Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20090105833 A1
Publication typeApplication
Application numberUS 12/255,731
Publication dateApr 23, 2009
Filing dateOct 22, 2008
Priority dateOct 22, 2007
Also published asEP2209444A1, EP2209444A4, US8758441, US20090105834, US20090105835, WO2009055477A1, WO2009055478A1, WO2009055481A1
Publication number12255731, 255731, US 2009/0105833 A1, US 2009/105833 A1, US 20090105833 A1, US 20090105833A1, US 2009105833 A1, US 2009105833A1, US-A1-20090105833, US-A1-2009105833, US2009/0105833A1, US2009/105833A1, US20090105833 A1, US20090105833A1, US2009105833 A1, US2009105833A1
InventorsDavid Hovda, Yves Arramon
Original AssigneeSpinalmotion, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and Spacer Device for Spanning a Space Formed upon Removal of an Intervertebral Disc
US 20090105833 A1
Abstract
An intervertebral spacer is designed particularly for patients who are not candidates for total disc replacement. The spacer maintains disc height and prevents subsidence with a large vertebral body contacting surface area while substantially reducing recovery time by eliminating the need for bridging bone. The intervertebral spacer or fusion spacer includes a rigid spacer body sized and shaped to fit within an intervertebral space between two vertebral bodies. In one embodiment, the spacer body has two opposed metallic vertebral contacting surfaces, at least one fin extending from each of the vertebral contacting surfaces and configured to be positioned within slots cut into the two vertebral bodies. Holes, if present, cover less than 40 percent of the entire vertebral body contacting surfaces to provide increased bone ongrowth surfaces and to prevent subsidence.
Images(7)
Previous page
Next page
Claims(32)
1. A method of spanning a space formed by upon removal of an intervertebral disc, the method comprising:
performing a discectomy to remove disc material between two adjacent vertebral bodies;
placing an intervertebral spacer between the two adjacent vertebral bodies, the spacer comprising two end plates, each end plate having a metallic vertebral body contacting surface and an inner surface, and a connector interconnecting the inner surfaces of the two end plates in a rigid manner which limits motion between the plates to less than a total of 5 degrees, wherein the vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces; and
maintaining the disc space between the two adjacent vertebral bodies with the intervertebral spacer without the use of bone graft or bridging bone.
2. The method of claim 1, wherein the connector is a rigid connector.
3. The method of claim 1, wherein the two end plates and connector are formed of a single piece of metal.
4. The method of claim 1, wherein the intervertebral spacer is selected, such that when the spacer is positioned between the two vertebral bodies the spacer fills at least 50 percent of a vertebral space formed between the vertebral bodies.
5. The method of claim 1, wherein the vertebral body contacting surface of the end plates has holes which cover less than 25 percent of the vertebral body contacting surfaces.
6. The method of claim 1, further comprising cutting at least one slot in each of the adjacent vertebrae and placing a fin into the at least one slot.
7. The method of claim 6, further comprising at least one additional fixation means provided on the vertebral body contacting surfaces the intervertebral spacer.
8. The method of claim 7, wherein the additional fixation means is at least one of a screw, teeth, serrations or grooves.
9. The method of claim 1, wherein the metallic vertebral contacting surface is formed of titanium or a titanium alloy.
10. An intervertebral spacer for spanning a space formed by upon removal of an intervertebral disc, the spacer comprising:
two end plates sized and shaped to fit within an intervertebral space, each end plate having a metallic vertebral contacting surface and an inner surface;
a connector interconnecting the inner surfaces of the two end plates in a rigid manner which limits motion between the plates to less than a total of 5 degrees; and
wherein the vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces.
11. The spacer of claim 10, wherein the connector is a rigid connector.
12. The spacer of claim 10, wherein the two end plates and connector are formed of a single piece of metal.
13. The spacer of claim 10, wherein the vertebral body contacting surface of the end plates has holes which cover less than 25 percent of the vertebral body contacting surfaces.
14. The spacer of claim 10, further comprising at least one fin extending from the vertebral contacting surfaces.
15. The spacer of claim 10, wherein the two end plates and connector are formed of PEEK with metallic screens, layers or coatings on the vertebral body contacting surfaces.
16. The spacer of claim 10, wherein the metallic vertebral contacting surface is formed of titanium or a titanium alloy.
17. A method of performing an anterior/posterior fusion, the method comprising:
performing a discectomy to remove disc material between two adjacent vertebral bodies;
placing an intervertebral spacer between the two adjacent discs, the spacer comprising two end plates, each end plate having a metallic vertebral contacting surface and an inner surface, and a rigid connector interconnecting the inner surfaces of the two end plates, wherein the vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces;
maintaining the disc space between the two adjacent discs with the intervertebral spacer; and
posteriorly placing a stabilization system to fix the angle between the vertebral bodies.
18. The method of claim 17, wherein the intervertebral spacer is placed anteriorly.
19. The method of claim 17, wherein the intervertebral spacer is place posteriorly.
20. The method of claim 19, wherein the posteriorly placed intervertebral spacer includes a two part spacer in which the two parts together cover about 40 percent or more of the vertebral surface.
21. The method of claim 19, wherein the posteriorly placed stabilization system includes at least one screw placed into each of the vertebral bodies and at least one connector therebetween.
22. The method of claim 19, wherein the method is performed without the use of bone graft.
23. The method of claim 19, wherein the vertebral body contacting surfaces of the end plates have holes which cover less than 25 percent of the vertebral body contacting surfaces.
24. A fusion system, the system comprising:
an intervertebral spacer comprising:
two end plates sized and shaped to fit within an intervertebral space, each end plate having a vertebral contacting surface an inner surface, wherein the vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces; and
a rigid connector interconnecting the inner surfaces of the two end plates; and
a posteriorly placed stabilization system including at least two screws configured to be placed into the vertebral bodies and at least one connector therebetween.
25. The system of claim 24, wherein the intervertebral spacer is a unitary spacer sized to be placed anteriorly.
26. The system of claim 24, wherein the intervertebral spacer is a two part spacer sized to be place posteriorly.
27. The system of claim 24, wherein the vertebral body contacting surfaces of the end plates have holes which cover less than 25 percent of the vertebral body contacting surfaces.
