastrointestinal disorders such as tumors, inflammatory conditions, and traumatic injuries. The timing of restarting feeding after the surgery is a debated topic due to its potential impact on patient recovery. Early enteral feeding, administered soon after surgery, aims to counteract the negative effects of prolonged fasting and improve outcomes.

OBJECTIVE

This study analyzed the early and late enteral feeding following gastrointestinal anastomosis surgery.

METHODS

Forty patients undergoing abdominal surgery were prospectively randomized into early or late feeding groups. Demographics, laboratory values, operative time, blood loss, transfusion rates, nasogastric tube (NGT) removal, hospital stay, gastrointestinal recovery, postoperative body mass index (BMI), and complications were compared. Data was organized in Excel and analyzed using the Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 27.0, Armonk, NY). Qualitative data were presented with numbers and percentages, while parametric quantitative data used means, standard deviations, and ranges. Non-parametric quantitative data were represented with medians and interquartile ranges. Chi-square tests were used for comparing two qualitative groups with predicted counts less than 5, while independent t-tests and Mann-Whitney tests were employed for comparing two quantitative groups with parametric and non-parametric distributions, respectively. The analysis used a 95% confidence interval, a 5% margin of error, and considered P values less than 0.05 as significant.

RESULTS

Early feeding was associated with significantly shorter NGT removal times (p=0.005) and hospital stays (p=0.001) than late feeding. Postprandial potassium levels were higher in the early group (p=0.007), while CRP levels were significantly lower (p=0.004). No significant differences were found in operative time, blood loss, transfusion rates, gastrointestinal recovery, postoperative BMI, or complication rates between groups.

CONCLUSIONS

Early enteral feeding appears safe and effective after gastrointestinal anastomosis surgery, potentially reducing hospital stay and improving inflammatory markers without increasing adverse events.

Double-layer adhesives for preventing anastomotic leakage and reducing post-surgical adhesion

Preventing anastomotic leakage (AL) and postoperative adhesions after gastrointestinal surgery is crucial for ensuring a favorable surgical prognosis. However, AL prevention using tissue adhesives can unintentionally lead to undesirable adhesion formation, while anti-adhesive agents may interfere with wound healing and contribute to AL. In this study, we have developed a double-layer patch, consisting of an adhesive layer on one side, utilizing gallic acid-conjugated chitosan (CHI-G), and an anti-adhesive layer on the opposite side, employing crosslinked hyaluronic acid (cHA). These CHI-G/cHA double-layer adhesives significantly prevented AL by forming physical barriers of CHI-G and reduced post-surgical adhesion at the anastomosis sites by the anti-adhesive layers of cHA. The bursting pressure (161.1 ± 21.6 mmHg) of double-layer adhesives-applied rat intestine at postoperative day 21 was far higher than those of the control (129.4 ± 5.7 mmHg) and the commercial anti-adhesives-applied group (120.8 ± 5.2 mmHg). In addition, adhesion score of double-layer adhesives-applied rat intestine was 3.6 ± 0.3 at postoperative day 21, which was similar to that of the commercial anti-adhesives-applied group (3.6 ± 0.3) and lower than that of the control group (4.9 ± 0.5). These findings indicate that the double-layer patch (CHI-G/cHA) has the potential to effectively prevent both postoperative adhesions and anastomotic leakage, offering a promising solution for gastrointestinal surgery.

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.

Endoscopic management of postoperative bleeding

Postoperative gastrointestinal bleeding is a rare but serious complication that can lead to prolonged hospitalization and significant morbidity and mortality. It can be managed by reoperation, endoscopy, or radiological intervention. Although reoperation carries risks, particularly in critically ill postoperative patients, minimally invasive interventions, such as endoscopy or radiological intervention, confer advantages. Endoscopy allows localization of the bleeding focus and hemostatic management at the same time. Although there have been concerns regarding the potential risk of creating an anastomotic disruption or perforation during early postoperative endoscopy, endoscopic management has become more popular over time. However, there is currently no consensus on the best endoscopic management for postoperative gastrointestinal bleeding because most practices are based on retrospective case series. Furthermore, there is a wide range of individual complexities in anatomical and clinical settings after surgery. This review focused on the safety and effectiveness of endoscopic management in various surgical settings.

Evaluation of colonic anastomosis healing using hybrid nanosheets containing molybdenum disulfide (MOS2) scaffold of human placental amniotic membrane and polycaprolactone (PCL) in rat animal model

Anastomosis is a standard technique following different conditions such as obstruction, tumor, and trauma. Obstruction, adhesion, or anastomosis leakage can be some of its complications. To improve healing and prevent postoperative complications, we design a hybrid scaffold containing acellular human amniotic membranes and polycaprolactone-molybdenum disulfide nanosheets for colon anastomosis. The animal model of colocolonic anastomosis was performed on two groups of rats: control and scaffold. The hybrid scaffold was warped around the anastomosis site in the scaffold group. Samples from the anastomosis site were resected on the third and seventh postoperative days for histopathological and molecular assessments. Histopathologic score and burst pressure had shown significant improvement in the scaffold group. No mortality and anastomosis leakage was reported in the scaffold group. In addition, inflammatory markers were significantly decreased, while anti-inflammatory cytokines were increased in the scaffold group. The result indicates that our hybrid scaffold is a proper choice for colorectal anastomosis repair by declining postoperative complications and accelerating healing.

Real-time quantification of bowel perfusion using Laparoscopic Laser Speckle Contrast Imaging (LSCI) in a porcine model

BACKGROUND/PURPOSE

Real-time quantification of tissue perfusion can improve intraoperative surgical decision making. Here we demonstrate the utility of Laser Speckle Contrast Imaging as an intra-operative tool that quantifies real-time regional differences in intestinal perfusion and distinguishes ischemic changes resulting from arterial/venous obstruction.

METHODS

Porcine models (n = 3) consisted of selectively devascularized small bowel loops that were used to measure the perfusion responses under conditions of control/no vascular occlusion, arterial inflow occlusion, and venous outflow occlusion using laser speckle imaging and indocyanine green fluoroscopy. Laser Speckle was also used to assess perfusion differences between small bowel antimesenteric-antimesenteric and mesenteric-mesenteric anastomoses. Perfusion quantification was measured in relative perfusion units calculated from the laser speckle perfusion heatmap.

RESULTS

Laser Speckle distinguished between visually identified perfused, watershed, and ischemic intestinal segments with both color heatmap and quantification (p < .00001). It detected a continuous gradient of relative intestinal perfusion as a function of distance from the stapled ischemic bowel edge. Strong positive linear correlation between relative perfusion units and changes in mean arterial pressure resulting from both arterial (R2 = .96/.79) and venous pressure changes (R2 = .86/.96) was observed. Furthermore, Laser Speckle showed that the antimesenteric anastomosis had a higher perfusion than mesenteric anastomosis (p < 0.01).

