The new adhesion prophylaxis membrane A-part--from in vitro testing to first in vivo results.

Abstract

Formation of postoperative intra-abdominal adhesions is a severe problem in surgery. Apart from standard surgical procedures, a variety of different substances is available to prevent adhesions, but no universal method has been developed so far. A membrane consisting of polyvinyl alcohol (PVA) and carboxymethylcellulose (CMC) has been demonstrated to be antiadhesive. Here, the in vitro testing and first in vivo results in a rabbit sidewall model are reported. A-part membrane contains a PVA/CMC mixture in a thickness of 40 microm. The composition, dissolution, tensile strength, and elasticity were examined to characterize the membrane in vitro. Experiments in vivo were carried out using a 'rabbit sidewall model' in which a standardized peritoneal trauma was covered with a 5 x 6 cm A-part membrane. Adhesion formation in A-part-treated animals was compared with that in Adept (15 mL/kg body weight) and untreated controls. An 80/20 PVA/CMC mixture forms a stable, elastic, transparent membrane, which can easily be placed intraoperatively. The dissolution shows a half-life of about 2 weeks [day 15: (45.1 +/- 4.9)% SD], which affords good adhesion protection during the initial critical phase of adhesion formation. In wet conditions, the membrane follows abdominal movements without tearing (tensile strength 5.0 +/- 4.2 N/cm SD; elasticity 29.5%). In a rabbit sidewall model, A-part membrane significantly reduced adhesion development by (83.1 +/- 31.5)% SD compared with the control and the Adept group (p < 0.001). The properties of the A-part membrane suggest that it may be useful as an antiadhesive in surgery. A-part is effective in in vivo testing as determined in a rabbit sidewall model.