title: Novel technique of overlaying a poly-L: -lactic acid nanosheet for adhesion prophylaxis and fixation of intraperitoneal onlay polypropylene mesh in a rabbit model.
abstract: BACKGROUND
  One problem with polypropylene mesh (PPM) used to repair abdominal wall hernias is dense adhesions to the visceral surface. The authors developed the biocompatible poly-L: -lactic acid (PLLA) nanosheet (thickness < 100 nm), which has the unique ability to adhere tightly to tissues but not to opposing tissues. This study investigated the antiadhesive and fixative characteristics of the PLLA nanosheet after placement of intraperitoneal onlay PPM (IPOM) overlaid with a PLLA nanosheet on intact peritoneum.
  
  
  METHODS
  The PLLA nanosheet was fabricated by the spin-coating method and peeling technique with polyvinyl alcohol (PVA) as a supporting film. Two 1.5-cm-square pieces of mesh were implanted on each peritoneal side of the midline incision. The mesh was fixed to the peritoneum with a suture and then overlaid with a 4-cm-square piece of Seprafilm or nanosheet. To examine the fixative property, mesh was overlaid with Seprafilm or nanosheet without a fixed suture. After 4 weeks, mesh adhesion, inflammatory reaction, fixation, and dislocation of mesh were evaluated.
  
  
  RESULTS
  Nanosheet-overlaid meshes were flexible and fit over the peritoneum. Adhesion was observed in 10% of the nanosheet-overlaid meshes and in 50% of the Seprafilm-overlaid meshes. The adhesion tenacity grade was significantly lower with the nanosheet-overlaid meshes (0.1 ± 0.1) than with the Seprafilm-overlaid meshes (1.0 ± 0.4) (p = 0.029), and the percentage of the adhesion area also was lower with the nanosheet-overlaid meshes (1.0 ± 1.0% vs 8.5 ± 3.2%; p = 0.037). The mean inflammatory cell counts were lower with the nanosheet-overlaid meshes (p = 0.0023). Regarding the fixative property, 37.5% of the nanosheet-overlaid meshes were fixated on the peritoneum, but no Seprafilm-overlaid mesh was fixated.
  
  
  CONCLUSIONS
  Overlaying of a PLLA nanosheet was effective for adhesion prophylaxis of intraperitoneal mesh. It also may have a possible beneficial effect on fixation of mesh.
authors.affiliation: Department of General Medicine, National Defense Medical College, Saitama, Japan. kei805@mac.com
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fujino
authors.forename: Manabu
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Akihiro
authors.initials: A
authors.lastname: Saitoh
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Yano
authors.forename: Kahoko
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Toshinori
authors.initials: T
authors.lastname: Fujie
authors.forename: Keiichi
authors.initials: K
authors.lastname: Iwaya
authors.forename: Minoru
authors.initials: M
authors.lastname: Kakihara
authors.forename: Shinji
authors.initials: S
authors.lastname: Takeoka
authors.forename: Daizoh
authors.initials: D
authors.lastname: Saitoh
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D004195:Disease Models, Animal; D046449:Hernia, Abdominal / Q000601:surgery*; D019344:Lactic Acid; D011091:Polyesters; D011108:Polymers; D011817:Rabbits; D018709:Statistics, Nonparametric; D013526:Surgical Mesh; D013536:Suture Techniques; D000267:Tissue Adhesions / Q000517:prevention & control*
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)