In the treatment of diseases, injuries or malformations affecting spinal motion segments, and especially those affecting disc tissue, it has long been known to remove some or all of a degenerated, ruptured or otherwise failing disc. In cases involving intervertebral disc tissue that has been removed or is otherwise absent from a spinal motion segment, corrective measures are indicated to insure the proper spacing of the vertebrae formerly separated by the removed disc tissue. Sometimes, the two adjacent vertebrae are fused together using transplanted bone tissue, an artificial fusion component, or other compositions or devices. Other times, different types of intervertebral disc arthroplasty devices have been employed to prevent the collapse of the intervertebral space between adjacent vertebrae while maintaining a certain degree of stability and range of pivotal and rotational motion therebetween. Such devices typically include two or more articular components that are attached to respective upper and lower vertebrae. The articular components are anchored to the upper and lower vertebrae by a number of methods, including the use of bone screws that pass through corresponding openings in each of the elements and thread into vertebral bone, and/or by the inclusion of spikes or teeth that penetrate the vertebral endplates to inhibit migration or expulsion of the device. The articular components are typically configured to allow the elements, and correspondingly the adjacent vertebrae, to pivot and/or rotate relative to one another.
However, it is not always possible to determine a priori whether a fusion approach or an articulating joint approach is appropriate for a given situation. Further, it may be necessary to change the type or size of the articulating joint, and/or to change from an articulating joint to a fusion joint, after a first articulating joint has been installed. As such, there remains a need for intervertebral prosthesis systems that address one or more of these problems.
The present invention relates generally to a modular intervertebral prosthesis system and a method of using the same. While the actual nature of the invention covered herein can only be determined with reference to the claims appended hereto, certain forms of the invention that are characteristic of embodiments disclosed herein are described briefly as follows.
One embodiment of the modular intervertebral prosthesis system of the present invention includes first and second baseplates and an insert designed to mate to the baseplates. The baseplates include a mounting section and an intervertebral section extending away from the mounting section such that the baseplates have a generally L-shaped side profile. The intervertebral section has at least one aperture passing therethrough. When installed, the insert is disposed between the intervertebral sections of the baseplates, and faces the apertures. In this way, the insert is not insulated from the vertebral members, thereby allowing for osteoinduction and/or osteoconduction and/or osteointegration, if desired. The insert may take the form of an articulating-type insert or a fusion-type insert, with the baseplates being operative with both types of inserts.
After installation of the insert between the baseplates, the insert may be readily removed, so as to allow the surgeon to try another size or type of insert during the same surgery without removing the baseplates from the vertebral members. In addition, if the insert has not fused to the vertebral members, the insert may be removed during a later surgery to allow for replacement of the insert, or substitution of another type of insert.
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Referring to
The intervertebral section 50 may extend away from the mounting section 30 so that the baseplate 20 has a L-shaped side profile (see FIG. 3). Indeed, the intervertebral section 50 may advantageously extend away from the mounting section 30 in a generally perpendicular (i.e., 90°±20°) fashion. The intervertebral section 50 includes an aperture 60 that extends through the intervertebral section 50 (e.g., from the inferior side to the superior side). The aperture 60 may take the form of a hole, or may be simply the space between two arms 52 that extend out from the mounting section 30 (see
One advantage of the prosthesis system 10 shown in
In one embodiment, the articulating type inserts 70a are removable from the baseplates 20 once installed. For the embodiments shown in
As an alternative to the articulating type inserts 70a discussed above, the insert 70 may be of a type known as “fusion” inserts 70b. For example, the insert 70b may comprise a portion of precision milled allograft bone harvested from a cadaver, a portion of autograft bone harvested from the same patient, or some synthetic material. One example of a commercially available product that may be used as a fusion-type insert 70b is sold under the trademark “CORNERSTONE” by Medtronic Sofamor Danek of Memphis, Tenn. In one embodiment, the insert 70b includes a central passage that extends 82 from one end to the other of the insert 70b. When the insert 70b is positioned between the baseplates 20, the passage 82 faces the apertures 60 in the baseplates 20, thereby providing a direct path from the vertebral member 4,6 to the fusion insert 70b, so as to promote osteoinduction and osteoconduction.
The baseplates 20 should be made from a suitable rigid material, such as stainless steel, various titanium alloys known in the art, cobalt-chrome-molybdenum alloys ASTM F-799 or F-75, or any other metallic alloy known in the art. The articulating type inserts 70a may also be made from metallic alloys, but may also include suitable plastic and/or ceramic materials as desired. The fusion inserts 70b may be made from actual bone material, demineralized bone matrix, ceramics (e.g., hydroxy apatite), polymers (e.g., polyetheretherketone bioinert polymer (PEEK)), or any other suitable material, including bioresorbable materials. Indeed, the fusion inserts 70b may be made from, or filled with, bone growth inducing materials, such as a sponge, matrix, and/or other structural carrier impregnated with a protein such as bone morphogenic protein (BMP), LIM mineralization protein (LMP), etc.
