Abstract:
A device, system, and method are disclosed that supplements a human spinal column&#39;s structure by replacing a damaged intervertebral disc with a machined spacer comprising a movable pair of blades that rotate to expand from the spacer in-situ to interlock with a patient&#39;s vertebras, and a locking system that provides secondary protection from blade movement within the spacer.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present disclosure relates generally to interbody spacers used to repair damaged intervertebral discs. 
       BACKGROUND OF THE INVENTION 
       [0002]    Human spines comprise movable vertebrae, with cushioning disks between them. These intervertebral disks can be damaged in many ways, and they degenerate with age. Damage to these disks can often be debilitating and cause excruciating pain. 
         [0003]    The medical community has worked for decades to develop methods of repairing damaged spines and alleviate the associated pain. Ruptured intervertebral disks are a very common back problem, caused when a disk is ruptured or loses the fluid within it, and thus can no longer provide a proper cushion between vertebras. 
         [0004]    One common method of addressing this damage is to employ spinal fusion, a surgical technique used to facilitate the growth of bone between two vertebrae. The procedure involves implanting an “interbody”, packed with grafting material into the disc space, to stabilize the spine while bone grows in between two vertebrae. As the bone graft material heals, one long bone is formed with the adjacent vertebrae. 
         [0005]    The interbody, a spacer most often made from titanium or polyetheretherketone (“PEEK”) material, is set between the vertebras on either side of the damaged disk. 
         [0006]    Recent developments have resulted in the “stand alone” interbody spacer, as discussed in U.S. Pat. 8,328,870 (Patel, et al.), in which the spacer contains its own support means of fixation. Previous to this industry development, doctors had to add screws and other devices to the spacer to keep it in place, relative to the vertebra. 
         [0007]    The industry has not fully adopted the stand alone spacer, as current devices still struggle to stay in place. One example of a modern device is shown in U.S. Pat. No. 8,273,127, where the spacer has a load-bearing piece, and a second piece designed to prevent the spacer from migrating, as well as two screws that extend to engage in the vertebra both above and below the spacer. 
         [0008]    An additional need by the medical industry is a device that can be implanted with minimal invasion to a patient&#39;s body. 
         [0009]    The industry still seeks a stand-alone interbody spacer that can reliably be installed using a minimally invasive procedure, such that a patient&#39;s spine can fuse around the spacer without continuous medical attention to prevent spacer movement. 
       SUMMARY OF THE INVENTION 
       [0010]    The present disclosure provides a device, system, and method to supplement a human spinal column&#39;s structure by replacing a damaged intervertebral disc with a PEEK spacer comprising a movable pair of blades. The blades sit within the envelope of the spacer body during the implantation surgery until the spacer is properly set. After properly situated, the medical team actuates the rotation of the blades, which then extend both up and down from the spacer&#39;s body, providing an interlock with the vertebras above and below the spacer. The blades are locked in place, preventing the spacer from migrating out of position. 
         [0011]    Novel and inobvious aspects of the invention comprise a new locking feature for the interlocking blade and blade shape. Other features and advantages of the present disclosure will be apparent to those of ordinary skill in the art upon reference to the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    For a better understanding of the disclosure, and to show by way of example how the same may be carried into effect, reference is now made to the detailed description along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which: 
           [0013]      FIG. 1  depicts an orthogonal view of one embodiment of an 18 mm Spacer Body  100 . 
           [0014]      FIG. 2  depicts a front view of the embodiment of an 18 mm Spacer Body  100  (without hidden lines). 
           [0015]      FIG. 3  depicts a left view of the embodiment of an 18 mm Spacer Body  100  (without hidden lines). 
           [0016]      FIG. 4  depicts the sectional view of an 18 mm Spacer Body  100  along section lines A-A of  FIG. 2 . 
           [0017]      FIG. 5  depicts a top view of an 18 mm embodiment as shown in  FIG. 1-4 . 
           [0018]      FIG. 6  depicts a section view defined by  FIG. 5  along section lines H-H. 
           [0019]      FIG. 7  depicts a bottom view of the embodiment of a 10 mm embodiment of the Interbody Spacer Assembly  10  with the Blade Pair  300  in the open position. 
           [0020]      FIG. 8A  shows an orthogonal view of a Center Shaft  200  for the embodiment depicted in  FIG. 1 . 
           [0021]      FIG. 8B  shows the torx head of the Center Shaft  200  for the embodiment depicted in  FIG. 1 . 
           [0022]      FIG. 8C  shows a side view of the Center Shaft  200  for the embodiment depicted in  FIG. 1 . 
           [0023]      FIG. 8D  shows a sectional view of the Center Shaft  200  for the embodiment depicted in  FIG. 1  along the shaft&#39;s central axis. 