CONCLUSIONS

Laser Speckle Contrast Imaging provides objective, quantifiable tissue perfusion information in both color heatmap and relative numerical units. Laser Speckle can detect spatial/temporal differences in perfusion between antimesenteric and mesenteric borders of a bowel segment and precisely detect perfusion changes induced by progressive arterial/venous occlusions in real-time.

Indocyanine green angiography for lower incidence of anastomotic leakage after transanal total mesorectal excision: a propensity score-matched cohort study

Background

Anastomotic leakage (AL) is the most serious complication that can arise during colorectal surgery. Indocyanine green (ICG) angiography offers an intraoperative assessment of colonic vascular perfusion in real time. We aimed to assess ICG's effects on the AL rate in patients who have undergone transanal total mesorectal excision (TaTME) for rectal cancer.

Methods

This retrospective cohort study was conducted at our center from October 2018 to March 2022 to analyze the clinical data of patients with rectal cancer who have undergone TaTME after propensity score matching (PSM). The primary outcome was the proximal colonic transection line modification and clinical AL rate.

Results

A total of 143 patients in the non-ICG group and 143 patients in the ICG group were included after PSM. The proximal colonic transection line of seven patients in the non-ICG group was modified, while 18 were in the ICG group (4.9% vs. 12.5%, p = 0.023). Twenty-three patients (16.1%) in the non-ICG group and five patients (3.5%) in the ICG group were diagnosed with AL (p < 0.001). The ICG group had a less hospital readmission rate than the non-ICG group (0.7% vs. 7.7%, p = 0.003). The between-group differences in basic line and other outcomes were not significant.

Conclusions

ICG angiography is a safe and feasible method to help surgeons identify potentially poor colonic vascular perfusion and modify the proximal colonic transection line, resulting in a significant reduction in AL and hospital readmission rates.

Novel external reinforcement device for gastrointestinal anastomosis in an experimental study

BACKGROUND

Anastomotic leakage has been reported to occur when the load on the anastomotic site exceeds the resistance created by sutures, staples, and early scars. It may be possible to avoid anastomotic leakage by covering and reinforcing the anastomotic site with a biocompatible material. The aim of this study was to evaluate the safety and feasibility of a novel external reinforcement device for gastrointestinal anastomosis in an experimental model.

METHODS

A single pig was used in this non-survival study, and end-to-end anastomoses were created in six small bowel loops by a single-stapling technique using a circular stapler. Three of the six anastomoses were covered with a novel external reinforcement device. Air was injected, a pressure test of each anastomosis was performed, and the bursting pressure was measured.

RESULTS

Reinforcement of the anastomotic site with the device was successfully performed in all anastomoses. The bursting pressure was 76.1 ± 5.7 mmHg in the control group, and 126.8 ± 6.8 mmHg in the device group, respectively. The bursting pressure in the device group was significantly higher than that in the control group (p = 0.0006).

CONCLUSIONS

The novel external reinforcement device was safe and feasible for reinforcing the anastomoses in the experimental model.

Mesenchymal stem cell secretome-loaded fibrin glue improves the healing of intestinal anastomosis

Anastomotic leakage is a serious complication following gastrointestinal surgery and one of the leading causes of patient mortality. Despite the significant clinical and economic burden, there are currently no reliable treatment options to improve the healing of intestinal anastomosis and subsequently prevent anastomotic leakage. Recently, the development of regenerative medicine has shown promise for improving anastomotic healing. Recent studies have illustrated that stem cell-derived secretome can enhance tissue regeneration without the safety and ethical limitations of stem cell transplantation. Herein, we developed a fibrin glue topical delivery system loaded with mesenchymal stem cells (MSCs)-derived secretome for controlled delivery of bioactive factors, and evaluated its application potential in improving the healing of intestinal anastomosis. Under in vitro conditions, the MSCs secretome significantly promoted cell proliferation viability in a dose-dependent manner and resulted in the controlled release of growth factors via fibrin glue delivery. We established a rat surgical anastomotic model and experimentally found that MSCs secretome-loaded fibrin glue enhanced anastomotic bursting pressure, increased granulation tissue formation and collagen deposition, and significantly promoted anastomotic healing. Mechanistically, fibrin glue accelerated cell proliferation, angiogenesis, and macrophage M2 polarization at the surgical anastomotic site by releasing bioactive factors in the secretome, and it also alleviated the inflammatory response and cell apoptosis at the anastomotic site. Our results demonstrated for the first time that MSCs-derived secretome could promote the healing of intestinal anastomosis. Considering the accessibility and safety of the cell-free secretome, we believed that secretome-loaded fibrin glue would be a cell-free therapy to accelerate the healing of intestinal anastomosis with great potential for clinical translation.

Synbiotics and Surgery: Can Prebiotics and Probiotics Affect Inflammatory Surgical Outcomes?

PURPOSE OF REVIEW

Prebiotics, probiotics, and synbiotics have received increasing attention over the years for their beneficial impact on the gut microbiome and for their systemic anti-inflammatory effects. They have also been shown to improve surgical outcomes. Here, we review the inflammatory effects of surgery as well as the data which suggests a benefit of prebiotics, probiotics, and synbiotics taken in the perioperative period.

RECENT FINDINGS

Synbiotics and fermented foods may have an even greater anti-inflammatory effect than probiotics or prebiotics alone. Recent data suggest that the anti-inflammatory effects and microbiome changes brought on by prebiotics, probiotics, and synbiotics have the potential to improve surgical outcomes. We highlight the potential to alter systemic inflammation, surgical and hospital-acquired infections, colorectal cancer formation, recurrence, and anastomotic leak. Synbiotics could also impact metabolic syndrome. Prebiotics, probiotics, and especially synbiotics may be extremely beneficial when taken in the perioperative period. Even short-term gut microbiome pre-habilitation could alter surgical outcomes significantly.

The Impact of Phase-Specific Macrophage Depletion on Intestinal Anastomotic Healing

Intestinal anastomotic healing (AH) is critical in colorectal surgery, since disruptive AH leads to anastomotic leakage, a feared postoperative complication. Macrophages are innate immune cells and are instrumental in orchestrating intestinal wound healing, displaying a functional dichotomy as effectors of both tissue injury and repair. The aim of this study was to investigate the phase-specific function and plasticity of macrophages during intestinal AH. Transgenic CD11b diphtheria toxin receptor (CD11b-DTR) mice were used to deplete intestinal macrophages in a temporally controlled manner. Distal colonic end-to-end anastomoses were created in CD11b-DTR, and wild-type mice and macrophages were selectively depleted during either the inflammatory (day 0–3), proliferative (day 4–10), or reparative (day 11–20) phase of intestinal AH, respectively. For each time point, histological and functional analysis as well as gene set enrichment analysis (GSEA) of RNA-sequencing data were performed. Macrophage depletion during the inflammatory phase significantly reduced the associated inflammatory state without compromising microscopic AH. When intestinal macrophages were depleted during the proliferative phase, AH was improved, despite significantly reduced perianastomotic neoangiogenesis. Lastly, macrophages were depleted during the reparative phase and GSEA revealed macrophage-dependent pathways involved in collagen remodeling, cell proliferation, and extracellular matrix composition. However, AH remained comparable at this late timepoint. These results demonstrate that during intestinal AH, macrophages elicit phase-specific effects, and that therapeutic interventions must critically balance their dual and timely defined role.