Referring to
It should be noted that the insert 70a is readily removable from the baseplates 20 immediately after installation. For the illustrated embodiments, the surgeon need only undo the locking mechanism, such as by removing locking screws 40b and retaining rings 37, and then slide the insert portions 72,78 out of engagement with the baseplates 20. With the first insert 70a removed, another insert 70a or 70b may be mated to the baseplates 20 without removing the baseplates 20 from the vertebral member 4,6. As such, the surgeon is free to try another an insert 70 of a different configuration (e.g., different in size, design, or type) in order to achieve the desired results. Indeed, the surgeon may initially try an articulating-type insert 70a, but then change to a fusion-type insert 70b without the need to install new baseplates 20, and during the same surgery. Once the proper insert 70 has been selected and installed, the surgeon may add an optional flexible or rigid element (not shown) secured to the exterior of mounting sections 30 of the two baseplates 20, if desired. If the optional element is flexible, it may function as an artificial ligament; if the optional element is rigid, it may function as a stabilizer.
One advantage of the present prosthesis system 10 is that it enables a fusion-type insert 70b to “see” the bone of the relevant vertebral members 4,6. That is, when to the insert 70b is installed in the baseplates 20, the insert 70b faces the bone through the aperture 60 of the corresponding baseplate 20. Over time, bone may grow through these apertures 60, “fusing” the insert 70b to the vertebral members 4,6. As such, while fusion-type inserts 70b may be readily removable immediately after installation, the insert 70b may become fixed in place over time. In order to promote this fusion process, the insert 70b may include appropriate ridges and/or pores on its end surfaces, and the insert 70b may include fusion promoting materials, as indicated above.
While the illustrative embodiments discussed above have assumed that the prosthesis system 10 replaces a single intervertebral disc, the present invention also encompasses situations where the prosthesis system 10 replaces more than one intervertebral disc—a so-called corpectomy construct. This can be achieved through the use of longer length inserts 70, or by having the insert 70 include an additional member acting as a substitute vertebral member between parts of the insert.
The discussion above has also described a situation where one insert 70 is installed, then removed and replaced with another insert 70 during the same surgery. However, the subsequent replacement may alternatively occur during a subsequent surgery, such as to replace a worn insert 70 or the like.
Additionally, although the devices and methods illustrated and described above are particularly useful in treating the cervical region of the spine, it should nevertheless be understood that the present invention is also applicable to other portions of the spine, including the lumbar or thoracic regions of the spine.
While the invention has been illustrated an described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. For instance, a different method of mounting the baseplates 20 to the vertebral members 4,6, such as using a different number of holes 32 and screws 40a and/or adhesives, may be employed if desired. Likewise, other locking mechanisms may be used to retain the inserts 70 in the baseplates 20, such as clips, snaps, of the like, and the retaining ring 37 may be integrated into the locking screw 40b if desired. It should therefore be understood that only some embodiments have been shown and described and that all changes and modifications that come within the meaning and equivalency range of the appended claims are intended to be embraced therein.
Number | Name | Date | Kind |
---|---|---|---|
4759709 | Luken, Jr. et al. | Jul 1988 | A |
4805602 | Puno et al. | Feb 1989 | A |
5002576 | Fuhrmann et al. | Mar 1991 | A |
5005562 | Cotrel | Apr 1991 | A |
5176678 | Tsou | Jan 1993 | A |
5236460 | Barber | Aug 1993 | A |
5258031 | Salib et al. | Nov 1993 | A |
5370697 | Baumgartner | Dec 1994 | A |
5425773 | Boyd et al. | Jun 1995 | A |
5458641 | Ramirez Jimenez | Oct 1995 | A |
5458642 | Beer et al. | Oct 1995 | A |
5534029 | Shima | Jul 1996 | A |
5556431 | Büttner-Janz | Sep 1996 | A |
5562738 | Boyd et al. | Oct 1996 | A |
5674296 | Bryan et al. | Oct 1997 | A |
5865846 | Bryan et al. | Feb 1999 | A |
5899901 | Middleton | May 1999 | A |
6019792 | Cauthen | Feb 2000 | A |
6106557 | Robioneck et al. | Aug 2000 | A |
6113637 | Gill et al. | Sep 2000 | A |
6146421 | Gordon et al. | Nov 2000 | A |
6179874 | Cauthen | Jan 2001 | B1 |
6375683 | Crozet et al. | Apr 2002 | B1 |
6419706 | Graf | Jul 2002 | B1 |
6440168 | Cauthen | Aug 2002 | B1 |
6517580 | Ramadan et al. | Feb 2003 | B1 |
6579290 | Hardcastle et al. | Jun 2003 | B1 |
6579320 | Gauchet et al. | Jun 2003 | B1 |
6610093 | Pisharodi | Aug 2003 | B1 |
6648917 | Gerbec et al. | Nov 2003 | B2 |
6682561 | Songer et al. | Jan 2004 | B2 |
20030187506 | Ross et al. | Oct 2003 | A1 |
20030204261 | Eisermann et al. | Oct 2003 | A1 |
20040030387 | Landry et al. | Feb 2004 | A1 |
20040034423 | Lyons et al. | Feb 2004 | A1 |
20040049270 | Gewirtz | Mar 2004 | A1 |
20040073314 | White et al. | Apr 2004 | A1 |
20040102846 | Keller et al. | May 2004 | A1 |
20040133278 | Marino et al. | Jul 2004 | A1 |
Number | Date | Country |
---|---|---|
0 699 426 | Mar 1996 | EP |
2 718 635 | Oct 1995 | FR |
2 805 457 | Aug 2001 | FR |
WO 9965412 | Dec 1999 | WO |
Number | Date | Country | |
---|---|---|---|
20040068318 A1 | Apr 2004 | US |