28. A fusion spacer comprising:
a rigid spacer body sized and shaped to fit within an intervertebral space between two vertebral bodies, the body having two opposed metallic vertebral contacting surfaces;
at least one fin extending from each of the vertebral contacting surfaces, the fins configured to be positioned within slots cut into the two vertebral bodies;
a plurality of serrations on the vertebral contacting surfaces; and
wherein holes cover less than 40 percent of the entire vertebral body contacting surfaces.
29. The spacer of claim 28, wherein holes cover less than 25 percent of the vertebral body contacting surfaces.
30. The spacer of claim 28, wherein the metallic vertebral contacting surfaces are formed of titanium or a titanium alloy.
31. The spacer of claim 30, wherein the body is a unitary metallic body.
32. The spacer of claim 30, wherein the body is formed of PEEK.
Description
    CROSS-REFERENCES TO RELATED APPLICATIONS
  • [0001]
    The present application claims priority from U.S. Provisional Patent Application No. 60/981,665 filed Oct. 22, 2007, entitled “Method and Spacer Device for Spanning a Space Formed Upon Removal of an Intervertebral Disc,” the full disclosure of which is incorporated herein by reference.
  • BACKGROUND OF THE INVENTION
  • [0002]
    The present invention relates to medical devices and methods. More specifically, the invention relates to intervertebral spacers and methods of spanning a space formed upon removal of an intervertebral disc.
  • [0003]
    Back pain takes an enormous toll on the health and productivity of people around the world. According to the American Academy of Orthopedic Surgeons, approximately 80 percent of Americans will experience back pain at some time in their life. In the year 2000, approximately 26 million visits were made to physicians' offices due to back problems in the United States. On any one day, it is estimated that 5% of the working population in America is disabled by back pain.
  • [0004]
    One common cause of back pain is injury, degeneration and/or dysfunction of one or more intervertebral discs. Intervertebral discs are the soft tissue structures located between each of the thirty-three vertebral bones that make up the vertebral (spinal) column. Essentially, the discs allow the vertebrae to move relative to one another. The vertebral column and discs are vital anatomical structures, in that they form a central axis that supports the head and torso, allow for movement of the back, and protect the spinal cord, which passes through the vertebrae in proximity to the discs.
  • [0005]
    Discs often become damaged due to wear and tear or acute injury. For example, discs may bulge (herniate), tear, rupture, degenerate or the like. A bulging disc may press against the spinal cord or a nerve exiting the spinal cord, causing “radicular” pain (pain in one or more extremities caused by impingement of a nerve root). Degeneration or other damage to a disc may cause a loss of “disc height,” meaning that the natural space between two vertebrae decreases. Decreased disc height may cause a disc to bulge, facet loads to increase, two vertebrae to rub together in an unnatural way and/or increased pressure on certain parts of the vertebrae and/or nerve roots, thus causing pain. In general, chronic and acute damage to intervertebral discs is a common source of back related pain and loss of mobility.
  • [0006]
    When one or more damaged intervertebral discs cause a patient pain and discomfort, surgery is often required. Traditionally, surgical procedures for treating intervertebral discs have involved discectomy (partial or total removal of a disc), with or without interbody fusion of the two vertebrae adjacent to the disc. When the disc is partially or completely removed, it is necessary to replace the excised material to prevent direct contact between hard bony surfaces of adjacent vertebrae. Oftentimes, pins, rods, screws, cages and/or the like are inserted between the vertebrae to act as support structures to hold the vertebrae and graft material in place while they permanently fuse together.
  • [0007]
    One typical fusion procedure is achieved by inserting a “cage” that maintains the space usually occupied by the disc to prevent the vertebrae from collapsing and impinging the nerve roots. The cage is used in combination with bone graft material (either autograft or allograft) such that the two vertebrae and the graft material will grow together over time forming bridging bone between the two vertebrae. The fusion process typically takes 6-12 months after surgery. During in this time external bracing (orthotics) may be required. External factors such as smoking, osteoporosis, certain medications, and heavy activity can prolong or even prevent the fusion process. If fusion does not occur, patients may require reoperation.
  • [0008]
    One known fusion cage is described in U.S. Pat. No. 4,904,261 and includes a horseshoe shaped body. This type cage is currently available in PEEK (polyetheretherketone). PEEK is used because it does not distort MRI and CT images of the vertebrae. However, PEEK is a material that does not allow bone to attach. Thus, fusion with a PEEK cage requires bridging bone to grow through the holes in the cage to provide stabilization.
  • [0009]
    It would be desirable to achieve immobilization of the vertebrae and maintain spacing between the adjacent vertebrae without the associated patient discomfort and long recovery time of traditional interbody fusion which may require immobilization for several months.
  • [0010]
    Another problem associated with the typical fusion procedure is the subsidence of the cage into the vertebral body. The typical fusion cage is formed with a large percentage of open space to allow the bone to grow through and form the bridging bone which immobilizes the discs. However, the large amount of open space means that the load on each segment of the cage is significantly higher than if the cage surface area was larger. This results in the cage subsiding or sinking into the bone over time causing the disc space to collapse. In addition, the hard cortical bone on the outer surface of the vertebral body that transfers load to the interbody cage or spacer is often scraped, punctured or otherwise damaged to provide blood to the interbody bone graft to facilitate bone growth. This damage to the bone used to promote bone growth can also lead to subsidence.
  • [0011]
    The U.S. Food and Drug Administration approved the use of a genetically engineered protein, or rhBMP-2, for certain types of spine fusion surgery. RhBMP-2 is a genetically engineered version of a naturally occurring protein that helps to stimulate bone growth, marketed by Medtronic Sofamor Danek, Inc. as InFUSE™ Bone Graft. When InFUSE™ is used with the bone graft material it eliminates the need for painful bone graft harvesting and improves patients' recovery time. However, InFUSE™ adds significantly to the cost of a typical fusion surgery. Additionally, even with the bone graft and InFUSE™ bone may fail to grow completely between the two vertebrae or the cage may subside into the vertebrae such that the fusion fails to achieve its purpose of maintaining disc height and preventing motion.