Laparoscopic D3 lymph node dissection with left colic artery and first sigmoid artery preservation in rectal cancer

BACKGROUND

D3 lymph node dissection with left colic artery (LCA) preservation in rectal cancer surgery seems to have little effect on reducing postoperative anastomotic leakage. So we first propose D3 lymph node dissection with LCA and first sigmoid artery (SA) preservation. This novel procedure deserves further study.

METHODS

Rectal cancer patients who underwent laparoscopic D3 lymph node dissection with LCA preservation or with LCA and first SA preservation between January 2017 and January 2020 were retrospectively assessed. The patients were categorized into two groups: the preservation of the LCA group and the preservation of the LCA and first SA group. A 1:1 propensity score-matched analysis was performed to decrease confounding.

RESULTS

Propensity score matching yielded 56 patients in each group from the eligible patients. The rate of postoperative anastomotic leakage in the preservation of the LCA and first SA group was significantly lower than that in the LCA preservation group (7.1% vs. 0%, P=0.040). No significant differences were observed in operation time, length of hospital stay, estimated blood loss, length of distal margin, lymph node retrieval, apical lymph node retrieval, and complications. A survival analysis showed patients' 3-year disease-free survival (DFS) rates of group 1 and group 2 were 81.8% and 83.5% (P=0.595), respectively.

CONCLUSION

D3 lymph node dissection with LCA and first SA preservation for rectal cancer may help reduce the incidence of anastomotic leakage without compromising oncological outcomes compare with D3 lymph node dissection with LCA preservation alone.

Imaging Photoplethysmography for Noninvasive Anastomotic Perfusion Assessment in Intestinal Surgery

INTRODUCTION

Anastomotic leakage after gastrointestinal surgery has a high impact on patient's quality of life and its origin is associated with inadequate perfusion. Imaging photoplethysmography (iPPG) is a noninvasive imaging technique that measures blood-volume changes in the microvascular tissue bed and detects changes in tissue perfusion.

MATERIALS AND METHODS

Intraoperative iPPG imaging was performed in 29 patients undergoing an open segment resection of the small intestine or colon. During each surgery, imaging was performed on fully perfused (true positives) and ischemic intestines (true negatives) and the anastomosis (unknowns). Imaging consisted of a 30-s video from which perfusion maps were extracted, providing detailed information about blood flow within the intestine microvasculature. To detect the predictive capabilities of iPPG, true positive and true negative perfusion conditions were used to develop two different perfusion classification methods.

RESULTS

iPPG-derived perfusion parameters were highly correlated with perfusion-perfused or ischemic-in intestinal tissues. A perfusion confidence map distinguished perfused and ischemic intestinal tissues with 96% sensitivity and 86% specificity. Anastomosis images were scored as adequately perfused in 86% of cases and 14% inconclusive. The cubic-Support Vector Machine achieved 90.9% accuracy and an area under the curve of 96%. No anastomosis-related postoperative complications were encountered in this study.

CONCLUSIONS

This study shows that noninvasive intraoperative iPPG is suitable for the objective assessment of small intestine and colon anastomotic perfusion. In addition, two perfusion classification methods were developed, providing the first step in an intestinal perfusion prediction model.

Wettability and biological responses of titanium surface's biomimetic hexagonal microstructure

In this research, an experiment was conducted on how the surface wettability and biocompatibility of staplers' titanium nails impact the healing of gastrointestinal tissue. Firstly, the bionic hexagonal structure was prepared on the surface of Ti metal by laser processing technology, and the laser textured titanium samples were observed by scanning electron microscope. Then, the liquid-solid contact angle-measuring instrument was used to characterize the wettability of titanium samples. Finally, cells were cultured on the surface of different titanium samples, CCK8 assay and qRT-PCR were carried out to investigate cell adhesion and collagen secretion on the surface of different samples. The results showed that the bionic hexagonal surface increased the surface roughness, reduced the liquid-solid contact angle, and promoted the adhesion and collagen secretion of fibroblasts. The increased wettability provided a better growth environment for cell growth. Microtexture is an important factor affecting the behavior of cells and its size parameters regulate cell gene expression, which is worthy of further study.

Efficacy of air leak test in detection of anastomotic leaks after rectal excision: a retrospective case-controlled study

Purpose

Although its efficacy is uncertain, an intraoperative air leak test (ALT) is commonly used to detect mechanical defects following bowel anastomosis. This study aimed to evaluate the efficacy of ALT to detect anastomotic leakage (AL) following rectal excision.

Methods

We reviewed our database for patients with rectal cancers who had undergone curative surgery between January 2012 and January 2018. Patients were grouped according to whether or not an ALT was performed. Propensity score analyses were performed to compare outcomes for groups in a 1:1 case-matched cohort.

Results

In total, 1,191 patients underwent rectal excision; 438 (219 in each group) formed the case-matched cohort for analysis. The protective stoma rate was 16.0% and 14.6% in the ALT and the no-ALT groups, respectively (P = 0.791). In the ALT group, 2 patients (0.9%) showed a positive result and were treated with rectal tube drainage, resulting in no leakage. There was no significant difference in postoperative AL rate between the groups (ALT group: 4.6% vs. no-ALT group: 4.1%, P > 0.999).

Conclusion

ALT played a minimal role in detecting AL following rectal excision. Further studies are warranted to validate our results and clarify whether AL can be prevented with ALT or alternative methods.

Gaining Mesenteric Length following Colorectal Resection: Essential Maneuvers to Avoid Anastomotic Tension

A surgeon must possess the knowledge and technical skill to obtain length following a left-sided colorectal resection to perform a tension free anastomosis. The distal target organ - either rectum or anus - is fixed in location, and therefore requires surgeons to acquire mastery of proximal mobilization of the colonic conduit. Generally, splenic flexure mobilization (SFM) provides adequate length. Surgeons benefit from clearer understanding of the multiple steps involved in SFM as a result of improved visualization and demonstration of the relevant anatomy - adjacent organs and the attachments, embryologic planes, and mesenteric structures. Much may be attributed to laparoscopic and robotic platforms which provided improved exposure and as a result, development or refinement of novel approaches for SFM with potential advantages. Complete mobilization draws upon the sum or combination of the varied approaches to accomplish the goal. However, in the situation where extended resection is necessary or in the case of re-operative surgery sacrificing either more proximal or distal large intestine often occurs, the transverse colon or even the ascending colon represents the proximal conduit for anastomosis. This challenging situation requires familiarity with special maneuvers to achieve colorectal or coloanal anastomosis using these more proximal conduits. In such instances, operative techniques such as either ileal mesenteric window with retroileal anastomosis or de-rotation of the right colon (Deloyer's procedure) enable the intestinal surgeon to construct such anastomoses and thereby avoid stoma creation or loss of additional large intestine.

