US20040230307A1 - Device for fusing two bone segments - Google Patents

Abstract

A fusion-promoting, spinal plating assembly is described. The plating assembly includes a first plate, and at least one additional plate connected to the first plate, the at least one additional plate extending transversely to the first plate. The plating assembly is adapted to be completely inserted within an intervertebral space defined between a first vertebral body and a second vertebral body.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of U.S. Provisional Application No. 60/446,963 filed on Feb. 12, 2003. U.S. Provisional Application No. 60/446,963 is herein incorporated by reference for all legitimate purposes. This application is a continuation of U.S. patent application Ser. No. ______ (Attorney Docket No. 31132.44), entitled “Device For Fusing Two Bone Segments” (Inventor: Lukas Eisermann) filed on Jan. 7, 2004. U.S. patent application Ser. No. ______ (Attorney Docket No. 31132.44) is herein incorporated by reference for all legitimate purposes. This application is also related to U.S. patent application Ser. No. 10/430,473, which is herein incorporated by reference for all legitimate purposes.[0001]
BACKGROUND
• The present disclosure relates generally to the field of orthopedics and spinal surgery, and in some embodiments, the present disclosure relates to fusion-promoting prosthetic devices for insertion into an intervertebral disc space.[0002]
• 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 taken to ensure the proper spacing of the vertebrae formerly separated by the removed disc tissue. In some instances, fusion-promoting prosthetic devices, such as fusion cages and the like, are inserted into the disc space to maintain the structural integrity of the spinal column.[0003]
• Anterior plating is often used in conjunction with fusion devices to supplement the stability provided by such fusion devices. However, in some instances, anterior plating is inappropriate for use due to the presence of vascular structure, which impedes the implantation and positioning of the anterior plating.[0004]
• Therefore, what is needed is an implantable fusion device which eliminates, or at least reduces, the need for supplemental plating external of the intervertebral space.[0005]
SUMMARY
• A fusion-promoting prosthetic device for insertion into an intervertebral space is described. The prosthetic device includes a sagitally-extending plate having caudal and cephalad edges, the caudal edge being adapted for complete insertion within a first vertebral body and the cephalad edge being adapted for complete insertion within a second vertebral body adjacent to the first vertebral body. The prosthetic device further includes a first transverse plate connected to the sagitally-extending plate, and a second transverse plate connected to the sagitally-extending plate, the first and second transverse plates being adapted for complete insertion within the intervertebral space.[0006]
• A fusion-promoting, spinal plating assembly is described. The plating assembly includes a first plate adapted to engage a first vertebral body and a second vertebral body, and at least one additional plate connected to the first plate, the at least one additional plate extending transversely to the first plate, wherein the at least one additional plate is adapted to be inserted within an intervertebral space.[0007]
• A method for promoting fusion in an intervertebral space defined between first and second vertebral bodies is described. The method includes providing a prosthetic device having a first plate adapted to engage each of the first and second vertebral bodies, and a pair of additional plates connected to the first plate, the additional pair of plates extending in a direction transverse to the first plate. The method further includes inserting the prosthetic device into the intervertebral space such that a first edge of the first plate is completely inserted within the first vertebral body, a second edge of the first plate is completely inserted within the second vertebral body, and each of the additional pair of plates are completely disposed within the intervertebral space.[0008]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a lateral view of a pair of adjacent vertebral bodies.[0009]
• FIG. 2 is a lateral view of a prosthetic device for insertion between the adjacent vertebral bodies of FIG. 1.[0010]
• FIG. 3[0011]ais a longitudinal view of the prosthetic device of FIG. 2.
• FIG. 3[0012]bis a longitudinal view of an alternative prosthetic device.
• FIG. 4[0013]ais a longitudinal view of a pair of the verterbral bodies of FIG. 1 having longitudinally-formed slots for receiving the prosthetic device of FIG. 2.
