We have studied the application of irradiation crosslinked collagen-coated polyester mesh as a dural substitute. Earlier, the bioprostheses were characterized by in vitro measuring of physicochemical and biological properties as well as by in vivo testing on experimental animals. Further. very satisfactory effect was obtained in results on application of these bioprostheses in patients, Consequently, this work concerns mainly a delayed observation of the patients after implantation of biomaterial in repairing cerebral and spinal dura. It was found among others, that application of the bioprosthesis in the surgical treatment of dysraphic defect on central nervous system in children such as: meningocele. meningoencephalocele. meningomyelocele makes it possible to approach large hernias, disqualified for operation so far. Neither allergy nor inflammation after operation of patients with intracranial rumor in early and delayed observation was noticed. The authors suggest that the bioprosthesis could be used not only as a very satisfactory dural substitute but also as a substitute of other connective tissues.