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.

New understanding of gut microbiota and colorectal anastomosis leak: A collaborative review of the current concepts

Anastomotic leak (AL) is a life-threatening postoperative complication following colorectal surgery, which has not decreased over time. Until now, no specific risk factors or surgical technique could be targeted to improve anastomotic healing. In the past decade, gut microbiota dysbiosis has been recognized to contribute to AL, but the exact effects are still vague. In this context, interpretation of the mechanisms underlying how the gut microbiota contributes to AL is significant for improving patients' outcomes. This review concentrates on novel findings to explain how the gut microbiota of patients with AL are altered, how the AL-specific pathogen colonizes and is enriched on the anastomosis site, and how these pathogens conduct their tissue breakdown effects. We build up a framework between the gut microbiota and AL on three levels. Firstly, factors that shape the gut microbiota profiles in patients who developed AL after colorectal surgery include preoperative intervention and surgical factors. Secondly, AL-specific pathogenic or collagenase bacteria adhere to the intestinal mucosa and defend against host clearance, including the interaction between bacterial adhesion and host extracellular matrix (ECM), the biofilm formation, and the weakened host commercial bacterial resistance. Thirdly, we interpret the potential mechanisms of pathogen-induced poor anastomotic healing.

Intraoperative Patterns of Gastric Microperfusion During Laparoscopic Roux-en-Y Gastric Bypass

INTRODUCTION

Visible light spectroscopy (VLS) represents a sensitive, non-invasive method to quantify tissue oxygen levels and detect hypoxemia. The aim of this study was to assess the microperfusion patterns of the gastric pouch during laparoscopic Roux-en-Y gastric bypass (LRYGB) using the VLS technique.

METHODS

Twenty patients were enrolled. Tissue oxygenation (StO2%) measurements were performed at three different localizations of the gastric wall, prior and after the creation of the gastric pouch, and after the creation of the gastro-jejunostomy.

RESULTS

Prior to the creation of the gastric pouch, the lowest StO2% levels were observed at the level of the distal esophagus with a median StO2% of 43 (IQR 40.8-49.5). After the creation of the gastric pouch and after the creation of the gastro-jejunostomy, the lowest StO2% levels were recorded at the level of the His angle with median values of 29% (IQR 20-38.5) and 34.5% (IQR 19-39), respectively. The highest mean StO2 reduction was recorded at the level of the His angle after the creation of the gastric pouch, and it was 18.3% (SD ± 18.1%, p < 0.001). A reduction of StO2% was recorded at all localizations after the formation of the gastro-jejunostomy compared to the beginning of the operation, but the mean differences of the StO2% levels were statistically significant only at the resection line of the pouch and at the His angle (p = 0.044 and p < 0.001, respectively).

CONCLUSION

Gastric pouch demonstrates reduction of StO2% during LRYGB. VLS is a useful technique to assess microperfusion patterns of the stomach during LRYGB.

Gut microbiota from nCAL patients promotes colon anastomotic healing by inducing collagen synthesis in epithelial cells

BACKGROUND AND AIMS

Colon anastomotic leak (CAL) is considered one of the most feared and serious postoperative complications in colorectal cancer (CRC) patients, with no effective prevention strategies to date. Based on previous studies, gut microbiota is associated with anastomotic healing, but its ability to effectively promote anastomotic healing remains largely unknown.

METHODS

We performed a clinical study to analyze the gut microbiota profiling in CRC patients who developed CAL and those who did not (nCAL) using 16S-rRNA-based next-generation sequencing (NGS). To investigate these changes in an in vivo model, we performed fecal microbiota transplantation in a colon anastomosis rat experimental model to elucidate the causal effect between gut microbiota and anastomotic healing. Notably, RNA-seq in the anastomotic tissue of the latter experimental model was utilized to discover the potential molecular mechanism.

RESULTS

Our analysis implicated that gut microbiota profiling was profoundly different between CAL and nCAL patients. Strikingly, the rat experimental model transplanted with fecal microbiota derived from nCAL patients demonstrated enhanced anastomotic healing properties. Moreover, collagen synthesis, EMT, and TGF-β/Smad signaling pathways were upregulated in the same rats. Concordantly, we discovered that the better anastomotic healing profiling displayed in gut microbiota derived from nCAL patients is dependent on the TGF-β/Smad-induced EMT in vitro and in vivo.

CONCLUSIONS

Collectively, our clinical study identified the postoperative gut microbiota profile is associated with CAL in CRC patients. On the contrary, fecal microbiota from nCAL patients promotes anastomotic healing via TGF-β/Smad-induced EMT, with subsequent collagen synthesis and enhanced anastomosis healing.

Qualitative features of esophageal fluorescence angiography and anastomotic outcomes in children

BACKGROUND

Indocyanine green (ICG) is commonly used to assess perfusion, but quality defining features are lacking. We sought to establish qualitative features of esophageal ICG perfusion assessments, and develop an esophageal anastomotic scorecard to risk-stratify anastomotic outcomes.

METHODS

Single institution, retrospective analysis of children with an intraoperative ICG perfusion assessment of an esophageal anastomosis. Qualitative perfusion features were defined and a perfusion score developed. Associations between perfusion and clinical features with poor anastomotic outcomes (PAO, leak or refractory stricture) were evaluated with logistic and time-to-event analyses. Combining significant features, we developed and tested an esophageal anastomotic scorecard to stratify PAO risk.

RESULTS

From 2019 to 2021, 53 children (median age 7.4 months) underwent 55 esophageal anastomoses. Median (IQR) follow-up was 14 (10-19.9) months; mean (SD) perfusion score was 13.2 (3.4). Fifteen (27.3%) anastomoses experienced a PAO and had significantly lower mean perfusion scores (11.3 (3.3) vs 14.0 (3.2), p = 0.007). Unique ICG perfusion features, severe tension, and primary or rescue traction-induced esophageal lengthening [Foker] procedures were significantly associated with PAO on both logistic and Cox regression. The scorecard (range 0-7) included any Foker (+2), severe tension (+1), no arborization on either segment (+1), suture line hypoperfusion >twice expected width (+2), and segmental or global areas of hypoperfusion (+1). A scorecard cut-off >3 yielded a sensitivity of 73% and specificity of 93% (AUC 0.878 [95%CI 0.777 to 0.978]) in identifying a PAO.

