Abstract: An apparatus for mixing dry and liquid components is used to form a setting paste. A holder is mounted on the apparatus for reciprocating movement with respect to a base of the apparatus. The movement has an amplitude with components in first and second perpendicular directions. A drive system is operatively connected to the holder for imparting said reciprocating movement to said holder at a predetermined number of cycles per minute. A container having a mass of said dry and liquid components therein is mounted in the holder. The mass, amplitude and cycles per minute of reciprocation being chosen to produce an energy input of at least about 3×10−3 Joules per second per 3 cc of mixture.

Abstract: A method for controlling the formation of a hydroxyapatite bone filler from dry calcium phosphate precursors in an aqueous solution uses coated sodium phosphate powder. The sodium phosphate powder is coated with a water soluble cellulose. Until the calcium dissolves in the aqueous solution setting of the cellulose phosphate cements proceeds slowly but when the exposed sodium phosphate particles start to solubilize in the aqueous solution the setting rate increases.

Abstract: An apparatus for mixing dry and liquid components is used to form a setting paste. A holder is mounted on the apparatus for reciprocating movement with respect to a base of the apparatus. The movement has an amplitude with components in first and second perpendicular directions. A drive system is operatively connected to the holder for imparting said reciprocating movement to said holder at a predetermined number of cycles per minute. A container having a mass of said dry and liquid components therein is mounted in the holder. The mass, amplitude and cycles per minute of reciprocation being chosen to produce an energy input of at least about 3×10−3 Joules per second per 3 cc of mixture.

Abstract: An apparatus and method for mixing a liquid component and a powdered component to form a bone filler has first and second syringes each having a barrel, a plunger and an exit port. The plunger is moveable with the barrel of each syringe along a longitudinal axis of the barrel. An end portion of each plunger extends beyond the end of each barrel when the plunger tip is spaced from the exit port and can be activated to move the plunger tip toward the exit port. A mechanism for mixing the liquid and powdered components is operatively connected to each of the barrels and plunger of the first and second syringes so that the relative sliding movement of first and second parts of the mechanism simultaneously moves the plungers and barrels of the first and second syringes relative to one another to move the combined liquid and powdered components back and forth between the first and second syringe.

Abstract: An article for use in the preparation of a hydrogel prosthetic nucleus, for an intervertebral disc, having equilibrium water contents (EWCs) of from about 30 to about 90% and compressive strengths of at least 4 meganewtons per square meter (MNm−2), at their EWCs, when subjected to the same constraints as the normal nucleus, comprising one or more xerogel rods containing from zero to less than the EWC.

Abstract: An article for use in the preparation of a hydrogel prosthetic nucleus, for an intervertebral disc, having equilibrium water contents (EWCs) of from about 30 to about 90% and compressive strengths of at least 4 meganewtons per square meter (MNm.sup.-2), at their EWCs, when subjected to the same constraints as the normal nucleus, comprising one or more xerogel rods containing from zero to less than the EWC. A method for preparing a hydrogel prosthetic nucleus, for a vertebral disc, comprising one or more hydrogel rods containing from about 30 to about 90% water, and having compressive strengths of at least 1 MNm.sup.-2, at their EWCs, which comprises inserting one or more hydrophilic xerogel rods, which at their EWC will contain from about 30 to about 90% water and have compressive strengths of at least 1 MNm.sup.

Abstract: A femoral hip component for use in hip arthroplasty has a stem portion for contact with bone cement. The stem portion is formed from a biocompatible material having a surface finish of less than about four microinches. This surface is coated with a uniform layer of material selected from the group consisting of diamond-like carbon, chromium carbide, titanium nitride, titanium carbo-nitride, chromium and zirconium and a combination thereof.

Abstract: A method and apparatus for injecting an elastic spinal implant into a cavity in a spinal disc so as to treat disc degeneration are given. The method and apparatus can be used in a variety of surgical approaches with respect to the patient. An elastic spinal nucleus prosthesis is very quickly inserted into the cavity through a small opening in the disc so that permanent deformation of the prosthesis is avoided.

