A PORCINE MODEL OF CROHN´S DISEASE ANASTOMOTIC STRICTURE FOR TRAINING IN ADVANCED ENDOSCOPIC TREATMENT METHODS

Aims Currently, options in post-surgical recurrence of stricturing Crohn´s disease (CD) are limited to another surgery or balloon dilation with unsatisfactory long-term effects. However, development of new invasive endoscopic techniques is hindered by safety issues with testing these methods on patients. Aim was to create a large animal model of anastomotic stricture with CD properties enabling development of new endoscopic techniques and serving as a training subject for endoscopists to familiarize themselves with these methods.

Methods A side-to-side ileo-colonic anastomosis 20 cm from anus was created in a modified Y-roux manner with bowel continuity preserved. Two weeks after surgery we started submucosal injection of 5% Phenol and 0.2% Trinitrobenzensulfonic acid solution. This solution was injected every 2 weeks in each quadrant of the anastomosis until development of a stricture. The site of anastomosis was assessed and measured endoscopically 2 weeks after the last application and then every 2 months until month 6. Subsequently, it was resected and sent for histology.

Results Nineteen minipigs (48.8 ± 8.1 kg) were included with no postoperative complications. After a mean of 4.4 ± 0.7 injections of 10.5 ± 3.0 ml of the solution the anastomotic stricture was created in 16 pigs (84.2%). Mean diameter of the stricture at baseline was 11.6 ± 2.2 mm. The strictures were macroscopically inflamed and ulcerated, not passable for the endoscope. The follow-up of 6 months was successfully finished in 15 animals (79.0%) with the mean deviation from the initial diameter in every measurement of −0.02 ± 2.26 mm (p = 0.963) and mean final diameter of 11.7 ± 3.4 mm. In one animal, the anastomosis closed 4 months in the follow-up. The histopathologic evaluation revealed presence of severe submucosal fibrosis, signs of chronic inflammation and microgranulomas like those in CD.

Conclusions We have developed reproducible porcine model of anastomotic stricture with histologically verified changes mimicking CD and stable diameter. This experimental model has proven successful in endoscopic stricturotomy hands-on training.