CONCLUSIONS

A scoring system comprised of qualitative ICG perfusion features, tissue quality, and anastomotic tension can help risk-stratify esophageal anastomotic outcomes accurately.

LEVELS OF EVIDENCE

Diagnostic - II.

The Effect of Epidermal Growth Factor on Anastomotic Leaks: An Experimental Study in Rats

INTRODUCTION

To investigate the effects of local epidermal growth factor (EGF) use on anastomotic healing during primary repair of anastomosis in rats with anastomotic leaks (AL).

METHODS

Thirty albino Wistar rats were divided into three groups. Anastomoses were performed in group 1 after colon transection. In groups 2 and 3, ALs were created with an incomplete colon anastomosis model. Relaparotomy was conducted on rats in groups 2 and 3 72 h after the first procedure. ALs of the rats were repaired with a primary suture in group 2 and with a primary suture and the application of submucosal EGF in group 3. All rats were sacrificed through cervical dislocation on the 6th day after the first procedure. Four-centimeter colonic segments containing 2-cm distal and proximal parts of the anastomotic lines of the subjects were resected. The primary outcome was anastomotic burst pressure (ABP). The secondary outcomes included limitation in inflammation, increased neovascularization, increased fibroblast activation and increased collagen synthesis.

RESULTS

The ABP value of group 2 was significantly lower than that of group 3 (P < 0.05). No significant difference was detected in the ABP value between group 3 and group 1 (P > 0.05). There was significantly less inflammatory cell infiltration in group 3 than in group 2 (P < 0.05). Collagen synthesis and neovascularization were significantly higher in group 3 than in group 2 (P < 0.05).

CONCLUSIONS

A single-dose of submucosal EGF applied to the AL line limited inflammation and stimulated neovascularization. It also had a positive effect on the strength of the anastomosis.

Remote ischemic postconditioning has a detrimental effect and remote ischemic preconditioning seems to have no effect on small intestinal anastomotic strength

BACKGROUND

The effect of remote pre- and postconditioning on anastomotic healing has been sparsely studied. The aim of our study was to investigate whether remote ischemic conditioning (RIC) applied before and after the creation of a small bowel anastomosis had an effect on anastomotic healing on postoperative day five evaluated by a tensile strength test and histological analysis.

MATERIALS AND METHODS

Twenty-two female piglets were randomized into two groups. The intervention group (n = 12) received RIC on the forelimbs consisting of 15 min of ischemia followed by 30 min of reperfusion before the first end-to-end ileal anastomosis was created. The RIC procedure was repeated and the second and more distal anastomosis was performed. The control group (n = 10) had two similar anastomoses with similar time intervals but without RIC. On postoperative day five, the anastomoses were subjected to macroscopic evaluation, tensile strength test and histological examination.

RESULTS

Mean tensile strength when the first transmural rupture appeared (MATS-2) was significantly lower in the first anastomosis in the intervention group compared to the control group (11.4 N vs 14.7 N, p < .05). Similar result was found by the maximal strength (MATS-3) as defined by a drop in the load curve (12.3 N vs 15.9 N, p < .05). Histologically, a significantly higher necrosis score was found in the anastomosis in the intervention group (1.4 vs 0.8, p < .05). No other significant differences were found.

CONCLUSIONS

In conclusion, post-anastomotic remote ischemic conditioning had a detrimental effect and pre-anastomotic conditioning seems to have no effect on small intestinal anastomotic strength.

Coating of Intestinal Anastomoses for Prevention of Postoperative Leakage: A Systematic Review and Meta-Analysis

Background

For several decades, scientific efforts have been taken to develop strategies and medical aids for the reduction of anastomotic complications after intestinal surgery. Still, anastomotic leakage (AL) represents a frequently occurring postoperative complication with serious consequences on health, quality of life, and economic aspects. Approaches using collagen and/or fibrin-based sealants to cover intestinal anastomoses have shown promising effects toward leak reduction; however, they have not reached routine use yet. To assess the effects of covering intestinal anastomoses with collagen and/or fibrin-based sealants on postoperative leakage, a systematic review and meta-analysis were conducted.

Method

PubMed, Web of Science, Cochrane Library, and Scopus (01/01/1964 to 17/01/2022) were searched to identify studies investigating the effects of coating any intestinal anastomoses with collagen and/or fibrin-based sealants on postoperative AL, reoperation rates, Clavien-Dindo major complication, mortality, and hospitalization length. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

Results

Overall, 15 studies (five randomized controlled trials, three nonrandomized intervention studies, six observational cohort studies) examining 1,387 patients in the intervention group and 2,243 in the control group were included. Using fixed-effects meta-analysis (I 2 < 50%), patients with coated intestinal anastomoses presented significantly lower AL rates (OR = 0.37; 95% CI 0.27-0.52; p < 0.00001), reoperation rates (OR, 0.21; 95% CI, 0.10-0.47; p = 0.0001), and Clavien-Dindo major complication rates (OR, 0.54; 95% CI, 0.35-0.84; p = 0.006) in comparison to controls, with results remaining stable in sensitivity and subgroup analyses (stratified by study design, age group, intervention used, location of anastomoses, and indication for surgery). The length of hospitalization was significantly shorter in the intervention group (weighted mean difference (WMD), -1.96; 95% CI, -3.21, -0.71; p = 0.002) using random-effects meta-analysis (I 2 ≥ 50%), especially for patients with surgery of upper gastrointestinal malignancy (WMD, -4.94; 95% CI, -7.98, -1.90; p = 0.001).

Conclusion

The application of collagen-based laminar biomaterials or fibrin sealants on intestinal anastomoses can significantly reduce postoperative rates of AL and its sequelae. Coating of intestinal anastomoses could be a step toward effective and sustainable leak prevention. To assess the validity and robustness of these findings, further clinical studies need to be conducted.