Abstract: A femoral hip component for use in hip arthroplasty has a stem portion for contact with bone cement. The stem portion is formed from a biocompatible material having a surface finish of less than about four microinches. This surface is coated with a uniform layer of material selected from the group consisting of diamond-like carbon, chromium carbide, titanium nitride, titanium carbo-nitride, chromium and zirconium and a combination thereof.

Abstract: A prosthetic nucleus for a vertebral disc is made of a hydrogel material. The hydrogel prosthetic nucleus has a shape generally conforming to the natural nucleus pulposus, and it exhibits diminished lateral bulging under high compressive loads. The hydrogel has a water content of from 30% to 90% and has a compressive strength of 4 MNm.sup.-2 or greater. When the hydrogel material is dehydrated, it has a dimension of less than half of that of the hydrated hydrogel nucleus. The prosthetic nucleus may be formed of two or more pieces of hydrogel material which pieces, when combined, have a shape generally conforming to the natural nucleus. The prosthetic nucleus may have a stiff posterior periphery and/or a thickened anterior wall.

Abstract: A method of modifying salts of alginic acid in situ for prevention and treatment of various intra-articular and extra-articular (spine) complications modifies the alginate in situ to an insoluble gel. This in situ modification provides a final product which can be compressed within the intra-articular space thus remaining localized. The modified material can have varied mechanical strengths and thus varied degradation times and can serve as a matrix for localizing and slowly releasing therapeutic agents. The modified material is biocompatible and biodegradable, thus requiring no reoperation for removal.

Abstract: An implantable material for promoting bone growth has a microporous structure exhibiting an average pore size of at least 30 .ANG.. The porous biomaterial is capable of retaining macromolecules having a molecular weight of at least 15,000 and up to 500,000.

Abstract: A bone cement is disclosed wherein the liquid component contains a therapeutic or diagnostic substance in combination with an emulsifying agent for said substance.

Abstract: A prosthetic nucleus for implantation in the disc space after removal of a damaged or degenerated nucleus is formed from a multiplicity of hydrogel beads having a water content of at least 30%. The beads are covered by a semi-permeable membrane. The membrane has porosity less than the size of the beads to thereby retain the beads therein but permit fluids to flow in and out of the prosthetic nucleus.

Abstract: A bone cement is disclosed wherein the liquid component contains a therapeutic or diagnostic substance in combination with an emulsifying agent for said substance.

Abstract: A method for preventing adhesion between vital tissues includes the step of placing between the tissues a material made up of biodegradable derivatives of chitin which are soluble in aqueous solutions containing dilute acids such as acetic acid. This material has the advantage of requiring no reoperation for its removal since it would be degraded and absorbed after completing its function in vivo. These materials may be in the form of a visco-elastic fluid, a gel, a film or a membrane.

Abstract: A prosthetic nucleus for a vertebral disc is made of a hydrogel material. The hydrogel prosthetic nucleus has a shape generally conforming to the natural nucleus pulposus. The hydrogel has a water content of at least 30% and has a compressive strength of 4MNm.sup.-2 or greater. When the hydrogel material is dehydrated, it has a dimension of less than half of that of the hydrated hydrogel nucleus. The prosthetic nucleus may be formed of two or more pieces of hydrogel material which pieces, when combined, have a shape generally conforming to the natural nucleus.

Abstract: A method for preventing adhesion utilizes a viscoelastic gel formed from xanthan gum. The gel is more viscous than blood and is soluble in aqueous solutions. The gel is placed between the tissues by a syringe. The method includes mixing the xanthan gum with either a saline solution or Tyrode's solution to form the gel.

Abstract: A bone cement is disclosed wherein the liquid component contains a therapeutic or diagnostic substance in combination with an emulsifying agent for said substance.