Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
  • A61L27/52—Hydrogels or hydrocolloids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/44—Joints for the spine, e.g. vertebrae, spinal discs
  • A61F2/441—Joints for the spine, e.g. vertebrae, spinal discs made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/44—Joints for the spine, e.g. vertebrae, spinal discs
  • A61F2/442—Intervertebral or spinal discs, e.g. resilient
  • A61F2002/444—Intervertebral or spinal discs, e.g. resilient for replacing the nucleus pulposus

Definitions

• the present invention relates to methods and apparatus for replacing or supplementing the natural nucleus pulposus of the intervertebral disc, and more particularly to an expandable or inflatable balloon prosthesis made from a hydrogel for replacing or supplementing the nucleus pulposus.
• the human intervertebral disc is comprised of two major structures, an inner gelatinous structure (i.e., the nucleus pulposus) and an outer tendinous structure (i.e., the annulus fibrosus). Degeneration of the nucleus can lead to disc degradation and loss of function. Thus, another surgical option for the relief of lower back pain is replacement of the nucleus while leaving the annulus intact.
• an inner gelatinous structure i.e., the nucleus pulposus
• an outer tendinous structure i.e., the annulus fibrosus
• a biocompatible material which may be a liquid, a gel, or the like, can relieve pain, restore healthy physiologic function to the disc, and/or prevent additional wear on the annulus.
• the invention of this application addresses the many problems relating to confinement of gels, liquids, or the like, introduced into the region of the nucleus pulposus.
• a hollow expandable or inflatable vessel made from a hydrogel is inserted into the nucleus pulposus region of an intervertebral disk, optionally after a portion or the entirety of the natural nucleus pulposus has been removed, and the vessel is then expanded by introducing a gel, liquid, or the like, to provide an intradiscal structure that supplements or replaces the natural nucleus pulposus.
• one aspect of the invention is to provide a structure for replacing or supplementing the natural nucleus pulposus of an intervertebral disc.
• a further aspect is to provide a structure that can confine an injected liquid but which can also expand and deform to completely fill a cavity within an intervertebral disk.
• a further aspect is to provide an expandable structure, such as a balloon, that is made of a biocompatible polymer.
• a further aspect is to provide an expandable structure, such as a balloon, that is made of a hydrogel containing poly(vinyl alcohol) or a mixture of associating polymers containing poly (vinyl alcohol).
• a further aspect is to provide an expandable structure, such as a balloon, that is made of a hydrogel containing poly(vinyl alcohol), or a mixture of associating polymers containing poly(vinyl alcohol), that can be formed by a process of dip-coating a mandrel.
• a further aspect is to provide an expandable structure, such as a balloon, that is made of a hydrogel containing poly(vinyl alcohol) or a mixture of associating polymers containing poly (vinyl alcohol).
• a further aspect is to provide a method for replacing or supplementing a nucleus pulposus of an intervertebral disk by inserting a flexible-walled container or balloon made from a hydrogel into the nucleus pulposus region of the intervertebral disk by a minimally invasive surgical procedure and subsequently expanding the container or balloon by introducing a material having properties appropriate for replacing or supplementing a natural nucleus pulposus.
• Figure 1 shows an expandable hollow prosthesis of one embodiment of the invention.
• Figure 2 shows a cross-section of the prosthesis of Figure 1 taken along the line 2-2 in Figure 1.
• Figure 3 shows a plan view of another embodiment of the prosthesis of one embodiment of the invention wherein the expandable container is molded generally in the shape of a natural nucleus pulposus.
• Figure 4 shows an elevation view of the prosthesis of Figure 3 in the direction indicated by the arrows 4-4 in Figure 3.
• Figure 5 shows a cross-section of the prosthesis of Figures 3 and 4 taken along the line 5-5 in Figure 3.
• Figure 6 shows a schematic cross-section of a spinal motion segment showing a tubular insertion instrument with a prosthesis of one embodiment of the invention in collapsed form mounted on a filling tube within the insertion tube.
• Figure 7 shows the prosthesis in collapsed form inserted into the nucleus pulposus cavity of an intervertebral disk, optionally after removal of all or part of the natural nucleus pulposus.
• Figure 8 shows the prosthesis being expanded within the intervertebral disk by insertion of a filler material through the filling tube.
• Figure 9 shows the prosthesis fully expanded within the intervertebral disk and sealed.
