Vertebral Fusion Implants and Methods of Use
A vertebral implant for use in vertebral fusion surgeries includes a body with an exterior surface and an interior surface. The interior surface defines an interior cavity into which bone growth promoting materials such as bone graft are insertable. The body also includes a plurality of apertures that extend from the exterior surface to the interior surface. Further, the vertebral implant includes a cutting feature to decorticate bone that protrudes outward from the exterior surface at each aperture. The cutting feature is shaped so that as a cutting force is applied to move the implant in a cutting direction, the removed bone matter is directed through the apertures and into the interior cavity.
Latest Warsaw Orthopedic, Inc. Patents:
This application is a continuation of U.S. patent application Ser. No. 11/403,348, filed on Apr. 13, 2006, and incorporated in its entirety herein by reference.
BACKGROUNDVertebral implants are often used in the surgical treatment of spinal disorders such as degenerative disc disease, disc herniations, curvature abnormalities, and trauma. Many different types of treatments are used. In some cases, spinal fusion is indicated to inhibit relative motion between vertebral bodies. Motion between vertebral bodies is naturally provided in part by the flexible disc material that resides between adjacent vertebral bodies. Spinal fusion often involves the removal of the vertebral disc and insertion of an interbody implant to create a fused junction between a pair of vertebral bodies. Fusion may also occur at multiple vertebral levels or between vertebral bodies that are several levels apart. Interbody implants may be coated, filled, or surrounded by growth promoting materials such as BMP, DBM, allograft, autograft or other osteoinductive growth factors to facilitate fusion between the vertebral bodies and the implant.
Conventionally, interbody implants are inserted into the space between vertebral bodies after the disc material has been removed and after the vertebral end plates are prepared. This end plate preparation may include shaping, planing, scraping, or other decorticating processes in which bone matter is removed and blood flow is initiated to enhance bone growth into the interbody implant. Ideally, new bone matter forms and bridges the gap between the vertebral bodies and the growth promoting material. In certain instances, particularly where the growth promoting material is contained within the interbody implant, new bone matter does not sufficiently span the gap between the vertebral endplate and the growth promoting material. Consequently, the fusion site may be compromised.
SUMMARYIllustrative embodiments disclosed herein are directed to a vertebral implant for use in vertebral fusion surgeries. The vertebral implant includes a body with an exterior surface and an interior surface. The body may be shaped for use in ALIF, PLIF, and TLIF surgeries.
The implant may include a hollow body with an enclosed interior cavity. The body may include a first side configured to contact against the first vertebral member and a second side configured to contact against the second vertebral member after the implant has been inserted into the patient. A plurality of apertures and cutting features may be positioned about the first and second sides. Each of the apertures may extend through one of the first and second sides. Each of the cutting features may extend outward from the body at one of the plurality of apertures. Each of the cutting features may include a tapered shape that terminates at a pointed tip that cuts into one of the first and second vertebral members. The enclosed interior cavity may be configured to capture and maintain portions of the first and second vertebral members that are cut by the cutting features and enter the enclosed interior cavity through the plurality of apertures.
The implant may include a hollow body with an enclosed interior cavity. The body may include a first section configured to contact against the first vertebral member and a second section configured to contact against the second vertebral member after the implant has been inserted into the patient. A plurality of apertures and cutting features may be positioned about the first section. Each of the apertures may extend through the first section and into the interior cavity. Each of the cutting features may extend outward from the first section at one of the plurality of apertures. A first one of the cutting features may include a first leading surface facing a first direction and a second one of the cutting features may include a second leading surface facing a different second direction. The enclosed interior cavity may be configured to capture and maintain portions of the first and second vertebral members that are cut by the cutting features and enter the enclosed interior cavity through the plurality of apertures.
The implant may include a hollow body with an enclosed interior cavity. The body may include a first side configured to contact against the first vertebral member and a second side configured to contact against the second vertebral member after the implant has been inserted into the patient. The first side may include an inner surface that faces into the interior cavity and an opposing outer surface. A plurality of paired cutting features may be positioned about the first side. Each of the paired cutting features may include an aperture that extends through the first side and into the interior cavity and a tooth at the aperture that extends outward from the outer surface. The body may have different thickness over the first side with the inner surface of the first side having a different geometry than the outer surface of the first side. The enclosed interior cavity may be configured to capture and maintain portions of the first vertebral member that are cut by the plurality of paired cutting features and enter the enclosed interior cavity through the plurality of apertures.
The various embodiments disclosed herein relate to a vertebral implant in which bone-contact surfaces are constructed with cutting features that remove bone matter from vertebral bodies in the human spine. Further, the cutting features are configured to guide the removed bone matter through apertures in the vertebral implant and into contact with bone-growth-promoting material contained therein. Reference number 10 in
The vertebral implant 10 shown in
The vertebral implant 10 may be constructed from biocompatible metal alloys such as titanium, cobalt-chrome, and stainless steel. The vertebral implant 10 may be constructed from non-metallic materials, including for example, ceramics, resins, or polymers, such as UHMWPE and implantable grade polyetheretherketone (PEEK) or other similar materials (e.g., PAEK, PEKK, and PEK). The vertebral implant 10 may be constructed of synthetic or natural bone or bone composites. Those skilled in the art will comprehend a variety of other material choices that are suitable for the illustrated vertebral implant 10.
