The present invention generally relates to an apparatus for the treatment of spinal disorders and, in particular, an artificial intervertebral disc, an implant that replaces a diseased or damaged intervertebral disc.
There are many painful disorders of the spine, many relating, at least in part, to diseased or damaged intervertebral discs. Disorders include Degenerative Disc Disease, generally an age related disorder where the intervertebral disc gradually loses its water content, resiliency, and height. With a loss in intervertebral disc height and associated loss of normal spacing between vertebrae, motion of the vertebrae can place pressure on the spinal cord or exiting nerve roots. The intervertebral disc itself can also be a source of pain. Spinal disorders, commonly referred to as disc herniation and bulging disc, place painful pressure on the spinal cord and exiting nerve roots. Abnormal bone growth, called osteophytes, can place pressure on nerves or the spinal cord. Often, a surgeon must at least partially remove an intervertebral disc to access and remove an osteophyte.
A surgical approach to treating chronic spinal disorders relates to bony fusion of two adjacent vertebrae in a treatment called spine fusion. Following the achievement of appropriate spacing and alignment of the vertebral bodies, bone graft material and stabilization provide an environment for spine fusion. Implant systems, to include plate and rod systems and interbody devices, such as, interbody spacers and fusion cages can be used to support the spine during fusion. Concerns persist regarding spinal fusion treatment stemming from modest clinical success rates and the creation of rigid regions along an otherwise flexible spine.
Artificial intervertebral discs, or simply artificial discs, are an alternative to spinal fusion and represent an emerging technology. These spinal implants are designed to restore or maintain the appropriate alignment and spacing of adjacent vertebral bodies. In addition, an artificial disc is also designed for kinematic behavior similar to a healthy natural disc. Known artificial disc concepts use numerous means for providing motion and stiffness similar to a natural healthy disc, to include the adaptation of elastomers, mechanical springs, and articulating surfaces.
Prior art artificial discs often use articulating surfaces to create a joint between adjacent vertebrae. Disc implants using articulating surfaces rely on methodology and proven technology used in total joint arthroplasty of the hip, knee, and shoulder. Numerous prior art artificial discs resemble artificial hip and artificial knee joints. Numerous known artificial disc devices resemble variations of a ball-and-socket. Kuntz, in U.S. Pat. No. 4,349,921 (Sep. 21, 1982) discloses an artificial disc, with two components that articulate by means of a projection on one component pivotally engaging a depression on the second component. An artificial disc resembling an artificial knee joint has also been suggested. Shelokov, in U.S. Pat. No. 6,039,763 (Mar. 21, 2000) discloses an artificial spinal disc, similar in configuration to an artificial knee joint.
Heggeness et. al., in U.S. Pat. No. 5,514,180 (May 1996) categorizes the shape or contours of vertebral endplates into five groups: “ramp”, “saddle”, “irregular”, “bowl”, and “hump”. Heggeness et. al., teaches the importance of endplate shape relating to fit and load distribution of a prosthetic devices within intervertebral disc spaces, but Heggeness et. al. does not discuss endplate shape relating to articulating surfaces or spinal kinematics.
Spine kinematics and anatomical shapes vary by region of the spine (cervical, thoracic, and lumbar), and a need exists for artificial discs addressing specific regions of the spine, especially the unique geometry and kinematics of the cervical spine.
For the middle and lower regions of the cervical spine, the artificial disc of the present invention adapts an articulating surface with a concave-convex shape, also called a saddle shape. The artificial disc of the present invention is intended to fit substantially within the intervertebral space bound by adjacent vertebral bodies. A bone anchor for fixation of an artificial disc to vertebra is also disclosed.
A first embodiment of the artificial disc of the present invention for the cervical spine includes a disc body having an articulating concave-convex surface secured to a base plate, which may incorporate a bone anchor. A second embodiment of the artificial disc of the present invention is comprised of an articulating concave-convex surface, bone anchor, and a disc body slidably attached to a base plate to permit additional motion. A third embodiment of the artificial disc of the present invention includes an upper disc body and a lower disc body cooperatively forming a saddle-joint. The upper disc body and lower disc body of the third embodiment are securely anchored to vertebral bodies using bone anchors. Further embodiments of the artificial disc of the present invention include an upper disc body and a lower disc body cooperatively forming a saddle-joint, and bone anchors adapted with a tension element to provide additional stability.
