Development and in vivo Assessment of a Rapidly Collapsible Anastomotic Guide for Use in Anastomosis of the Small Intestine: A Pilot Study Using a Swine Model

The comparison of anastomosis strength and leakage between double-layer full-thickness and single-layer extramucosal intestine anastomosis

Various intestine anastomosis techniques have been studied and used, but which is best is still debated. In our center, double-layer full-thickness intestine anastomosis was still considered as standard. However, a single-layer extramucosal intestine anastomosis has shown favorable results. This study created an anastomotic model to compare the anastomosis strength and leakage between double-layer full-thickness and single-layer extramucosal intestine anastomosis.

METHODS

This experimental study was performed in 20 randomized healthy male pigs, to be included either in Group A (Single-layer extramucosal intestine anastomosis) or Group B (Double-layer full-thickness intestine anastomosis). Enterotomy followed by an end-to-end anastomosis suture was performed in the jejunum. Fourteen days after the operation, any anastomosis leakage and its location was documented. The anastomosis strength was evaluated using manometry. Data were compared between groups using the Mann-Whitney U and Fischer Exact test, considering a significance level of P<0.05.

RESULTS

The overall mean intraluminal anastomotic bursting pressure was 4,257±1,185. Group A had a higher intraluminal anastomotic bursting pressure but was not statistically significant compared to group B (4.726±0.952 vs. 3.787±1.252 kilopascals, P=0.063). One leakage (5%, antimesenteric area) occurred in Group A and three leakages (15%, antimesenteric and mesenteric area) occurred in Group B. However, statistical analysis with Fischer exact showed no significant difference of leakage rate between those groups (P=0.291).

CONCLUSIONS

The anastomosis strength and leakage did not differ significantly between the single-layer extramucosal intestine anastomosis group and the double-layer full-thickness anastomosis group. However, the location of leakage was most common in the antimesenteric area in the double-layer full-thickness anastomosis group.

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.

Development of a polymeric biomedical device platform with controlled disassembly and in vivo testing in a swine intestinal model

The aim of this study was to create a surgical guide platform that maintains its integrity while the surgeon performs an intestinal anastomosis or another similar procedure, which then breaks apart and is eliminated from the body in a controlled manner. The device contains mixed polymeric structures that give it a controlled rate of disassembly that could meet the requirements of a specific surgical purpose. The intraluminal anastomotic guide was manufactured as a hollow cylinder composed of layers of porous polyurethane/PCL with polyvinylpyrrolidone as the binding agent similar to a "brick-mortar" architecture. This combination of polymeric structures is a promising manufacturing method from which a variety of tunable devices can be fabricated for specific medical procedures and site-specific indications. The guide was designed to rapidly disassemble within the intestinal lumen after use, reliably degrading while maintaining sufficient mechanical rigidity and stability to support manipulation during complex surgical procedures. The nature of the device's disassembly makes it suitable for use in hollow structures that discharge their contents, resulting in their elimination from the body. A swine model of intestinal anastomosis was utilized to validate the use and function of the device.

Evaluation of a bone filler scaffold for local antibiotic delivery to prevent Staphylococcus aureus infection in a contaminated bone defect

We previously reported the development of an osteogenic bone filler scaffold consisting of degradable polyurethane, hydroxyapatite, and decellularized bovine bone particles. The current study was aimed at evaluating the use of this scaffold as a means of local antibiotic delivery to prevent infection in a bone defect contaminated with Staphylococcus aureus. We evaluated two scaffold formulations with the same component ratios but differing overall porosity and surface area. Studies with vancomycin, daptomycin, and gentamicin confirmed that antibiotic uptake was concentration dependent and that increased porosity correlated with increased uptake and prolonged antibiotic release. We also demonstrate that vancomycin can be passively loaded into either formulation in sufficient concentration to prevent infection in a rabbit model of a contaminated segmental bone defect. Moreover, even in those few cases in which complete eradication was not achieved, the number of viable bacteria in the bone was significantly reduced by treatment and there was no radiographic evidence of osteomyelitis. Radiographs and microcomputed tomography (µCT) analysis from the in vivo studies also suggested that the addition of vancomycin did not have any significant effect on the scaffold itself. These results demonstrate the potential utility of our bone regeneration scaffold for local antibiotic delivery to prevent infection in contaminated bone defects.