Pre-emptive active drainage of reflux (PARD) in Ivor-Lewis oesophagectomy with negative pressure and simultaneous enteral nutrition using a double-lumen open-pore film drain (dOFD)

Background Postoperative reflux can compromise anastomotic healing after Ivor-Lewis oesophagectomy (ILE). We report on Pre-emptive Active Reflux Drainage (PARD) using a new double-lumen open-pore film drain (dOFD) with negative pressure to protect the anastomosis. Methods To prepare a dOFD, the gastric channel of a triluminal tube (Freka®Trelumina, Fresenius) is coated with a double-layered open-pore film (Suprasorb®CNP drainage film, Lohmann & Rauscher) over 25 cm. The ventilation channel is blocked. The filmcoated segment is placed in the stomach and the intestinal feeding tube in the duodenum. Negative pressure is applied with an electronic vacuum pump (− 125 mmHg, continuous suction) to the gastric channel. Depending on the findings in the endoscopic control, PARD will either be continued or terminated. Results PARD was used in 24 patients with ILE and started intraoperatively. Healing was observed in all the anastomoses. The median duration of PARD was 8 days (range 4–21). In 10 of 24 patients (40%) there were issues with anastomotic healing which we defined as “at-risk anastomosis”. No additional endoscopic procedures or surgical revisions to the anastomoses were required. Conclusions PARD with dOFD contributes to the protection of anastomosis after ILE. Negative pressure applied to the dOFD (a nasogastric tube) enables enteral nutrition to be delivered simultaneously with permanent evacuation and decompression.

New Technologies to Prevent Anastomotic Leak

Leaks from anastomoses can be a serious complication of any gastrointestinal resection. Leaks lead to increased morbidity, delayed postoperative recovery, and potential delays in adjuvant treatment in cancer cases. Prevention of anastomotic leak has been an area of ongoing research for decades. Methods of assessing bowel perfusion have been developed that may provide forewarning of anastomotic compromise. Physical reinforcement of the anastomosis with buttressing material is an available method employed with the goal of preventing leaks. Liquid-based sealants have also been explored. Lastly, interactions between the gut microbiome and anastomotic healing have been investigated as a mean of manipulating the microenvironment to reduce leak rates. Though no single technology has been successful in eliminating leaks, an understanding of these developing fields will be important for all surgeons who operate on the gastrointestinal tract.

The preoperative abundance of Prevotella associates with anastomotic healing after colorectal surgery.

Anastomotic leakage (AL) is a frequent and potentially life-threatening postoperative complication in patients undergoing colorectal surgery with a multifactorial yet unknown pathophysiology. In the present study, we aimed to unravel AL etiology and intestinal anastomotic healing (AH) physiology focusing on both host epithelial and gut microbial components. We make use of patients-related samples and two high throughput next generation sequencing analysis approaches, including anastomotic tissue-associated bulk RNA sequencing and preoperative fecal 16S rRNA gene sequencing. We find that in the absence of host epithelial gene expression differences, the preoperative fecal microbiota of patients who undergo colorectal resection with successful AH differs in the group of patients who develop AL in the abundance of Prevotella and suggests a potential beneficial role of Prevotella that may prove useful as predictive biomarker for AH.

Intestinal anastomotic healing models during experimental colitis

Background Anastomotic leakage represents a major complication following resections in colorectal surgery. Among others, intestinal inflammation such as in inflammatory bowel disease is a significant risk factor for disturbed anastomotic healing. Despite technical advancements and several decades of focused research, the underlying mechanisms remain incompletely understood. Animal experiments will remain the backbone of this research in the near future. Here, instructions on a standardized and reproducible murine model of preoperative colitis and colorectal anastomosis formation are provided to amplify research on anastomotic healing during inflammatory disease. Methods We demonstrate the combination of experimental colitis and colorectal anastomosis formation in a mouse model. The model allows for monitoring of anastomotic healing during inflammatory disease through functional outcomes, clinical scores, and endoscopy and histopathological examination, as well as molecular analysis. Discussion Postoperative weight loss is used as a parameter to monitor general recovery. Functional stability can be measured by recording bursting pressure and location. Anastomotic healing can be evaluated macroscopically from the luminal side by endoscopic scoring and from the extraluminal side by assessing adhesion and abscess formation or presence of dehiscence. Histologic examination allows for detailed evaluation of the healing process. Conclusion The murine model presented in this paper combines adjustable levels of experimental colitis with a standardized method for colorectal anastomosis formation. Extensive options for sample analysis and evaluation of clinical outcomes allow for detailed research of the mechanisms behind defective anastomotic healing.

