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The cytotoxic and immunosuppressive effects of azathioprine, which mitigate the disease activity in inflammatory bowel disease, may compromise the healing of intestinal anastomoses leading to an increased risk of anastomotic leakage. The effect of azathioprine treatment on intestinal healing was tested. In an experimental study, rats were randomly given one oral dose of azathioprine (5 mg or 20 mg/kg body weight per day) or placebo. After 28 days of treatment, a left colonic anastomosis was performed. After three days of healing, the breaking strengths of the anastomoses were tested, along with measurements of azathioprine major metabolite concentrations: 6-thioguanine and 6-methyl-mercaptopurine. There were no significant differences in the anastomotic breaking strength between the three groups. Daily treatment for four weeks with high or low azathioprine doses has no inhibitory effect on colonic healing in rats. [ABSTRACT FROM AUTHOR]

PURPOSE: Magnetic fields have been shown to affect biologic processes. Accordingly, an experimental study was designed to investigate the effect of electromagnetic field stimulation on intestinal healing and to compare small and large intestinal anastomoses. METHODS: An ileal or a colonic anastomosis was constructed in rats. Beginning the day after surgery, randomly assigned groups were exposed to sinusoidal electromagnetic field stimulation of 10.76-mT intensity and 50-Hz frequency, with 2-hour-on/10-hour-off cycles. After seven days, intestinal anastomoses were assessed for hydroxyproline content and breaking strength. Statistical comparison between each experimental and control group yielded significance (P < 0.05) in all cases. RESULTS: Hydroxyproline content increased significantly in ileum from 1.650 ± 0.11 (mean ± standard error of the mean) to 2.036 ± 0.11 µg/mg (P = 0.0249) and in colon from 1.526 ± 0.11 to 1.922 ± 0.11 µg/mg (P = 0.0135). Breaking strength also increased significantly in ileum from 0.213 ± 0.01 to 0.255 ± 0.01 MPa (P = 0.001) and in colon from 0.227 ± 0.01 to 0.270 ± 0.01 MPa (P = 0.006). CONCLUSIONS: Electromagnetic field stimulation provided a significant gain in anastomotic healing in both small and large intestine. There were no apparent differences detected between the healing of small and large intestinal anastomoses except for slight differences in the time sequences of events and magnitude. The study demonstrated a significant increase in both biochemical and mechanical parameters. Additional investigations are needed to determine optimal conditions and promote selective biologic responses. [ABSTRACT FROM AUTHOR]

Anastomotic breaking strength and collagen metabolism in the colonic wall were studied after resection of a standardized left-colon stenosis in the rat. An increased complication rate was found in the stenosis group compared with the control group (27 percent us. 2 percent) and the complications arise soon after surgery. The collagen turnover in the anastomotic area, as well as the changes of breaking strength, were equal between the groups in the early healing course, implying that the stenosis group, as an entity, did not show impairment in the studied parameters predisposing for complications. Other factors such as mechanical strain by the increased fecal bulk and increased bacterial load may contribute to occurrence of the anastomotic complications. [ABSTRACT FROM AUTHOR]

In spite of modern suture materials and different techniques in colonic anastomoses after resection, leakage is still the most feared complication in colonic surgery. In female pigs of Swedish land breed, standardized 5-cm long colonic resection was performed 10 cm above the peritoneal deflection, usign either a single layer of Gambee-stitches (n=6, Vicryl® 4-0), two-layer interrupted stitches (n=6, Vicryl® 4-0) or the intraluminal stapling device (n=6, ILS Ethicon®). After one week, the animals were sacrificed and an anastomotic index was calculated usingin vitro x-ray. Also, anastomotic circulation (calculated by the microsphere technique), breaking strength, and histologic evaluation were performed. All animals survived and no leakage was observed. The time to perform, the anastomosis was significantly shorter (P<0.05) for the stapling device compared with the manual techniques used. The anastomotic index was lower (P<0.05) for two rows (0.24) compared with Gambee-stitches (0.38) or stapler anastomoses (0.37). There were no differences in blood flow among the three groups and no differences in breaking strength. Macroscopic investigation revealed mucosal defects in two of the stapled anastomoses and histologic investigation showed small areas of necrosis. The stapling device did not induce any inflammatory reaction. On the other hand, a severe inflammatory reaction was seen when using conventional suture materials. In conclusion, this study shows that a single row of Gambee-stitches is equal to the ILS stapling device when performing colonic anastomoses and these two methods seem to be superior to the two-layer technique. [ABSTRACT FROM AUTHOR]

The reason for the higher leakage frequency after low anterior resection compared with high resection is unexplained. With the development of stapling devices, we have a unique opportunity to investigate anastomotic healing during standardized conditions. In female pigs, six in each group, a high anterior resection was performed by resection of a 5-cm colon segment, 10 cm above the peritoneal fold, and low anterior resection was performed after resection of a 5-cm segment at the peritoneal fold and downward. Differences in healing parameters,i.e., blood flow, breaking strength, and radiologic and histologic appearance between low and high anterior resection, were evaluated. Two leakages occurred after low and none after high anterior resection. The anastomotic index was 0.37 (high) and 0.26 (low) (P<0.05). The breaking strength was higher in low resections; this might be due to the thicker wall. There were no differences in blood circulation between high and low anastomoses, but the blood flow was significantly higher in the anastomotic area in both groups. This is probably due to the inflammatory reaction taking place in the healing anastomoses. This study, performed in a standardized fashion with a stapler adjusted to wall thickness and size of the intestine, cannot, on the basis of microcirculation, explain why leakage is more common in lower anastomoses. [ABSTRACT FROM AUTHOR]