           [0024]      FIG. 9A  shows an orthogonal view of a Washer Nut  500  for the embodiment depicted in  FIG. 1 . 
           [0025]      FIG. 9B  shows a top view of a Washer Nut  500  for the embodiment depicted in  FIG. 1 . 
           [0026]      FIG. 9C  shows a side view of a Washer Nut  500  for the embodiment depicted in  FIG. 1 . 
           [0027]      FIG. 9D  shows a sectional view of a Washer Nut  500  along section lines A-A of  FIG. 9B . 
           [0028]      FIG. 9E  shows a bottom view of one embodiment of a Washer Nut  500 . 
           [0029]      FIG. 10A  shows an orthogonal view of the embodiment of a Lock Sleeve  400 . 
           [0030]      FIG. 10B  shows a rear view of the embodiment of a Lock Sleeve  400  shown in  FIG. 10A . 
           [0031]      FIG. 10C  shows a front view of the embodiment of a Lock Sleeve  400  shown in  FIG. 10A . 
           [0032]      FIG. 10D  shows a sectional view defined by the section lines A-A of  FIG. 10B . 
           [0033]      FIG. 10E  shows a sectional view defined by the section lines B-B of  FIG. 10C . 
           [0034]      FIG. 10F  shows a sectional view defined by the section lines C-C of  FIG. 10C . 
           [0035]      FIG. 11A  shows an exploded view of an 18 mm embodiment of an Interbody Spacer  10 . 
           [0036]      FIG. 11B  shows an orthogonal view of the embodiment of a Blade Pair  300  as shown in  FIG. 11A . 
           [0037]      FIG. 11C  shows a front view of the embodiment of a Blade Pair  300  as shown in  FIG. 11A . 
           [0038]      FIG. 11D  shows a rear view of the embodiment of a Blade Pair  300  shown in  FIG. 11A . 
           [0039]      FIG. 11E  shows a right side view of the embodiment of a Blade Pair  300  shown in  FIG. 11A . 
           [0040]      FIG. 11F  shows a cross-sectional right side view of the embodiment of a Blade Pair  300  defined by the section lines A-A of  FIG. 11C . 
           [0041]      FIG. 11E  shows a sectional view defined by the section lines B-B of  FIG. 10C . 
           [0042]      FIG. 11G  shows the detail sectional area defined by the circular area B of  FIG. 11F . 
           [0043]      FIG. 11H  shows a top view of the embodiment of a Blade Pair  300  shown in  FIG. 11A . 
           [0044]      FIG. 11I  shows a sectional view defined by the section lines G-G of  FIG. 11H . 
           [0045]      FIG. 12  shows a rear view of an embodiment of an Interbody Spacer  10  as embodied in the previous figures. 
           [0046]      FIG. 13  shows the construction details of a Spike  210 . 
           [0047]      FIG. 14  shows a side view of an Interbody Spacer Assembly  10  with Blade Pair extended from the Spacer Body  100 . 
       
    
    
       [0048]    It should be noted that these drawings show two different embodiments, a 10 mm and an 18 mm version. 
         [0049]    These two embodiments are mere exemplars, and not intended to represent the extent of the invention. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0050]    While the making and using of various embodiments of the present disclosure are discussed in detail below, it should be appreciated that the present disclosure provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. The disclosure is primarily described and illustrated hereinafter in conjunction with various embodiments of the presently-described systems and methods. The specific embodiments discussed herein are, however, merely illustrative of specific ways to make and use the disclosure and do not limit the scope of the disclosure. 
         [0051]    The Shark Fin PEEK Spacer Method is intended for spinal fusion procedures in skeletally mature patients with degenerative disc disease (ODD) at one or two contiguous levels in the lumbar spine (L2-S1). DOD is defined as back pain of discogenic origin with degeneration of the disc confirmed by patient history and radiographic studies—DOD patients may also have a spondylolisthesis at the involved levels and may also have had a previous non-fusion surgical history. 
         [0052]    The Shark Fin PEEK Spacer Method is intended to address this type pathology and is designed to host autograft when implanted. It is not uncommon for patients to have undergone a regimen of at least six months of non-operative treatment prior to being recommended for the Shark Fin Spacer Method. 
         [0053]    The Shark Fin PEEK Spacer Method offers a surgeon a reliable, integrated standalone AUF (Anterior Lumbar Inter-body Fusion) solution that is simple to implant versus other similar type implants. The Shark Fin PEEK Spacer Method also meets the preferences of surgeons to improve care for diverse patient anatomies. This design, like others, includes a variety of implant heights and widths and lordotic angles to allow the AUF approach to harmonize to a given patient&#39;s anatomy. And because the Keel Locking Method eliminates lock-down screws this style implant is especially advantageous for difficult cases in the L5 to S1 region of the spine. 