Evaluation of the SafeHeal Colovac+ Anastomosis Protection Device: A Preclinical Study

BackgroundThe protective ostomy is the current standard of care to protect a low colorectal anastomosis from leakage, but exposes patients to complications requiring an alternative strategy. The Colovac+ is a vacuum-based intraluminal bypass device designed to shield the anastomosis from fecal content, preventing the clinical outcomes of anastomotic leakage. The objective of this study was to evaluate the preliminary efficacy, safety, and technical feasibility of the Colovac+ in a porcine model. Methods: Twelve pigs received a colorectal anastomosis with Colovac+ implantation. The device was left in situ for 10 days and then retrieved endoscopically. Six pigs were to be sacrificed immediately after device retrieval and the other 6 were to be sacrificed on day 38. Clinical, endoscopic, and histopathological examinations were performed to evaluate the following endpoints: prevention of contact between the anastomosis and fecal content, device migration, feasibility of the implantation and retrieval procedure, collateral damage to the colonic wall, colon healing after device retrieval, and systemic toxicity related to the device. Results: Eleven pigs completed the study. One pig died prematurely due to a surgical complication unrelated to the device (bladder damage with uroperitoneum). There was no evidence of contact between the anastomosis and fecal content, none of the pigs developed symptomatic anastomotic leakage, there were no significant device migrations, and there was no evidence of systemic toxicity. Colovac+ implantation was easily performed in all cases except 1 (due to an inappropriate lubricant). Colovac+ retrieval was achieved successfully in all cases. Postretrieval examinations on day 10 revealed ulcerations at the anchoring site in 4 cases indicating mechanical damage caused by the stent. However, in the recovery group, no ulcerations were observed on day 38, and the colonic wall had properly healed in all animals. Conclusions: The Colovac+ is a technically feasible, safe, and efficient device for the protection of a colorectal anastomosis in a porcine model. The device holds promise for clinical use and warrants further research.

OUP accepted manuscript

Background

Methods

Results

Conclusion

Unfavorable effect of high postoperative fluid balance on outcome of pancreaticoduodenectomy

Purpose

Despite the many efforts to overcome postoperative complications, pancreaticoduodenectomy (PD) is still accompanied with considerable concerns of lethal complications. The clinical factors are known to affect postoperative outcomes such as diameter of pancreatic duct, texture of pancreas, and comorbidity of the patients are mostly uncorrectable. Thus, investigation for correctable risk factors is required. Recently, perioperative fluid volume was reported to be associated with complications after PD. This study aims to determine the relationship between postoperative fluid balance and surgical outcome after open PD.

Methods

We reviewed, retrospectively, 172 consecutive patients who underwent open PD in a single institution between 2015 and 2019. The status of perioperative fluid balance 2 days after surgery and clinical factors were investigated to determine the association with postoperative outcome including postoperative pancreatic fistula (POPF). According to postoperative fluid balance, patients were divided into high- and low-balance groups, and clinical features and surgical outcomes were compared between both groups. Multivariate analysis were performed to identify risk factors for POPF.

Results

The percentage of morbidity and the incidence of POPF were higher in the high-balance group compared to the low-balance group (61.6% vs. 37.2%, P = 0.001; 15.1% vs. 3.5%, P = 0.009). High postoperative fluid balance and the presence cardiovascular disease were correlated with POPF on multivariate analysis (odds ratio [OR], 4.574; 95% confidence interval [CI], 1.229–17.029; P = 0.023 and OR, 3.517; 95% CI, 1.209–12.017; P = 0.045).

Conclusion

Higher amount of postoperative fluid balance and the presence of cardiovascular disease are associated with POPF after PD.

Titanium implants modified by laser microtexturing enhance the bioactivity of gastric epithelial cells and fibroblast cells

The clinical application of anastomotic instruments improves the efficiency of the digestive tract surgery. However, the stapler with titanium nails implanted is still controversial in terms of anastomotic complications, and further improvement and optimization are needed. The purpose of this study was to explore the optimal microtextured parameters that could enhance the bioactivity of titanium implants in vitro. Laser microtexturing technology was used to construct the groove-type microstructural surfaces with different parameters, and human gastric mucosal epithelial cells (GES-1 cells) and mouse fibroblasts (3T3 cells) were cultured on the surface of the titanium plates in vitro. The data of cell adhesion, cell proliferation and cell activity were obtained and statistically analyzed. The textured titanium plates meet the expected design. GES-1 and 3T3 cell adhesion were better in the surface of titanium plates in microstructural group than that in the polished group. GES-1 and 3T3 cells also showed higher proliferative activity in the microstructural group compared with the polished group. The laser textured titanium plates have good groove-type microstructure, which increase the surface roughness, change the surface wettability, promote the adhesion, proliferating and orderly growth of GES-1 and 3T3 cells, and show good biological properties.

Colorectal anastomotic leak: transcriptomic profile analysis

BACKGROUND

Anastomotic leakage in patients undergoing colorectal surgery is associated with morbidity and mortality. Although multiple risk factors have been identified, the underlying mechanisms are mainly unknown. The aim of this study was to perform a transcriptome analysis of genes underlying the development of anastomotic leakage.

METHODS

A set of human samples from the anastomotic site collected during stapled colorectal anastomosis were used in the study. Transcriptomic profiles were generated for patients who developing anastomotic leakage and case-matched controls with normal anastomotic healing to identify genes and biological processes associated with the development of anastomotic leakage.

RESULTS

The analysis included 22 patients with and 69 without anastomotic leakage. Differential expression analysis showed that 44 genes had adjusted P < 0.050, consisting of two upregulated and 42 downregulated genes. Co-functionality analysis of the 150 most upregulated and 150 most downregulated genes using the GenetICA framework showed formation of clusters of genes with different enrichment for biological pathways. The enriched pathways for the downregulated genes are involved in immune response, angiogenesis, protein metabolism, and collagen cross-linking. The enriched pathways for upregulated genes are involved in cell division.

CONCLUSION

These data indicate that patients who develop anastomotic leakage start the healing process with an error at the level of gene regulation at the time of surgery. Despite normal macroscopic appearance during surgery, the transcriptome data identified several differences in gene expression between patients who developed anastomotic leakage and those who did not. The expressed genes and enriched processes are involved in the different stages of wound healing. These provide therapeutic and diagnostic targets for patients at risk of anastomotic leakage.

Post-Operative Monitoring of Intestinal Tissue Oxygenation Using an Implantable Microfabricated Oxygen Sensor

Anastomotic leakage (AL) is a common and dangerous post-operative complication following intestinal resection, causing substantial morbidity and mortality. Ischaemia in the tissue surrounding the anastomosis is a major risk-factor for AL development. Continuous tissue oxygenation monitoring during the post-operative recovery period would provide early and accurate early identification of AL risk. We describe the construction and testing of a miniature implantable electrochemical oxygen sensor that addresses this need. It consisted of an array of platinum microelectrodes, microfabricated on a silicon substrate, with a poly(2-hydroxyethyl methacrylate) hydrogel membrane to protect the sensor surface. The sensor was encapsulated in a biocompatible package with a wired connection to external instrumentation. It gave a sensitive and highly linear response to variations in oxygen partial pressure in vitro, although over time its sensitivity was partially decreased by protein biofouling. Using a pre-clinical in vivo pig model, acute intestinal ischaemia was robustly and accurately detected by the sensor. Graded changes in tissue oxygenation were also measurable, with relative differences detected more accurately than absolute differences. Finally, we demonstrated its suitability for continuous monitoring of tissue oxygenation at a colorectal anastomosis over a period of at least 45 h. This study provides evidence to support the development and use of implantable electrochemical oxygen sensors for post-operative monitoring of anastomosis oxygenation.

