Abstract: The self-sealing tissue expander includes inner and outer layers of relatively nonflowable material and a median layer of flowable material. The median layer of flowable material which can include one or more sublayers of flowable material is under a predetermined compression imposed by the inner and outer layers due to a prestressing of the tissue expander shell during formation of the tissue expander. The self-sealing shell seals an opening in the shell wall following removal of an infusion needle. In all embodiments of the invention a needle stop member is provided to prevent the needle that accesses the fluid chamber from passing outwardly of the tissue expander. The need for a septum, a fluid conduit or a special fluid entry opening in the tissue expander shell is thus optional. The shell can also be made relatively more stretchable in some areas than in other areas.

Abstract: The tissue expander includes a closed shell structure having a shell wall formed of a needle-penetrable material with self-sealing characteristics. The shell defines a fluid expandable chamber. In some embodiments of the invention, a self-sealing layer of elastomeric material is joined or otherwise bonded to an inner surface of a non-flowable layer of elastomeric material. In other embodiments of the invention, the self-sealing layer is joined to the outer surface of a layer of non-flowable elastomeric material. The self-sealing layer may also be sandwiched between two layers of non-flowable elastomeric material. In a further embodiment the self-sealing layer constitutes the entire shell of the tissue expander. In all embodiments of the invention, a needle stop member is provided to prevent a needle that accesses the fluid chamber from passing outwardly of the tissue expander in the same direction in which it has accessed the fluid chamber.

Abstract: The self-sealing tissue expander includes inner and outer layers of relatively nonflowable material and a median layer of flowable material, The median layer of flowable material which can include one or more sublayers of flowable material is under a predetermined compression imposed by the inner and outer layers due to a prestressing of the tissue expander shell during formation of the tissue expander. The self-sealing shell seals an opening in the shell wall following removal of an infusion needle. In all embodiments of the invention a needle stop member is provided to prevent the needle that accesses the fluid chamber from passing outwardly of the tissue expander. The need for a septum, a fluid conduit or a special fluid entry opening in the tissue expander shell is thus optional. The shell can also be made relatively more stretchable in some areas than in other areas.

Abstract: A ureteral stent has a main body that is soft and flexible and a proximal hook portion which is stiffer to minimize expulsion from the kidney.

Abstract: An implantable fluid transfer device or septum which includes a hollow spherical housing containing a chamber therein for receiving fluid. A needle infuses fluid into or withdraws fluid from the chamber. The housing has a surface that is capable of both omni-directional penetration by the needle and sealing itself when the needle is withdrawn from the housing. A spherical needle stop is provided with the housing to prevent the needle that accesses the chamber from one side of the housing from passing through the opposite side of the housing.

Abstract: A process for preparing polyurethanes comprising reacting a polyol with an organic polyisocyanate in the presence of a catalytic amount of nickel acetylacetonate, wherein the polyol and nickel acetylacetonates are held at elevated temperatures prior to being mixed with the polyisocyanate.

Abstract: Method of preparing polyurethane composite mold by injecting a composite reaction mixture onto a master form in a mold cavity, curing said reaction composite and removing it from the master form in a step-wise process involving a pressure manipulation. Said composite comprises 100 parts by weight inorganic water insoluble inert granular material and about 50 to about 200 parts by weight liquid polyurethane reaction mixture substantially free of volatile solvents.