Preparation of a pig experimental model of defective colon anastomosis - review.

Anastomotic leak is a serious complication in colorectal surgery. The problem of intestinal anastomosis healing disorders is dealt with by a number of experimental studies, especially in applied research. The design of animal models is diverse and the results of individual studies are difficult to compare. This paper summarizes the main issues of planning animal models of intestinal anastomoses, which are discussed individually. The main part of the text is a description of the defective intestinal anastomosis model of the pig. The anastomosis is constructed in the model with a localized mucosal protrusion. The animals are monitored for 3 weeks postoperatively, the clinical condition and changes in vital values and laboratory parameters are monitored, and CT examinations are performed at defined points. At the end of the observation period, samples are taken, macroscopic findings in the abdominal cavity are evaluated, adhesions are scored, and signs of leakage or passage disorders are assessed. The preparations are evaluated histologically both by standard methods analyzing vascularity, inflammatory infiltration and the proportion of collagen, and by methods developed de novo for the needs of the experiment, such as the analysis of the integrity of the intestinal wall at the site of the mucosal protrusion. We value the experimental model for the possibility of a systematic and detailed analysis of the healing state of the anastomosis in combination with a detailed observation protocol, which produces clinically relevant results.

Permanent intravenous access in experimental surgery ­ our experience

Introduction: Permanent intravenous access is usually required in pigs used for surgical experiments, not only to enable repeated blood sample collections. The aim of this study was to evaluate the patency and complications of vascular access ports (VAP) implanted in pigs included in different surgical experiments. Methods: VAPs were implanted via the external jugular vein in a total of 211 pigs from 7 different experiments. All observed complications were retrospectively evaluated. Results: No complications were observed in 157 animals (74.4%). Complications of the least severity were edema or seroma around the port which were observed in 12 (5.7%) and 3 (1.4%) animals, respectively. Temporary problems with aspiration of blood via the port occurred in 13 animals (6.2%). The most severe complications which prevented the use of the VAP for aspiration and application were recorded in 26 animals (12.3%). These complications included: abscess formation around the port (12 animals), skin necrosis over the port (2 animals), partial wound dehiscence (2 animals) and loss of the VAP function due to an unspecified cause (10 animals). Removal of the VAP was not needed in any of the animals and none of the animals had to be excluded from the experiment due to the complications. The VAP can also be used for safe administration of iodine contrast agent during CT examination. Conclusion: Despite the observed complications the VAP is suitable as permanent intravenous access in pigs used for surgical experiments. This method helps to minimize the stress of the animals in the postoperative period and to reduce the number of experimental animals.