  • [0012]
    In an attempt to treat disc related pain without fusion and to maintain motion, an alternative approach has been developed, in which a movable, implantable, artificial intervertebral disc (or “disc prosthesis”) is inserted between two vertebrae. A number of different artificial intervertebral discs are currently being developed. For example, U.S. Patent Application Publication Nos. 2005/0021146, 2005/0021145, and 2006/0025862, which are hereby incorporated by reference in their entirety, describe artificial intervertebral discs. Other examples of intervertebral disc prostheses are the LINK SB CHARITLÉ™ disc prosthesis (provided by DePuy Spine, Inc.) the MOBIDISK™ disc prosthesis (provided by LDR Medical), the BRYAN™ cervical disc prosthesis (provided by Medtronic Sofamor Danek, Inc.), the PRODISC™ disc prosthesis or PRODISC-C™ disc prosthesis (from Synthes Stratec, Inc.), the PCM™ disc prosthesis (provided by Cervitech, Inc.), and the MAVERICK™ disc prosthesis (provided by Medtronic Sofomor Danek). Although existing disc prostheses provide advantages over traditional treatment methods, many patients are not candidates for an artificial disc due to facet degeneration, instability, poor bone strength, previous surgery, multi-level disease, and pain sources that are non-discogenic.
  • [0013]
    Therefore, a need exists for an improved spacer and method for spanning a space and maintaining disc spacing between two vertebrae after removal of an intervertebral disc. Ideally, such improved method and spacer would avoid the need for growth of bridging bone across the intervertebral space.
  • BRIEF SUMMARY OF THE INVENTION
  • [0014]
    Embodiments of the present invention provide a rigid intervertebral spacer and methods of spanning a space formed upon removal of an intervertebral disc.
  • [0015]
    In accordance with one aspect of the present invention, a method of spanning a space formed by upon removal of an intervertebral disc includes the steps of performing a discectomy to remove disc material between two adjacent vertebral bodies; placing an intervertebral spacer between the two adjacent vertebral bodies; and maintaining the disc space between the two adjacent vertebral bodies with the intervertebral spacer without the use of bone graft or bridging bone. The spacer includes two end plates, each end plate having a metallic vertebral body contacting surface and an inner surface, and a connector interconnecting the inner surfaces of the two end plates in a rigid manner which limits motion between the plates to less than a total of 5 degrees. The vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surface.
  • [0016]
    In accordance with another aspect of the present invention, an intervertebral spacer for spanning a space formed by upon removal of an intervertebral disc includes two end plates sized and shaped to fit within an intervertebral space and a connector interconnecting the inner surfaces of the two end plates in a rigid manner which limits motion between the plates to less than a total of 5 degrees. Each end plate has a metallic vertebral contacting surface and an inner surface and the vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces.
  • [0017]
    In accordance with a further aspect of the invention, a method of performing an anterior/posterior fusion comprises performing a discectomy to remove disc material between two adjacent vertebral bodies; placing an intervertebral spacer between the two adjacent discs; maintaining the disc space between the two adjacent discs with the intervertebral spacer; and posteriorly placing a stabilization system to fix the angle between the vertebral bodies. The spacer includes two end plates each having a metallic vertebral contacting surface and an inner surface, and a rigid connector interconnecting the inner surfaces of the two end plates. The vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces.
  • [0018]
    In accordance with another aspect of the invention, a fusion system includes an intervertebral spacer and a posteriorly placed stabilization system including at least two screws configured to be placed into the vertebral bodies and at least one connector there between, The intervertebral spacer includes two end plates sized and shaped to fit within an intervertebral space, each end plate having a vertebral contacting surface an inner surface and a rigid connector interconnecting the inner surfaces of the two end plates. The vertebral body contacting surfaces of the end plates have no holes therein or have holes which cover less than 40 percent of the vertebral body contacting surfaces.
  • [0019]
    In accordance with an additional aspect of the invention, a fusion spacer includes a rigid spacer body sized and shaped to fit within an intervertebral space between two vertebral bodies, the body having two opposed metallic vertebral contacting surfaces; at least one fin extending from each of the vertebral contacting surfaces, the fins configured to be positioned within slots cut into the two vertebral bodies; and a plurality of serrations on the vertebral contacting surfaces. Holes, if present, cover less than 40 percent of the entire vertebral body contacting surfaces.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0020]
    FIG. 1 is a perspective view of an intervertebral spacer according to one embodiment of the present invention;
  • [0021]
    FIG. 2 is a cross sectional side view of the intervertebral spacer of FIG. 1;
  • [0022]
    FIG. 3 is a top view of the intervertebral spacer of FIG. 1;
  • [0023]
    FIG. 4 is a bottom view of the intervertebral spacer of FIG. 1;
  • [0024]
    FIG. 5 is a perspective view of an intervertebral spacer according to another embodiment of the present invention;
  • [0025]
    FIG. 6 is a perspective view of an intervertebral spacer according to an embodiment with added screw fixation; and
  • [0026]
    FIG. 7 is a perspective view of a further intervertebral spacer with added screw fixation.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0027]
    Various embodiments of the present invention generally provide for an intervertebral spacer having upper and lower plates connected by a central connector which is substantially rigid. The intervertebral spacer according to the present invention can maintain disc height and prevent subsidence with a large vertebral body contacting surface area while substantially reducing recovery time by eliminating the need for bridging bone. The fusion spacer described herein is designed particularly for patients who are not candidates for total disc replacement.
  • [0028]
    One example of an intervertebral spacer 10 for maintaining disc height between two adjacent vertebral discs is shown in FIG. 1. The spacer includes two end plates 20, 22, each end plate having a vertebral contacting surface 24 and an inner surface 26, and a connector 30 interconnecting the inner surfaces of the two end plates in a substantially rigid manner. The intervertebral spacer 10 when implanted between two vertebral discs maintains a desirable disc space between the two adjacent discs similar to that provided by a natural disc and eliminates the long recovery time required to grow bridging bone which is required in the traditional fusion surgery.
  • [0029]
    Although the connector 30 has been shown as circular in cross section, other shapes may be used including oval, elliptical, or rectangular. Although the connector has been shown as a solid member connecting the plates 20, 22 in the center of the plates one or more connectors may be provided in other configurations and at other locations. By way of example, a connector may be the same or substantially the same diameter and shape as the plate, as in FIGS. 6 and 7. Alternatively, multiple connectors can be arranged in a pattern, such as a rectangular pattern, or a hollow cylindrical connector can be used.
