Correlation Between Peritonitis and Incisional Infections in Horses.

This research paper investigates the link between peritonitis and wound infection in horses following abdominal surgery. It suggests that surgical site infection may be a symptom of peritonitis, and that infected wounds may heal in a way that increases the chance of hernia formation.

Overview of the Study

• The study sought to examine how abdominal surgical wounds healed and if there was a correlation between peritonitis—an inflammation of the peritoneum, the tissue that lines the inner wall of the abdomen—and the occurrence of wound infections and hernias.
• A group of nine horses underwent a standardized laparotomy procedure (a surgical incision into the abdominal cavity) which included intestinal exploration and induced septic peritonitis. A repeat procedure known as relaparotomy was performed on these horses at two, four, and six months intervals.

Findings and Observations

• All horses exhibited signs of endotoxemia (the presence of endotoxins in the blood), controllable peritonitis, a heat and touch-sensitive swelling of the belly and an infection of the surgical wound with purulent discharge.
• Physical observations during subsequent procedures indicated that parts of the large intestine attached to the inner part of the surgical wound.
• It was noted that healing of the infected surgical wounds occurred by secondary intention, meaning the wound healed from the inner layer to the surface layer, thereby leaving a gap between the rectus abdominis muscles. It was observed that this gap, which was filled by scar tissue, contributed to the formation of an incisional hernia—an abnormal bulge that can form at the site of a surgical incision.

Further Analysis and Conclusions

• On further analysis of the healed surgical site, researchers found that as time progressed the collagen content of the wound increased, implying a strengthening of the tissue, while the inflammation decreased.
• The wound’s tensile strength, which refers to the resistance of a material to breaking under tension, also increased over time, with the highest strength observed after six months.
• Interestingly, it was found that after the second surgical procedure there was no infection observed in any of the surgical wounds in the horses, and they healed by primary intention—the wound edges directly connected and healed with minimal scar formation.
• Given these findings, the study concluded that a surgical site infection might be indicative of peritonitis in horses recovering from abdominal surgery. Furthermore, it was deduced that when surgical wounds become infected, the healing process alters—resulting in secondary intention healing—which may lead to the formation of incisional hernias.