WO2004098465A1

WO2004098465A1 - Method and apparatus for spine joint replacement

Info

Publication number: WO2004098465A1
Application number: PCT/US2003/013764
Authority: WO
Inventors: E. Marlowe Goble; T. Wade Fallin; Robert W. Hoy
Original assignee: Medicinelodge, Inc.
Priority date: 2003-05-02
Filing date: 2003-05-02
Publication date: 2004-11-18
Also published as: CA2525463A1; CA2525463C; AU2003228821A1; AU2003228821B2

Abstract

A prosthesis (1075, 1085, 1160) for the replacement of the cartilaginous structures of a spine motion segment is described. The prosthesis (1075, 1085, 1160) comprises an intervertebral disc prosthesis (AD) in combination with a facet joint prosthesis (4, 5).

Description

METHOD AND APPARATUS FOR SPINE JOINT REPLACEMENT

Reference To Pending Prior Patent Applications This patent application claims benefit of: (1) pending prior U.S. Provisional Patient

Application Serial No. 60/273,031, filed 03/^02/01 by E. Marlowe Goble et al. for TOTAL SPINE JOINT REPLACEMENT (Attorney's Docket No. MED-3 PRQV) ;

(2) pending prior U.S. Patent Application Serial No. 09/726,169, filed 11/29/00 by E. Marlowd Goble et al. for FACET JOINT REPLACEMENT (Attorney's Docket No. MED-1) ;

(3) pending prior U.S. Patent Application Serial No. 09/736,103, filed 12/13/00 by E. Marlowd Goble et al. for MULTIPLE FACET JOINT REPLACEMENT (Attorney's Docket No. MED-2) ; and

(4) pending prior U.S. Patent Application Serial No. 09/797,309, filed 03/01/01 by T. Wade Fejllin et al . for PROSTHESIS FOR THE REPLACEMENT OF A POSTERIOR ELEMENT OF A VERTEBRA (Attorney's Docket No. MED-4).

The four above-identified patent applications are • hereby incorporated herein by reference. Field Of The Invention

This invention relates to surgical devices and methods in general, and more particularly tc surgical devices and methods for replacing a damaged, diseased, or otherwise painful spinal joint.

Background Of The Invention

Traumatic, inflammatory, metabolic, synovial, neoplastic and degenerative disorders of the spine can produce debilitating pain that can have severe socioeconomic and psychological effects.

One of the most common surgical interventions today is arthrodesis, or spine fusion, in wηich two or more adjacent vertebral bodies are fused toe ether in order to alleviate pain associated with the disc(s) located between those vertebral bodies. Approximately 300,000 such procedures are performed annually in the United States alone. Clinical success varies considerably, depending upon technique and indications, and consideration must be given to the concomitant risks and complications.

For example, while spine fusion generally helps to eliminate certain types of pain, it has alsc been shown to decrease function by limiting the range of motion for patients in flexion, extension, rotation and lateral bending. Furthermore, it is believed that spine fusion creates increased stresses on (and, therefore, accelerated degeneration of) adjacent non-fused motion segments. Additionally, pseudoarthrosis, resulting from an incomplete or

problems for the patient.

Recently, attempts have been made to recreate the natural biomechanics of the spine through the use of an artificial disc. Artificial discs are inter ded to restore articulation between vertebral bodies so as to recreate the full range of motion normally allowed by the elastic properties of the natural disc, which directly connects two opposing vertebral bodes. Various artificial discs are described by Stefee et al. in U.S. Pat. No. 5,071,437; Gill et al . in I^'.S. Pat. No. 6,113,637; Bryan et al. in U.S. Pat. No. 6,001,130; - A -

Hedman et al. in U.S. Patent No. 4,759,769; Ray in U.S. Patent No. 5,527,312; Ray et al. in U.S^". Pat. 5,824,093; Buttner-Janz in U.S. Patent No. 5,401,269; and Serhan et al. in U.S. Patent No. 5,824,094; all which documents are hereby incorporated herein by reference. Still other artificial discs are, known in the art.

Unfortunately, however, artificial discs alone do not adequately address all of the mechanics of the motion of the spinal column.

In addition to the intervertebral disc, posterior elements called the facet joints help to support axial, torsional and shear loads that act on the spinal column. Furthermore, the facet joints are ciarthroidal joints that provide both sliding articulatiαn and load transmission features. However, the facet jo<ints can also be a significant source of spinal disoiders and, in many cases, debilitating pain. For example, a patient may suffer from arthritic facet joirts, severe facet joint tropism or otherwise deformed fεcet joints, facet joint injuries, etc. There is currently a lack of good interventions for facet joint disorcers. Facetectomy, or the removal of the facet joints, may - 5 -

provide some relief, but it is also believe to produce significant decreases in the stiffness of the spinal column (i.e., hyper obility) in all planes qf motion flexion and extension, lateral bending, and rotation, Furthermore, problems with the facet joints can also complicate treatments associated with other portions of the spine. By way of example, contraindications for artificial discs include arthritic facet joints, absent facet joints, severe facet joint tropism or otherwise deformed facet joints.

A superior vertebra with its inferior facets, an inferior vertebra with its superior facets, the intervertebral disc, and seven spinal ligaments together comprise a spinal motion segment oi functional spine unit. The spinal motion segment provides complex motion along three orthogonal axis, both in rotation (lateral bending, flexion and extension, anc axial rotation) and in translation (anterior-posterior, medial-lateral, and cranial-caudal) . Furthermore, the spinal motion segment provides physiologicai limits and stiffnesses in each rotational and translati onal direction to create a stable and strong column structure to support physiological loads. 6 -

As mentioned above, compromised facet joints are a contraindication for disc replacement, due to the inability of the artificial disc (when used with compromised facet joints, or when used with missing facet joints) to properly restore the natural biomechanics of the spinal motion segment. It would therefore be an improvement in the art to provide a spine implant system that facilitates concurrent replacement of the intervertebral disc and facet joints where both have been compromised due to disease or trauma.

U.S. Patent No. Re. 36,758 (Fitz) discloses an artificial facet joint where the inferior fεcet, the mating superior facet, or both, are covered with a cap. This cap requires no preparation of the bone or articular surfaces; it covers and, therefore, preserves the bony and articular structure. The capping of the facet has several potential disadvantages, however. If the facet joint is osteoarthritic, a cap will not remove the source of the pain. Additionally, at least in the case of surface replacements for osteoarthritic femoral heads, the capping of articular bone ends has proven to lead to clinical failure by means of mechanical loosening. This clinical failure is hypothesized to be a sequela of disrupting the periosteum and ligamentum teres femoris, both serving a nutrition delivery role to the femoral head, thereby leading to avascular necrosis of the bony support structure for the surface replacement. It is possible that corresponding problems could develop from capping the facet. Another potential disadvantage qf facet capping is that in order to accommodate the wide variability in anatomical morphology of the facets, not only between individuals but also between leVels within the spinal column, a very wide range of cap sizes and shapes is required.

U.S. Patent No. 6,132,464 (Martin) discloses a spinal facet joint prosthesis that is supported on the lamina (which is sometimes also referred to as the posterior arch) . Extending from this support structure are inferior and/or superior blades that replace the cartilage at the facet joint. Like the design of the aforementioned U.S. Patent No. Re. 36,758, the prosthesis of U.S. Patent No. 6,132,464 generally preserves existing bony structures and ther fore does not address pathologies which affect the bore of the facets in addition to affecting the associated cartilage. Furthermore, the prosthesis of l.S. Patent No. 6,132,464 requires a secure mating between the prosthesis and the lamina. However, the laπ.ina is a very complex and highly variable anatomical surface. As a result, in practice, it is very difficult to design a prosthesis that provides reproducible positioning against the lamina so as to correctly locate the cartilage-replacing blades for the facet joints.

