Radiolucent spinal fusion cage

• US 20110098818A1
• Filed: 05/10/2010
• Published: 04/28/2011
• Est. Priority Date: 05/01/2001
• Status: Abandoned Application

• Current Assignee: Ashok C. Khandkar, Bret M. Berry, Darrel S. Brodke, Lakshminarayanan Ramaswamy, Mahendra S. Rao
• Original Assignee: Ashok C. Khandkar, Bret M. Berry, Darrel S. Brodke, Lakshminarayanan Ramaswamy, Mahendra S. Rao
• Inventors: Berry, Bret M., Rao, Mahendra S., Khandkar, Ashok C., Lakshminarayanan, Ramaswamy, Brodke, Darrel S.
• Application Number:
  US12/800,219
• Publication Number:
  US 20110098818A1
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30016 differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61F 2002/30064 Coating or prosthesis-covering structure made of biodegradable material
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30266 wedge-shaped parallelepipeds
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30677 : Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30733 : Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30822 : Circumferential grooves
• CPC Class Codes: A61F 2002/30827 : Plurality of grooves
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30881 : Circumferential ribs, flanges or fins
• CPC Class Codes: A61F 2002/30891 : Plurality of protrusions
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30896 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2002/4648 : Means for culturing bone graft
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0019 : differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61F 2310/00928 : Coating or prosthesis-covering structure made of glass or of glass-containing compounds, e.g. of bioglass
• CPC Class Codes: A61F 2310/0097 : Coating or prosthesis-covering structure made of pharmaceutical products, e.g. antibiotics
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF
• CPC Class Codes: A61L 2430/02 : for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 2430/38 : for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/10 : Ceramics or glasses
• CPC Class Codes: A61L 27/30 : Inorganic materials
• CPC Class Codes: A61L 27/32 : Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: A61L 27/3608 : Bone, e.g. demineralised bone matrix [DBM], bone powder
• CPC Class Codes: A61L 27/365 : Bones
• CPC Class Codes: A61L 27/3804 : characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
• CPC Class Codes: A61L 27/3834 : Cells able to produce different cell types, e.g. hematopoietic stem cells, mesenchymal stem cells, marrow stromal cells, embryonic stem cells
• CPC Class Codes: A61L 27/3847 : Bones
• CPC Class Codes: A61L 27/56 : Porous materials, e.g. foams or sponges

Abstract

An improved bone graft is provided for human implantation, particularly such as a spinal fusion cage for implantation into the inter-vertebral space between two adjacent vertebrae. The improved spinal fusion cage includes a substrate block of high strength biocompatible material having a selected size and shape to fit the anatomical space, and a controlled porosity analogous to natural bone. The substrate block may be coated with a bio-active surface coating material such as hydroxyapatite or a calcium phosphate to promote bone ingrowth and enhanced bone fusion. Upon implantation, the fusion cage provides a spacer element having a desired combination of mechanical strength together with osteoconductivity and osteoinductivity to promote bone ingrowth and fusion, as well as radiolucency for facilitated post-operative monitoring. The fusion cage may additionally carry one or more natural or synthetic therapeutic agents for further promoting bone ingrowth and fusion.

Claims

1-84. -84. (canceled)

85. An implantable prosthetic component for ingrowth attachment with adjacent spinal tissue, comprising:

a substrate block consisting essentially of a ceramic material, and having surfaces for ingrowth attachment with adjacent spinal tissue, the substrate block comprising;

a top surface configured for ingrowth attachment with a first vertebral body;

a bottom surface configured for ingrowth attachment with a second vertebral body adjacent to the first vertebral body; and

a substantially radiolucent body visible under X-ray imaging, but having a density allowing for passage of X-rays through the ceramic material of the body under medial-lateral X-ray imaging thus facilitating post-operative assessment of bone ingrowth from the first and second vertebral bodies into the body through the top and bottom surfaces.

86. The implantable prosthetic component of claim 85 wherein said substrate block includes a first, lower porosity region and a second, higher porosity region, said second region including said top and bottom exterior surfaces for ingrowth attachment with said first and second vertebral bodies.

87. The implantable prosthetic component of claim 86 wherein said second region has a porosity ranging from about 30% to about 80% by volume.

88. The implantable prosthetic component of claim 87 wherein the pore sizes in the second region range from about 100 microns to about 500 microns.

89. The implantable prosthetic component of claim 86 wherein said first region has a porosity of less than about 5% by volume.

90. The implantable prosthetic component of claim 86 wherein said first region has a relatively high strength corresponding substantially with cortical bone, and wherein said second region has a porosity corresponding substantially with cancellous bone.