[Ion-beam irradiated ePTFE for an artificial dura mater]

Expanded polytetrafluoroethylene (ePTFE) is a stable polymer and widely used as a prosthesis because of its chemical inertness. However, ePTFE as an artificial dura mater is often associated with postoperative leakage of the cerebrospinal fluid (CSF) due to its very low adhesiveness to fibrin glue and surrounding tissue. The surfaces of ePTFE were modified by ion-beam irradiation in order to improve tissue adhesiveness. The morphological changes of ePTFE that was irradiated with 150 keV-He+, Net, Ar+ and Kr+ ions applied at a rate of 1 x 10(14), 5 x 10(14) and 1 x 10(15) ions/cm2 were examined with scanning electron microscopy. Next, surrounding tissue reactions to the implanted ePTFE into the rabbit calvarial defects were analyzed at intervals from 1 week up to 1 month. The micromesh structures of the ePTFE were destroyed by ion-beam irradiation, and the depth and width of the gaps increased with heavy particle ion and irradiated fluence. In an implantation study using experimental rabbits, a dura defect was patched with four types of ion-beam irradiated ePTFE with different in irradiation fluence. A CSF leakage was observed in the rabbit covered with non-irradiated ePTFE, but, CSF leakage did not occur in any of the rabbits covered with ion-beam irradiated ePTFE that adhered in a water-tight manner to surrounding tissues. Histological study indicated that fibroblast-like cells had infiltrated and anchored the gaps in the ion-beam irradiated ePTFE. Ar+ or Kr+ with 1 x 10(15) ions/cm2 irradiated ePTFE had the highest adhesiveness and produced the best healing of dura defects.