Histologic study of peritoneal adhesions in children and in a rat model

Peritoneal adhesions (PA) represent a major cause of morbidity in pediatric surgical patients. The pathogenesis is still largely unknown. A possible role could be played by foreign bodies (FB) accidentally contaminating the operative field during surgery. We report a histologic study of PA in a rat model and in children, investigating the role of FB in their formation. Abdominal adhesions were studied in 18 rats. In 6 (group A) we performed a laparotomy and rubbed the visceral and parietal peritoneum with a cotton bud. In 6 (group B) we performed a minimal laparotomy and injected powdered autologous and heterologous material into the peritoneal cavity, avoiding any peritoneal abrasions. In 6 (group C) we performed a laparotomy and applied both treatment methods, i.e., rubbing and injection of FB. After 1 month, at autopsy rats were classified according to the presence and grade of surgical adhesions. Twenty-two PA were also collected from seven children undergoing abdominal surgery in whom one or more procedures had been previously performed. The adhesions were stained with hematoxylin-eosin and Giemsa stains for histologic examination. Adhesions were found in 4 rats of group A and all 6 rats of group C. None were identified in group B. Group C rats showed a higher grade of adhesions with respect to group A. In both humans and animals PA were always found to coexist with microscopic particles of solid substances, which were incorporated inside the connective tissue. However, after simple injection of FB into the abdominal cavity we did not observe any PA. These data suggest that two different stimuli are necessary for adhesion formation: a direct lesion of the mesothelial layers and a solid substrate (FB). We underline the importance of reducing contamination with FB during surgery. On the basis of these considerations, the laparoscopic approach seems to be particularly pertinent.