The exemplary vertebral implant 10 includes a plurality of apertures 18 disposed about the superior surface 14. The apertures 18 are shown as substantially cylindrical, though it should be understood that other shapes, including for example, square, hex, triangular, diamond, crescent, elliptical apertures may be used. Additional apertures 18 are also disposed about the inferior surface 16, though their existence is not immediately apparent from
In the illustrated embodiment, a cutting feature 20 is associated with each aperture 18. In other embodiments, the vertebral implant 10 may have apertures without associated cutting features 20 or cutting features 20 without associated apertures 18. The cutting features 20 may be implemented as teeth, hooks, serrations, blades, or other features adapted to remove cortical bone from a vertebral body as the vertebral implant 10 is inserted. The cutting features 20 may be constructed of the same material as the remainder of the vertebral implant 10 as described above. In one embodiment, the cutting features 20 are constructed of rigid, hardened materials such as titanium, ceramic, or polymers impregnated with carbon fibers. In the embodiment illustrated in
The lateral cross section view of the vertebral implant 10 provided in
The right side of
In the depicted embodiment, the leading surface 24 of the cutting feature 20 extends generally upward from the aperture 18 in the walls 34 of the vertebral implant 10. In this configuration, the leading surface 24 and aperture 18 share a common wall. Thus, the cutting feature 20 curves at least partly around the aperture. In other embodiments, the aperture 18 may have straight sides and the leading surface 24 may share one or more sides of the aperture 18. Further, the leading surface 24 is generally concave, bent, or curved in the direction of the aperture 18. Consequently, through motion of the vertebral implant 10 in the cutting direction C, the leading surface 24 tends to divert removed bone matter through the aperture 18, past the interior surface 28 and into the interior cavity 30.
Specifically,
Initially, the disc 116 is removed from the space between the vertebrae 102, 104. Also, the vertebral implant 10 is packed with a bone growth promoting material such as those described above. The bone growth promoting material is identified by numeral 40 in
Ultimately, once the vertebral implant 10 is inserted completely between the vertebral bodies 106, 108 as shown in
In one embodiment, the cutting features 20 overlap one another in the transverse direction T by an amount that leaves a nominal space 46 between the cutting features 20. This space 46 may permit the removed bone matter 44 to fill gaps between the vertebral implant 10 and the vertebral bodies 106, 108. That is, the space 46 strikes a balance between directing all removed bone matter 44 into the interior cavity 30 of the vertebral implant 10 and allowing the removed bone matter 44 to fill gaps between the vertebral implant 10 and the vertebral bodies 106, 108.
Embodiments described above included a plurality of cutting features 20 arranged along a common cutting direction C. In the embodiment of the vertebral implant 110 shown in
The cutting features 20 may be incorporated on different types of fusion implants, including ALIF cages similar in structure to the above-described embodiments. The cutting features 20 may be incorporated in PLIF or TLIF cages as well.
The vertebral implants 210 may include a generally rectangular shape as depicted in the perspective view in
In one embodiment shown in
The vertebral implant 310 may include an insertion feature 336 to which an insertion tool (not shown) may be attached. The insertion feature 336 may be elongated or may comprise multiple features disposed on opposite sides of the longitudinal axis A. This type of insertion feature may allow a surgeon to impart a rotating, reciprocating motion about axis A, in the two different cutting directions C and C′ to remove bone matter along a generally cylindrical pattern. This rotating motion is in contrast with the non-rotating motion imparted on previously described embodiments to remove the bone matter.
The cutting features 20 may be arranged at gradually increasing heights in a manner similar to a broach.
In the first exemplary embodiment, the cutting features 20 are substantially the same size. Therefore, the increase in height of the cutting features 20 primarily derives from an increase in the height of the implant body 512 from a first height D1 at the leading end 522 to a larger second height D2 at the trailing end 524. Alternatively, the increase in height may be obtained through different size cutting features 20a, 20b, 20c as shown in
Embodiments described above related to vertebral implants that are implanted into the space normally occupied by a vertebral disc. In other procedures, such as vertebrectomies or corpectomies, one or more vertebral bodies are removed and an implant is inserted in the space left by the removed vertebrae. These types of devices, such as the vertebral implant 710 shown in
The cutting features 20 illustrated in
In one embodiment shown in
As
Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc and are also not intended to be limiting. Like terms refer to like elements throughout the description.
