Comparison of polydioxanone and silicone plastic in the prevention of adhesive otitis media in the Mongolian gerbil.

Adhesion of the tympanic membrane to the promontory may occur in chronic otitis media or in the postoperative ear. Silicone plastic sheets are commonly used to form a physical barrier to adhesion. These sheets are generally well tolerated, but they are subject to occasional extrusion, encapsulation, or foreign body reaction. The ideal barrier to adhesion formation would be a nonreactive, flexible, absorbable substance that would obviate long-term toxicity considerations. In this study polydioxanone sheets were compared with silicone plastic sheets in the middle ear of the Mongolian gerbil. The eustachian tube was cauterized to create severe tympanic membrane retraction. A fabricated sheet of polydioxanone was implanted in the middle ear of 30 Mongolian gerbils and compared with silicone plastic sheets implanted in another group of 30 animals. A sham operation was performed on the other ear to serve as a surgical control. Evaluation of the temporal bones at 5, 10, and 15 weeks showed no significant differences in the rate of adhesion formation, effusion formation, or polymorphonuclear infiltration by the Fisher exact test. There was histologic evidence that polydioxanone was still providing an effective barrier at 10 weeks. The results of this study demonstrate that polydioxanone sheets are as effective and as well tolerated as silicone plastic sheets in an animal model. Further study of polydioxanone in this role is warranted.