Improved abdominal wall wound healing by helium pneumoperitoneum.

Background: Despite widespread use of the endoscopic technique in the treatment of inguinal and incisional hernias, knowledge about its impact on abdominal wall wound healing is rare. Questions remain regarding the risk of port-site hernias and hernia recurrence. The current study investigated the gas-dependent effects of pneumoperitoneum on laparotomy wound healing.

Methods: Laparotomy was performed in 54 male Sprague-Dawley rats. A carbon dioxide (n = 18) or helium (n = 18) pneumoperitoneum of 3 mmHg was maintained before and after laparotomy, with an overall duration of 30 min. The rats in the control group (n = 18) received no pneumoperitoneum. The animals were killed after 5 and 10 days, and the abdominal wall was explanted for subsequent histopathologic examinations of the laparotomy wound. The granuloma formation in hematoxylin and eosin-stained sections was analyzed. Infiltration of macrophages (CD68) and expression of matrix metalloproteinases (MMP-8 and MMP-13) were examined by immunohistochemistry. The collagen type 1 to type 3 ratio was investigated by cross-polarization microscopy after Sirius Red staining.

Results: After 5 and 10 days, the percentages of CD68-positive cells, granuloma formation, and expression of MMP-8 did not differ between the groups. In contrast, after both 5 and 10 days, the expression of MMP-13 and the collagen 1 to 3 ratio were significantly higher after helium pneumoperitoneum than in the control animals.

Conclusion: The results suggest that helium pneumoperitoneum may ameliorate wound healing within the abdominal wall and could therefore represent a beneficial gas for endoscopic hernia repair.