Another approach to surgical intervention for spinal facets is disclosed in International Patent Publication No. W09848717A1 (Villaret et al.). While this publication teaches the replacement of spinal facets, the replacement is interlocked in a manner so as to immobilize the joint.

Thus it will be seen that previous attempts to provide facet joint replacement have proven inadequate.

In some circumstances, additional structures of a vertebra beside the facets may have been coπpromised by disease or trauma. For example, the lamina, the spinous process and/or the two transverse processes may have been compromised by disease or trauma. In such a circumstance, it would be useful to have a prosthesis which would allow the replacement of the same.

Summary Of The Invention

One object of the present invention is to provide a spine joint reconstruction assembly that replaces the intervertebral disc and one or more of the facet joints in order to restore the natural biomechanics of a spinal motion segment.

Another object of the present invention is to provide a method for reconstructing the spire joint by replacing the intervertebral disc and one or more of the facet joints in order to restore the natural biomechanics of a spinal motion segment.

Still another object of the present invention is to provide a kit for the reconstruction of multiple spine joints to replace intervertebral discs and facet joints in order to restore the natural biomechanics of a spinal motion segment.

In accordance with the present inventiqn, the preferred embodiment, the intervertebral di: c is excised and replaced with an artificial disci. This artificial disc may be a device such as is described by Stefee et al. in U.S. Pat. No. 5,071,437; Gil11 et al in U.S. Pat. No. 6,113,637; Bryan et al . in U.S. Pat. No. 6,001,130; Hedman et al. in U.S. Patent No. 4,759,769; Ray in U.S. Patent No. 5,527,312; Ray et al, in U.S. Pat. 5,824,093; Buttner-Janz in U.S Patent No, 5,401,269; and Serhan et al. in U.S. Patent No.

5,824,094; all which documents are hereby incorporated herein by reference. Alternatively, the artificial disc may be some other artificial disc of th_,e sort known in the art.

In addition to replacing the intervertebral disc, at least one of the facet joints is replaced, in accordance with the apparatus and methods described hereinafter. Alternatively, the facet joints may be replaced as described by Fitz in U.S. Pat. ISO. Re. 36,758; Martin in U.S. Pat. No. 6,132,464; and/or

Villaret et al. in International Patent PubJuication No,

WO 9848717A1, which documents are hereby incorporated herein by reference. Or one or more of the facet joints may be replaced by other apparatus and methods known in the art .

The present invention has several advantages over the prior art. For one thing, the present invention can provide a complete replacement of all ofl the articulation surfaces of a spine motion segment: the intervertebral disc and the facet joints. E roper disc height is restored while degenerated facet joints and the underlying painful bone is replaced. The prosthetic disc and prosthetic facet joints work together to reproduce the desired physiological range of motion and to provide low friction articulations, so that adjacent motion segments are returned to physiological levels of stress and strain. Furthermore, osteophytic growth can be concurrently removed, and the artificial disc and facet joint prosthesis together reestablish intervertebral and central foraminal spaces to ensure decompreε sion of any nerve structure. Thus, all sources of pain, such as pain associated with osteoarthritis, instability, and nerve compression, are removed while restoring full function of the spine motion segment.

Brief Description Of The Drawings

These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed cescription of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:

Fig. 1 is a perspective view of a portion of the spine;

Fig. 2 is a dorsal view of the portion of the spine shown in Fig. 1;

Fig. 3 is a lateral view of a spine joint reconstructed in accordance with one aspect of the present invention;

Fig. 4 is a dorsal view of the facet jcint shown in Fig. 3;

Fig. 5 is a perspective view of the impilanted left inferior facet prosthesis shown in Figs. 3 and 4;

Fig. 6 is a perspective view of the left inferior facet prosthesis shown in Figs. 3 and 4;

Fig. 7 is a cranial view of the implantjed left superior facet prosthesis shown in Figs. 3 and 4;

Fig. 8 is a perspective view of the left superior facet prosthesis shown in Figs. 3 and 4;

Fig. 9 is a perspective view of an alternate implanted left superior facet prosthesis; Fig. 10 is a perspective view of an alternate left superior facet prosthesis;

Fig. 11 is a lateral view of an alternative reconstructed spine joint;

Fig. 12 is a dorsal view of an alternative reconstructed spine joint;

Fig. 13 is a perspective view of the implanted left inferior facet prosthesis shown in Figs. 11 and 12;

Fig. 14 is a perspective view of the alternative left inferior facet prosthesis shown in Figs . 11 and 12;

•Fig. 15 is a cranial view of the alternative implanted left superior facet prosthesis shewn in Figs. 11 and 12;

Fig. 16 is a perspective view of the alternative left superior facet prosthesis shown in Figs . 11 and 12;

Fig. 17 is a perspective view of an alternate bearing surface for the superior facet prosthesis shown in Fig. 16;

Fig. 18 is a perspective view of a spir^e motion segment; Fig. 19 is a dorsal view of a bilateral facet joint reconstructed in accordance with the pjresent invention;

Fig. 20 is a lateral view of the bilatdral facet joint prosthesis shown in Fig. 19;

Fig. 21 is a dorsal view of the implanted inferior bilateral facet prosthesis shown in Figs. IS and 20;

Fig. 22 is an inferior view of the implanted inferior bilateral facet prosthesis shown irj Figs. 19 and 20;

Fig. 23 is a ventral view of the inferior bilateral facet prosthesis shown in Figs. 21 and 22;

Fig. 24 is a dorsal view of the implanted superior bilateral facet prosthesis shown in Figs. IE and 20;

Fig. 25 is a superior view of the implanted superior bilateral facet prosthesis shown irf Figs. 19 and 20;

Fig. 26 is a ventral view of the superior bilateral facet prosthesis shown in Figs. and 25;

Fig. 27 is a perspective view of an alternative embodiment of the superior bilateral facet prosthesis shown in Figs. 24 and 25; Fig. 28 is a dorsal view of a two level] facet joint replacement;

Fig. 29 is a lateral view of the two level facet joint replacement of Fig. 28; Fig. 30 is a dorsal view of the implanted four facet prosthesis shown in Figs. 28 and 29;

Fig. 31 is a perspective view of the fdur facet prosthesis shown in Fig. 30;

Fig. 32 is a perspective view of an alternative form of inferior bilateral facet prosthesis;

Fig. 33 is a perspective view of an implanted superior and inferior unilateral facet prosthesis;

Fig. 34 is a perspective view of the unilateral facet prosthesis shown in Fig. 33; Fig. 35 is a perspective view of a lumbar vertebra;

Fig. 36 is a perspective view of a novejl prosthesis that replaces the lamina, the four facets, the spinous process and the two transverse processes of a vertebra;

Fig. 37 is an anterior view of the prosthesis shown in Fig. 36; Fig. 38 is a perspective view of a vertebra which has been resected to receive the prosthesis shown in Fig. 36;

Fig. 39 is a perspective view of the prjosthesis shown in Fig. 36 mounted to the resected vertebra shown in Fig. 38;

Fig. 40 is a dorsal view of the prosth sis shown in Fig. 36 mounted to the resected vertebra shown in Fig. 38;

Fig. 41 is a lateral view of the prostrjesis shown in Fig. 36 mounted to the resected vertebra shown in Fig. 38;

Fig. 42 is a perspective view of a novel prosthesis that replaces the lamina, the four facets and the spinous process of a vertebra;

Fig. 43 is a perspective view of a novdl prosthesis that replaces the lamina, the four facets and the two transverse processes of a vertetra;

Fig. 44 is a perspective view of a novejl prosthesis that replaces the lamina and the four facets of a vertebra;

Fig. 45 is a perspective view of a novejl prosthesis that replaces the two pedicles, the lamina, the four facets, the spinous process and thd two transverse processes of a vertebra;

Fig. 46 is a lateral view of the prostrjesis shown in Fig. 45;

Fig. 47 is an anterior view of the prosthesis shown in Fig. 45;

Fig. 48 is a perspective view of a verηebra which has been resected to receive the prosthesis shown in Fig. 45;

Fig. 49 is a perspective view showing the prosthesis of Fig. 45 mounted to the resected vertebra shown in Fig. 48;

Fig. 50 is a perspective view of a novel prosthesis that replaces the two pedicles, the lamina, the four facets and the spinous process of a vertebra;

Fig. 51 is a perspective view of a novel prosthesis that replaces the two pedicles, the lamina, the four facets and the two transverse processes of a vertebra;

Fig. 52 is a perspective view of a novel prosthesis that replaces the two pedicles, the lamina and the- four facets of a vertebra; and Fig. 53 is a- perspective view showing an alternative arrangement for mounting the prcsthesis of Fig. 45 to a vertebra.