Consistent with common medical nomenclature, superior is nearer the head in relation to a specific reference point, whereas, inferior is nearer the feet in relation to a specific reference point. Anterior is forward in relation to a specific reference point and posterior is rearward in relation to a specific reference point. The midsagittal plane is an imaginary plane dividing the body into a right side and left side. A frontal plane is any imaginary vertical plane orthogonal to the midsagittal plane.
Primarily addressing the middle and lower cervical spine, the present invention uses a generally concave-convex articulating surface. As will become apparent in subsequent discussion, a concave-convex articulating surface is an essential element of the present invention, providing anatomical and biomechanical advantages. Referring now to
The anatomically aligned shape of the present invention also has biomechanical benefits associated with natural kinematics of the spine. To assist with the analysis of spine kinematics, Panjabi and White established the Instantaneous-Axis-of-Rotation (IAR) for planer motion analysis of vertebrae. Planar motion of vertebrae is fully described by the position of the IAR and the angle of rotation about the IAR. The IAR is an instantaneous measure and therefore may shift within a region through a range-of-motion, such as, but not limited to, flexion/extension range-of-motion. The present inventors have discovered a relation between the shape of a vertebra's inferior endplate and the natural motion of the same vertebra.
Flexion/extension is the most commonly considered degree-of-freedom when evaluating cervical spine kinematics.
Within the scope of the present invention, multiple components may be allowed to articulate to address multiple degrees-of-freedom associated with spinal motion, to include, but not limited to, torsional and translational degrees-of-freedom. Accordingly,
For a number of reasons, to include anatomical variation, the inferior endplate of a superior vertebra may not be suitable as an articulating surface. During treatment of a cervical spine disorders, endplates are often partially or completely removed in order to access and remove offending soft tissue (e.g., extruded disc nucleus) or offending hard tissue (e.g., posterior bone spurs). A total joint artificial disc is often warranted. Accordingly,
Using an anterior approach to the cervical spine, the anterior longitudinal ligament is at least partially resected with associated loss of stability, especially in extension. An artificial disc with a tension element provides stability during extension. Referring now to
Within the scope of the current invention, an artificial disc may have an upper articulating surface and a lower articulating surface for sliding interaction with vertebral bodies.
The present invention, to include, but not limited to the aforementioned embodiments, can be constructed of established orthopaedic materials. Established wear resistant materials for components with articulating surfaces include metals (e.g., stainless-steel, cobalt-chrome, and titanium), plastics (e.g., Ultra-High-Molecular-Weight-Polyethylene), and ceramics (e.g., alumina and zironia). Non-articulating features of an artificial disc of the present invention may have features or material characteristics to facilitate rigid attachment to bone. An artificial disc of the present invention may be adapted additional features known for attachment to bone including, but not limited to, spikes, screws, serration, and plate-like appendages generally exterior to the intervertebral disc space. Components may be made, in part, constructed of substantially porous materials for bone in-growth, yet have smooth non-porous regions for articulating surfaces. Surface treatments commonly practiced, such as beaded-coatings, may also be used for attachment to bone through eventual bone in-growth. In addition, within the scope of the current invention, components may be given flexibility through the use of geometry and materials to replicate the cushioning characteristics of the natural intervertebral disc. Additional components, such as, springs might be added to provide flexibility. In addition, portions of the patient's annulus may remain intact, such that the present invention augments a patient's existing intervertebral disc. Although the utility of the disclosed artificial disc is best achieved in the cervical region of the spine, adaptations for the thoracic and lumbar regions of the spine are also within the scope and spirit of the present invention.
This application is a divisional of U.S. patent application Ser. No. 10/766,684 filed on Jan. 28, 2004.
