Poly(vinyl alcohol) membranes for adhesion prevention

Abstract

The abnormal joining of anatomic structures after abdominal and pelvic surgery can lead to such major complications as bowel obstruction or infertility. Poly(vinyl alcohol) (PVA) membranes and hydrogels were placed over the injured tissue to act as a physical barrier and prevent such adhesions from occurring in a rabbit sidewall model. The membranes were sutured into place to prevent their slipping or curling on the moist tissue. Various in vitro experiments (including testing for swelling and mechanical strength) were conducted in order to better understand the behavior of these membranes in the wound. The results showed that both the PVA membranes and PVA hydrogels significantly reduced the number and severity of adhesions in the rabbit sidewall model, and even indicated a distinct improvement over SEPRAFILM as antiadhesion barriers. Contact-angle measurements were taken in order to evaluate the surface properties of the membranes and hydrogels. Three approaches were taken to render the membranes more bioadhesive, and forego the need for future additional suturing: imprinting a texture onto the membrane, coating the membrane with carboxy methyl cellulose (CMC), and producing bi-layered, porous PVA membranes through a process of lyophilization. Though the surface of the PVA hydrogels is more hydrophilic than the surface of the PVA membranes, neither would adhere untreated to moist tissue. However, all three approaches aimed at improving their bioadhesion yielded excellent results and demonstrated that PVA could indeed be considered a viable method of adhesion prevention.

Novel technique of overlaying a poly-l-lactic acid nanosheet for adhesion prophylaxis and fixation of intraperitoneal onlay polypropylene mesh in a rabbit model

“…As an antiadhesive material, findings have shown Seprafilm to be highly effective in reducing both the incidence and severity of adhesion formation to midline abdominal closures in humans [18]. Although Seprafilm is highly effective in preventing adhesions to the PPM [19,23], its adhesional barrier provides definite but incomplete inhibition of visceral adhesions to the PPM [20,21].…”

The new adhesion prophylaxis membrane A‐part®—From in vitro testing to first in vivo results

“…25 No adhesions could be detected in 75% of the rabbits treated with A-part 1 . In our setup Adept 1 showed no effect as an antiadhesive prophylaxis agent.…”

Barriers to Prevent Tissue Adhesion

“…A-Part ® gel is a bioabsorbable transparent gel composed of PVA and CMC [ 25 ] . Material characteristics such as viscosity and adherence to the wound were tested with good results [ 26,27 ] . Preclinical data in animal studies revealed high effi cacy in adhesion prevention, and wound and anastomosis healing were not negatively affected by the application of this gel in animal models.…”