Pneumoperitoneum impairs blood flow and augments tumor growth in the abdominal wall - An experimental study in rats

Background: Despite several clinical and experimental studies, the mechanisms behind the development of port site metastases in laparoscopic surgery have remained largely unknown. The current study was designed to investigate the effect of pneumoperitoneum on blood flow in the abdominal wall and its possible effects on tumor growth at this site. Methods: A total of 40 Wistar Fu rats had a laser Doppler probe placed on their left rectus muscle and a suspension of 50,000 adenocarcinoma cells was injected into their right rectus muscle. The experimental group (n = 20) was insufflated with air at 10 mmHg for 45 min while abdominal blood flow was registered before and during insufflation and after exsufflation. The control group (n = 20) was not insufflated but the blood flow was recorded in the same manner. After 9 days, all animals were killed and the occurrence of tumor was observed. The tumors were analyzed with respect to weight and volume. Results: The insufflation caused an 82% reduction in blood flow in the experimental group (p < 0.001). No reduction in blood flow was registered in the control group. Tumor nodules developed significantly more often in the insufflated group (20/20) compared to the controls (14/20) (p = 0.016). Tumor weight (p = 0.003) and volume (p < 0.001) were significantly increased in the insufflated group. Conclusions: Pneumoperitoneum seems to enhance tumor growth. It also causes a significant reduction in blood flow in the abdominal wall, which may contribute to the increased susceptibility of tumor take.