Detailed Description Of The Preferred Embodiments

Disc Prosthesis And Single Facet Prostihesis

Referring now to Figs. 1 and 2, there i s shown a superior vertebra 1 and an inferior vertebra 3, with an intervertebral disc 2 located in between. Vertebra 1 has superior facets 43, inferior facets 6, posterior arch 35 and spinous process 46. Vertebra 3 has superior facets 7, inferior facets 44, posterior arch 36 and spinous process 45.

Referring now to Fig. 3, in accordance with one aspect of the present invention, the intervdrtebral disc 2 has been replaced by an artificial disc AD. This artificial disc AD may be a device such as is described by Stefee et al. in U.S. Pat. No. 5,071,437; Gill et al. in U.S. Pat. No. 6,113,637; Bryan et al. in

U.S. Pat. No. 6,001,130; Hedman et al. in U. S. Patent No. 4,759,769; Ray in U.S. Patent No. 5,527, 312; Ray et al. in U.S. Pat. 5,824,093; Buttner-Janz in U.S. Patent No. 5,401,269; and Serhan et al. in U.S. Patient No. 5,824,094; all which documents are hereby incorporated herein by reference. Alternatively, the artificial disc may be some other artificial disc of the sort known in the art.

In addition to the foregoing, the left inferior facet 6 of vertebra 1 has been resected and an inferior facet prosthesis 4 has been attached to vertebra 1. Similarly, the left superior facet of vertetra 3 has been resected and a superior facet prosthesis 5 has been attached to vertebra 3.

Fig. 4 illustrates a dorsal view of the elements shown in Fig. 3. It can be appreciated that inferior facet prosthesis 4 replicates the natural anatomy when compared to the contralateral inferior facet 6 of vertebra 1. Similarly, it can be appreciated that superior facet prosthesis 5 replicates the natural anatomy when compared to the contralateral sjuperior facet 7 of vertebra 3.

Turning now to Fig. 5, a perspective view of vertebra 1 with implanted inferior facet prcsthesis 4 is provided'. Resection at 31 has removed tie natural inferior facet 6 at the bony junction betweejn the inferior facet 6 and the posterior arch 35. In this manner, bone pain associated with a disease, such as osteoarthritis, or trauma may be eliminated as the involved bony tissue has been osteotomized.

Fig. 6 illustrates a perspective view c f: inferior facet prosthesis 4. Surface 8 replicates the natural articular surface of the replaced inferior facet 6. Post 9 provides a means to affix inferior facet prosthesis 4 to vertebra 1. Post 9 is implanted into the interior bone space of the left pedicle P (Fig. 7) on vertebra 1 and may or may not extend intc the vertebral body of vertebra 1 to provide additional stability.

Fig. 7 illustrates a cranial view of vejrtebra 3 with implanted superior facet prosthesis 5. Resection surface 32 represents the bony junction between the natural superior facet and the posterior arch 35.

Fig. 8 illustrates a perspective view cf superior facet prosthesis 5. Surface 36 replicates the natural articular surface of the replaced superior facet 7. Post 37 provides a means for affixing superior facet prosthesis 5 to vertebra 3. Post 37 is implanted into the interior bone space of the left pedicle P (Fig. 7) on vertebra 3 and may or may not extend intd the vertebral body of vertebra 3 to provide add!tional stability.

When the total facet joint is replaced, as shown in Figs. 3 and 4, then surface 8 (Fig. 6) articulates with surface 36 (Fig. 8) to recreate the natural biomechanics of the spine motion segment made up of vertebra 1, vertebra 3, and intervertebral else 2.

Fig. 9 illustrates an alternative inferior facet prosthesis 10 which is implanted into the interior bone space of posterior arch 35. The interior bcne space is accessed from the resection 31.

Fig. 10 shows details of alternative inferior facet prosthesis 10, including the fin 13 that extends into the interior bone space of posterior arch 35. Surface 12 replicates the natural articular surface of the replaced facet.

If desired, a corresponding fin construction can be used to form a prosthetic superior facet.

The surfaces of post 9 (Fig. 6) , post , 7 (Fig. 8) and fin 13 (Fig. 10) may or may not include porous coatings to facilitate bone ingrowth to enhance the long term fixation of the implant. Furthermore, such porous coatings may or may not include osteqinductive or osteoconductive substances to further enhance the bone remodeling into the porous coating.

Referring now to Fig. 11, there is shown a lateral view of a superior vertebra 14 and an inferior vertebra 16, with an intervertebral disc 15 located in between is shown. The left inferior facet of vertebra 14 has been resected and an inferior facet prosthesis 18 has been attached to vertebra 14 by means of a screw fastener 17. Similarly, the left superior facet of vertebra 16 has been resected and a superior} facet prosthesis 19 has been attached to vertebra 16 by means of a screw fastener 17.

Fig. 12 illustrates a dorsal view of tie elements of Fig. 11. It can be appreciated that inferior facet prosthesis 18 replicates the natural anatomy when compared to the contralateral inferior facet 22 of vertebra 14. Similarly, it can be appreciated that superior facet prosthesis 19 replicates the natural anatomy when compared to the contralateral superior facet 21 of vertebra 16.

Turning now to Fig. 13, there is provided a perspective view of vertebra 14 with implanted inferior acet prosthesis 18. Resection 34 has removed the

substrate 42. The bearing surface 41 is a bioco patible polymeric material, such as ultra high molecular weight polyethylene. Alternately, the bearing surface can be ceramic, such as zirconia or alumina, or metal. The substrate is a bioccmpatible metal alloy, such as an alloy of titanium, cobalt, or iron.

Disc Prosthesis And Double Facet Prosthesis

Referring next to Fig. 18, there is shqwn a superior vertebra 1005 and an inferior vertebra 1010, with an intervertebral disc 1015 located in between.

Vertebra 1005 has superior facets 1020, inferior facets 1025, a lamina (also sometimes referred to as a posterior arch) 1030, a spinous process 1033, and pedicles 1040. Vertebra 1010 has superior facets 1045, inferior facets 1050, a posterior arch 1055, a spinous process 1060, and pedicles 1065 (only one off which is seen in Fig. 18) .

Referring now to Figs. 19 and 20, in accordance with another aspect of the invention, intervertebral disc 1015 has been replaced by an artificial disc AD. This artificial disc AD may be a device such as is described by Stefee et al. in U.S. Pat. No. 5,071,437; Gill et al . in U . S . Pat . No . 6, 113 , 637 ; Bryain et al . in

U.S. Pat. No. 6,001,130; Hed an et al. in U S. Patent No. 4,759,769; Ray in- U.S. Patent No. 5,527, 312; Ray et al. in U.S. Pat. 5,824,093; Buttner-Janz in U.S. Patent No. 5,401,269; and Serhan et al . in U.S. Patient No. 5,824,094; all which documents are hereby incorporated herein by reference. Alternatively, the artificial disc may be some other artificial disc of the sort known in the art .

