Page 78 - Postoperative Intra-Abdominal Adhesions- New insights in prevention and consequences

Chapter 4
irradiated bowel anastomosis in rats resulted in significantly more peri- anastomotic abscesses than were seen in non-treated controls18. Such results stress the importance of testing adhesion barriers in situations were the impairment of wound healing has severe and potentially life- threatening consequences.
One dead animal was found at day 3. The death probably was not related to the A-Part Gel, as there was dehiscence of the laparotomy, and the stitch was bitten through. Measurements of collagen showed no significant differences between PVA rats and controls after seven days, indicating this adhesion barrier does not interact with collagen synthesis during wound healing. The seventh post-operative day was chosen for collagen measurement and ABP, as collagen synthesis is greatest between the fifth and the seventh post-operative days, and anastomotic strength depends mainly on newly formed collagen 34.
This study has several weaknesses. Pre-study power analysis showed 16 animals per group to be sufficient; however a power analysis always implies some theoretical supposition. With a p-value of 0.08 a trend towards more anastomotic leakage in the study group cannot be excluded completely. Therefore, more experimental research with A-Part gel® and intestinal anastomoses is necessary. Also, the effect of the coverage of the anastomoses with adhesions is not certain. In our rodent model, we practically always see a large area of coverage of the anastomosis by adhesions on day 7, with the adhesions coming mainly from omentum attached to suture material and anastomotic edges, without anastomotic leakage. Adhesion formation in this setting may be secondary to a foreign body reaction to suture material, which differs from the response seen to bacterial soiling or blood clot. Lauder et al.35 and Silva et al36, have observed similar results: persistence of adhesions to the anastomosis in both the control group and the adhesion-barrier group. In this study, we saw coverage of the anastomosis with adhesions in both groups; therefore, whether there is an influence of these adhesions on anastomotic leakage cannot be known. In our model, no reduction of adhesions was found. However, the effect of PVA gel on adhesions
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