Impact of Deserosalization on Small Bowel Anastomosis Healing in Swine: A Pilot Study

BACKGROUND

Healing is related to gastrointestinal anastomotic leak, which is a severe and common complication. This study aimed to investigate the feasibility and the impact of deserosalization on healing of jejuno-jejunal anastomoses in an animal model.

MATERIALS AND METHODS

Seven swine underwent three types of side-to-side jejuno-jejunal anastomosis twice and survived seven days. Three different types of jejuno-jejunal side-to-side anastomoses were performed twice at 20-cm distance from each other in each animal: no serosa removal, one-sided, and two-sided serosa removal, respectively. Bursting pressure, tissue hydroxyproline concentration, and pathology scores were evaluated.

RESULTS

Hydroxyproline tissue concentration was a mean±standard deviation of 0.37±0.09, 0.38±0.08, and 0.30±0.05 nmoI/ml respectively (p<0.05). Bursting pressure was a mean±standard deviation of 59.02±8.60, 73.20±11.09, and 100.01±7.49 mmHg, respectively (p<0.001). The histopathological assessment did not find any statistically significant differences.

CONCLUSION

Deserosalization in jejuno-jejunal anastomosis was technically feasible and seemed to improve mechanical strength and collagen deposition in this experimental porcine model. Further investigation is warranted.

Predictive and Diagnostic Biomarkers of Anastomotic Leakage: A Precision Medicine Approach for Colorectal Cancer Patients

Development of an anastomotic leak (AL) following intestinal surgery for the treatment of colorectal cancers is a life-threatening complication. Failure of the anastomosis to heal correctly can lead to contamination of the abdomen with intestinal contents and the development of peritonitis. The additional care that these patients require is associated with longer hospitalisation stays and increased economic costs. Patients also have higher morbidity and mortality rates and poorer oncological prognosis. Unfortunately, current practices for AL diagnosis are non-specific, which may delay diagnosis and have a negative impact on patient outcome. To overcome these issues, research is continuing to identify AL diagnostic or predictive biomarkers. In this review, we highlight promising candidate biomarkers including ischaemic metabolites, inflammatory markers and bacteria. Although research has focused on the use of blood or peritoneal fluid samples, we describe the use of implantable medical devices that have been designed to measure biomarkers in peri-anastomotic tissue. Biomarkers that can be used in conjunction with clinical status, routine haematological and biochemical analysis and imaging have the potential to help to deliver a precision medicine package that could significantly enhance a patient's post-operative care and improve outcomes. Although no AL biomarker has yet been validated in large-scale clinical trials, there is confidence that personalised medicine, through biomarker analysis, could be realised for colorectal cancer intestinal resection and anastomosis patients in the years to come.

Quantitative fluorescence angiography aids novice and experienced surgeons in performing intestinal resection in well-perfused tissue

Background

Anastomotic leakage (AL) after gastrointestinal resection is a devastating complication with huge consequences for the patient. As AL is associated with poor blood supply, tools for objective assessment of perfusion are in high demand. Indocyanine green angiography (ICG-FA) and quantitative analysis of ICG-FA (q-ICG) seem promising. This study aimed to investigate whether ICG-FA and q-ICG could improve perfusion assessment performed by surgeons of different experience levels.

Methods

Thirteen small bowel segments with a varying degree of devascularization, including two healthy sham segments, were constructed in a porcine model. We recruited students, residents, and surgeons to perform perfusion assessment of the segments in white light (WL), with ICG-FA, and after q-ICG, all blinded to the degree of devascularization.

Results

Forty-five participants fulfilled the study (18 novices, 12 intermediates, and 15 experienced). ICG and q-ICG helped the novices correctly detect the healthy bowel segments to experienced surgeons’ level. ICG and q-ICG also helped novice surgeons to perform safer resections in healthy tissue compared with normal WL. The relative risk (RR) of leaving ischemic tissue in WL and ICG compared with q-ICG, even for experienced surgeons was substantial, intermediates (RR = 8.9, CI95% [4.0;20] and RR = 6.2, CI95% [2.7;14.1]), and experienced (RR = 4.7, CI95% [2.6;8.7] and RR = 4.0, CI95% [2.1;7.5]).

Conclusion

Q-ICG seems to guide surgeons, regardless of experience level, to safely perform resection in healthy tissue, compared with standard WL. Future research should focus on this novel tool’s clinical impact.

The effect of high intraoperative blood loss on pancreatic fistula development after pancreatoduodenectomy: An international, multi-institutional propensity score matched analysis

BACKGROUND

The association between intraoperative estimated blood loss and outcomes after pancreatoduodenectomy has, thus far, been rarely explored.

METHODS

In total, 7,706 pancreatoduodenectomies performed at 18 international institutions composing the Pancreas Fistula Study Group were examined (2003-2020). High estimated blood loss (>700 mL) was defined as twice the median. Propensity score matching (1:1 exact-match) was employed to adjust for variables associated with high estimated blood loss and clinically relevant pancreatic fistula occurrence. The study was powered to detect a 33% clinically relevant pancreatic fistula increase in the high estimated blood loss group, with α = 0.05 and β = 0.2.

RESULTS

The propensity score model included 966 patients with high estimated blood loss and 966 patients with lower estimated blood loss; all covariate imbalantces were solved. Patients with high estimated blood loss patients experienced higher clinically relevant pancreatic fistula rates (19.4 vs 12.6%, odds ratio 1.66; P < .001), as well as higher severe complication rates (27.8 vs 15.6%), transfusions (50.1 vs 14.3%), reoperations (9.2 vs 4.0%), intensive care unit transfers (9.9 vs 4.8%) and 90-day mortality (4.7 vs 2.0%, all P < .001). High estimated blood loss was an independent predictor for clinically relevant pancreatic fistula (odds ratio 1.78, 95% confidence interval 1.37-2.32), as were prophylactic Octreotide administration (odds ratio 1.95, 95% confidence interval 1.46-2.61) and soft pancreatic texture (odds ratio 5.32, 95% confidence interval 3.74-5.57; all P < .001). Moreover, a second model including 1,126 pancreatoduodenectomies was derived including vascular resections as additional confounder (14.0% vascular resections performed in each group). On multivariable regression, high estimated blood loss was confirmed an independent predictor for clinically relevant pancreatic fistula reduction (odds ratio 1.80, 95% confidence interval 1.32-2.44; P < .001), whereas vascular resection was not (odds ratio 0.64, 95% confidence interval 0.34-1.88; P = .156).

CONCLUSION

This study better establishes the relationship between estimated blood loss and outcomes after pancreatoduodenectomy. Despite inherent contributions to blood loss, its minimization is an actionable opportunity for clinically relevant pancreatic fistula reduction and performance optimization in pancreatoduodenectomy. Accordingly, practical insights are offered to achieve this goal.