In addition to the foregoing, the left and right inferior facets 1025 of vertebra 1005 have been resected at 1070 and a bilateral inferior facet prosthesis 1075 has been attached to vertebra 1005 using screw fasteners 1080. Similarly, the left and right superior facets 1045 of vertebra 1010 have been resected at 1082 (Fig. 24) and a bilateral superior facet prosthesis 1085 has been attached to vertebra 1010 using screw fasteners 1090.

In Fig. 20 it can be appreciated that bilateral inferior facet prosthesis 1075 replicates tie natural anatomy when compared to the intact inferior facet 1025 of vertebra 1005. Furthermore, bilateral fajcet prosthesis 1075 extends from its attachment point in a manner that does not require contact with, cjr mating to, the complex geometry of the lamina (or posterior arch) 1030. Resection surfaces 1070 provide adequate clearance for bilateral inferior facet prosthesis 1075 and provide complete removal of the diseased_, or traumatized natural inferior facets 1025.

Figs. 21 and 22 illustrate how the geometry of the bridge 1095 of bilateral inferior facet prosthesis 1075 matches that of the posterior arch 1030 of vertebra

1005 in order to provide adequate clearance for the central foramen 1100. Articular surfaces 1105 articulate with the opposing superior facets 1045 (or their prosthetic replacements) of the vertex: ra 1010.

Fig. 23 illustrates the bilateral inferior facet prosthesis 1075 with flanges 1110 that abut against the pedicles 1040 of vertebra 1005. Bridge 109 connects the articular surfaces 1105. Holes 1115 allow the attachment of bilateral inferior facet prosthesis 1075 to vertebra 1005 by means of screw fasteners 1080

Alternatively, screw fasteners 1080 could b replaced with staples, pins, tacks, anchors, modular fixation posts, or the like. These alternative fasteners could further include porous coatings to further enhance bony fixation, and could also include os.teocondudtive or osteoinductive substances.

In Fig. 24 it can be appreciated that bilateral superior facet prosthesis 1085 replicates the natural anatomy when compared^'to the intact superior facets 1045 of vertebra 1010. Furthermore, bilateral facet prosthesis 1085 extends from its attachment point in a manner that does not require contact with, cr mating td, the complex geometry of the lamina (or posterior arch) 1055. Resection surfaces 1082 provide adequate clearance for bilateral superior facet prosthesis 1085 and provide complete removal of the diseasec or traumatized natural superior facets 1045.

Fig. 25 illustrates how the geometry of} the bridge 1120 of bilateral superior facet prosthesis 1085 atches that of the posterior arch 1055 of λjertebra

1010 in order to provide adequate clearance for the central foramen 1125. Articular surfaces ll|30 articulate with the opposing inferior facetεj of the vertebra 1005.

Fig. 26 illustrates the bilateral supertior facet prosthesis 1085 with flanges 1135 that abut against the pedicles 1065 of vertebra 1010. Bridge 112C connects the articular surfaces 1130 (seen in Fig. 25} but not seen in Fig. 26) . Holes 1140 allow the attachment of bilateral superior facet prosthesis 1085 to vertebra 1010 by means of screw fasteners 1090.

Fig. 27 illustrates an alternative superior facet prosthesis 1085A with a bearing surface 113CA that mounts to substrate 1131A. The bearing surface 1130A is preferably a biocompatible polymeric material, such as ultra high- olecular weight polyethylene. Alternately, the bearing surface 1130A can he ceramic, such as zirconia or alumina. The substrate 1131A is preferably a' biocompatible metal alloy, such as an alloy of titanium, cobalt, or iron.

Fig. 28 illustrates a superior vertebra 1145, a middle vertebra 1150, and an inferior vertehra 1155. Superior facet prosthesis 1085 articulates with quad-facet prosthesis 1160 to recreate the natural biomechanics of the replaced facet joints, Inferior facet prosthesis 1075 articulates with quad- facet prosthesis 1160 to recreate the natural biomechanics of the replaced facet joints at the next upper level

Thus, Fig. 28 illustrates a two level reconstruction of facet joints. Superior facet prosthesis 108 5, quad-facet prosthesis 1160, and inferior facfet prosthesis 1075 are each attached to bone by means of screw fasteners 1165.

In the lateral view of Fig. 29, it can be appreciated that superior facet prosthesis 1085, quad-facet prosthesis 1160, and inferior facet prosthesis 1075 do not encroach into the intervertebral foraminal spaces 1167 where nerve roots extejnd laterally from the spinal cord.

Referring next to Fig. 30, it should be appreciated that superior bridge 1170 and inferior bridge 1175 of quad-facet prosthesis 1160 dc not contact any portion of vertebra 1150. Mounting holes 1180 (shown in Fig. 31) are used to secure tjhe flanges 1185 against the pedicles of vertebra 1150.

In Fig. 32, an alternative inferior bilateral facet prosthesis 1190 is presented. To further stabilize the implant and to counter moments that act upon the two points of fixation into the pedicles, a set of parallel flanges 1195 extend posteriorly such that the two flanges straddle the spinous process 1035. A bolt 1200 is used to fasten the parallel langes to the spinous process. 'Alternatively, other adjunctive structural features could be added to further stabilize the prosthesis. For example, a strut that extends, and attaches, to the transverse process could be used to further stabilize the prosthesis.

Looking next at Figs. 33 and 34, there is shown a superior and inferior unilateral facet prosthesis 1300. Unilateral facet prosthesis 1300 comprises a body 1305 and a stem 1310 extending out of body 1305. A superior element 1315 extends vertically upward from body 1305, and an inferior element 1310 extends vertically downward from body 1305. Unilateral facet prosthesis 1300 is configured so that when its stem 1310 extends into the pedicle of vertebra 1325, superior element 1315 will replace a resected superior facet, and inferior element 1320 will replace a resected inferior facet. If desired, stem 1310 could be replaced with a screw extending through a hole in body 1305 and into the pedicle.

Disc Prosthesis And Quadruple Facet Prosthesis

Referring next to Fig. 35, there is shewn a natural lumbar vertebra 2005 comprising a na tural vertebral body 2010, a pair of natural pedi les 2015 extending from natural vertebral body 2010, a natural lamina 2020 extending from natural pedicles 2015, a pair of natural superior facets 2025 extending from natural pedicles 2015 and natural lamina 202 0, a pair of natural inferior facets 2030 extending frjom natural lamina 2020, a natural spinous process 2035 extending from natural lamina 2020, and a pair of natural transverse processes 2040 extending from natjural pedicles 2015.

In accordance with another aspect of the invention, the intervertebral disc on one side or the other of vertebral body 2010 is replaced by an artificial disc. This artificial disc may he a device such as is described by Stefee et al. in U.£. Pat. No. 5,071,437; Gill et al . in U.S. Pat. No. 6,113,637; Bryan et al. in U.S. Pat. No. 6,001,130; Hecman et al. in U.S. Patent No. 4,759,769; Ray in U.S. Patent No. 5,527,312; Ray et al. in U.S. Pat. 5,824,092; Buttner- Janz in U.S. Patent No. 5,401,269; and Serhen et al . in U.S. Patent No. 5,824,094; all which documents are hereby incorporated herein by reference. Alternatively, the artificial disc may be scjme other artificial disc of the sort known in the art . In addition to the foregoing, and looking next at Figs. 36 and 37, there is shown a novel prosthesis 2100 which is adapted to replace the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040. To this end, prosthesis 2100 comprises a pair of prcsthetic mounts 2115, a prosthetic lamina 2120 extenc.ing from prosthetic mounts 2115, a pair of prosthetic superior facets 2125 extending from prosthetic mounts 2115 and prosthetic lamina 2120, a pair of prosthetic inferior facets 2130 extending from prosthetic lamina 2120, a prosthetic spinous process 2135 extending from prosthetic lamina 2120, and a pair of prosthetic transverse processes 2140 extending from prcsthetic mounts 2115.

