Evaluation of Unmeshed and 1:1 Meshed AlloDerm Bolsters for Stapled Rectal Anastomoses in a Porcine Model

Effect of Doxycycline-Release Anastomotic Augmentation Ring on Porcine Colorectal Anastomosis

INTRODUCTION

Collagen degradation can lead to early postoperative weakness in colorectal anastomosis. Matrix metalloproteinase inhibitors (MMPIs) are shown to decrease collagen breakdown and enhance healing in anastomosis in animal models. Here, we evaluated the effectiveness of a novel anastomotic augmentation ring (AAR) that releases doxycycline, an MMPI, from a poly(lactic-co-glycolic) acid ring in porcine anastomoses.

METHODS

Two end-to-end stapled colorectal anastomoses were performed in 20 Yorkshire-Hampshire pigs. AAR was randomly incorporated into either the proximal or distal anastomosis as treatment, while nonaugmented anastomosis served as a control. Animals were then euthanized on days 3, 4, and 5 before anastomosis explantation and burst pressure measurement. Each anastomosis site was also collected for histology, hydroxyproline content, and gene expression microarray analyses.

RESULTS

No abscess or anastomotic leak was detected. Average burst pressures were not significantly different at any time point. There is no statistical difference in collagen content between the treatment group and controls. Gene expression analysis revealed no statistically significant in differentially expressed genes. However, genes related to inflammation, such as C-C motif chemokine ligand 11 (CCL11), CD70, and C-X-C motif chemokine ligand 10 (CXCL10), were upregulated (not statistically significant) in AAR compared to non-AAR anastomosis sites on days 3 and 4.

CONCLUSIONS

This pilot study shows that doxycycline-release AAR is feasible and safe. While burst pressure and collagen content did not change significantly with doxycycline treatment, upregulating genes related to the inflammatory process for pathogen and debris clearance in AAR may improve the early stage of colorectal anastomotic healing.

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.

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.

Staple line/anastomotic reinforcement and other adjuncts: do they make a difference?

Since the development of the stapled intestinal anastomosis, efforts have been aimed at reducing complications and standardizing methods. The main complications associated with stapled anastomoses include bleeding, device failure, and anastomotic failure (leaks and strictures). These complications are associated with increased cost of care, increase in cancer recurrence, decreased overall survival, poor quality of life, and in some cases the need for further procedures including a diverting ostomy. Reducing these complications therefore has important implications. To this end, techniques to reduce the incidence of anastomotic complications have been the focus of many investigators. In this review, we summarize the current staple line reinforcement technology as well as other adjunctive measures, and specifically discuss the role of biologic materials in this realm.

Evaluation of Bioabsorbable Seamguard for Staple Line Reinforcement in Stapled Rectal Anastomoses

Introduction. The concept of staple line reinforcement is a growing area of interest. This study evaluated the feasibility and effect of using bioabsorbable Seamguard (BSG) to bolster end-to-end stapled rectal anastomoses in a porcine model. Methods. Eleven female 45-kg Yucatan domestic pigs were used. Each animal served as its own control by creating a BSG and nonreinforced anastomosis using a 29-mm end-to-end anastomotic stapling device. Reinforced anastomoses were randomized to proximal and distal positions along the rectum. Each staple line reinforcement agent consisted of adding BSG to the stapling device according to the manufacturer’s instructions. Barium enemas were then performed and the 2 anastomotic sites harvested. Each anastomosis underwent burst testing. The internal diameter of each anastomosis was measured and underwent pathologic review. Results. Bolstered anastomoses offered no strength advantage as burst pressures were no different as compared with unbolstered anastomoses. There was also no difference in anastomotic internal or external diameters. Only 1 stapled anastomosis burst during testing and none in the bolstered group. On histological analysis, there was a significant increase in inflammatory infiltrate in the bolstered group as compared with the stapled group ( P = .041), with a higher incidence of lymphocytes ( P = .047) and giant cells ( P = .037). There was no difference in mucosal loss at the anastomotic site, neovascularization, fibroblast presence, extent of fibrosis, muscle layer disruption, percentage of anastomosis replaced by collagen, and elastin deposition. Conclusions. The routine use of BSG bolsters in stapled rectal anastomoses is safe and results in equivalent anastomotic strength as traditional stapled anastomoses.

Comparison of the Compression Anastomosis Ring (EndoCAR) With a Circular Stapled Anastomosis in a Porcine Model

Purpose. The aim of this study was to compare characteristics of rectal compression and stapled anastomoses at multiple time points. Methods. A total of 50 domestic pigs underwent a rectal anastomosis with a compression device or a circular stapler. They were sacrificed at zero-time, 2 days, 1 week, 1 month, and 3 months. Burst and maximal tolerated pressure and sites of failure, internal diameters, and radiographic leak rates were assessed. Desmosine (elastin) levels were determined. Results. There were no clinical or radiographic leaks. Overall, 10 out of 27 (37%) compression anastomoses burst at higher pressures than the 14 out of 24 (58%) stapled anastomoses. Mean circumference and anastomotic index were greater for the EndoCAR at 1 week and 3 months. Desmosine levels were similar. Conclusions. In the porcine model, compression rectal anastomoses with the EndoCAR had improved bursting pressures and internal circumference compared with circular stapled anastomoses.

1.5:1 Meshed AlloDerm Bolsters for Stapled Rectal Anastomoses Does Not Provide Any Advantage in Anastomotic Strength in a Porcine Model

Introduction: The most feared complication of colorectal anastomoses is leaks resulting in severe morbidity. The concept of staple-line reinforcement is a growing area of interest. In this study, the authors evaluated the feasibility and effect of using 1.5:1 meshed AlloDerm to bolster end-to-end stapled rectal anastomoses in a porcine model. Methods: A total of 30 female 45-kg domestic pigs were studied, and each served as its own control by creating a bolstered and unbolstered anastomosis in each animal. All anastomoses were created with a 29-mm end-to-end stapling device. Bolstered anastomoses were randomized to proximal and distal positions along the rectum, and each rectorectal anastomosis was separated by an average of 10 cm. The animals were survived to 3, 5, and 30 days. Barium enemas were then performed and the 2 anastomotic sites harvested. Each anastomosis underwent burst testing. The internal diameter of each anastomosis was measured, and a biochemical analysis was performed for elastin and collagen content. Results: Bolstered anastomoses offered no strength advantage as burst pressures were no different when compared with unbolstered anastomoses. There was also no difference in anastomotic internal diameter, biochemical analysis of elastin or collagen, or presence of adhesions when comparing bolstered with unbolstered anastomoses. There were 4 subclinical leaks—1 in the unbolstered group and 3 in the bolstered group. Conclusions: The routine use of 1.5:1 meshed AlloDerm sandwich bolsters in stapled rectal anastomosis does not confer any detectable advantage in anastomotic strength. Further studies are needed to determine equivalence to traditional stapled anastomoses.