Experimental evaluation of a bovine pericardium-derived collagen matrix buttress in ileocolic and colon anastomoses

The clinical effectiveness of staple line reinforcement with different matrix used in surgery

Staplers are widely used in clinics; however, complications such as bleeding and leakage remain a challenge for surgeons. To tackle this issue, buttress materials are recommended to reinforce the staple line. This Review provides a systematic summary of the characteristics and applications of the buttress materials. First, the physical and chemical properties of synthetic polymer materials and extracellular matrix used for the buttress materials are introduced, as well as their pros and cons in clinical applications. Second, we review the clinical effects of reinforcement mesh in pneumonectomy, sleeve gastrectomy, pancreatectomy, and colorectal resection. Based on the analysis of numerous research data, we believe that buttress materials play a crucial role in increasing staple line strength and reducing the probability of complications, such as bleeding and leakage. However, considering the requirements of bioactivity, degradability, and biosafety, non-crosslinked small intestinal submucosa (SIS) matrix material is the preferred candidate. It has high research and application value, but further studies are required to confirm this. The aim of this Review is to provide comprehensive guidance on the selection of materials for staple line reinforcement.

Light-activated photosealing with human amniotic membrane strengthens bowel anastomosis in a hypotensive, trauma-relevant swine model

BACKGROUND

Gastrointestinal anastomotic leakage is a dreaded complication despite advancements in surgical technique. Photochemical tissue bonding (PTB) is a method of sealing tissue surfaces utilizing photoactive dye. We evaluated if crosslinked human amniotic membrane (xHAM) photosealed over the enteroenterostomy would augment anastomotic strength in a trauma-relevant swine hemorrhagic shock model.

METHODS

Yorkshire swine (40-45 kg, n = 14) underwent midline laparotomy and sharp transection of the small intestine 120 cm proximal to the ileocecal fold. Immediately following intestinal transection, a controlled arterial bleed was performed to reach hemorrhagic shock. Intestinal repair was performed after 60 minutes and autotransfusion of the withdrawn blood was performed for resuscitation. Animals were randomized to small intestinal anastomosis by one of the following methods (seven per group): suture repair (SR), or SR with PTB augmentation. Animals were euthanized at postoperative Day 28 and burst pressure (BP) strength testing was performed on all excised specimens.

RESULTS

Mean BP for SR, PTB, and native tissue groups were 229 ± 40, 282 ± 21, and 282 ± 47 mmHg, respectively, with the SR group statistically significantly different on analysis of variance (p = 0.02). Post-hoc Tukey all-pairs comparison demonstrated a statistically significant difference in burst pressure strength between the SR only and the PTB group (p = 0.04). All specimens in SR group ruptured at the anastomosis upon burst pressure testing, while all specimens in the PTB group ruptured at least 2.5 cm from the anastomosis.

CONCLUSION

Photosealing with xHAM significantly augments the strength of small intestinal anastomosis performed in a trauma porcine model.

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.

A Novel, Easy-to-Use Staple Line Reinforcement for Surgical Staplers

Background

Staple line reinforcement (SLR) is a popular tool used by surgeons to increase staple line strength and improve peri-operative hemostasis. However, currently marketed buttress materials require special attention in attachment to the staple anvil and cartridge and may come loose during typical maneuvering of stapling procedures. We have evaluated a new SLR that has an attachment material that affixes buttress across the entire anvil and cartridge face to prevent slipping, twisting, sliding and/or bunching.

Methods

In benchtop and preclinical testing, the new buttress material (ECHELON ENDOPATH™ Staple Line Reinforcement) was compared to a commercially available SLR for physical characteristics, including strength, absorption, security on the anvil and cartridge during stapler manipulation, impact on the tissue healing response and tissue abrasion. The two SLR’s were also compared to a staple line without buttress for hemostasis.

Results

The new SLR was 180% stronger initially and maintained a greater strength for up to 14 days of exposure to an in vitro solution (p≤0.001), even though it was lighter and exhibited a faster rate of degradation. The new buttress material maintained complete adherence to the anvil and cartridge throughout tissue manipulation, whereas the commercial product lost substantial coverage in 72% of samples. Both SLR’s provided superior hemostasis to the non-buttress control, with minimal impact on tissue healing or abrasion.