In the use of prosthesis 2100, natural lumbar vertebra 2005 is resected at its natural pecicles 2015 so as to remove the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, leaving a pair of pedicle end surfaces 2041 (Fig. 38) . Thqn the prosthesis 2100 may be attached to the natu al pedicles 2015, e.g., by placing prosthetic mounts 2115 against pedicle surfaces 2041 and then passing screws 2145 through screw holes 2147 and into natural pediicles 2015, as shown in Figs. 39-41. As seen in the drawings, the relative size, shape and posit ioning of the prosthetic lamina 2120, the two prosthet ic superior facets 2125, the two prosthetic inferior facets 2130, the prosthetic spinous process 2135, and the two prosthetic transverse processes 2140 essenti ally mimic the relative size, shape and positioning of the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, whereby to effectively restore the vertebra. If desired, holes 2150 may be provided in the p rosthetic spinous process 2135 and/or the two prosthet ic transverse processes 2140 so as to facilitat e re-attaching soft tissue to these structures Looking next at Fig. 42, there is showr a novel prosthesis 2200 which is adapted to replace natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, and natur 1 spinous process 2035. To this end, prosthesis 2200 comprises a pair of prosthetic mounts 2215, a prosthetid lamina 2220 extending from prosthetic mounts 2215, a pair of prosthetic superior facets 2225 extending from prosthetic mounts 2215 and prosthetic lamina 2220, a pair of prosthetic inferior facets 2230 extending from prosthetic lamina 2220, and a prosthetic spinous process 2235 extending from prosthetic lamina 2220

In the use of prosthesis 2200, natural lumbar vertebra 2005 is resected at its natural pedicles 2015 so as to remove the natural lamina 2020, the} two natural superior facets 2025, the two natur 1 inferior facets 2030, the spinous process 2,035 and tliie two natural transverse processes 2040, leaving a pair of pedicle surfaces 2041 (Fig. 38) . Then the prosthesis 2200 may be attached to the natural pedicles 2015, e.g., by placing prosthetic mounts 2215 against pedicle surfaces 2041 and then passing screws 2145 tjhrough holes 2247 and into natural pedicles 2015, As seen in the drawing, the relative size, shape and pd:sitioning of prosthetic lamina 2220, the two prosthetiic superior facets 2225, the two prosthetic inferior facets 2230, and the prosthetic spinous process 2235 essentially mimic the relative size, shape and positioning of the natural lamina 2020, the two natural supericr facets 2025, the two natural inferior facets 2030, and the natural spinous process 2035, whereby to effectively restore the vertebra. If desired, holes 2150 may be provided in the prosthetic spinous process 2235 so as to facilitate re-attaching soft tissue to this structure.

Looking next at Fig. 43, there is shown¹ a novel prosthesis 2300 which is adapted to replace the natura lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, and the two natural transverse processes 2040. To this end, prcsthesis 2300 comprises a pair of prosthetic mounts 2315, a prosthetic lamina 2320 extending from prosth etic mounts 2315, a pair of prosthetic superior facets 2325 extending from prosthetic mounts 2315 and prosthetic lamina 2320, a pair of prosthetic inferior facets 2330 extending from prosthetic lamina 2320, and a pair of prosthetic transverse processes 2340 extending from prosthetic mounts 2315.

In the use of prosthesis 2300, natural lumbar vertebra 2005 is resected at natural pedicles 2015 so as to remove natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035 and the two natural transverse processes.2040, leaving a. pair of pedicle surfaces 2041 (Fig. 38) . Then the prosthesis 2300 may be attached to the natural pedicles 2015, e.g., by placing prosthetic mounts 2315 against pedicle surfaces 2041 and then passing screws 2145 -through holes 2347 and into natural pedicles 2015. As seen in the drawing, the relative size, shape and positioning of the prosthetic lamina 2320, the two prosthetic superior facets 2325, the two prosthetic inferior facets 2330, and the two prosthetic transverse processes 2340 essentially mimic the relativie size, shape and positioning of the natural lamina 2020, the two natural superior facets 2025, the two naitural inferior facets 2030, and the two natural transverse processes 2040, whereby to effectively restcre the vertebra. If desired, holes 2150 may be prcvided in the two prosthetic transverse processes 234Q so as to facilitate re-attaching soft tissue to these, structures. Looking next at Fig. 44, there is shown a novel prosthesis 2400 which; is adapted to replace the natural lamina 2020, the two natural superior facets 2025, and the two natural inferior facets 2030. To this end, prosthesis 2400 comprises a pair of prosthetic mounts 2415, a prosthetic lamina 2420 extending from prosthetic mounts 2415, a pair of prosthetic superior facets 2425 extending from prosthetic mounts 2415 and prosthetic lamina 2420, and a pair of prosthetic inferior facets 2430 extending from prosthetic lamina 2420.

In the use of prosthesis 2400, natural lumbar vertebra 2005 is resected at pedicles 2015 so as to remove the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, leaving a pair of pedicle surfaces 2041 (Fig. 38). Then the prosthesis 2400 may be attached to the natural pedicles 2015, e.g., by placing prosthetic mounts 2415 against pedicle surfaces 2041 and then passing screws 2145 through holes 2447 and into natural pedicles 2015. As seen in the drawing, the relative size, shape and pcsitioning of prosthetic lamina 2420, the two prosthetic superior facets 2425, and the two prosthetic inferior facets 2430 essentially mimic the relative size, slape and positioning of the natural lamina 2020, the two natural superior facets 2025 and the two natural inferior facets 2030, whereby to effectively restore the vertebra.

Looking next at Figs. 45-47, there is shown a novel prosthesis 2500 which is adapted to replace a pair of natural pedicles 2015, the natural 1 amina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 204 0. To this end, prosthesis 2500 comprises a pair of pre sthetic pedicles 2515, a prosthetic lamina 2520 extending from prosthetic pedicles 2515, a pair of prosthetic superior facets 2525 extending from prosthetic pedicles 2515 and prosthetic lamina 2520, a pair of prosthetic inferior facets 2530 extending from prosthetic lamina 2520, a prosthetic spinous process 2535 extending from prosthetic lamina 2520, and a pair of prosthetic transverse processes 2540 extending from prcsthetic pedicles 2515. In the use of prosthesis 2500, natural lumbar vertebra 2005 is resected at the bases of natural pedicles 2015 so as to remove to two natural pedicles 2015, the natural lu ina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, leaving a vertebral body end face 2042 (Fig. 48) . Then the prosthesis 2500 may be attached to the natural vertebral body 2010, e.g., by placing prosthetic pedicles 2515 against vertebral body end face 2042 and then passing screws 2145 through holes 2547 and into natural vertebral body 2010, as shown in Fig. 49. As seen in the drawings, the relative size, shape and positioning of the two prosthetic pedicles 2515, the prosthetic lamina 2520, the two prosthetic superior facets 2525, the two prosthetic inferior facets 2530, the prosthetic spinous process 2535, and the two prosthetic transverse processes 2540 essentially mimic the relative size, shape and positioning of the two natural pecicles 2015, the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, whereby to effectively restore the vertebra. If desired, holes 215J0 may be provided in prosthetic spinous process 2535 and the two prosthetic transverse processes 2540 so as t facilitate re-attaching soft tissue to these structures.

Looking next at Fig. 50, there is shown¹ a novel prosthesis ^' 2600 which is adapted to replace the two natural pedicles 2015, the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, and the natural spinous process 2035. To this end, prosthesis 2600 comprises a pair cf prosthetic pedicles 2615, a prosthetic lamira 2620 extending from prosthetic pedicles 2615, a pair of prosthetic superior facets 2625 extending from prosthetic pedicles 2615 and prosthetic lamina 2620, a pair of prosthetic inferior facets 2630 extending from prosthetic lamina 2620, and a prosthetic spinous process 2635 extending from prosthetic lamina 2620.

