[Development of a dural substitute for preventing prion diseases induced by grafting of freeze-dried human dura mater].

To provide a substitute for the dura mater a new bioabsorbable composite sheet was developed. This composite was composed of two L-lactic acid-epsilon-caprolactone (50:50) copolymer films and a poly (glycolic acid) nonwoven fabric. They displayed good mechanical properties and were completely absorbed 24 weeks after implantation in the back of rats. Histological evaluation of the composite sheet was undertaken by implanting it in 31 rabbits with dural defects and examining the sites of implantation 2 weeks to 26 months later. Any infection, cerebrospinal fluid leakage, evidence of convulsive disorders, significant adhesion to underlying cortex, and calcification was not noticed in any cases. In addition, the regenerated duralike tissue had a high pressure-resistant strength 2 weeks after implantation.