  • [0030]
    In some embodiments, the outer surface 24 is planar. Oftentimes, the outer surface 24 will include one or more surface features and/or materials to enhance attachment of the spacer 10 to vertebral bone. For example, as shown in FIG. 2, the outer surface 24 may be machined to have serrations 40 or other surface features for promoting adhesion of the plates 20, 22 to a vertebra. In the embodiments shown, the serrations 40 are pyramid shaped serrations extending in mutually orthogonal directions and arranged on opposite sides of a fin 50. The serrations 40 may also be disposed in a region between fins 52 when the outer surface 24 has two fins. Other geometries such as teeth, grooves, ridges, pins, barbs or the like would also be useful in increasing fixation of the spacer 10 to the adjacent vertebral bodies. When the bone integration structures are ridges, teeth, barbs or similar structures, they may be angled to ease insertion and prevent migration. These bone integration structures can be used to precisely cut the bone during implantation to cause bleeding bone and encourage bone integration. Additionally, the outer surface 24 may be provided with a rough microfinish formed by blasting with aluminum oxide microparticles or the like to improve bone integration. In some embodiments, the outer surface may also be titanium plasma sprayed or HA coated to further enhance attachment of the outer surface 24 to vertebral bone.
  • [0031]
    The outer surface 24 may also carry one or more upstanding fins 50, 52 extending in an anterior-posterior direction. The fins 50, 52 are configured to be placed in slots cut into the vertebral bodies. Preferably, the fins 50, 52 each have a height greater than a width and have a length greater than the height. In one embodiment, the fins 50, 52 are pierced by transverse holes 54 for bone ingrowth. The transverse holes 54 may be formed in any shape and may extend partially or all the way through the fins 50, 52. In alternative embodiments, the fins 50, 52 may be rotated away from the anterior-posterior axis, such as in a lateral-lateral orientation, a posterolateral-anterolateral orientation, or the like to accommodate alternate implantation approaches.
  • [0032]
    The fins 50, 52 provide improved attachment to the bone and prevent rotation of the plates 20, 22 in the bone. In some embodiments, the fins 50, 52 may extend from the surface 24 at an angle other than 90°. For example on one or more of the plates 20, 22 where multiple fins 52 are attached to the surface 24 the fins may be canted away from one another with the bases slightly closer together than their edges at an angle such as about 80-88 degrees. The fins 50, 52 may have any other suitable configuration including various numbers, angles and curvatures, in various embodiments. In some embodiments, the fins 50, 52 may be omitted altogether. The embodiment of FIG. 1 illustrates a combination of a first plate 20 with a single fin 50 and a second plate 22 with a double fin 52. This arrangement is useful for double level disc replacements and utilizes offset slots in the vertebral body to prevent the rare occurrence of vertebral body splitting by avoiding cuts to the vertebral body in the same plane for multi-level implants.
  • [0033]
    The spacer 10 has been shown with the fins 50, 52 as the primary fixation feature, however, the fins may also be augmented or replaced with one or more screws extending through the plates and into the bone. For example in the spacer 10 of FIG. 1 the upper fin 50 may be replaced with a screw while the two lower fins 52 remain. The plates 20, 22 can be provided with one or a series of holes to allow screws to be inserted at different locations at the option of the surgeon. However, the holes should not be of such size or number that the coverage of the plate 20, 22 is decreased to such an extent that subsidence occurs. When one or more screws are provided, they may incorporate a locking feature to prevent the screws from backing out. The screws may also be provided with a bone integration coating.
  • [0034]
    The upper and lower plates 20, 22 and connector 30 may be constructed from any suitable metal, alloy or combination of metals or alloys, such as but not limited to cobalt chrome alloys, titanium (such as grade 5 titanium), titanium based alloys, tantalum, nickel titanium alloys, stainless steel, and/or the like. They may also be formed of ceramics, biologically compatible polymers including PEEK, UHMWPE (ultra high molecular weight polyethlyne) or fiber reinforced polymers. However, the vertebral contacting surfaces 24 are formed of a metal or other material with good bone integration properties. The metallic vertebral body contacting surfaces 24 may be coated or otherwise covered with the metal for fixation. The plates 20, 22 and the connector 20 may be formed of a one piece construction or may be formed of more than one piece, such as different materials coupled together. When the spacer 10 is formed of multiple materials these materials are fixed together to form a unitary one piece spacer structure without separately moving parts.
  • [0035]
    Different materials may be used for different parts of the spacer 10 to optimize imaging characteristics. For example, the plates may be formed of titanium while the connector is formed of cobalt chromium alloy for improved imaging of the plates. Cobalt chrome molybdenum alloys when used for the plates 20, 22 may be treated with aluminum oxide blasting followed by a titanium plasma spray to improve bone integration. Other materials and coatings can also be used such as titanium coated with titanium nitride, aluminum oxide blasting, HA (hydroxylapatite) coating, micro HA coating, and/or bone integration promoting coatings. Any other suitable metals or combinations of metals may be used as well as ceramic or polymer materials, and combinations thereof. Any suitable technique may be used to couple materials together, such as snap fitting, slip fitting, lamination, interference fitting, use of adhesives, welding and/or the like.
  • [0036]
    As shown in FIG. 5, some limited holes 60 may also be provided in the plates 20, 22 to allow bone in growth. Holes provided in a typical fusion spacer provide a spacer with little structural support and maximum area for bone growth. Thus, the load transferred across the disc space per unit area of spacer is quite high resulting in possible subsidence of the typical spacer. In the spacer 10 of the present invention, the load transfer is spread across a larger area. If the outer surfaces 24 have holes 60 therein, the holes will cover less than 40 percent of the outer surface 24 which contacts the bone to prevent subsidence of the plates into the vertebral bodies. Preferably the holes will cover less than 25 percent, and more preferably less than 10 percent of the outer bone contacting surfaces. At the option of the surgeon, when the small holes 60 are present in the plates 20, 22, bone graft can be placed in the space between the inner surfaces 26 of the plates to encourage bone to grow through the plates. The holes 60, when present can take on a variety of shapes including circular, as shown, rectangular, polygonal or other irregular shapes. The holes 60 may extend through the various parts of the spacer including through the connector or through the fins. The holes 60 may change shape or size as they pass through portions of the spacer, for example, holes through the plates and the connector may taper to a smaller interior diameter.