Conclusion

Because the new buttress material comes with attachment material affixed across the entire anvil and cartridge face of the stapler and maintains coverage during manipulations, it should be much easier to use. The physical characteristics of the new SLR were as good as or better than current product that requires the buttress to be applied to the cartridge and anvil. In addition, the new SLR is similar in hemostasis to standard products and superior to stapling without the use of buttress. Further research is needed to determine whether these preclinical benefits carry over into a clinical setting.

Development of hyaluronan-based membranes for the healing of intestinal surgical wounds: a preliminary study

Implantable membranes based on alginate and hyaluronic acid (HA) were manufactured to obtain a rapidly resorbing pliable mesh for the in situ administration of HA to intestinal tissue. Morphological analyses of this interpenetrated matrix pointed out a homogeneous polymeric texture while degradation studies demonstrated that the material is able to dissolve in physiological solutions within few days. Biological studies in vitro showed that the membrane is biocompatible towards human dermal fibroblasts and that liquid extracts from the HA-containing membrane can stimulate wound healing. A preliminary in vivo biocompatibility study on rats showed that the membranes in direct contact with the intestine did not elicit any acute adverse reaction or immune response, while only a mild inflammatory reaction was noticed at the mesenteric or serosal region. Overall, these results appear to support the application of these polysaccharide-based materials for intestinal wound healing.

A new direction in anastomotic research: should we redesign the 'angle of sorrow'?

INTRODUCTION

Despite advances in oncological outcomes in colo-rectal surgery, rates of anastomotic leak have not improved. The precise mechanisms of anastomotic leak remain poorly understood. Current research has focused on anastomotic reinforcement to tackle anastomotic leak with little success. The 'Angle of Sorrow', the corner of the anastomosis is prone to anastomotic leak, but remains a persistent feature in the gastrointestinal anastomosis. The tendency for stress forces to concentrate in the vulnerable 'Angle of Sorrow' prompts the need for anastomotic design research.

AIM

The aim of this study is to explore if redesigning the 'Angle of Sorrow' can reduce the stress forces in the ileocolic anastomosis.

METHODS

A simulation-based experimental study compared two anastomotic designs: traditional Slit Enterotomy Anastomosis (SEA) vs a novel Radiused Enterotomy Anastomosis (REA). The finite element analysis simulations were performed using FEBIO to measure peak sheer stress in pressurised bowel.

RESULTS

Tissue stress was found to concentrate at the 'Angles of Sorrow' in traditional anastomosis design while the REA design distributed sheer stress across the anastomosis. The SEA model had greater peak sheer stress factors than REA for the hand-sewn and stapled 'Barcelona' anastomosis (1.58 (k) vs 0.64 (k), 0.91 (k) vs 0.63 (k)). The REA anastomosis resulted in significantly less peak stress across all anastomotic experiments (p = 0.0047). The mucosa of the SEA model tended to unfavourably evert.

CONCLUSION

Redesigning the 'Angle of Sorrow' decreased tissue stress concentration. The direction of future anastomotic research may involve going back to the drawing board, rather than attempting to reinforce a potentially flawed design. Despite advances in colorectal surgery, rates of anastomotic leak have not improved. The 'Angle of Sorrow', the corner of the anastomosis is prone to anastomotic leak, but remains a persistent feature in gastrointestinal anastomosis. The direction of future research may involve going back to redesign this vulnerable area.

International consensus statement regarding the use of animal models for research on anastomoses in the lower gastrointestinal tract

PURPOSE

This project aimed to reach consensus on the most appropriate animal models and outcome measures in research on anastomoses in the lower gastrointestinal tract (GIT). The physiology of anastomotic healing remains an important research topic in gastrointestinal surgery. Recent results from experimental studies are limited with regard to comparability and clinical translation.

