title: Impact of pressure and gas type on adhesion formation and biomaterial integration in laparoscopy.
abstract: BACKGROUND
  Laparoscopic mesh repair of inguinal and incisional hernias has been widely adopted. Nevertheless, knowledge about the impact of pneumoperitoneum on mesh integration is rare. The present study investigates pressure and gas-dependent effects of pneumoperitoneum on adhesion formation and biomaterial integration in a standardized animal model.
  
  
  METHODS
  Laparoscopic intraperitoneal onlay mesh implantation (IPOM) was performed in 32 female chinchilla rabbits using CO(2) or helium for pneumoperitoneum. Intra-abdominal pressures were 3 or 6 mmHg. Animals were killed after 21 days, and the abdominal wall was explanted for subsequent histopathological examinations. Adhesions were assessed qualitatively with a scoring system, and the adhesion surface was analyzed semiquantitatively by planimetry. Infiltration of macrophages (CD68), expression of matrix metalloproteinase 13 (MMP-13), and cell proliferation (Ki67) were analyzed at the mesh to host interface by immunohistochemistry. The collagen type I/III ratio was analyzed by cross-polarization microscopy to determine the quality of mesh integration.
  
  
  RESULTS
  After 21 days, perifilamental infiltration with macrophages (CD68) and percentage of proliferating cells (Ki67) were highest after 6 mmHg of CO(2) pneumoperitoneum. The extent of adhesions, as well as the expression of MMP-13 and the collagen type I/III ratio, were similar between groups.
  
  
  CONCLUSIONS
  Our experiments showed no pressure or gas-dependent alterations of adhesion formation and only minor effects on biomaterial integration. Altogether, there is no evidence for a clinically negative effect of CO(2) pneumoperitoneum.
authors.affiliation: Department of Surgery, University Hospital, Pauwelsstr. 30, 52074 Aachen, Germany. rrosch@ukaachen.de
authors.forename: R
authors.initials: R
authors.lastname: Rosch
authors.forename: M
authors.initials: M
authors.lastname: Binnebösel
authors.forename: C D
authors.initials: CD
authors.lastname: Klink
authors.forename: J
authors.initials: J
authors.lastname: Otto
authors.forename: K
authors.initials: K
authors.lastname: Junge
authors.forename: U P
authors.initials: UP
authors.lastname: Neumann
mesh_terms: D034861:Abdominal Wall / Q000601:surgery*; D000818:Animals; D001672:Biocompatible Materials; D002245:Carbon Dioxide; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D005260:Female; D006371:Helium; D006552:Hernia, Inguinal / Q000601:surgery; D006555:Hernia, Ventral / Q000601:surgery; D010535:Laparoscopy / Q000009:adverse effects*; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects*; D011126:Polypropylenes; D011312:Pressure; D011817:Rabbits; D013526:Surgical Mesh; D000267:Tissue Adhesions / Q000209:etiology* / Q000378:metabolism / Q000473:pathology
chemical_list: D001672:Biocompatible Materials; D024042:Collagen Type I; D024061:Collagen Type III; D011126:Polypropylenes; D002245:Carbon Dioxide; D006371:Helium