  • [0037]
    The typical fusion spacer requires bleeding bone to stimulate the growth of bridging bone. In this typical method, the cortical endplates are damaged purposefully to obtain bleeding by rasping or cutting the bone. This damage weakens the bone and can cause subsidence of the spacer. The spacer 10 described herein does not rely on bridging bone and does not require damaging the bone to cause bleeding. The spacer 10 can be implanted after simply cleaning the disc space and cutting slots into the vertebral endplates configured to receive the fins 50, 52. The rest of the endplates remain undamaged, providing better support and disc height maintenance.
  • [0038]
    FIG. 6 shows another embodiment of a spacer 100 having a single fin 50 on the top and bottom and two fixation screws 70 extending at an angle of about 30 to about 60 degrees with respect to the vertebral body contacting surfaces 24 of the spacer. The spacer 100 also includes a connector 30 between the vertebral body contacting surfaces 24 which is formed in one piece with the upper and lower plates. The fixation screws 70 can include a locking mechanism, such as a locking thread or a separate locking member which is inserted into the screw holes 80 after the screws are inserted to prevent backing out of the screws.
  • [0039]
    FIG. 7 illustrates an alternative embodiment of a spacer 110 having a single superior fin 50, two inferior fins 52, and three alternating holes 80 for receiving bone screws (not shown). The spacer 110 has multiple fixation structures to provide the patient near immediate mobility after the fusion procedure. As an alternative to the alternating angled holes 80, the spacer 110 can be formed with an anterior flange extending from the top and the bottom at the anterior side of the plate. This optional flange can include one or more holes for receiving bone screws placed laterally. The laterally placed bone screws can prevent interference in the event of multilevel fusions and are particularly useful for a cervical fusion where space is more limited.
  • [0040]
    The intervertebral spacer 10 shown herein is configured for placement in a lumbar intervertebral space from an anterior approach. It should be understood that all approaches can be used including PLIF (posterior lumbar interbody fusion), TLIF (transverse lumbar interbody fusion), XLIF (Lateral extracavitary interbody fusion), ALIF (anterior lumbar interbody fusion), trans-sacral, and other approaches. The shape of the intervertebral spacer would be modified depending on the approach. For example, for a posterior approach, the spacer may include two separate smaller spacers which are either positioned separately side-by-side in the intervertebral space or two spacers which are joined together once inside the intervertebral space. For a lateral approach, the intervertebral spacer may be formed in a more elongated, kidney bean or banana shape with a transversely oriented fin.
  • [0041]
    The spacers 10, 100 can be provided in different sizes, with different plate sizes, angles between plates, lordosis angles, and heights for different patients or applications. The spacers 10, 100 are primarily designed for use in the lumbar spine, however the spacers may also be used for fusions of the cervical spine. In one variation, the height of the spacer can be adjustable, such as by rotating an adjustment screw in the connector 30 before or after implantation. The spacers preferably are sized to provide substantial coverage of the vertebral surfaces. For example in an anterior procedure, the plates are sized to cover at least 50 percent of the vertebral surface, and preferably cover at least 70 percent of the vertebral surface. In posterior or lateral procedures the coverage of the vertebral surface may be somewhat smaller due to the small size of the access area, i.e. the posterior or lateral spacers may cover about 40 percent or more of the vertebral surface with a one or two part spacer, and preferably at least 50 percent of the vertebral surface.
  • [0042]
    The size of the intervertebral spacers 10, 100, 110 can also be described in terms of the amount of the volume of the intervertebral space occupied by the spacer. According to a preferred embodiment, the total volume of the intervertebral spacer selected for a particular intervertebral space fills at least 50 percent of the volume of the space available between the adjacent vertebrae. More preferably, the volume of the spacer is at least 70 percent of the volume of the intervertebral space. The volume of the intervertebral space is defined as the volume of the space between the vertebrae when the vertebrae are distracted to a normal physiologic position for the particular patient without over or under distracting. The size of the intervertebral spacers 10, 100, 110 can also be determined by the amount of the support provided to the ring of cortical bone surrounding each vertebrae. The cortical bone surrounds a more spongy cancellous. Preferably, the intervertebral spacer is selected to support at least 75 percent of the diameter of the ring of cortical bone.
  • [0043]
    One common fusion procedure, referred to as an anterior/posterior fusion, uses of one or more fusion cages to maintain the disc space while bridging bone grows and also uses a system of posterior screws and rods for further stabilization. Fusing both the front and back provides a high degree of stability for the spine and a large surface area for the bone fusion to occur. Also, approaching both sides of the spine often allows for a more aggressive reduction of motion for patients who have deformity in the lower back (e.g. isthmic spondylolisthesis).
  • [0044]
    According to a method of the present invention, the anterior approach is performed first by removing the disc material and cutting the anterior longitudinal ligament (which lays on the front of the disc space). The spacer is positioned anteriorly and then the patient is turned over for the implantation of a posterior stabilization system. The intervertebral spacers of the present invention may be used in combination with a posterior stabilization system, dynamic rod stabilization system, or interspinous spacer to achieve the anterior/posterior fusion.
  • [0045]
    In another example, a posterior intervertebral spacer formed in two parts can be used with a posterior stabilization system including screws and rods. This system provides the advantage of maintenance of disc height and stabilization with an entirely posterior approach.