Biomaterial-Assisted Anastomotic Healing: Serosal Adhesion of Pectin Films

Anastomotic leakage is a frequent complication of intestinal surgery and a major source of surgical morbidity. The timing of anastomotic failures suggests that leaks are the result of inadequate mechanical support during the vulnerable phase of wound healing. To identify a biomaterial with physical and mechanical properties appropriate for assisted anastomotic healing, we studied the adhesive properties of the plant-derived structural heteropolysaccharide called pectin. Specifically, we examined high methoxyl citrus pectin films at water contents between 17–24% for their adhesivity to ex vivo porcine small bowel serosa. In assays of tensile adhesion strength, pectin demonstrated significantly greater adhesivity to the serosa than either nanocellulose fiber (NCF) films or pressure sensitive adhesives (PSA) (p < 0.001). Similarly, in assays of shear resistance, pectin demonstrated significantly greater adhesivity to the serosa than either NCF films or PSA (p < 0.001). Finally, the pectin films were capable of effectively sealing linear enterotomies in a bowel simulacrum as well as an ex vivo bowel segment. We conclude that pectin is a biomaterial with physical and adhesive properties capable of facilitating anastomotic healing after intestinal surgery.

Obsidian ASG® Autologous Platelet-Rich Fibrin Matrix and Colorectal Anastomotic Healing: A Preliminary Study

Introduction: Anastomotic leakage (AL) following colorectal resection is a devastating complication affecting morbidity, mortality, and quality of life of patients in the long term. Different tissue sealants and biologic glues were tested showing conflicting results regarding their influence on anastomotic healing and leak prevention. Application of autologous platelet-rich fibrin (Vivostat A/S, Alleroed, Denmark), which acts as a source of angiogenic growth factors and cytokines, showed promising results in an in-vivo porcine model. Herein, we present the first human study of stapled colorectal anastomoses supplemented with an autologous-derived platelet-rich fibrin matrix (Obsidian ASG®, Rivolution GmbH, Rosenheim, Germany and Vivostat A/S, Alleroed, Denmark). Materials and Methods: A retrospective analysis of prospectively accumulated data was performed in two colorectal centers (Linz, Vienna) on patients undergoing left-sided colorectal or coloanal stapled anastomosis between October 2018 and December 2019. The Obsidian ASG® Matrix was applied to the rectal stump, and after closure with the circular stapling device, at the circumference of anastomosis in every single case. Anastomoses were supplemented with intra- and extra-anastomotic application (IAA—intra-anastomotic application developed by Rivolution GmbH, Rosenheim, Germany) of Obsidian ASG® Matrix. The primary endpoints were incidence of perioperative complications and anastomotic leak rate. Results: Two-hundred-sixty-one (138 female) patients underwent left-sided colonic (n=177) or rectal resection (n=84). In 253 (96.9%) cases, a laparoscopic or robotic-assisted approach was used. There were no complications attributable to the intraoperative application of the Obsidian ASG® Matrix. All intraoperative leak tests were negative. Overall, anastomotic leak rate accounted for 2.3% (6/261). AL following colonic and rectal resection was seen in 2.3% (4/177) and 2.4% (2/84), respectively. Complication and leak rate was similar in the two participating centers. Postoperative fever and elevated CRP levels were significantly correlated to AL. There was no significant risk factor for AL on multivariate analysis. Conclusion: Application of an autologous-derived platelet-rich fibrin matrix (Obsidian ASG®) at anastomotic site following colorectal resection is safe and associated with a low rate of anastomotic leakage.

A229 PROMOTION OF COLONIC ANASTOMOTIC HEALING WITH PERIOPERATIVE SUPPLEMENTATION WITH OLIGOSACCHARIDES

Background Colorectal resection is a standard procedure in the management of colorectal cancer (CRC) and inflammatory bowel disease. Anastomotic leak (AL) is a major complication in colorectal resections, and the gut microbiota may play a role in the healing and development of AL. Short-chain fatty acids (SCFAs), namely butyrate, have been involved in anastomotic healing when administered into the bowel via enema. Due to the mechanical stress associated with enemas after the confection of a fresh and fragile anastomosis, other butyrate-increasing strategies are required. Aims To promote anastomotic healing and prevent AL by using inulin and galacto-oligosaccharides (GOS) supplementation to modulate the microbiota toward a butyrate-producing profile. Methods Mice were fed diets supplemented with inulin, GOS or cellulose, as a non-fermentable control, for two weeks and underwent a proximal colonic anastomosis under general anesthesia. Healing of the anastomosis, both macroscopically and microscopically, was assessed six days after surgery. Epithelial proliferation, mucus production and integrity of the gut barrier were assessed. Results Inulin and GOS supplementation increased SCFAs in the colon and were associated with better postoperative weight recovery and macroscopic anastomotic healing. Microscopically, mucosal continuity was promoted by inulin and GOS. Mucus production was found to be similar in all groups. The gut barrier was found to be improved with inulin and GOS as shown by less bacterial translocation. Conclusions Inulin and GOS may prevent AL and promote anastomotic healing. This effect appears to be mediated by improved mucosal proliferation. Funding Agencies CIHRNatural Sciences and Engineering Research Council of Canada; Institut du cancer de Montréal; Fonds de recherche du Québec en santé