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  Expandable vertebral implant and methods of useUSPTO Application #: 20080021556Title: Expandable vertebral implant and methods of use Abstract: An implant for insertion between vertebral body endplates includes first and second end members, each with a respective endplate contact surface. The implant further includes a collapsible intermediate section disposed between the first and second end members and an inflatable member contained within the intermediate section. The intermediate section may be expandable upon the introduction of a substance into the inflatable member between a first size to space the first and second end members a first distance apart and a second enlarged size to space the first and second end members a second greater distance apart. The inflatable member may increase in size from a compressed size in which the inflatable member will pass through an opening in the intermediate section and an expanded size in which the inflatable member will not pass through the opening and is thereby captively retained within the intermediate section. (end of abstract) Agent: Coats & Bennett, PLLC - Cary, NC, US Inventor: Jason A. Edie USPTO Applicaton #: 20080021556 - Class: 623 1711 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20080021556. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND [0001]Spinal implants are often used in the surgical treatment of spinal disorders such as degenerative disc disease, disc herniations, scoliosis or other curvature abnormalities, and fractures. Many different types of treatments are used, including the removal of one or more vertebral bodies and/or intervertebral disc tissue. In some cases, spinal fusion is indicated to inhibit relative motion between vertebral bodies. In other cases, dynamic implants are used to preserve motion between vertebral bodies. In yet other cases, relatively static implants that exhibit some degree of flexibility may be inserted between vertebral bodies. [0002]Regardless of the type of treatment and the type of implant used, surgical implantation tends to be a difficult for several reasons. For instance, access to the affected area may be limited by other anatomy. Further, a surgeon must be mindful of the spinal cord and neighboring nerve system. The size of the implant may present an additional obstacle. In some cases, a surgeon may discover that an implanted device has an inappropriate size for a particular application, which may require removal of the implant and insertion of a different implant. This trial and error approach may increase the opportunity for injury and is certainly time-consuming. Expandable implants are becoming more prevalent as a response to some of these concerns. However, the expansion mechanism in these devices tends to be complex and large. Consequently, existing devices do not appear to address each of these issues in a manner that improves the ease with which the device may be surgically implanted. SUMMARY [0003]Illustrative embodiments disclosed herein are directed to an implant for insertion between vertebral body endplates. The implant may include first and second end members, each with a respective endplate contact surface. The implant may further include a collapsible intermediate section disposed between the first and second end members and an inflatable member contained within the intermediate section. The collapsible intermediate section may be flexible and may be implemented using, for example, a continuous threaded tether, multiple tethers, or a mesh member. The collapsible intermediate section may be compliant or semi-rigid and naturally assume a compressed, but expandable insertion height. The intermediate section may be expandable upon the introduction of a substance into the inflatable member between a first size to space the first and second end members a first distance apart and a second enlarged size to space the first and second end members a second greater distance apart. The inflatable member may increase in size from a compressed size in which the inflatable member will pass through an opening in the intermediate section and an expanded size in which the inflatable member will not pass through the opening and is thereby captively retained within the intermediate section. BRIEF DESCRIPTION OF THE DRAWINGS [0004]FIG. 1 is a side elevation view of a vertebral implant according to one embodiment positioned between vertebral bodies; [0005]FIG. 2 is a section view of the vertebral implant according to the section lines in FIG. 1; [0006]FIG. 3 is a perspective view of an exploded vertebral implant assembly according to one embodiment; [0007]FIGS. 4-6 illustrate a sequence of implantation steps to obtain a desired vertebral body spacing, each Figure depicting a lateral view of a vertebral implant according to one or more embodiments shown relative to vertebral bodies; [0008]FIG. 7 is a side view of a vertebral implant assembly according to one embodiment; [0009]FIG. 8 is a top view of a vertebral implant assembly according to one embodiment; [0010]FIG. 9 is a perspective view of one embodiment of a vertebral implant; and [0011]FIG. 10 is a side view of a vertebral implant assembly according to one embodiment. DETAILED DESCRIPTION [0012]The various embodiments disclosed herein are directed to vertebral implants that are characterized by at least one expandable portion. The expandable portion may be assume a compressed first state during installation of the implant and may be expanded once the implant is positioned within the body. An exemplary implant 10 for supporting vertebral bodies is illustrated in FIG. 1. In one embodiment, the implant 10 is a vertebrectomy or corpectomy cage assembly positionable within an intervertebral space to span one or more vertebral levels along the longitudinal axis of the spinal column. Although the illustrated embodiment of the implant 10 spans one vertebral level, it should be understood that the implant 10 may be configured to span multiple vertebral levels. [0013]FIGS. 1-3 illustrate that the implant 10 generally includes a first end member 22, a second end member 24, and one or more expandable portions 26 between the first and second end members 22, 24. In one embodiment, the end members 22, 24 are formed of a biocompatible material, such as, for example, a carbon fiber material, or non-metallic substances, including polymers or copolymers made from materials such as PEEK and UHMWPE. In further embodiments, the end members 22, 24 may be formed of other suitable materials, such as, for example, stainless steel, titanium, cobalt-chrome, and shape memory alloys or other biocompatible metals. [0014]The end members 22, 24 are adapted to engage the endplates of upper and lower vertebral bodies V1, V2. The expandable portion 26 is engaged between the end members 22, 24 to maintain an intervertebral axial space S between the upper and lower vertebral bodies V1, V2 following the removal of one or more vertebral