  • [0046]
    While the exemplary embodiments have been described in some detail, by way of example and for clarity of understanding, those of skill in the art will recognize that a variety of modifications, adaptations, and changes may be employed. Hence, the scope of the present invention should be limited solely by the appended claims.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3867728 *Apr 5, 1973Feb 25, 1975Cutter LabProsthesis for spinal repair
US4759766 *Sep 9, 1987Jul 26, 1988Humboldt-Universitaet Zu BerlinIntervertebral disc endoprosthesis
US4904261 *Aug 4, 1988Feb 27, 1990A. W. Showell (Surgicraft) LimitedSpinal implants
US4917704 *Jun 8, 1988Apr 17, 1990Sulzer Brothers LimitedIntervertebral prosthesis
US4932969 *Dec 17, 1987Jun 12, 1990Sulzer Brothers LimitedJoint endoprosthesis
US5192327 *Mar 22, 1991Mar 9, 1993Brantigan John WSurgical prosthetic implant for vertebrae
US5314477 *Mar 4, 1991May 24, 1994J.B.S. Limited CompanyProsthesis for intervertebral discs and instruments for implanting it
US5320644 *Jul 30, 1992Jun 14, 1994Sulzer Brothers LimitedIntervertebral disk prosthesis
US5370697 *Feb 19, 1993Dec 6, 1994Sulzer Medizinaltechnik AgArtificial intervertebral disk member
US5401269 *Mar 10, 1993Mar 28, 1995Waldemar Link Gmbh & Co.Intervertebral disc endoprosthesis
US5782832 *Oct 1, 1996Jul 21, 1998Surgical Dynamics, Inc.Spinal fusion implant and method of insertion thereof
US5797917 *Feb 12, 1997Aug 25, 1998Sdgi Holdings, Inc.Anterior spinal instrumentation and method for implantation and revision
US5824094 *Oct 17, 1997Oct 20, 1998Acromed CorporationSpinal disc
US5865846 *May 15, 1997Feb 2, 1999Bryan; VincentHuman spinal disc prosthesis
US5865848 *Sep 12, 1997Feb 2, 1999Artifex, Ltd.Dynamic intervertebral spacer and method of use
US5989251 *Jun 17, 1998Nov 23, 1999Surgical Dynamics, Inc.Apparatus for spinal stabilization
US5989291 *Feb 26, 1998Nov 23, 1999Third Millennium Engineering, LlcIntervertebral spacer device
US6106557 *Jul 22, 1999Aug 22, 2000Howmedica GmbhReconstruction system for vertebra
US6136031 *Jun 17, 1998Oct 24, 2000Surgical Dynamics, Inc.Artificial intervertebral disc
US6296664 *Jun 17, 1998Oct 2, 2001Surgical Dynamics, Inc.Artificial intervertebral disc
US6315797 *Jul 20, 2000Nov 13, 2001Surgical Dynamics, Inc.Artificial intervertebral disc
US6582468 *Dec 9, 1999Jun 24, 2003Spryker SpineIntervertebral disc prosthesis with compressible body
US6592624 *Nov 16, 2000Jul 15, 2003Depuy Acromed, Inc.Prosthetic implant element
US6733532 *Dec 9, 1999May 11, 2004Stryker SpineIntervertebral disc prosthesis with improved mechanical behavior
US6740118 *Jan 9, 2002May 25, 2004Sdgi Holdings, Inc.Intervertebral prosthetic joint
US6764515 *Jan 7, 2002Jul 20, 2004Spinecore, Inc.Intervertebral spacer device utilizing a spirally slotted belleville washer and a rotational mounting
US6793678 *Mar 27, 2003Sep 21, 2004Depuy Acromed, Inc.Prosthetic intervertebral motion disc having dampening
US6846328 *Apr 18, 2003Jan 25, 2005Sdgi Holdings, Inc.Articulating spinal implant
US6882562 *Aug 7, 2002Apr 19, 2005Agilent Technologies, Inc.Method and apparatus for providing pseudo 2-port RAM functionality using a 1-port memory cell
US6964686 *Sep 5, 2002Nov 15, 2005Vanderbilt UniversityIntervertebral disc replacement prosthesis
US6989011 *Jan 23, 2004Jan 24, 2006Globus Medical, Inc.Spine stabilization system
US7011684 *Jan 16, 2003Mar 14, 2006Concept Matrix, LlcIntervertebral disk prosthesis
US7022138 *Jul 31, 2003Apr 4, 2006Mashburn M LaineSpinal interbody fusion device and method
US7044972 *Jul 30, 2003May 16, 2006Synthes Ag ChurBone implant, in particular, an inter-vertebral implant
US7066958 *May 9, 2003Jun 27, 2006Ferree Bret AProsthetic components with partially contained compressible resilient members
US7083651 *Mar 3, 2004Aug 1, 2006Joint Synergy, LlcSpinal implant
US7217291 *Dec 8, 2003May 15, 2007St. Francis Medical Technologies, Inc.System and method for replacing degenerated spinal disks
US7235101 *Sep 15, 2003Jun 26, 2007Warsaw Orthopedic, Inc.Revisable prosthetic device
US7235103 *Jan 12, 2005Jun 26, 2007Rivin Evgeny IArtificial intervertebral disc
US7250060 *Jan 27, 2004Jul 31, 2007Sdgi Holdings, Inc.Hybrid intervertebral disc system
US7255714 *Sep 30, 2003Aug 14, 2007Michel H. MalekVertically adjustable intervertebral disc prosthesis
US7261739 *Nov 18, 2003Aug 28, 2007Spinecore, Inc.Intervertebral spacer device having arch shaped spring element
US7267688 *Oct 22, 2003Sep 11, 2007Ferree Bret ABiaxial artificial disc replacement
US7331995 *Feb 6, 2004Feb 19, 2008Sdgi Holdings, Inc.Method for inserting an articular disc prosthesis via the transforaminal approach
US7575598 *Jul 7, 2005Aug 18, 2009Cervical Xpand, LlcAnterior lumbar intervertebral stabilizer
US7578848 *Jul 7, 2005Aug 25, 2009Cervical Xpand, LlcIntervertebral stabilizer
US7615078 *Jan 17, 2006Nov 10, 2009Warsaw Orthopedic, Inc.Vertebral body and disc space replacement devices
US7655045 *Jul 27, 2006Feb 2, 2010Aesculap Implant Systems, LlcArtificial intervertebral disc