In the use of prosthesis 2600, natural lumbar vertebra 2005 is resected at the bases of natural pedicles 2015 so as to remove the two natural pedicles 2015, the natural lamina 2020, the two naturjal superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035 and the two natural transverse processes 2040, leaving a vertebral body end face 2042 (Fig. 48) . Then the prosthesis 2600 may be attached to the natural vertebral body 2010, e.g., by placing prosthetic pedicles 2615 against vertebral body end face 2042 and then passing screws 2145 through holes 2647 and into natural vertebral body 2010. As seen in the drawing, the relative size, shape and positioning of the two prosthetic pedicles 2615, the prosthetic lamina 2620, the two prosthetic superior facets 2625, the two prosthetic inferior facets 2630, and the prosthetic spinous process 2635 essentially mimic the relative size, shape and positioning of the two natural pedicles 2015, the natural la ira 2020, the two natural superior facets 2025, the two natural inferior facets 2030, and the natural spinous process 2035, whereby to effectively restore the vertebra. If desired, holes 2150 may be provided in prosthetic spinous process 2635 so as to facilitate re-jattaching soft tissue to this structure.

Looking next at Fig. 51, there is showri a novel prosthesis 2700 which is adapted to replace the two natural pedicles 2015, the natural lamina 2C20, the two natural superior facets 2025, the two natural inferior facets 2030, and the two natural transverse processes 2040. To this end, prosthesis 2700 comprises a pair of prosthetic pedicles 2715, a prosthetic lamira 2720 extending from prosthetic pedicles 2715, a pair of prosthetic superior facets 2725 extending from prosthetic pedicles 2715 and prosthetic lamina 2720, a pair of prosthetic inferior facets 2730 extending from prosthetic lamina 2720, and a pair of prosthetic transverse processes 2740 extending from pr sthetic pedicles 2715.

In the use of prosthesis 2700, natural lumbar vertebra 2005 is resected at the bases of natural pedicles 2015 so as to remove the two natural pedicles 2015, the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, leaving a vertebral body end face 2042 (Fig. 48). Then the prosthesis 2100 may be attached to the^" natural vertebral body 2010, e.g., by placing prosthetic pedicles 2715 against vertebral body end face 2042 and then passing screws 2145 tjhrough holes 2747 and into vertebral body 2010. As! seen in the drawing, the relative size, shape and pcsitioning of the two prosthetic pedicles 2715, the prcsthetic lamina 2720, the two prosthetic superior facets 2725, the two prosthetic inferior facets 2730, anc the two prosthetic transverse processes 2740 essentially mimic the relative size, shape and positioning of the two natural pedicles 2015, the natural lamina 2C20, the two natural superior facets 2025, the two natural inferior facets 2030, and the two natural transverse processes 2040, whereby to effectively restore the vertebra. If desired, holes 2150 may be provided in the two prosthetic transverse processes 2740 so as to facilitate re-attaching soft tissue to these structures.

Looking next at Fig. 52, there is showrj. a novel prosthesis 2800 which is adapted to replace the two natural pedicles 2015, the natural lamina 2C 20, the two natural superior facets 2025, and the two natural inferior facets 2030. To this end, prosthe≤ is 2800 comprises a pair of prosthetic pedicles 281 prosthetic lamina 2820 extending from prosthjetic pedicles 2815, a pair' of prosthetic superior facets 2825 extending from prosthetic pedicles 2815] and prosthetic lamina 2820, and a pair of prosthetic inferior facets 2830 extending from prosthetic lamina 2820.

In the use of prosthesis 2800, natural lumbar vertebra 2005 is resected at the bases of natural pedicles 2015 so as to remove the two natural pedicles 2015, the natural lamina 2020, the two natural superior facets 2025, the two natural inferior facets 2030, the natural spinous process 2035, and the two natural transverse processes 2040, leaving a vertebral body end face 2042 (Fig. 48). Then the prosthesis 2£00 may be attached to natural vertebral body 2010, e.c., by placing prosthetic pedicles 2715 against vertebral body end face 2042 and then passing screws 2145 through holes 2847 and into natural vertebral body 2010. As seen in the drawing, the relative size, shape and positioning of the two prosthetic pedicles 2815, the prosthetic lamina 2820, the two prosthetic superior facets 2825, and the two prosthetic inferior facets 2830 essentially mimic the relative size, shape and positioning of the two natural pedicles 2015, the natural lamina 2020, the two natural supericr facets 2025, and the two natural inferior facets 2CJ30, whereby to effectively restore the vertebra.

It should also be appreciated that prostheses 2100, 2200, 2300, 2400, 2500, 2600, 2700 anc 2800 may be attached to natural vertebra 2005 with apparatus other than the screws 2145 discussed above, Thus, for example, prostheses 2100, 2200, 2300, 2400, 2500, 2600,

2700 and 2800 may be attached to natural vertebra 2005 with rods or posts, etc. See, for example, Fig. 53, where prosthesis 2500 is shown attached to natural vertebra 2005 with rods 2146 which pass through, and snap into engagement with, prosthetic pedicles 2515.

Having thus described preferred embodiments of the invention with reference to the accompanyinc drawings, it is to be understood that the embodiments shown herein are provided by way of example only, and that various changes and modifications may be effected by one skilled in the art without departing from the .scope

)r spirit of the invention as defined in the} claims.

Claims

What Is Claimed Is:

1. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of at least a portion of the bone of a facet located on a [mammalian vertebra, comprising: a surface that articulates with another facet surface; and a fixation portion that is implantjed into an interior bone space of said vertebra, said surface being connected to sajid fixation portion; wherein said artificial disc and said prosthesis cooperate so as to restore the natural biom chanics of a spinal motion segment.

2. The kit of claim 1 wherein said fixation portion is a post that is adapted to be fittjed into the interior bone space o a pedicle.

3. The kit of claim 2 wherein said pcjst is porous coated to allow for bone ingrowth.

4. The kit of claim 3 wherein said porous coating includes osteoconductive or osteoincuctive substances.

5. The kit of claim 1 wherein said fixation portion is a fin that 'is adapted to be fittqd into the

10 interior bone space of the posterior arch.

6. The kit of claim 5 wherein said fin is porous coated to allow for bone ingrowth.

15.

7. The kit of claim 6 wherein said pcrous coating includes osteoconductive or osteoincuctive substances.

8. The kit of claim 1 wherein said surface that

20 articulates is comprised of one of a group consisting of a polymeric bearing material attached to a metal substrate, a ceramic bearing material, and a metal bearing material.

9. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of at least a portion of the bone of a facet located on a mammalian vertebra, comprising: a surface that articulates with another facet; a bone contacting surface that contacts one of an exterior surface or a resected surface of said vertebra, said surface that articulates beiηg connected to said bone contacting surface; and a fixation element that attaches S^al^d bone contacting surface to -said vertebra; and wherein said prosthesis is coη'figured so that no portion of said prosthesis contacts the posterior arch of said vertebra; and wherein said artificial disc and said prosthesis cooperate so as to restore the natural biomechanics of a spinal motion segment.

10. The kit of claim 9 wherein said fixation element is a screw.

11. The kit of claim 9 wherein said flange has a bone side adapted to contact one of said exterior surface or said resected surface of said vertebra, wherein said bone side is porous coated to allow for bone ingrowth.

12. The kit of claim 9 wherein said surface that articulates is comprised of one of a group consisting of a polymeric bearing material attached to a metal substrate, a ceramic bearing material, and a metal bearing material.

13. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of at least a portion of the bones of opposed and articulating facets located on a mammalian vertebra, where said facets are diseased or traumatized, comprising: an inferior component adapted to h e attached to a first vertebra and having a first fixat ion portion adapted to be implanted into a first interic r bone space and a first articulation portion connected to said first fixation portion; a superior component adapted to be attached to a second vertebra and having a second fixation portion adapted to be implanted into a second interior bone space and second articulation portion connected to said second fixation portion; where the first vertebra is adjacent and superior to the second vertebra; and wherein said artificial disc and said prosthesis cooperate so as to restore the natural biomechanics of a spinal motion segment.