• FIG. 4[0014]bis a lateral view of the prosthetic device of FIG. 2 shown longitudinally disposed between the vertebral endplates of FIG. 1.
• FIG. 5[0015]ais a lateral view of a pair of verterbral bodies having laterally-formed slots for receiving a prosthetic device.
• FIG. 5[0016]bis a lateral view of an alternative prosthetic device shown laterally disposed between the vertebral bodies of FIG. 5a.
DESCRIPTION
• For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments, or examples, illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which this disclosure relates.[0017]
• Referring now to FIG. 1, shown therein is a lateral view of a portion of a spinal column[0018]10, illustrating a pair of adjacent upper and lower vertebrae V1 and V2, respectively, separated by an intervertebral space S created by the removal of a natural intervertebral disc. The illustration of two vertebrae is only intended as an example. Another example would be a sacrum and one vertebrae.Vascular structure12, such as, for example, the aortic artery and associated segmental arteries, is shown disposed anteriorly adjacent to the upper and lower vertebrae V1, V2. As can be appreciated, it is not desirable to impart pressure to, or otherwise contact, thevascular structure12 during insertion and upon implantation of a prosthetic device.
• Referring now to FIGS. 2 and 3[0019]a, a prosthetic device for insertion into the space S (FIG. 1) is generally referred to byreference numeral20. In one embodiment, thedevice20 includes a sagittally-extendingsupport plate22 and a pair ofadditional support plates24,26 integrally formed with and extending generally transverse to the sagittal plate. It is understood that thetransverse plates24,26 may alternatively be removably connected to thesagittal plate22 such that theprosthetic device20 is generally modular in nature. Although thesagittal plate22 and thetransverse plates24,26 of theprosthetic device20 may be formed from a wide variety of materials, in one embodiment of the disclosure, thesagittal plate22 and thetransverse plates24,26 are formed of a cobalt-chrome-molybdenum metallic alloy (ASTM F-799 or F-75). However, in alternative embodiments of the disclosure, thesagittal plate22 and thetransverse plates24,26 may be formed of other materials such as titanium or stainless steel, a polymeric material such as polyethylene, or any other biocompatible material that would be apparent to one of ordinary skill in the art.
• The[0020]sagittal plate22 is adapted to engage the upper and lower vertebrae V1, V2, respectively, and in the present example, thesagittal plate22 extends in a plane substantially parallel to the sagittal plane (represented by axis Y lying in the sagittal plane in FIG. 1) when engaged with the upper and lower vertebrae. Thesagittal plate22 includes ananterior edge30, aposterior edge32, acaudal edge34 and acephalad edge36. It is understood that reference to anatomical directions in this specification such as sagittal, anterior, posterior, caudal and cephalad is for purposes of descriptive clarity only, and is not intended to limit theprosthetic device20 to having a specific orientation relative to such anatomical directions.
• The caudal and[0021]cephalad edges34,36 of thesagittal plate22 are formed as keel-like structures, which aid in the insertion of theprosthetic device20 into the intervertebral space S. For example, in one embodiment, thecaudal edge34 of thesagittal plate22 is beveled at the posterior portion thereof to provide a sharp,forward edge38 with which to pierce the vertebral body V2 upon insertion of theprosthetic device20. In a like manner, thecephalad edge36 of thesagittal plate22 is beveled at the posterior portion thereof to provide a sharp,forward edge39 with which to pierce the vertebral body V1 upon insertion of theprosthetic device20.
• It should be understood that other shapes and orientations of the caudal and[0022]cephalad edges34,36 are also contemplated. For example, the caudal andcephalad edges34,36 may be angled along the entire surface thereof to aid in the circumvention ofvascular structure12, or other obstacles, that may be in place during insertion of theprosthetic device20. Also, the caudal and cephalad edges34,36 may be angled, tapered, or configured in some other shape to facilitate the functional demands of insertion. In still another embodiment, such as the one depicted in FIG. 3b, the caudal and cephalad edges34,36 may be configured as having winged portions, including atransverse portion34a,36aextending across eachedge34,36, respectively.