         [0054]    To date, this new standalone cage design has received to positive feedback in its concept form from surgeons experienced in the art of Standalone AUF procedures—it easily meets patient anatomy and may provide one of the more time efficient surgical procedures versus other AUF devices in its class. A variety of materials such as PEEK OPTIMA, titanium, cobalt, chrome, carbon fiber, PEKK, etc. can define the body and related mechanical components respectively while an anterior plate and other supplemental add-on devices such as a buttress plate could be used to reinforce the construct predominantly defined by this device. 
         [0055]    The Locking Keel is a novel component that provides the surgeon with a simplified two-step implant locking procedure to secure an Interbody Spacer Assembly  10  into final position to prevent migration. 
         [0056]    As seen in the drawings and currently embodied, the Interbody Spacer Assembly  10  comprises a Spacer Body  100 , a Center Shaft  200  which an operator turns while it is engaged with a Blade Pair  300  which is held in place by a Lock Sleeve  400  and Washer Nut  500 , and Spikes  600  on the Spacer Body  100  to exterior. 
         [0057]    The Spikes  600  on the Upper Surface  110  and Lower Surface  120  of the Interbody Spacer Assembly  10  prevent migration of the Assembly  10  after installation. 
         [0058]    Upper and Lower Surfaces  110 ,  120  possess an angle called a lordotic angle to allow the implant to match patient specific segmental angular anatomy with lordotic angles ranging between 0 and 7 degrees. 
         [0059]    The upper and lower surface Spikes  600  can include an ovoid shape as well (a slightly convex curve), as shown in FIGS.  1 ,  5 ,  7  and  11 A, to also help match the implant to patient anatomy. 
         [0060]    The wide central opening in the Shark Fin PEEK Spacer Body  100  essentially is used to hold optimal graft material. As seen in  FIG. 12 , after the Blades  300  are turned to their open position extending above and below the Spacer Body  100 , a user can inject additional materials into the volume encased by the Body  100  through the Access Hole  150 , even mounting instruments on the Body  100  in the threaded Instrumentation Mount  140 . 
         [0061]    The Shark Fin Spacer Assembly  10  can be constructed in many sizes, most notably in the range of range of 10 mm to 22 mm in height and 32 mm to 36 mm in width, but is not restrained to those sizes. 
         [0062]    Tantalum X-ray markers may be located on the upper and lower surfaces of the implant body to provide clear radiographic identification. However, given the Keel-Plate design strategy, fewer implant markers may be necessary, such as using the markers only on the distal part of the implant body. 
         [0063]    Two lateral openings are built into the Spacer Body  100 . The Instrumentation Mount  140  allows for insertion tool attachment, providing a threaded hole in the Body  100 . Due to mechanical implant locking design multiple implant deliver angles can be accommodated. The Access Hole  150  allows medical personnel to have access to the volume encased by the Body  100 . 
         [0064]    The Keel Locking Blade is a distinct construction employing a slight cord-wise twist definition to increase blade deflection resistance, which mitigates blade failure during service life and helps surgeons to more easily and securely lock the implant into a permanent location. 
         [0065]    The Blade Pair  300  is constructed so that when the pair is turned in the open position (such that the blades are extended above and below the installed Interbody Spacer Assembly  10 ), the unthreaded Access Hole  150  in the rear of the Assembly allows medical personnel to insert biologics into the internal volume enclosed by the Spacer Body  100 . 
         [0066]    A threaded Instrument Mount Hole  140  is also positioned on the rear of the Spacer Body, as shown on  FIG. 12 . This threaded hole acts as a mounting position for insertion tool, biologic injection guns, and other similar medical gear. 
         [0067]    The chord-wise twist definition of the Blade Pair  300  is defined similar to radially extending a jack screw thread pattern (i.e. if the Blades&#39; chord-wise planar surfaces were projected outward in a radial manner, the resulting geometry would describe a typical jack screw thread pattern; this not only creates maximum blade deflection resistance, but also creates subtle mechanical leverage during blade rotation to better purchase the implant into its final resting position. 
         [0068]    This design strategy provides a constant “sweep angle” along the length of each blade on Blade Pair  300  to optimize blade lengthwise stiffness and reduce blade failure likelihood anywhere along the blades&#39; span, including the blades&#39; root. 
         [0069]    The leading edge of each blade of the Blade Pair  300  will have a sharpened edge to allow easy penetration into the boney upper and lower plates of the vertebra when the Blade Pair  300  is rotated from its resting “near horizontal” position into a locked “vertical” position. The edge geometry may have serrated edges or smooth edges, or smooth edges with a partial serration so the Blade Pair can more easily penetrate a user&#39;s surface with minimal surface fracture. 
         [0070]    The root of each of the blades of the Blade Pair  300  will possess a graduating thickness where maximum bending moments occur to prevent the blade from fatigue due to the blades&#39; surrounding cyclical environmental loading conditions. 