• the nucleus pulposus may experience certain pathological conditions. Normal aging causes the water content of the nucleus to decrease, resulting in a reduced ability to support the loads imposed on it and a reduction in the height of the intervertebral disc. As a result of degeneration of the annulus fibrosus, a portion of the nucleus may become herniated through cracks in the annulus and cause pain by impinging upon the spinal nerve roots. Accordingly, at least the herniated portion of the nucleus may be removed surgically to alleviate the pain. In some conditions the entire nucleus pulposus may be surgically removed.
• Such surgery may be effective to relieve pain, but may leave the intervertebral disc without an adequately functioning nucleus pulposus, thus leaving the possibility of further degeneration of the intervertebral disc. Accordingly, it may be desirable to supplement a degenerated nucleus pulposus or to replace an excised portion or even the entire nucleus in order to restore at least some of the functionality provided by the intact, undegenerated nucleus pulposus.
• a prosthesis for replacing or supplementing the nucleus pulposus of an intervertebral disk comprises an expandable balloon made from a hydrogel material, whereby the wall of the balloon is comprised of a hydrogel.
• the wall of the balloon may have a thickness from 0.01 to 2.00, more preferably, from 0.02 mm to 1.00 mm.
• the balloon may have a tensile modulus of 0.02 MPa to 0.8 MPa at 30% strain.
• the wall of the balloon may have a thickness from 0.01 to 2.00, more preferably, from 0.02 mm to 1.00 mm, and the balloon may have a tensile modulus of 0.02 MPa to 0.8 MPa at 30% strain.
• the balloon is capable of having a volume expansion of 3 to 5 times the original volume before bursting.
• the balloon is collapsible, e.g., by folding, rolling, or the like, to a relatively small size preferably for insertion into the central cavity of the intervertebral disk through a minimally invasive opening, optionally after a portion or substantially all of the nucleus pulposus has been removed.
• the wall of the balloon is made as a flexible membrane having a thickness and strength sufficient to support the internal pressure exerted by a filling material.
• the balloon prosthesis is collapsed to a relatively small volume and inserted into the central cavity of the intervertebral disc, e.g., through a cannula inserted through the annulus fibrosus or through a channel made in the body of an adjacent vertebra.
• the balloon prosthesis is typically inserted by a conventional minimally invasive surgical technique.
• the balloon is expanded by insertion of a relatively incompressible material into its interior in order to supplement or replace the nucleus pulposus.
• the balloon may deform as it is expanded to substantially completely fill the available volume within the space left by the degeneration and/or surgical removal of the body of the nucleus pulposus.
• the balloon may be originally made in a shape to conform to a cavity left by such degeneration or surgical removal.
• the filling of the balloon is preferably continued until it has substantially filled the available volume within the nucleus pulposus cavity and has been pressurized to substantially restore the natural pressure within the nucleus pulposus region of the intervertebral disk.
• the balloon is expanded within the nucleus pulposus region to the extent that the natural disk height for a given individual patient is restored.
• the hydrogel material that forms the wall of the balloon prosthesis may include any biocompatible hydrogel that has sufficient strength to confine the filling material under pressures existing within the region of the nucleus pulposus. Suitable hydrogels may be selected from among the many known hydrogels, including those disclosed, e.g., in U.S. Patent No. 5,047,055, to Bao et al., the entire disclosure of which is incorporated herein by reference.
• a preferred material for forming the balloon prosthesis is a hydrogel based on poly(vinyl alcohol) (PVA) that can be formed by repeated freeze-thaw cycles of an aqueous solution of PVA as described, e.g., in U.S. Patent Nos.
• cryogels are solid materials having elastomeric properties containing a large proportion, e.g., over 80%, of water, which are produced when solutions of relatively high molecular weight PVA of a high degree of hydrolysis are subjected to repeated freeze-thaw cycles.
• cryogels are tough, elastomeric, resilient, substantially insoluble in water below about 50°C, and nontoxic.
• a particularly preferred material is a cryogel formed by repeated freeze-thaw cycles of an aqueous solution of a mixture of PVA with another associating polymer such as poly( vinyl pyrrolidone) (PVP).
• the preferred embodiments of the cryogel may comprise a blend of PVA and 0.1% to 50%, more preferably 1% to 5% of a second polymer, preferably PVP or copolymers of PVP and poly(methyl methacrylate), poly(acrylamide), poly(acrylic acid), poly(acrylonitrile), or poly(ethylene glycol).
• the polymer component of such hydrogels may comprise from about 0.5% by weight to about 25% by weight of PVP, the remainder being PVA.
• the polymer component may incorporate from about 0.5% to about 5% by weight of PVP, for example, about 2.5% of PVP, the remainder being PVA.
• PVP polymer component
• Such hydrogels are disclosed in U.S. Patent Application No. 10/111,782, to Marcolongo et al. (European Patent No. EP 1 229 873), the entire disclosure of which is incorporated herein by reference.