Intraoperative evaluation of colorectal anastomotic integrity: a comparison of air leak and dye leak tests

BACKGROUND

Air leak tests (ALTs) and dye leak tests (DLTs) are the most common techniques for Intraoperative colorectal anastomosis assessment. The aim of our study was to compare the sensitivity of ALT with DLT in intraoperative evaluation of colorectal anastomotic integrity and to quantify the pressures routinely used in these tests.

METHODS

A prospective clinical trial was conducted on patients who had elective colorectal resection and primary anastomosis from November 2017 until July 2019 in a single academic referral center. Each patient underwent both tests. The ALT was a transanal insufflation of CO₂ and inspection of escaping bubbles around the anastomosis immersed in saline. The DLT was a transanal infusion of diluted methylene blue and inspection of dye stains on surgical gauze wrapping the anastomosis. Peak pressures were measured. Primary endpoints were the sensitivity of ALT and DLT in detecting intraoperative leaks, quantification of intraluminal pressure routinely used in these settings and assessment of postoperative complications such as a clinical leak.

RESULTS

Forty patients underwent elective colorectal resection and anastomosis for malignant (67%) or benign n (33%) etiology. Height of anastomoses ranged from 1 to 25 cm (mean ± SD 12 ± 6 cm). Mean pressures measured were 26.5 ± 6.6 mmHg for the DLT and 22 ± 4 mmHg for the ALT (p < 0.01). Twenty percent of the DLTs were positive (8 patients) compared to 2.5% (1 patient) of the ALTs (RR 1.97, CI 1.2-2.7; p = 0.03). All patients who had positive tests had a suture reinforcement of the anastomosis. Only 1 patient, who had a positive DLT and ALT, developed a clinical leak CONCLUSIONS: DLT is more sensitive in detecting anastomotic leak intraoperatively. This is the first study measuring anastomotic tests' pressures used in-vivo in humans demonstrating a range of 20-30 mmHg. Based on our data we believe that a positive DLT with a negative ALT may be treated with suture reinforcement alone.

CLINICAL TRIAL NUMBER

NCT03316677-10/17/2017.

Inhibition of HIF-prolyl hydroxylases improves healing of intestinal anastomoses

Anastomotic leakage (AL) accounts for a major part of in-house mortality in patients undergoing colorectal surgery. Local ischemia and abdominal sepsis are common risk factors contributing to AL and are characterized by upregulation of the hypoxia-inducible factor (HIF) pathway. The HIF pathway is critically regulated by HIF-prolyl hydroxylases (PHDs). Here, we investigated the significance of PHDs and the effects of pharmacologic PHD inhibition (PHI) during anastomotic healing. Ischemic or septic colonic anastomoses were created in mice by ligation of mesenteric vessels or lipopolysaccharide-induced abdominal sepsis, respectively. Genetic PHD deficiency (Phd1-/-, Phd2+/-, and Phd3-/-) or PHI were applied to manipulate PHD activity. Pharmacologic PHI and genetic PHD2 haplodeficiency (Phd2+/-) significantly improved healing of ischemic or septic colonic anastomoses, as indicated by increased bursting pressure and reduced AL rates. Only Phd2+/- (but not PHI or Phd1-/-) protected from sepsis-related mortality. Mechanistically, PHI and Phd2+/- induced immunomodulatory (M2) polarization of macrophages, resulting in increased collagen content and attenuated inflammation-driven immune cell recruitment. We conclude that PHI improves healing of colonic anastomoses in ischemic or septic conditions by Phd2+/--mediated M2 polarization of macrophages, conferring a favorable microenvironment for anastomotic healing. Patients with critically perfused colorectal anastomosis or abdominal sepsis could benefit from pharmacologic PHI.

Hypocalcemia: A possible risk factor for anastomotic leak in digestive surgery

Anastomotic leaks (ALs) remain the most severe complication in digestive surgery, as well as the most consumptive in terms of human and financial resources. There is an abundance of international research which has focused on identifying and correcting risk factors, and on individualized surgical management as well. The most frequent risk factors are male sex, obesity, diabetes, advanced malignant disease, ASA score, perioperative blood loss or perioperative transfusion, long operation time, emergency operation and altered nutritional status. The aim of the present study was to measure the preoperative serum calcium level and to find a possible correlation between calcium levels and the risk of AL occurrence. A retrospective analysis of medical records for 122 patients who underwent surgical gut resection with anastomosis for different pathologies was carried out. Preoperative serum calcium level and the occurrence of AL was noted. The results revealed that the average value of total blood calcium was 8.78 mg/dl, without a significant difference in sex groups. Hypocalcemia was identified in 44 patients (36.1%). AL was identified in 8 patients (6.6%), with a statistically insignificant difference between male and female patients. The average value of blood calcium in the AL patient group was 8.07 mg/dl, while in patients without AL the average value was 8.83 mg/dl. Hypocalcemia, defined as a serum calcium level below 8.5 mg/dl, was observed in 7 of the 8 patients presenting with AL (87.5%) and 37 patients who did not present with AL (32.5%), a significant difference with which to consider and include hypocalcemia in the group of risk factors for AL (P=0.001). In conclusion, preoperative low serum calcium level can represent a risk factor for AL in digestive surgery.

Incorporation of a Poly-ε-Caprolactone Scaffold in a ;Circular Stapled End-To-End Small Intestine Anastomosis Does Not Have Any Adverse Effects Within 30 days: A Study in Piglets

Background. Incorporation of a poly-ε-caprolactone (PCL) scaffold in circular stapled anastomoses has been shown to increase the anastomotic tensile strength on postoperative day (POD) 5 in a pig model. The aim of this study was to investigate the effects of incorporation of a PCL scaffold in a circular stapled end-to-end small intestine anastomosis, with stricture formation and anastomotic histology as primary outcomes in a 30-day observation period. Methods. A total of 15 piglets were included. In each piglet, three circular stapled end-to-end anastomoses were made in the small intestines. Two were interventional and one was a control. On POD 10, 20, or 30, the anastomoses were subjected to in vivo intraluminal contrast study, and the index for anastomotic lumen was calculated. The anastomotic segment was resected and subjected to a tensile strength test and histological examination. Results. At POD 10, the mean ± SD value for anastomotic index was .749 ± .065 in control anastomoses and .637 ± .051 in interventional anastomosis (P = .0046), at POD 20, .541 ± .150 and .724 ± .07 (P = .051), and at POD 30, .645 ± .103 and .686 ± .057 (P = .341), respectively. No significant difference was observed in maximum tensile strength and histology at POD 30. Conclusions. The incorporation of a PCL scaffold in a circular stapled end-to-end small intestine anastomosis does not increase the risk of stricture or impair wound healing after 30 days.