         [0071]    The Blade Pair  300  may possess optional Blade Pair Clearance Holes  330  in its body to provide apertures for bone growth, as shown in  FIG. 11C . The size of the aperture is a discretionary design option with its size and location to be ideally located so as not to reduce the structural integrity of the blade design.  FIG. 11C  shows two differing shapes and locations for Clearance Holes  330 , but this is a mere example and is not intended to be limiting. 
         [0072]    The hub geometry may or may not have a “keyed” hole and slot to allow the Blade Pair  300  to be rotated by a Center Shaft  200 , though the embodiment. In the current design, a press fit-welded pin will supplement and create the rigid mechanical connection between the blade and the shaft. 
         [0073]    The lengthwise distance of the Keel or Blade Pair  300  will be variable and will always be a minimum of 10 mm longer than the height of the implant body that it resides within (i.e., 5 mm beyond than the upper and lower profile horizon of the implant body). 
         [0074]    The Blade Center Shaft  200  is designed to rotationally articulate the Blade Pair  300  from a resting or closed position to a vertical locked position to prevent the Interbody Spacer  10  from migration after installation. 
         [0075]    As shown in  FIG. 9A-9E , the proximal portion of the Washer Nut  500  possesses a four fingered expansion collar that is designed to expand under the influence of an inner screw where the four fingers expand outward and into the Spacer Body  100  to create an almost cold weld mechanical interference. 
         [0076]    The bearing surface of the Center Shaft  200  to the Center Shaft Channel  130  is a high-precision cam geometry that allows for easy rotation within the Spacer Body  100 , and provides the predominant interface into the Spacer Body  100  where the majority of mechanical loading is translated. 
         [0077]    As seen in  FIGS. 8A &amp; 8C , just past the bearing surface is a region that may or may not be threaded that assists in the connectivity of the shaft to the blade. In early models, a press fit pin is used for this connectivity which may be optionally welded for final fastening. This assembly strategy precludes possible mating separation and provides a redundant mating method for the blade shaft interface. 
         [0078]    The largest lengthwise portion of the shaft that possesses a simple outer diameter is designed as a near “press-fit” feature that allows the shaft to engage the rotational Blade Pair  300  to reinforce the rigid interface required between the Shaft  200  and the Blade Pair  300 . 
         [0079]    This invention includes an innovative concept of an interlocking Lock Sleeve  400  as shown in  FIG. 10A . Two Lock Sleeve Fingers  410  extend from the Lock Sleeve  400 . During the installation of the invention, a user turns the Center Shaft  200 . The Blades  300  are pressed onto the Center Shaft  200  so they turn as one unit to the open position, extending vertically above and below the Spacer Body  100 . As shown in  FIG. 11A , the Center Shaft  200  is not cinched tight into the Spacer Body. Instead, movement of the Center Shaft  200  is prevented by a Washer Nut  500  that is tightened on the Center Shaft to the Spacer Body  100 . While it is tightened, however, it also pushes the Lock Sleeve Fingers  410  through the Lock Finger Channel  170  constructed in the Spacer Body  100  (as seen in  FIG. 6 ).  FIG. 11D  shows the Lock Finger Indent, which accepts the Lock Sleeve Fingers  410  to hold them in place. This interlocking finger/indent construction provides secondary protection from Blade  300  movement within the Body  100  should the washer loosen. 
         [0080]    The invention is superior to other industry offerings because this construction requires no bone screws and allows for easy load sharing. 
         [0081]    All embodiments described herein are presented for purposes of illustration and explanation only. These descriptions of one embodiment are not intended to be limiting to the embodiments described. Those skilled in the relevant art will be able to create other embodiments based on this disclosure and the claims that are attached with this application 
         [0082]    The figures of this patent application include the following components and nomenclature: 
         [0083]      10  Interbody Spacer Assembly 
         [0084]      100  Spacer Body 
         [0085]      110  Upper Surface 
         [0086]      120  Lower Surface 
         [0087]      130  Center Shaft Channel 
         [0088]      140  Instrumentation Mount 
         [0089]      150  Access Hole 
         [0090]      160  Spike Mounting Holes 
         [0091]      170  Lock Finger Channel 
         [0092]      200  Center Shaft 
         [0093]      210  Spike 
         [0094]      220  Spike Angle of Installation 
         [0095]      230  Spike Angle of Contact 
         [0096]      300  Blade Pair 
         [0097]      310  Lock Finger Indent 
         [0098]      330  Blade Pair Clearance Holes 
         [0099]      400  Lock Sleeve 
         [0100]      410  Lock Sleeve Finger 
         [0101]      420  Lock Sleeve Finger Engagement 
         [0102]      500  Washer Nut 
         [0103]      600  Spike