• Referring again to FIGS. 2 and 3[0023]a, thesagittal plate22 is adapted to promote fusion between the vertebral bodies V1, V2 (FIG. 1), and as such, in one embodiment, a plurality ofopenings40 are defined through the sagittal plate to promote fusion therethrough. It should be understood that any number ofopenings40 may be defined through thesagittal plate22, including a single opening or two or more openings. It should also be understood that theopenings40 need not necessarily extend entirely through thesagittal plate22, but may alternatively extend partially therethrough. It should further be understood that thesagittal plate22 need not necessarily define anyopenings40 extending either partially or entirely therethrough. Additionally, although theopenings40 are illustrated as having a circular configuration, it should be understood that other sizes and configurations of theopenings40 are also contemplated.
• To further promote fusion, the[0024]sagittal plate22 is preferably coated with a bone-growth promoting substance, such as, for example, a hydroxyapatite coating formed of calcium phosphate. Additionally, thesagittal plate22 may be roughened prior to being coated with the bone-growth promoting substance to further enhance bone on-growth. Such surface roughening may be accomplished by way of, for example, acid etching, knurling, application of a bead coating, or other methods of roughening that would occur to one of ordinary skill in the art.
• The[0025]sagittal plate22 may include one or more notches (not shown) or other types of indicia for receiving or engaging with a corresponding portion of a surgical instrument (not shown) to aid in the manipulation and insertion of theprosthetic device20 within the intervertebral space S (FIG. 1) between the adjacent vertebral bodies V1, V2 (FIG. 1). The surgical instrument (not shown) is preferably configured to release thesagittal plate22 once properly positioned between the adjacent vertebrae. One example of a surgical instrument that can be used to insert theprosthetic device20 is described in co-pending application U.S. Ser. No. 10/430,473.
• The[0026]transverse plates24,26 are adapted to engage the vertebral bodies V1, V2 via a pair of bearingsurfaces42,44, respectively. In the present example, thetransverse plates24,26 angle towards one another in the posterior direction to accommodate an angular relationship Φ defined between the upper and lower vertebrae V1, V2. As can be appreciated, the angular relationship between the vertebral bodies V1, V2 will vary depending on the particular region of the spine such as the thoracic and lumbar regions. Moreover, a variety of conditions can contribute to a variety of more pronounced angular relationships between the vertebral bodies V1, V2, such as lordosis, kyphosis, etc., and therefore, thetransverse plates24,26 may extend across thesagittal plate22 at a variety of angles relative to the sagittal plate, including at right angles.
• As with the[0027]sagittal plate22, thetransverse plates24,26 are adapted to promote fusion between the vertebral bodies V1, V2, and as such, a plurality ofopenings50 are defined through each of the transverse plates to promote fusion therethrough. It should be understood that any number ofopenings50 may be defined through thetransverse plates24,26, including a single opening or two or more openings. It should also be understood that theopenings50 need not necessarily extend entirely through thetransverse plates24,26, but may alternatively extend partially therethrough. It should further be understood that thetransverse plates24,26 need not necessarily define anyopenings50 extending either partially or entirely therethrough. Additionally, although theopenings50 are illustrated as having a circular configuration, it should be understood that other sizes and configurations of theopenings50 are also contemplated.
• To further promote fusion, the[0028]transverse plates24,26 are preferably coated with a bone-growth promoting substance, such as, for example, a hydroxyapatite coating formed of calcium phosphate. Additionally, thetransverse plates24,26 may be roughened prior to being coated with the bone-growth promoting substance to further enhance bone on-growth. Such surface roughening may be accomplished by way of, for example, acid etching, knurling, application of a bead coating, or other methods of roughening that would occur to one of ordinary skill in the art.