Number | Name | Date | Kind |
---|---|---|---|
3030951 | Mandarino | Apr 1962 | A |
3320957 | Sokolik | May 1967 | A |
3867728 | Stubstad et al. | Feb 1975 | A |
3875595 | Froning | Apr 1975 | A |
4065817 | Branemark et al. | Jan 1978 | A |
4309777 | Patil | Jan 1982 | A |
4349921 | Kuntz | Sep 1982 | A |
4369772 | Miller | Jan 1983 | A |
4403606 | Woo et al. | Sep 1983 | A |
4403607 | Woo et al. | Sep 1983 | A |
4493317 | Klaue | Jan 1985 | A |
4494535 | Haig | Jan 1985 | A |
4503848 | Caspar et al. | Mar 1985 | A |
4513744 | Klaue | Apr 1985 | A |
4653489 | Tronzo | Mar 1987 | A |
4743260 | Burton | May 1988 | A |
4751922 | DiPietropolo | Jun 1988 | A |
4759766 | Buettner-Janz et al. | Jul 1988 | A |
4759769 | Hedman et al. | Jul 1988 | A |
4773406 | Spector et al. | Sep 1988 | A |
4794918 | Wolter | Jan 1989 | A |
4863477 | Monson | Sep 1989 | A |
4874389 | Downey | Oct 1989 | A |
4911718 | Lee et al. | Mar 1990 | A |
4932975 | Main et al. | Jun 1990 | A |
4936848 | Bagby | Jun 1990 | A |
4946378 | Hirayama et al. | Aug 1990 | A |
4969888 | Scholten et al. | Nov 1990 | A |
5002544 | Klaue et al. | Mar 1991 | A |
5002576 | Fuhrmann et al. | Mar 1991 | A |
5019078 | Perren et al. | May 1991 | A |
5030201 | Palestrant | Jul 1991 | A |
5035716 | Downey | Jul 1991 | A |
5053036 | Perren et al. | Oct 1991 | A |
5062845 | Kuslich et al. | Nov 1991 | A |
5071437 | Steffee | Dec 1991 | A |
5085660 | Lin | Feb 1992 | A |
5108404 | Scholten et al. | Apr 1992 | A |
5108438 | Stone | Apr 1992 | A |
5118338 | Moller | Jun 1992 | A |
5123926 | Pisharodi | Jun 1992 | A |
5147361 | Ojima et al. | Sep 1992 | A |
5151103 | Tepic et al. | Sep 1992 | A |
5171281 | Parsons et al. | Dec 1992 | A |
5246458 | Graham | Sep 1993 | A |
5258031 | Salib et al. | Nov 1993 | A |
5275601 | Gogolewski et al. | Jan 1994 | A |
5314477 | Marnay | May 1994 | A |
5320644 | Baumgartner | Jun 1994 | A |
5344421 | Crook | Sep 1994 | A |
5364399 | Lowery et al. | Nov 1994 | A |
5370697 | Baumgartner | Dec 1994 | A |
5376100 | Lefebvre | Dec 1994 | A |
5401269 | Buttner-Janz et al. | Mar 1995 | A |
5403136 | Mathys | Apr 1995 | A |
5403317 | Bonutti | Apr 1995 | A |
5425773 | Boyd et al. | Jun 1995 | A |
5431671 | Nallakrishnan | Jul 1995 | A |
5445639 | Kuslich et al. | Aug 1995 | A |
5458642 | Beer et al. | Oct 1995 | A |
5458643 | Oka et al. | Oct 1995 | A |
5514137 | Coutts | May 1996 | A |
5514180 | Heggeness et al. | May 1996 | A |
5527311 | Procter et al. | Jun 1996 | A |
5534029 | Shima | Jul 1996 | A |
5545229 | Parsons et al. | Aug 1996 | A |
5549612 | Yapp et al. | Aug 1996 | A |
5556429 | Felt | Sep 1996 | A |
5562672 | Huebner et al. | Oct 1996 | A |
5562738 | Boyd et al. | Oct 1996 | A |
5607426 | Ralph et al. | Mar 1997 | A |
5613967 | Engelhardt et al. | Mar 1997 | A |
5616144 | Yapp et al. | Apr 1997 | A |
5645596 | Kim et al. | Jul 1997 | A |