levels (shown in phantom in FIG. 1). Generally, the expandable portion 26 includes a collapsible portion 41 and an inflatable portion 35. In the embodiment shown, the collapsible portion 41 includes a series of cords or tethers 42 and the inflatable portion 35 includes a balloon-like structure 36. A plurality of tethers 42 may extend around the perimeter 52 of the end members to form a cage. To facilitate insertion of the implant 10, the expandable portion 26 may be collapsed relative to the extended state shown in FIG. 1. Further details regarding process steps for insertion of the implant 10 are provided below. [0015]The expandable portion 26 is expandable in a direction that is substantially transverse to the bone contact surfaces 32, 34 of the end members 22, 24. The bone contact surfaces 32, 34 of the end members 22, 24 may be planar or define surface features and/or a number of anchor elements 80 adapted for engagement with the vertebral endplates to inhibit movement of the end members 22, 24 relative to the vertebral bodies V1, V2. For example, in one embodiment, the bone contact surfaces 32, 34 may be roughened, such as, for example, by knurling and/or etching (e.g., photochemical etching). In other embodiments, various types of projections or protrusions may extend from the bone contact surfaces 32, 34, such as, for example, a number of spikes, ridges, teeth, axial grooves, checkerboard-type grooves, or any other type of anchoring element 80 that would occur to one of skill in the art. Although the bone contact surfaces 32, 34 of the end members 22, 24 are illustrated in FIGS. 1 and 3 as being arranged substantially planar, it should be understood that the bone contact surfaces 32, 34 may be tapered or curved to more closely conform with the anatomical curvature of the vertebral bodies V1, V2 at the surgical site. [0016]In one or more embodiments, the implant 10 may be expanded through the introduction of an injectable substance that fills an inflatable balloon-like member 36, thereby causing the end members 22, 24 to move opposite one another. The number 90 in FIG. 2 identifies the injectable substance, which fills the balloon-like member 36. In the embodiment shown, the balloon-like member 36 includes a size and shape to fit within the end members 22, 24. Further, the balloon-like member 36 includes a compressed size (see dimension B) that is small enough to fit between adjacent tethers 42 (see dimension T) and an expanded size that is larger than the spacing between adjacent tethers 42. Accordingly, the expanded balloon-like member 36 is captively retained between the end members 22, 24 and inside the tethers 42. [0017]The end members 22, 24 include similar shapes, which permits the end members 22, 24 to fit the vertebral bodies V1, V2 in a similar manner. The end members 22, 24 generally include respective bone contact surfaces 32, 34 and an opposing surface 54 facing opposite the bone-contact surfaces 32, 34, and a peripheral wall 52 extending therebetween. In the illustrated embodiment, the end members 22, 24 include a kidney shape, though other shapes may be used. In further embodiments, the end members 22, 24 may take on other types of configurations, such as, for example, a circular shape, semi-oval shape, bean-shape, D-shape, elliptical-shape, egg-shape, or any other shape that would occur to one of skill in the art. In other embodiments, the end members 22, 24 could also be described as being annular, U-shaped, C-shaped, V-shaped, horseshoe-shaped, semi-circular shaped, semi-oval shaped, or other similar terms defining an implant including at least a partially open or hollow construction. Thus, end members 22, 24 may be constructed for use in a variety of procedures, including but not limited to those requiring an anterior approach, a lateral approach, a posterior approach, or a trans-foraminal approach. [0018]It should further be appreciated that the size and/or configuration of the end members 22, 24 may be specifically designed to accommodate any particular region of the spinal column and/or any particular vertebral level. For example, in embodiments associated with the upper thoracic or cervical region of the spine, the end members 22, 24 may be designed to have a D-shaped configuration, whereas embodiments associated with the lumbar region of the spine may be configured to have a horseshoe-shape, a U-shape, or other types of open-sided configurations. [0019]In one embodiment, the end members 22, 24 have an outer profile that is substantially complementary to the size and shape of the peripheral portion or outlying region of the vertebral bodies V1, V2, such as the cortical rim or the apophyseal ring of the vertebral endplates. For example, as illustrated in FIG. 2, the outer perimeter of the end member 24 is preferably disposed generally above the inner edge of the cortical rim R of the vertebral body V1. In this manner, at least a portion of the end members 22, 24 is engaged against the cortical region of the vertebral endplates, thereby minimizing the likelihood of subsidence into the relatively softer cancellous region of the vertebral bodies V1, V2 following insertion of the implant 10 within the intervertebral space S. [0020]Additionally, each of the bone contact surfaces 32, 34 may include one or more apertures or recesses 50 formed by an inner surface 82. The recess 50 is open at the bone contact surfaces 32, 34 and provided to enhance bony fusion between the end members 22, 24 and vertebral bodies V1, V2. The recesses 50 may be blind holes in that they do not extend through the end members 22, 24. The recesses 50 may be through-holes in that they do extend through the end members 22, 24. In one or more implementations, the implant 10 may be inserted in conjunction with bone growth materials that may include, for example, bone graft, bone morphogenetic protein (BMP), allograft, autograft, and various types of cement, growth factors and mineralization proteins. In a further embodiment, the bone growth promoting materials may be provided in a carrier (not shown), such as, for example, a sponge, a block, a cage, folded sheets, or paste. The bone growth materials may be loaded into the apertures 50 or generally applied to the bone-contact surfaces 32, 34. Continue reading... Full patent description for Expandable vertebral implant and methods of use Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Expandable vertebral implant and methods of use patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Expandable vertebral implant and methods of use or other areas of interest. ### Previous Patent Application: Expandable vertebral body implants and methods of use Next Patent Application: Spinal motion-preserving implants Industry Class: Prosthesis (i.e., artificial body members), parts thereof, or aids and accessories therefor ### FreshPatents.com Support Thank you for viewing the Expandable vertebral implant and methods of use patent info. 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