• Referring to FIGS. 4[0029]aand4b, the prosthetic device20 (FIGS. 2 and 3) may be inserted into the space S between the vertebrae V1, V2 from a variety of approaches. For example, in operation, to accommodate insertion of theprosthetic device20, the vertebral bodies V1, V2 can be prepared to accept the prosthetic device therebetween from an offset longitudinal, or anterior-oblique, approach. Specifically, elongate openings orslots60,62 may be formed in the vertebral endplates of the upper and lower vertebrae V1, V2, respectively, at a predetermined width and to a predetermined depth. Theslots60,62 can be substantially aligned with each other to accommodate thesagittal plate22, and more specifically, to accommodate the caudal and cephalad edges34,36 defined on the sagittal plate. In one embodiment, theelongate slots60,62 are rectangular-shaped and are formed by chiseling or curetting. However, other methods of forming theslots60,62 are also contemplated as would occur to one of ordinary skill in the art, such as, for example, by drilling or reaming. Furthermore, for some embodiments of theprosthetic device20, the caudal and cephalad edges34,36 can form their own corresponding slots by engagement and impaction of thebeveled edges38,39 with the vertebrae V1, V2, and thus no preformed slots are necessary.
• As is readily apparent from FIG. 4[0030]b, upon insertion into the intervertebral space S defined between the vertebrae V1, V2, theprosthetic device20 is completely disposed within the intervertebral space S such that no portion of the prosthetic device extends beyond the anterior or posterior portion of the vertebrae V1, V2. Moreover, no plating external of the intervertebral space S is required upon insertion of theprosthetic device20, which is advantageous in avoiding the problems associated with contacting thevascular structure12. In addition, the disposition of theprosthetic device20 in the intervertebral space S results in a relatively large graft area between the vertebrae V1, V2, the graft area being defined, in one embodiment, by that portion of the intervertebral space S not occupied by theprosthetic device20. As such, bone grafts (not shown) may be inserted into the graft area between the vertebrae V1, V2 to encourage fusion between the vertebrae. Moreover, although not required, supplemental screws (not shown) may be impacted into the vertebrae V1, V2 to provide additional support. Such screws, however, can be press-fit completely into the vertebrae V1, V2 such that no portion of the screws extends beyond the anterior or posterior portion of the vertebrae V1, V2.
• Referring now to FIGS. 5[0031]aand5b, in another embodiment, aprosthetic device70 may be laterally inserted into an intervertebral space S′ defined between an upper vertebra V1′ and a lower vertebra V2′. In this embodiment, the upper and lower vertebrae V1′, V2′ are substantially parallel to one another, and as such, theprosthetic device70 includes a pair oftransverse plates72,74, which are substantially parallel to one another and are substantially perpendicular to an associated sagittal plate76.
• To accommodate insertion of the[0032]prosthetic device70, the vertebral bodies V1ζ, V2′ can be prepared to accept the prosthetic device therebetween from the lateral approach by laterally forming elongate openings orslots78,80 in the vertebral endplates of the upper and lower vertebrae V1′, V2′, respectively, at a predetermined width and to a predetermined depth. Theslots78,80 can be substantially aligned with each other to accommodate the sagittal plate76. In one embodiment, theelongate slots78,80 are rectangular-shaped and are formed by chiseling or curetting. However, other methods of forming theslots78,80 are also contemplated as would occur to one of ordinary skill in the art, such as, for example, by drilling or reaming. Furthermore, as described above with respect to theprosthetic device20, theprosthetic device70 may be configured to form their own corresponding slots by engagement and impaction with the vertebrae V1, V2, and thus no preformed slots are necessary.
• The present disclosure has been described relative to several preferred embodiments. Improvements or modifications that become apparent to persons of ordinary skill in the art after reading this disclosure are deemed within the spirit and scope of the application. For example, although described with respect to circumventing[0033]vascular structure12, it is understood that the above-describedprosthetic device20 may be desirable for use in scenarios wherevascular structure12 is not present. Moreover, although described with respect to longitudinal and lateral insertion, it is understood that theprosthetic device20 may be inserted into the intervertebral space S from a variety of other approaches such as the transforaminal approach. Accordingly, it is understood that several modifications, changes and substitutions are intended in the foregoing disclosure and, in some instances, some features of the disclosure will be employed without a corresponding use of other features. It is also understood that all spatial references, such as “longitudinal,” “lateral,” and “transverse,” are for illustrative purposes only and can be varied within the scope of the disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.