• the expandable balloon prosthesis may be made in any shape that is suitable for filling the cavity of the nucleus pulposus of an intervertebral disk.
• Figure 1 shows a prosthesis 100 having a generally ellipsoidal chamber 102 and a filling tube 104 through which the prosthesis is filled with a relatively incompressible material after implantation.
• Figure 2 shows a cross-section of the prosthesis of Figure 1 along the line 2-2 in Figure 1, showing the thin membrane wall 106 surrounding an interior volume 108.
• a prosthesis may be prepared from a hydrogel that has sufficient elasticity to allow the balloon to deform under the internal pressure of the filling material to substantially fill void space within the nucleus pulposus region of the intervertebral disc.
• Figure 3 shows a plan view of another prosthesis 200 wherein the inflatable chamber 202 of the prosthesis 200 has been molded in the general shape of the natural nucleus pulposus.
• the prosthesis 200 is also provided with a filling tube 204.
• Figure 4 shows an elevational view of the prosthesis of Figure 3 in the direction indicated by the arrows 4-4 in Figure 3.
• Figure 5 shows a cross-sectional view of the prosthesis 200 of Figure 3 taken along the line 5-5 in Figure 3.
• Figure 5 shows the membrane wall 206 and internal volume 208 of the prosthesis.
• the balloon prosthesis may be manufactured by any conventional process for forming a hollow container having a flexible membrane wall.
• the container may be formed by conventional methods for forming objects from synthetic polymers such as blow molding, injection molding, rotational molding, extrusion, and the like.
• the container may also be formed by adhesive assembly of thin, flexible sheets of a hydrogel. It is preferred to form the balloon by dip-coating a mandrel with a dispersion or solution of a polymer capable of forming a cryogel in a suitable liquid vehicle, e.g., water, subsequently solidifying the coating on the mandrel by drying, chilling, or the like, and then subjecting the balloon to repeated freeze-thaw cycles to form a cryogel balloon.
• a suitable liquid vehicle e.g., water
• a particularly preferred method of forming the hydrogel balloon is by dip- coating a mandrel with an aqueous dispersion of a PVA or PVA-PVP blend followed by rapid chilling to a temperature that is effective to cause the coated layer to form a gel.
• a temperature will typically be below -20°C.
• Rapid chilling of the coating of polymer dispersion on the mandrel can be accomplished by dipping the coated mandrel into liquid nitrogen having a temperature of about -198.5°C (77.35 K).
• the hydrogel coating so formed may then be further processed by several cycles of freezing and thawing, as is conventional for such hydrogels.
• the balloon is then removed from the mandrel and is ready for use in the process of the invention.
• FIG. 6 The implantation and filling of a hydrogel balloon prosthesis is schematically illustrated in Figures 6-9.
• the figures illustrate schematically a superior or cranial view of a typical lumbar vertebra 300 with intervertebral disc 302 having an annulus fibrosus 304 and a central volume 306 representing a void space due to degeneration of the nucleus pulposus or removal thereof by a surgical procedure.
• An insertion cannula or trocar 308 is inserted through the annulus fibrosus 304 and into the central volume 306.
• a balloon prosthesis 100 is collapsed, as by folding or rolling, attached to a carrier tube 310, and introduced into the insertion tube 308.
• Figure 6 shows the balloon prosthesis 100 within the insertion tube 308, just before implantation.
• Figure 7 shows the initial stage of the implantation wherein the balloon prosthesis 100 has been positioned within the central volume 306 of the annulus fibrosus 304 by advancing the carrier tube 310 through the insertion tube 308.
• Figure 8 shows an intermediate stage in the implantation wherein the balloon prosthesis 100 has been partially inflated with material introduced through the carrier tube 310.
• Figure 9 shows the final stage of the implantation wherein the balloon prosthesis 100 has been completely inflated and substantially fills the central volume 306 of the annulus fibrosus 304.
• the fill tube is sealed by any conventional procedure, e.g., by insertion of a plug, tying off, etc., the carrier tube 310 is detached and withdrawn, and the insertion tube is withdrawn from the annulus fibrosus.
• the balloon prosthesis 100 may be inflated with any material that will remain confined by the hydrogel membrane of the balloon prosthesis and will provide mechanical properties similar to those of the natural nucleus pulposus.
• the balloon prosthesis may be filled with a curable material injected in a liquid or plastic state that will cure after injection to an elastic or viscoelastic material preferably having properties similar to those of the natural nucleus pulposus.