14. A kit for spine joint replacement} comprising: an artificial disc; and a prosthesis for the replacement of at least a portion of the bones of opposed and articulating facets located on a mammalian vertebra, comprising: an inferior component adapted to he attached to a first vertebra ; and a superior component adapted to be} attached to a second vertebra; where the first vertebra is adjacent and superior to the second vertebra; and where one of said inferior and superior components includes: a flange that connects to one of an exterior surface or a resected surface of said vertebra; and a fixation element that attaqhes said flange to said vertebra; and further wherein of said prosthesis is configured so that no portion of said prosthesis contacts the posterior arch of said vertebra ; and wherein said artificial disc and said prosthesis cooperate so as to restore the natural biomechanics of a spinal motion segment.

15. A method for replacing a spine joint, comprising the steps of: replacing an intervertebral disc with an artificial disc; resecting at least a portion of the boije of a facet; attaching a prosthetic facet to the regaining bone of said vertebra such that no portion of the prosthetic facet contacts the posterior arch of said vertebra; where said prosthetic facet is adapted to articulate with another facet; with the artificial disc and the prosthetic facet cooperating so as to restore the natural biomechanics of a spinal motion segment.

16. A method for replacing a spine joijnt, comprising the steps of: replacing an intervertebral disc with ajn artificial disc- resecting at least a portion of the boήe of a first facet on a first vertebra; attaching a first prosthetic facet to the remaining bone of said first vertebra such that no portion of said prosthetic facet contacts the posterior arch of said vertebra; resecting at least a portion of the boη'e of a second facet on a second vertebra; and attaching a second prosthetic facet to the remaining bone of said second vertebra such that no portion of said prosthetic facet contacts thje posterior arch of said vertebra; where said first prosthetic facet is adapted to articulate with said second prosthetic facet ; with the artificial disc and the prosthetic facet cooperating so as to restore the natural bicmechanics of a spinal motion segment.

17. A kit for spine joint replacement, comprising: an artificial disc; and a prosthesis for the replacement of at Least two facets located on a mammalian vertebra, comprising: at least one bone contacting surface that is adapted to be secured to a surface of the vertebra; and at least two bearing surfaces. for articulating with other facets, said at least two bearing surfaces being connected to said at least one bone contacting surface; and wherein no portion of said prdsthesis is supported by the lamina of the vertebra; and wherein said artificial disc and said prosthesis cooperate so as to¹ restore the natural biomechanics of a spinal motion segment.

18. The kit of claim 17 further comprising fixation elements for securing said at least) one bone contacting surface to the vertebra.

19. The kit of claim 18 wherein said fixation elements are screws.

20. The kit of claim 17 wherein said a least bone contacting surface is porous coated to allow for bone ingrowth.

21. The kit of claim 20 wherein said porous coating includes at least one from a group comprising osteoinductive and osteoconductive substances.

22. The kit of claim 17 wherein said bearing surfaces are formed from a material selectee, from the group consisting of a ceramic, a metal and a polymer.

23. The kit of claim 17 wherein said prosthesis is configured so that said at least two bearing surfaces are adapted to replace a pair of inferior facets .

24. The kit of claim 17 wherein said prosthesis is configured so that said at least two bearing - surfaces are adapted to replace a pair of superior facets .

25. The kit of claim 17 wherein said prosthesis is configured so that said at least two bearfing surfaces are adapted to replace an inferior facet and a superior facet.

26. The kit of claim 17 wherein said prosthesis is configured so that said at least two bearing surfaces are adapted to replace a pair of inferior facets and a pair of superior facets.

27. A method for replacing a spine joint, comprising the steps of: replacing an intervertebral disc with ejn artificial disc; resecting a pair of facets on the vertebra; and attaching a prosthesis to the vertebra so that a pair of bearing surfaces on the prosthesis are positioned in place of the resected facets, wherein the prosthesis is configured so that no portion of said prosthesis is supported by the lamina of thd vertebra; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

28. A method for replacing a spine joi|nt, comprising the steps of: replacing an intervertebral disc with an artificial disc- resecting at least a bony portion of thje inferior facets of a superior vertebra; attaching a first prosthesis that replaces said inferior facets of said superior vertebra; resecting at least a bony portion of thje superior facets of an inferior vertebra; and attaching a second prosthesis that replaces said superior facets of said inferior vertebra; wherein no portion of said first prosthesis is supported by the lamina of said superior vertebra, and further wherein no portion of said second prosthesis is supported by the lamina of said inferior vertebra; with the artificial disc and the first sprosthesis and the second prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

29. A method for replacing a spine joint, comprising the steps of: replacing an intervertebral disc with n artificial disc- resecting at least a bony portion of th}e inferior facets of a most superior vertebra; attaching a first prosthesis that replaces said inferior facets of said most superior vertebra; resecting at least a bony portion of the superior facets of a most inferior vertebra; attaching a second prosthesis that replaces said superior facets of said most inferior vertebra; resecting at least a bony portion of all of the facets of at least one intermediate vertebra^ located i between said most superior vertebra and said most inferior vertebra; wherein, for each of said at least one intermediate vertebra, .a prosthesis is attached that replaces all facets of said intermediate vertebra; with the artificial disc and the prostheses cooperating so as to restore the natural biomechanics of a spinal motion segment.

30. A spinal implant kit comprising: an artificial disc; and one facet prosthesis adapted to replace two superior facets; one facet prosthesis adapted to replace} two inferior facets; and one facet prosthesis adapted to replacej two superior facets and two inferior facets; with the artificial disc and the prostheses cooperating so as to restore the natural biomechanics of a spinal motion segment.

31. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a pJair of spinal facets, said prosthesis comprising: a first vertical member having a first end and a second end, said first end being adapted for disposition against, and attachment to, a first pedicle of a vertebra, and said second end comprisirg a bearing surface for engagement with a facet of an adjacent vertebra; a second vertical member having a first end and a second end, said first end being adapted for disposition against, and attachment to, the other pedicle of the vertebra, said second end comprising a bearing surface with a facet of an adjacent vertebra; and a bridge connecting said second end of said first vertical member to said second end of said second vertical member; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

against, and attached to, the other pedicle of the vertebra.

33. A spinal implant kit comprising: an artificial disc; and a superior facet prosthesis adapted to replace two superior facets; an inferior facet prosthesis adapted tq replace two inferior facets; wherein no portion of said superior facet prosthesis is supported by a lamina of a vertebra; and wherein no portion of said inferior facet prosthesis is supported by a lamina of a vertebra; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

34. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a pair of spinal facets, said prosthesis comprising: a first vertical member having a first end and a second end, said first end being adapted for disposition against, and attachment to, a first pedicle of a vertebra, and said second end comprising a bearing surface for engagement with a facet of an acjacent vertebra; a second vertical member having a first end and a second end, said first end being adapted for disposition against, and attachment to, the other pedicle of the vertebra, said second end comprising a bearing surface with a facet of an adjacent vertebra; and a bridge connecting said first vertical member to said second vertical member; wherein said first vertical member}, said second vertical member and said bridge are formed so j that said prosthesis is displaced from the liamina of the vertebra when said first end of said first vertical member is disposed against, and attached to, the first pedicle of a vertebra and said first end of said second vertical member is disposed against, and attached to, the other pedicle of the vertebra; with the artificial disc and the prosthesis

I cooperating so as to restore the natural biomechanics of a spinal motion segment.

35. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the r atural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the tw,o natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the naturajl lamina, a pair of natural inferior facets extending rom the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natur-al transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic mounts; a prosthetic lamina extending from said two prosthetic mounts; a pair of prosthetic superior facets extending from said two prosthetic mounts arid said prosthetic lamina; a pair of prosthetic inferior facets extending from said prosthetic lamina; a prosthetic spinous process extending from said prosthetic lamina; and a pair of prosthetic transverse processes extending from said two prosthetic mounts; with the artificial disc and the prosth'esis cooperating so as to restore the natural biqmechanics of a spinal motion segment.

36. The kit of claim 35 wherein at least one of said prosthetic spinous process and said twc prosthetic transverse processes includes at least one opening for attaching soft tissue to said prosthesis.

37. The kit of claim 35 wherein said two prosthetic mounts comprise openings for attaching said prosthesis to the natural vertebra;

38. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the r atural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the tvjo natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic mounts; a prosthetic lamina extending froπ} said two prosthetic mounts; a pair of prosthetic superior facets extending from said two prosthetic mounts and said prosthetic lamina; a pair of prosthetic inferior facets extending from said prosthetic lamina; and a prosthetic spinous process extending from said prosthetic lamina; with the artificial disc and the prosthesis i cooperating so as to restore the natural biomechanics of a spinal motion segment.

39. The kit of claim 38 wherein said prosthetic spinous process includes at least one opening for attaching soft tissue to said prosthesis.

40. The kit of claim 38 wherein said two prosthetic mounts comprise openings for attaching said prosthesis to the natural vertebra.

41. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the natural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the tvfo natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two Ijnatural pedicles, said prosthesis comprising: a pair of prosthetic mounts; a prosthetic lamina extending from said two prosthetic mounts; a pair of prosthetic superior facets extending from said two prosthetic mounts ar.d said prosthetic lamina; a pair of prosthetic inferior facets extending from said prosthetic lamina; and a pair of prosthetic transverse processes extending from said two prosthetic mounts; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

42. The kit of claim 41 wherein at least one of j said two prosthetic transverse processes includes at least one opening for attaching soft tissue to said prosthesis .

43. The kit of claim

prosthetic mounts comprise openings for attach ng said prosthesis to the natural vertebra.

44. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the r.atural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the tvf<o natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic mounts; a prosthetic lamina extending from said two prosthetic mounts; a pair of prosthetic superior facets extending from said two prosthetic mounts arid said prosthetic lamina; and a pair of prosthetic inferior facdts extending from said prosthetic lamina; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

45. The kit of claim 44 wherein said tjwo prosthetic mounts comprise openings for attaching said prosthesis to the natural vertebra.

46. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the r atural vertebra comprises a natural vertebral body, a pair of atural pedicles extending from the natural vertebral

a

transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic pedicles; a prosthetic lamina extending front said two prosthetic pedicles; a pair of prosthetic superior facejts extending from said two prosthetic pedicles and said prosthetic lamina; a pair of prosthetic inferior facets extending from said prosthetic lamina; a prosthetic spinous process extending from said prosthetic lamina; and a pair of prosthetic transverse processes extending from said two prosthetic pedicles; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

47. The kit of claim 46 wherein at least one of said pro.s±letic spinous process and said two prosthetic transverse processes includes at least one opening for attaching soft tissue to said prosthesis.

48. The kit of claim 46 wherein said two prosthetic pedicles comprise openings for attaching said prosthesis to the natural vertebra.

49. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the natural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the twco natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending fjrom the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic pedicles; a prosthetic lamina extending from said two prosthetic pedicles; a pair of prosthetic superior facejts extending from said two prosthetic pedicles and said prosthetic lamina; a pair of prosthetic inferior fac ts extending from said prosthetic lamina; and a prosthetic spinous process extending from said prosthetic lamina; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

50. The kit of claim 49 wherein said prosthetic spinous process includes at least one opening for attaching soft tissue to said prosthesis.

51. The kit of claim 49 wherein said two prosthetic pedicles comprise openings for attaching said prosthesis to the natural vertebra.

52. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the natural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the two natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic pedicles; a prosthetic lamina extending fro said two prosthetic pedicles; a pair of prosthetic superior facdts extending from said two prosthetic pedicles and said prosthetic lamina; a pair of prosthetic inferior facets extending from said prosthetic lamina; and a pair of prosthetic transverse processes extending from said two prosthetic pedicles; with the artificial disc and the prosthesis cooperating so as to restore the natural biqmechanics of a spinal motion segment.

53. The kit of claim 52 wherein at le; st one of said two prosthetic transverse processes includes at least one opening for attaching soft tissue to said prosthesis .

54. The kit of claim 52 wherein said two prosthetic pedicles comprise openings for attaching said prosthesis to the natural vertebra.

55. A kit for spine joint replacement comprising: an artificial disc; and a prosthesis for the replacement of a posterior element of a natural vertebra, wherein the natural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the t o natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two natural pedicles, said prosthesis comprising: a pair of prosthetic pedicles; a prosthetic lamina extending froi said two prosthetic pedicles; a pair of prosthetic superior facets extending from said two prosthetic pedicles and said prosthetic lamina; and a pair of prosthetic inferior facets extending from said prosthetic lamina; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

56. The kit of claim 55 wherein said two prosthetic pedicles comprise openings for attaching said prosthesis to the natural vertebra.

57. A method for replacing a spine joint, wherein the natural vertebra comprises a natural vertebral body, a pair of natural pedicles extending from the natural vertebral body, a natural lamina extending from the two natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the two natural pedicles, said method comprising the steps of: replacing an intervertebral disc with an artificial disc; making a resection at the most dorsal dspect the two natural pedicles; and attaching a prosthesis to the resected vertebra, said prosthesis comprising a pair of prosthetic mounts, a prosthetic lamina extending from said two prosthetic mounts, a pair of prosthetic superior facets} extending from said two prosthetic mounts and said prcsthetic lamina, and a pair of prosthetic inferior facets extending from said prosthetic lamina; with the artificial disc and the prosthesis cooperating so as to restore the natural biomechanics of a spinal motion segment.

58. A method according to claim 57 whe rein said prosthesis further comprises a prosthetic sp inous process extending from said prosthetic lamir.a.

59. A method according to claim 57 wherein said prosthesis further comprises a pair of prosthetic transverse processes extending from said two prosthetic mounts .

60. A method according to claim 57 wh rein said prosthesis further comprises a prosthetic spinous process extending from said prosthetic lamir a and a pair of prosthetic transverse processes extending from said two prosthetic mounts and said prosthetic lamina.

61. A method for replacing a spine joi]nt, wherein the natural vertebra comprises a natural vertebral body, a pair of natural pedicles extending fjrom the natural vertebral body, a natural lamina extending from the two natural pedicles, a pair of natural superior facets extending from the two natural pedicles and the natural lamina, a pair of natural inferior facets extending from the natural lamina, a natural spinous process extending from the natural lamina, and a pair of natural transverse processes extending from the natural pedicles, said method comprising the, steps of: replacing an intervertebral disc with an artificial discmaking a resection at the junction of the natural vertebral body and the two natural pedicles; and attaching a prosthesis to the resected vertebra, said prosthesis comprising a pair of prosthetic pedicles, a prosthetic lamina extending from said prosthetic pedicles, a pair of prosthetic superior facets extending from said two prosthetic pedicles and said prosthetic lamina, and a pair of prosthetic inferior facets extending from said prosthetic lamina; with the artificial disc and the prosthesis cooperating so as to restore the natural biqmechanics of a spinal motion segment.

62. A method according to claim 61 wherein said prosthesis further comprises a prosthetic spinous process extending from said prosthetic lamiria.

63. A method according to claim 61 wherein said prosthesis further comprises a pair of prostihetic transverse processes extending from said twcj prosthetic pedicles .

64. A method according to claim 61 whdrein said prosthesis further comprises a prosthetic spinous process extending from said prosthetic lamiria and two prosthetic transverse processes extending from said two prosthetic pedicles and said prosthetic lamina.