METHODS

PubMed and EMBASE were searched for experimental studies investigating anastomotic healing in the lower GIT published between January 1, 2000 and December 31, 2014 to assess currently used models. All corresponding authors were invited for a Delphi-based analysis that consisted of two online survey rounds followed by a final online recommendation survey to reach consensus on the discussed topics.

RESULTS

Two hundred seventy-seven original articles were retrieved and 167 articles were included in the systematic review. Mice, rats, rabbits, pigs, and dogs are currently being used as animal models, with a large variety in surgical techniques and outcome measures. Forty-four corresponding authors participated in the Delphi analysis. In the first two rounds, 39/44 and 35/39 participants completed the survey. In the final meeting, 35 experts reached consensus on 76/122 items in six categories. Mouse, rat, and pig are considered appropriate animal models; rabbit and dog should be abandoned in research regarding bowel anastomoses. ARRIVE guidelines should be followed more strictly.

CONCLUSIONS

Consensus was reached on several recommendations for the use of animal models and outcome measurements in research on anastomoses of the lower GIT. Future research should take these suggestions into account to facilitate comparison and clinical translation of results.

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.

[Bursting pressure comparison between stapler and staple line reinforcement with sutures and butress biologic material: an experimental study]

BACKGROUND

Staple line leaks carry significant morbidity and mortality. Reinforcement is controversial. Several staple techniques have been described for this purpose. Oversuture and butressing material are more common.

AIM

To compare these two ways of reinforcement and staple line without any reinforcement regarding the bursting pressure.

METHOD

Ten segments of small bowel were created in a pig under general anesthesia. The bowel was inflatted until burst point and the pressure was measured.

RESULTS

The staple line bursting pressure was 94 mmHg +/- 18,52mmHg in the stapler technique; 87,5 mmHg +/- 18,59mmHg in the oversuture and 83,33 mmHg +/- 23,04mmHg with Surgisis®. There was no statistic difference among the techniques.

CONCLUSIONS

Oversuture or Surgisis® use did not increase the staple line resistance in pig.

Bovine pericardium patch wrapping intestinal anastomosis improves healing process and prevents leakage in a pig model

Failure of intestinal anastomosis is a major complication following abdominal surgery. Biological materials have been introduced as reinforcement of abdominal wall hernia in contaminated setting. An innovative application of biological patch is its use as reinforcement of gastrointestinal anastomosis. The aim of study was to verify whether the bovine pericardium patch improves the healing of anastomosis, when in vivo wrapping the suture line of pig intestinal anastomosis, avoiding leakage in the event of deliberately incomplete suture. Forty-three pigs were randomly divided: Group 1 (control, n = 14): hand-sewn ileo-ileal and colo-colic anastomosis; Group 2 (n = 14): standard anastomosis wrapped by pericardium bovine patch; Group 3 (n = 1) and 4 (n = 14): one suture was deliberately incomplete and also wrapped by patch in the last one. Intraoperative evaluation, histological, biochemical, tensiometric and electrophysiological studies of intestinal specimens were performed at 48 h, 7 and 90 days after. In groups 2 and 4, no leak, stenosis, abscess, peritonitis, mesh displacement or shrinkage were found and adhesion rate decreased compared to control. Biochemical studies showed mitochondrial function improvement in colic wrapped anastomosis. Tensiometric evaluations suggested that the patch preserves the colic contractility similar to the controls. Electrophysiological results demonstrated that the patch also improves the mucosal function restoring almost normal transport properties. Use of pericardium bovine patch as reinforcement of intestinal anastomosis is safe and effective, significantly improving the healing process. Data of prevention of acute peritonitis and leakage in cases of iatrogenic perforation of anastomoses, covered with patch, is unpublished.

Complications of colorectal anastomoses: leaks, strictures, and bleeding

Intestinal anastomosis is an essential part of surgical practice, and with it comes the inherent risk of complications including leaks, strictures, and bleeding, which result in significant morbidity and occasional mortality. Understanding the myriad of risk factors and the strength of the data helps guide a surgeon as to the safety of undertaking an operation in which a primary anastomosis is to be considered. This article reviews the risk factors, management, and outcomes associated with anastomotic complications.