5645605 | Klawitter | Jul 1997 | A |
5658310 | Berger | Aug 1997 | A |
5665110 | Chervitz et al. | Sep 1997 | A |
5674294 | Bainville et al. | Oct 1997 | A |
5674296 | Bryan et al. | Oct 1997 | A |
5681310 | Yuan et al. | Oct 1997 | A |
5681311 | Foley et al. | Oct 1997 | A |
5693011 | Onik | Dec 1997 | A |
5695513 | Johnson et al. | Dec 1997 | A |
5709686 | Talos et al. | Jan 1998 | A |
5720749 | Rupp | Feb 1998 | A |
5733287 | Tepic et al. | Mar 1998 | A |
5735853 | Olerud | Apr 1998 | A |
5766176 | Duncan | Jun 1998 | A |
5772662 | Chapman et al. | Jun 1998 | A |
5782832 | Larsen et al. | Jul 1998 | A |
5800433 | Benzel et al. | Sep 1998 | A |
5807396 | Raveh | Sep 1998 | A |
5824094 | Serhan et al. | Oct 1998 | A |
5827289 | Reiley et al. | Oct 1998 | A |
5827328 | Buttermann | Oct 1998 | A |
5843103 | Wulfman | Dec 1998 | A |
5865846 | Bryan et al. | Feb 1999 | A |
5871486 | Huebner et al. | Feb 1999 | A |
5888220 | Felt et al. | Mar 1999 | A |
5888226 | Rogozinski | Mar 1999 | A |
5891145 | Morrison et al. | Apr 1999 | A |
5893889 | Harrington | Apr 1999 | A |
5899941 | Nishijima et al. | May 1999 | A |
5904683 | Pohndorf et al. | May 1999 | A |
5925056 | Thomas et al. | Jul 1999 | A |
5928239 | Mirza | Jul 1999 | A |
5928284 | Mehdizadeh | Jul 1999 | A |
5935131 | Bonutti | Aug 1999 | A |
5935853 | Jones et al. | Aug 1999 | A |
5964762 | Biedermann et al. | Oct 1999 | A |
5972015 | Scribner et al. | Oct 1999 | A |
5990194 | Dunn et al. | Nov 1999 | A |
6017345 | Richelsoph | Jan 2000 | A |
6019792 | Cauthen | Feb 2000 | A |
6022350 | Ganem | Feb 2000 | A |
6030389 | Wagner et al. | Feb 2000 | A |
6039763 | Shelokov | Mar 2000 | A |
6048343 | Mathis et al. | Apr 2000 | A |
6063121 | Xavier et al. | May 2000 | A |
6066154 | Reiley et al. | May 2000 | A |
6071284 | Fox | Jun 2000 | A |
6113637 | Gill et al. | Sep 2000 | A |
6136031 | Middleton | Oct 2000 | A |
6139509 | Yuan et al. | Oct 2000 | A |
6140452 | Felt et al. | Oct 2000 | A |
6156067 | Bryan et al. | Dec 2000 | A |
6171312 | Beaty | Jan 2001 | B1 |
6179874 | Cauthen | Jan 2001 | B1 |
6210376 | Grayson | Apr 2001 | B1 |
6214012 | Karpman et al. | Apr 2001 | B1 |
6224604 | Suddaby | May 2001 | B1 |
6235043 | Reiley et al. | May 2001 | B1 |
6238391 | Olsen et al. | May 2001 | B1 |
6241734 | Scribner et al. | Jun 2001 | B1 |
6248110 | Reiley et al. | Jun 2001 | B1 |
6248131 | Felt et al. | Jun 2001 | B1 |
6264659 | Ross et al. | Jul 2001 | B1 |
6296639 | Truckai et al. | Oct 2001 | B1 |
6383188 | Kuslich et al. | May 2002 | B2 |
6410452 | Nishioka | Jun 2002 | B2 |
6440138 | Reiley et al. | Aug 2002 | B1 |
6527804 | Gauchet et al. | Mar 2003 | B1 |
6558386 | Cragg | May 2003 | B1 |
6558390 | Cragg | May 2003 | B2 |
6575979 | Cragg | Jun 2003 | B1 |
6607558 | Kuras | Aug 2003 | B2 |
6706068 | Ferree | Mar 2004 | B2 |
6740090 | Cragg et al. | May 2004 | B1 |