US7749272 *Jan 23, 2007Jul 6, 2010Zimmer Trabecular Metal Technology, Inc.Prosthetic disc and vertebral body replacement device having pyrolytic carbon bearing members
US7763055 *Jan 3, 2006Jul 27, 2010Warsaw Orthopedic, Inc.Instruments and methods for stabilization of bony structures
US7819922 *Oct 16, 2003Oct 26, 2010Spinal Generations, LlcVertebral prosthesis
US8092534 *Nov 16, 2006Jan 10, 2012Warsaw Orthopedic, Inc.Revision device
US8142505 *Feb 22, 2007Mar 27, 2012Faneuil Innovations Investment Ltd.Intervertebral disc replacement
US20030014116 *Apr 23, 2002Jan 16, 2003Ralph James D.Intervertebral spacer having a flexible wire mesh vertebral body contact element
US20030199982 *May 22, 2003Oct 23, 2003Sdgi Holdings, Inc.Peanut spectacle multi discoid thoraco-lumbar disc prosthesis
US20030199983 *May 23, 2003Oct 23, 2003Michelson Gary K.Interbody spinal fusion implants with end cap for locking vertebral body penetrating members
US20040054411 *Jun 20, 2003Mar 18, 2004Sdgi Holdings, Inc.Wear-resistant endoprosthetic devices
US20040097928 *Aug 20, 2003May 20, 2004Thomas ZdeblickInterbody fusion device and method for restoration of normal spinal anatomy
US20040143334 *Jan 8, 2004Jul 22, 2004Ferree Bret A.Artificial disc replacements (ADRS) with features to enhance longevity and prevent extrusion
US20040186569 *Mar 20, 2003Sep 23, 2004Berry Bret M.Height adjustable vertebral body and disc space replacement devices
US20040230307 *Feb 11, 2004Nov 18, 2004Sdgi Holdings, Inc.Device for fusing two bone segments
US20050021145 *May 26, 2004Jan 27, 2005Spinalmotion, Inc.Prosthetic disc for intervertebral insertion
US20050021146 *May 26, 2004Jan 27, 2005Spinalmotion, Inc.Intervertebral prosthetic disc
US20050027360 *Aug 1, 2003Feb 3, 2005Webb Scott A.Spinal implant
US20050038515 *Sep 10, 2004Feb 17, 2005Sdgi Holdings, Inc.Lumbar composite nucleus
US20050043800 *Apr 20, 2004Feb 24, 2005Paul David C.Prosthetic spinal disc replacement
US20050113928 *Oct 22, 2004May 26, 2005Cragg Andrew H.Dual anchor prosthetic nucleus apparatus
US20050187634 *Apr 15, 2005Aug 25, 2005Berry Bret M.Height adjustable vertebral body and disc space replacement devices
US20050234553 *Apr 14, 2005Oct 20, 2005Vanderbilt UniversityIntervertebral disc replacement prothesis
US20050251260 *Feb 11, 2005Nov 10, 2005David GerberControlled artificial intervertebral disc implant
US20050261772 *Apr 15, 2005Nov 24, 2005Zimmer GmbhIntervertebral disk implant
US20060020342 *Jul 20, 2005Jan 26, 2006Ferree Bret AFacet-preserving artificial disc replacements
US20060025862 *Jul 30, 2004Feb 2, 2006Spinalmotion, Inc.Intervertebral prosthetic disc with metallic core
US20060036325 *Oct 11, 2005Feb 16, 2006Globus Medical Inc.Anterior prosthetic spinal disc replacement
US20060041313 *May 18, 2005Feb 23, 2006Sdgi Holdings, Inc.Intervertebral disc system
US20060041314 *Aug 22, 2005Feb 23, 2006Thierry MillardArtificial disc prosthesis
US20060142858 *Dec 16, 2005Jun 29, 2006Dennis ColleranExpandable implants for spinal disc replacement
US20060142862 *Feb 15, 2005Jun 29, 2006Robert DiazBall and dual socket joint
US20060155378 *Mar 8, 2006Jul 13, 2006Concept Matrix, LlcIntervertebral disk prosthesis
US20060167549 *Mar 22, 2006Jul 27, 2006Synthes Ag Chur And Synthes (Usa)Bone implant, in particular, an inter-vertebral implant
US20060178744 *Feb 4, 2005Aug 10, 2006Spinalmotion, Inc.Intervertebral prosthetic disc with shock absorption
US20060200239 *Jul 7, 2005Sep 7, 2006Accin CorporationPosterior lumbar intervertebral stabilizer
US20060200242 *Jul 7, 2005Sep 7, 2006Accin CorporationIntervertebral stabilizer
US20060235525 *Apr 19, 2005Oct 19, 2006Sdgi Holdings, Inc.Composite structure for biomedical implants
US20060259144 *Jul 17, 2006Nov 16, 2006Warsaw Orthopedic Inc.Hybrid intervertebral disc system
US20060265068 *May 17, 2006Nov 23, 2006Schwab Frank JIntervertebral implant
US20070010826 *Mar 1, 2006Jan 11, 2007Rhoda William SPosterior prosthetic spinal disc replacement and methods thereof
US20070032875 *Aug 2, 2006Feb 8, 2007Terence BlacklockOrthopaedic Medical Device
US20070100453 *Oct 31, 2005May 3, 2007Depuy Spine, Inc.Intervertebral disc prosthesis
US20070100456 *May 12, 2006May 3, 2007Depuy Spine, Inc.Intervertebral disc prosthesis with shear-limiting core
US20070135923 *Dec 14, 2005Jun 14, 2007Sdgi Holdings, Inc.Ceramic and polymer prosthetic device
US20070168033 *Sep 26, 2006Jul 19, 2007Kim Daniel HProsthetic intervertebral discs having substantially rigid end plates and fibers between those end plates
US20070213821 *Feb 10, 2006Sep 13, 2007Depuy Spine, Inc.Intervertebral disc prosthesis having multiple bearing surfaces
US20070233077 *Mar 31, 2006Oct 4, 2007Khalili Farid BDynamic intervertebral spacer assembly
US20070233251 *Feb 20, 2007Oct 4, 2007Abdou M SUse of Magnetic Fields in Orthopedic Implants
US20080015698 *Jul 6, 2007Jan 17, 2008Marino James FSpinal disc implant
US20080015701 *Jul 6, 2007Jan 17, 2008Javier GarciaSpinal implant