Claims (22)

What is claimed is:

1. A fusion-promoting prosthetic device for insertion into an intervertebral space, comprising a sagitally-extending plate having caudal and cephalad edges, the caudal edge being adapted for complete insertion within a first vertebral body and the cephalad edge being adapted for complete insertion within a second vertebral body adjacent to the first vertebral body, a first transverse plate connected to the sagitally-extending plate, and a second transverse plate connected to the sagitally-extending plate, the first and second transverse plates being adapted for complete insertion within the intervertebral space.

2. The prosthetic device ofclaim 1 wherein the first transverse plate comprises a bearing surface, the bearing surface being adapted to engage the first vertebral body.

3. The prosthetic device ofclaim 1 wherein the second transverse plate comprises a bearing surface, the bearing surface being adapted to engage the second vertebral body.

4. The prosthetic device ofclaim 1 wherein the sagitally-extending plate further comprises a plurality of openings extending therethrough.

5. The prosthetic device ofclaim 1 wherein each of the first and second transverse plates comprises a plurality of openings extending therethrough.

6. The prosthetic device ofclaim 1 wherein the sagitally-extending plate is coated with a bone-growth promoting substance.

7. The prosthetic device ofclaim 1 wherein the first and second transverse plates are each coated with a bone-growth promoting substance.

8. The prosthetic device ofclaim 1 wherein the first transverse plate is angled relative to the sagitally-extending plate.

9. The prosthetic device ofclaim 8 wherein the second transverse plate is angled relative to the sagitally-extending plate, the angulation of the first and second transverse plates corresponding to an angular relationship defined between the first and second vertebral bodies.

10. The prosthetic device ofclaim 1 wherein the first and second transverse plates each extend at a substantially right angle to the sagitally-extending plate.

11. The prosthetic device ofclaim 1 wherein the caudal edge is beveled at a posterior portion thereof.

12. The prosthetic device ofclaim 1 wherein the cephalad edge is beveled at a posterior portion thereof.

13. A fusion-promoting, spinal plating assembly, comprising a first plate adapted to engage a first vertebral body and a second vertebral body, and at least one additional plate connected to the first plate, the at least one additional plate extending transversely to the first plate, wherein the at least one additional plate is adapted to be inserted within an intervertebral space.

14. The plating assembly ofclaim 13 wherein the at least one additional plate is integrally formed with the first plate.

15. The plating assembly ofclaim 13 wherein the at least one additional plate is removably connected to the first plate.

16. The plating assembly ofclaim 13 wherein the at least one additional plate extends at an angle relative to the first plate.

17. The plating assembly ofclaim 13 wherein the first plate is adapted to be impacted into each of the first and second vertebral bodies.

18. The plating assembly ofclaim 13 wherein the first plate is adapted to be inserted into a preformed opening in each of the first and second vertebral bodies.

19. A method for promoting fusion in an intervertebral space defined between first and second vertebral bodies, comprising:

providing a prosthetic device having a first plate adapted to engage each of the first and second vertebral bodies, and a pair of additional plates connected to the first plate, the additional pair of plates extending in a direction transverse to the first plate; and

inserting the prosthetic device into the intervertebral space such that a first edge of the first plate is completely inserted within the first vertebral body, a second edge of the first plate is completely inserted within the second vertebral body, and each of the additional pair of plates are completely disposed within the intervertebral space.

20. The method ofclaim 19 further comprising inserting bone grafts into the intervertebral space.

21. The method ofclaim 19 wherein inserting the prosthetic device comprises impacting the first and second edges of the first plate into the first and second vertebral bodies, respectively.

22. The method ofclaim 19 wherein inserting the prosthetic device comprises forming openings in each of the first and second vertebral bodies and inserting the first and second edges of the first plate into the preformed openings of the first and second vertebral bodies, respectively.

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