As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. For instance, aside from the disclosed apertures 18 and cutting features 20, embodiments disclosed above have not included any particular surface geometry, coating, or porosity as are found in conventionally known vertebral implants. Surface features such as these are used to promote bone growth and adhesion at the interface between an implant and a vertebral body. Examples of features used for this purpose include, for example, teeth, scales, keels, knurls, and roughened surfaces. Some of these features may be applied through post-processing techniques such as blasting, chemical etching, and coating, such as with hydroxyapatite. The superior and inferior bone interface surfaces of the vertebral implant may also include growth-promoting additives such as bone morphogenetic proteins. Alternatively, pores, cavities, or other recesses into which bone may grow may be incorporated via a molding process. Other types of coatings or surface preparation may be used to improve bone growth into or through the bone-contact surfaces. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
Claims
1. An implant for insertion into a patient between first and second vertebral members, the implant comprising:
- a hollow body with an enclosed interior cavity, the body including a first side configured to contact against the first vertebral member and a second side configured to contact against the second vertebral member after the implant has been inserted into the patient;
- a plurality of apertures and cutting features positioned about the first and second sides, each of the apertures extending through one of the first and second sides, and each of the cutting features extending outward from the body at one of the plurality of apertures, each of the cutting features including a tapered shape that terminates at a pointed tip that cuts into one of the first and second vertebral members;
- the enclosed interior cavity configured to capture and maintain portions of the first and second vertebral members that are cut by the cutting features and enter the enclosed interior cavity through the plurality of apertures.
2. The implant of claim 1, wherein each of the cutting features includes a leading surface relative to a cutting direction that extends at least partly around the corresponding aperture and is concave relative to the aperture.
3. The implant of claim 1, further comprising a plurality of second cutting features that each extend outward from one of the first and second sides and are spaced away from each of the plurality of apertures.
4. The implant of claim 1, wherein the plurality of cutting features positioned on the first side include different heights.
5. The implant of claim 1, wherein the cutting features in proximity to a leading end of the body include a smaller height than the cutting features in proximity to an opposing trailing end of the body.
6. The implant of claim 1, wherein the body includes a leading end and a trailing end that are parallel to each other.
7. The implant of claim 1, wherein the plurality of cutting features on the first side are equidistant from a common point on the first side.
8. The implant of claim 1, wherein the body includes an exterior geometry that is different than an interior geometry with the body having different thicknesses at various sections around the interior cavity.
9. An implant for insertion into a patient between first and second vertebral members, the implant comprising:
- a hollow body with an enclosed interior cavity, the body including a first section configured to contact against the first vertebral member and a second section configured to contact against the second vertebral member after the implant has been inserted into the patient;
- a plurality of apertures and cutting features positioned about the first section, each of the apertures extending through the first section and into the interior cavity, and each of the cutting features extending outward from the first section at one of the plurality of apertures;
- a first one of the cutting features includes a first leading surface facing a first direction and a second one of the cutting features includes a second leading surface facing a different second direction;
- the enclosed interior cavity configured to capture and maintain portions of the first and second vertebral members that are cut by the cutting features and enter the enclosed interior cavity through the plurality of apertures.
10. The implant of claim 9, wherein the first leading surface and the second leading surface face in opposing directions.
11. The implant of claim 9, wherein the body further includes a leading end and a trailing end each extending between the first and second sections, the first leading surface facing towards the leading end and the second leading surface facing towards the trailing end.
12. The implant of claim 9, further including a second plurality of apertures and cutting features positioned about the second section, each of the apertures extending through the second section and into the interior cavity and each of the cutting features extending outward from the second section at one of the plurality of apertures.
13. The implant of claim 9, wherein each of the cutting features includes a tapered shape that terminates at a pointed tip and is configured to cut into the first vertebral member.
14. The implant of claim 9, wherein a height of the plurality of cutting features increases from a leading end of the body to a trailing end of the body.
15. An implant for insertion into a patient between first and second vertebral members, the implant comprising:
- a hollow body with an enclosed interior cavity, the body including a first side configured to contact against the first vertebral member and a second side configured to contact against the second vertebral member after the implant has been inserted into the patient, the first side including an inner surface that faces into the interior cavity and an opposing outer surface;
- a plurality of paired cutting features positioned about the first side, each of the paired cutting features including an aperture that extends through the first side and into the interior cavity and a tooth at the aperture that extends outward from the outer surface;
- the body having different thickness over the first side with the inner surface of the first side having a different geometry than the outer surface of the first side;
- the enclosed interior cavity configured to capture and maintain portions of the first vertebral member that are cut by the plurality of paired cutting features and enter the enclosed interior cavity through the plurality of apertures.
16. The implant of claim 15, wherein the body includes a cylindrical shape with the plurality of paired cutting features extending around an exterior surface that includes the first and second sides.
17. The implant of claim 15, wherein the body includes a tapered shape that changes in height between a leading end and a trailing end.
18. The implant of claim 15, wherein a first portion of the plurality of paired cutting features are oriented in a first direction and a second portion of the plurality of paired cutting features are oriented in a different second direction.
19. The implant of claim 15, further comprising a second plurality of paired cutting features positioned about the second side, each of the second plurality of paired cutting features includes an aperture that extends through the second side and into the interior cavity and a tooth at the aperture that extends outward.
20. The implant of claim 15, wherein the body includes a substantially rectangular cross-sectional shape.
Type: Application
Filed: Dec 7, 2010
Publication Date: Mar 31, 2011
Applicant: Warsaw Orthopedic, Inc. (Warsaw, IN)
Inventor: Eric S. Heinz (Mountain View, CA)
Application Number: 12/961,858
International Classification: A61F 2/44 (20060101);