6770094 | Fehling et al. | Aug 2004 | B2 |
6770095 | Grinberg et al. | Aug 2004 | B2 |
6790210 | Cragg et al. | Sep 2004 | B1 |
6899716 | Cragg | May 2005 | B2 |
6921403 | Cragg et al. | Jul 2005 | B2 |
20010021852 | Chappius | Sep 2001 | A1 |
20010049527 | Cragg | Dec 2001 | A1 |
20020016583 | Cragg | Feb 2002 | A1 |
20020116064 | Middleton | Aug 2002 | A1 |
20020173796 | Cragg | Nov 2002 | A1 |
20030135237 | Cragg et al. | Jul 2003 | A1 |
20030158557 | Cragg et al. | Aug 2003 | A1 |
20030191474 | Cragg et al. | Oct 2003 | A1 |
20030195518 | Cragg | Oct 2003 | A1 |
20030204189 | Cragg | Oct 2003 | A1 |
20030229353 | Cragg | Dec 2003 | A1 |
20040024462 | Ferree et al. | Feb 2004 | A1 |
20040176772 | Zubok et al. | Sep 2004 | A1 |
20040176773 | Zubok et al. | Sep 2004 | A1 |
20040176774 | Zubok et al. | Sep 2004 | A1 |
20040176776 | Zubok et al. | Sep 2004 | A1 |
20040176777 | Zubok et al. | Sep 2004 | A1 |
20040176778 | Zubok et al. | Sep 2004 | A1 |
20040176843 | Zubok et al. | Sep 2004 | A1 |
20040176844 | Zubok et al. | Sep 2004 | A1 |
20040176845 | Zubok et al. | Sep 2004 | A1 |
20040176846 | Zubok et al. | Sep 2004 | A1 |
20040176847 | Zubok et al. | Sep 2004 | A1 |
20040176848 | Zubok et al. | Sep 2004 | A1 |
20040176849 | Zubok et al. | Sep 2004 | A1 |
20040176850 | Zubok et al. | Sep 2004 | A1 |
20040176851 | Zubok et al. | Sep 2004 | A1 |
20040176852 | Zubok et al. | Sep 2004 | A1 |
20040193272 | Zubok et al. | Sep 2004 | A1 |
20040220577 | Cragg et al. | Nov 2004 | A1 |
20040220590 | Zubok et al. | Nov 2004 | A1 |
20050070908 | Cragg | Mar 2005 | A1 |
20050071013 | Zubok et al. | Mar 2005 | A1 |
20050113919 | Cragg et al. | May 2005 | A1 |
20050113928 | Cragg et al. | May 2005 | A1 |
20050113929 | Cragg et al. | May 2005 | A1 |
20050131529 | Cragg | Jun 2005 | A1 |
20050137601 | Assell et al. | Jun 2005 | A1 |
20050137602 | Assell et al. | Jun 2005 | A1 |
20050137604 | Assell et al. | Jun 2005 | A1 |
20050137605 | Assell et al. | Jun 2005 | A1 |
20050137607 | Assell et al. | Jun 2005 | A1 |
20050137612 | Assell et al. | Jun 2005 | A1 |
20050149034 | Assell et al. | Jul 2005 | A1 |
20050149049 | Assell et al. | Jul 2005 | A1 |
20050149191 | Cragg et al. | Jul 2005 | A1 |
20050165406 | Assell et al. | Jul 2005 | A1 |
20050187633 | Ferree | Aug 2005 | A1 |
20050240271 | Zubok et al. | Oct 2005 | A1 |
20050240272 | Zubok et al. | Oct 2005 | A1 |
20050256577 | Baumgartner et al. | Nov 2005 | A1 |
20050261695 | Cragg et al. | Nov 2005 | A1 |
Number | Date | Country |
---|---|---|
3914164 | Jan 1991 | DE |
0 442 137 | Aug 1991 | EP |
WO-9007304 | Jul 1990 | WO |
WO-9851226 | Nov 1998 | WO |
WO-9851226 | Nov 1998 | WO |
9911203 | Mar 1999 | WO |
Number | Date | Country | |
---|---|---|---|
20070112429 A1 | May 2007 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 10766684 | Jan 2004 | US |
Child | 11648384 | US |