Effects of increased intra-abdominal pressure on the healing process after surgical stapling of the stomach of dogs

Purpose: To assess the initial healing after surgical stapling of the stomach using a linear cutting stapler and creating pneumoperitoneum (12-14 mmHg) for 60 minutes or 120 minutes, and compare it with the healing of a staple line not submitted to increased pressure. Methods: A total of 30 dogs were divided into three groups of 10 animals each: Group I (control group - surgical stapling), Group II (surgical stapling, and increased intra-abdominal pressure for 60 minutes) and Group III (surgical stapling and increased intra-abdominal pressure for 120 minutes). All dogs were maintained under general anesthesia for two hours after surgical stapling. Seven days after surgery, the area around the staple line was macroscopically and microscopically examined. Results: The macroscopic examination of the samples (n = 30) did not show dehiscence, fistula or abscess. Adhesions between the omentum and the staple line were observed in all animals of Groups II and III (n = 20), which were significantly different from Group I (p = 0.008*). The histopathological analysis showed normal healing up to day 7 in the control animals (n = 10). When these results were compared with those of Groups II and III (n = 20), non-parametric tests revealed that there was a significant difference with regard to certain parameters of the early stages of healing, such as fibroblast migration (p = 0.0II*), edema (p < 0.001*) and congestion (p = 0.0II*). These alterations affected reepithelization (p < 0.001*), and consequently the late stages of healing. Conclusions: Each group showed different healing stages, and the healing process was delayed in the groups submitted to increased pressure,, especially in the group submitted to increased pressure for longer time.