US20080161926 *Oct 16, 2006Jul 3, 2008Warsaw Orthopedic, Inc.Implants with Helical Supports and Methods of Use for Spacing Vertebral Members
US20090105834 *Oct 22, 2008Apr 23, 2009Spinalmotion, Inc.Dynamic Spacer Device and Method for Spanning a Space Formed upon Removal of an Intervertebral Disc
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US8002834Apr 28, 2009Aug 23, 2011Spinalmotion, Inc.Intervertebral prosthetic disc with metallic core
US8062371Apr 28, 2009Nov 22, 2011Spinalmotion, Inc.Intervertebral prosthetic disc with metallic core
US8090428Nov 11, 2009Jan 3, 2012Spinalmotion, Inc.Spinal midline indicator
US8092538Apr 15, 2008Jan 10, 2012Spinalmotion, Inc.Intervertebral prosthetic disc
US8206447Mar 7, 2008Jun 26, 2012Spinalmotion, Inc.Methods and apparatus for intervertebral disc prosthesis insertion
US8206449Jul 16, 2009Jun 26, 2012Spinalmotion, Inc.Artificial intervertebral disc placement system
US8262732May 30, 2008Sep 11, 2012Spinalmotion, Inc.Intervertebral prosthesis
US8444695May 12, 2009May 21, 2013Spinalmotion, Inc.Prosthetic disc for intervertebral insertion
US8454698Feb 13, 2008Jun 4, 2013Spinalmotion, Inc.Prosthetic disc for intervertebral insertion
US8486147Feb 4, 2008Jul 16, 2013Spinalmotion, Inc.Posterior spinal device and method
US8506631Sep 15, 2010Aug 13, 2013Spinalmotion, Inc.Customized intervertebral prosthetic disc with shock absorption
US8636805May 21, 2012Jan 28, 2014Spinalmotion, Inc.Artificial intervertebral disc placement system
US8734519Apr 12, 2007May 27, 2014Spinalmotion, Inc.Posterior spinal device and method
US8758441Oct 22, 2008Jun 24, 2014Spinalmotion, Inc.Vertebral body replacement and method for spanning a space formed upon removal of a vertebral body
US8764833Mar 9, 2009Jul 1, 2014Spinalmotion, Inc.Artificial intervertebral disc with lower height
US8771356Sep 14, 2012Jul 8, 2014Spinalmotion, Inc.Intervertebral prosthetic disc
US8801792Jul 22, 2010Aug 12, 2014Spinalmotion, Inc.Posterio spinal device and method
US8845729Nov 25, 2009Sep 30, 2014Simplify Medical, Inc.Prosthetic disc for intervertebral insertion
US8845730Jul 16, 2009Sep 30, 2014Simplify Medical, Inc.Posterior prosthetic intervertebral disc
US8956414Apr 21, 2010Feb 17, 2015Spinecraft, LLCIntervertebral body implant, instrument and method
US8974531Dec 30, 2009Mar 10, 2015Simplify Medical, Inc.Methods and apparatus for intervertebral disc prosthesis insertion
US8974533Jan 8, 2014Mar 10, 2015Simplify Medical, Inc.Prosthetic disc for intervertebral insertion
US8979928Jan 13, 2011Mar 17, 2015Jcbd, LlcSacroiliac joint fixation fusion system
US9011544Aug 17, 2010Apr 21, 2015Simplify Medical, Inc.Polyaryletherketone artificial intervertebral disc
US9017407Sep 19, 2011Apr 28, 2015Jcbd, LlcSystems for and methods of fusing a sacroiliac joint
US9034038Apr 7, 2009May 19, 2015Spinalmotion, Inc.Motion limiting insert for an artificial intervertebral disc
US9107762Nov 3, 2011Aug 18, 2015Spinalmotion, Inc.Intervertebral prosthetic disc with metallic core
US9220603Jul 1, 2009Dec 29, 2015Simplify Medical, Inc.Limited motion prosthetic intervertebral disc
US9333090Jul 19, 2013May 10, 2016Jcbd, LlcSystems for and methods of fusing a sacroiliac joint
US9351846Aug 25, 2014May 31, 2016Simplify Medical, Inc.Posterior prosthetic intervertebral disc
US9381045May 18, 2012Jul 5, 2016Jcbd, LlcSacroiliac joint implant and sacroiliac joint instrument for fusing a sacroiliac joint
US9402745Nov 24, 2009Aug 2, 2016Simplify Medical, Inc.Intervertebral prosthesis placement instrument
US9421109Jul 18, 2013Aug 23, 2016Jcbd, LlcSystems and methods of fusing a sacroiliac joint
US9439774Jan 7, 2011Sep 13, 2016Simplify Medical Pty LtdIntervertebral prosthetic disc
US9439775May 22, 2014Sep 13, 2016Simplify Medical Pty LtdArtificial intervertebral disc with lower height
US9554909Jul 19, 2013Jan 31, 2017Jcbd, LlcOrthopedic anchoring system and methods
US9554917Jul 12, 2013Jan 31, 2017Simplify Medical Pty LtdCustomized intervertebral prosthetic disc with shock absorption
US20080154382 *Mar 7, 2008Jun 26, 2008Spinalmotion, Inc.Methods and Apparatus for Intervertebral Disc Prosthesis Insertion
US20080294259 *Oct 31, 2007Nov 27, 2008Spinalmotion, Inc.Intervertebral prosthesis
US20100179419 *Mar 25, 2010Jul 15, 2010Spinalmotion, Inc.Intervertebral Prosthesis
Legal Events
DateCodeEventDescription
Jan 5, 2009ASAssignment
Owner name: SPINALMOTION, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HOVDA, DAVID;ARRAMON, YVES;REEL/FRAME:022056/0757;SIGNING DATES FROM 20081103 TO 20081104
Jul 16, 2014ASAssignment
Owner name: SIMPLIFY MEDICAL, INC., CALIFORNIA
Free format text: CHANGE OF NAME;ASSIGNOR:SPINALMOTION, INC.;REEL/FRAME:033347/0141
Effective date: 20140702
Aug 16, 2016ASAssignment
Owner name: SIMPLIFY MEDICAL PTY LTD, AUSTRALIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SIMPLIFY MEDICAL, INC.;REEL/FRAME:039696/0628
Effective date: 20141209
Sep 6, 2016ASAssignment
Owner name: SIMPLIFY MEDICAL PTY LTD, AUSTRALIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SIMPLIFY MEDICAL, INC.;REEL/FRAME:039643/0049
Effective date: 20141209