• a preferred material for filling the balloon prosthesis of the invention is a hydrogel that can be injected in a liquid or soft injectable state and that will preferably provide the prosthesis with mechanical properties similar to those of the natural nucleus pulposus.
• a particularly preferred material is a thermogelling composition that can be injected in a liquid form at a temperature approximating room temperature and that will then become converted to a gel form when it is heated to normal body temperature.
• Such compositions are known, and include, for example, thermogelling hydrogel materials based on poly(N-isopropylacrylamide) (PNIPAAm) or a copolymer or blend of PNIPAAm, as disclosed in U.S. Published Patent Application No. 2004/0220296 (Application No.
• thermogelling composition may be injected into the balloon at a relatively low temperature at which it remains a flowable liquid, e.g., about 2O 0 C to about 27 0 C.
• the thermogelling hydrogel is warmed, typically merely by conduction of heat from its surroundings, to body temperature of about 37 0 C and forms a solid hydrogel.
• the solid hydrogel so formed will not flow out through the neck of the balloon; accordingly no special sealing of the input stem or neck of the balloon is needed in this embodiment.
• thermogelling hydrogels based on PNIPAAm are disclosed in U.S. Published Patent Application No. 2004/0220296, and include those prepared from blends of aqueous solutions of PNIPAAm with aqueous solutions of polyvinyl alcohol) (PVA), and aqueous solutions of poly (ethylene glycols) (PEGs) of various molecular weights. Also disclosed are thermogelling hydrogels prepared from aqueous solutions of PNIPAAm-grafted PEG polymers and aqueous solutions of PEG-PNIPAAm-PEG triblock polymers. Such thermogelling hydrogels, and the like, are preferred materials for filling the balloon prosthesis.
• the balloon prosthesis can be filled with a conventional biocompatible liquid.
• the neck of the balloon is sealed by conventional procedures, e.g., sealing with a plug, sealing with an adhesive, heat-sealing, stitching, or the like.
• the balloon prosthesis may also be filled or packed with a solid hydrogel in the form of beads or a string that will serve to provide the prosthesis with the requisite mechanical properties.
• a solid hydrogel in the form of beads or a string that will serve to provide the prosthesis with the requisite mechanical properties.
• the neck or stem of the balloon may be sealed as indicated above. If the size, shape, stiffness, or other properties of the inserted solid hydrogel material are such that it will not be extruded through the neck of the balloon, special sealing of the stem need not be performed.

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• Health & Medical Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Veterinary Medicine (AREA)
• Engineering & Computer Science (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Transplantation (AREA)
• Public Health (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Biomedical Technology (AREA)
• Dispersion Chemistry (AREA)
• Cardiology (AREA)
• Heart & Thoracic Surgery (AREA)
• Vascular Medicine (AREA)
• Dermatology (AREA)
• Epidemiology (AREA)
• Neurology (AREA)
• Medicinal Chemistry (AREA)
• Prostheses (AREA)
• Materials For Medical Uses (AREA)
• Jellies, Jams, And Syrups (AREA)
• Colloid Chemistry (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (2)

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• 2006
  • 2006-08-25 DE DE602006013649T patent/DE602006013649D1/de active Active
  • 2006-08-25 KR KR1020087005531A patent/KR20080036217A/ko not_active Ceased
  • 2006-08-25 EP EP06813765A patent/EP1917050B1/en active Active
  • 2006-08-25 ES ES06813765T patent/ES2340526T3/es active Active
  • 2006-08-25 JP JP2008528212A patent/JP4896135B2/ja not_active Expired - Fee Related
  • 2006-08-25 US US11/510,747 patent/US8287595B2/en active Active
  • 2006-08-25 AU AU2006282883A patent/AU2006282883A1/en not_active Abandoned
  • 2006-08-25 CA CA002620239A patent/CA2620239A1/en not_active Abandoned
  • 2006-08-25 WO PCT/US2006/033276 patent/WO2007025164A2/en not_active Ceased
  • 2006-08-25 BR BRPI0615391-7A patent/BRPI0615391A2/pt active Search and Examination
  • 2006-08-25 NZ NZ566184A patent/NZ566184A/en unknown
  • 2006-08-25 CN CN2006800394346A patent/CN101365500B/zh not_active Expired - Fee Related
  • 2006-08-25 AT AT06813765T patent/ATE464076T1/de active
  • 2006-08-25 ZA ZA200802596A patent/ZA200802596B/xx unknown
  • 2006-08-25 PL PL06813765T patent/PL1917050T3/pl unknown
• 2009
  • 2009-10-29 US US12/608,565 patent/US20100047437A1/en not_active Abandoned

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