The effect of perioperative intraperitoneal (ip) (2 mg/kg) vs intravenous (iv) (1.5 mg/kg) mitomycin-C on healing of intestinal anastomoses was studied in rats after jejunal section and anastomosis. When the animals were killed 7 days after surgery 52.8% in the ip group had an anastomotic leak (41.2% causing death of the animals), compared to 20% in the iv group and none in the control group. Mean anastomotic bursting pressure was 156 mm Hg in the ip group, 178 mm Hg in the iv group, and 203 mm Hg in controls (P <0.01). Hydroxyproline content of the intestinal segment containing the anastomosis was 2.26 μg/mg in the ip group, 3.49 in the iv, and 4.91 in controls (ip vs controls, P <0.01). Histological examination of the anastomoses in rats given ip mitomycin showed significantly "slower" anastomotic healing than in iv rats and controls. Electron microscopy showed that the mean diameter of collagen fibers was significantly smaller (P <0.05) in ip rats (34 nm) than iv (51 nm) and controls (79 nm). An intraoperative bolus of mitomycin thus significantly impaired the healing of a jejunal anastomosis in the rat, more so after ip than iv injection. Thus in clinical practice ip adjuvant chemotherapy after surgery should perhaps be delayed until wound repair has reached an advanced stage.
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