Abstract:
An implant formed from an expandable spinal device which incorporates a main body, a flexible front body, a push arm, and a drive screw with the intention of expanding the footprint (surface area and bone grafting volume) of the device after insertion.

Description:
PRIORITY CLAIM 
       [0001]    In accordance with 37 C.F.R. 1.76, a claim of priority is included in an Application Data Sheet filed concurrently herewith. Accordingly, the present invention claims priority to U.S. Provisional Patent Application No. 62/216,656, entitled “EXPANDABLE SPINAL FUSION DEVICE”, filed Sep. 10, 2015. The contents of the above referenced application are incorporated herein by reference in its entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to the field of orthopedic surgery and, more particularly, to implants placed between vertebrae in the spine. 
       BACKGROUND OF THE INVENTION 
       [0003]    Spinal stabilization is known to alleviate chronic back pain caused by displaced disk material or excessive movement of individual vertebrae. Conventional stabilization techniques include fusing two or more vertebrae together to immobilize the area of excessive movement. In one technique, vertebral disk material which separates the vertebrae is removed and bone graft material is inserted in the space for interbody fusion. In addition to or, in place of, the bone graft material, a spinal implant may be inserted in the intervertebral space. 
         [0004]    The conventional surgical approach for stabilization has been posterior for ease of access to the spine and to avoid interfering with internal organs and tissue. Usually the implant site is prepared to maintain natural lordosis and to accept a certain sized implant within certain pressure limits. This requires considerable time and skill by the surgeon. 
         [0005]    Disclosed is an implant forming an expandable spinal device which incorporates a main body, a flexible front body, a push arm, and a drive screw with the intention of expanding the footprint (surface area and bone grafting volume) of the device after insertion. 
         [0006]    It is an objective of the instant invention to teach a lateral surgical approach for the placement of an intervertebral spacer implant for interbody fusion allowing the implant to be inserted through a small incision and increased in size in situ. 
         [0007]    Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with any accompanying drawings; wherein are set forth, by way of illustration and example, certain embodiments of this invention. Any drawings contained herein constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]      FIG. 1  is an isometric view of the implant in place in the spine. 
           [0009]      FIG. 2  is a side view of the implant between two vertebral bodies. 
           [0010]      FIG. 3  is a side view of the implant in the expanded state between two vertebral bodies. 
           [0011]      FIG. 4  is a top view of the implant in position on the spine. 
           [0012]      FIG. 5  is a top view of the implant in the expanded state in position on the spine. 
           [0013]      FIG. 6  is a prospective view of the implant. 
           [0014]      FIG. 7  is a prospective view of the implant in the expanded state. 
           [0015]      FIG. 8  is a top view of the implant. 
           [0016]      FIG. 9  is a top view of the implant in the expanded state. 
           [0017]      FIG. 10  is a side view of the implant. 
           [0018]      FIG. 11  is a side view of the implant. 
           [0019]      FIG. 12  is a back view of the implant. 
           [0020]      FIG. 13  is a front view of the implant. 
           [0021]      FIG. 14  is an exploded view of the implant. 
           [0022]      FIG. 15  is an exploded isometric view of the implant. 
           [0023]      FIG. 16  is an exploded isometric view of the implant. 
           [0024]      FIG. 17  is an exploded isometric view of the implant. 
           [0025]      FIG. 18  is an exploded isometric view of the implant. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The implant  10  is inserted in the intervertebral space to replace damaged, missing, or excised disk material. The implant  10  is placed between adjacent vertebrae which are forced apart to a desired spacing. 
         [0027]    Referring now in general to the figures, depicted is the implant  10  of the instant invention which consists of a main body  20 , a push arm  22 , a flexible body  24 , a drive screw  26 , flexible body guide pins  28 , a push arm pivot pin  30 , and a push arm guide pin  32 . 
         [0028]    The main body  20  has an aperture  21  that extends through it to create and open architecture. The aperture is defined by at least four interior walls  81 ,  83 ,  85 , and  87 . The main body  20  has a distal end  23 , a proximal end  25 , a side wall  27 , and a side wall  29  formed to make a reasonably rectangular shape. The implant  10  has a slot  31  which extends through the main body  20  as a travel limit for the push arm guide pin  32 . The main body  20  also has slots  33  configured to act as travel limiters for the flexible body guide pins  28 . The main body  20  incorporates an opening  35  at the proximal end which extends into the main cavity of  20 . The main body  20  has a threaded hole  37  at its proximal end to receive the drive screw  26 . The main body  20  has a slot  39  which extends through its side wall  29  to receive push arm  22  and flexible body  24 . The main body  20  has a top surface  41  and a bottom surface  43 . The main body  20  incorporates extended portions  45  as stabilizers (anchors) to maintain position during the expansion maneuver. 
         [0029]    The implant  10  can be made of conventional materials commonly used in surgical implants, such as stainless steel and its many different alloys, titanium, or any other material with the requisite strength and biologically inert properties. Polymeric materials with adequate strength and biological properties may also be used in the construction of the main body  20 , the push arm  22 , the flexible body  24 , the drive screw  26 , the flexible body guide pins  28 , the push arm pivot pin  30 , and the push arm guide pin  32 . 
         [0030]    The flexible body  24  has a top surface  47 , a bottom surface  49 , an exterior side wall  51 , and an interior side wall  53 . The flexible body  24  incorporates an arrangement of slots  55  which extend from the top surface  47  through the bottom surface  49  in a pattern along the exterior wall  51  to allow for a more flexible member. The flexible body  24  has extensions  57  and  59  that correspond with slot  39  in the main body  20 . The extensions  57  and  59  of the flexible body  24  incorporate thru holes  61  to receive the flexible body guide pins  28  which travel along slot  33  in the main body  20  in the assembled state. The flexible body  24  has an extension  63  which communicates with slot  65  in the push arm  22 . 
         [0031]    The push arm  22  and the flexible body  24  are joined in assembly by the push arm pivot pin  30  which goes through a thru hole  67  in the push arm  22  and a thru hole  69  in the flexible body  24 . The push arm  22  rides through slot  39  and slot  71  of the main body  20 . 
         [0032]    The push arm guide pin  32  goes through slot  31  and thru hole  73  in the push arm  22  in the assembled state. The push arm guide pin  32  travels in a restricted fashion in slot  31  of the main body  20  as the drive screw  26  is advanced. The drive screw  26  has a threaded portion  75  which communicates with the threaded opening of  37  of the main body  20 . The drive screw  26  has a distal end  77  which communicates with the push arm  22  to drive the expansion feature. The drive screw has a receiving end  79  to receive an appropriate screwdriver (not shown). 
         [0033]    As the drive screw  26  is advanced, the push arm  22  changes its angle as it travels towards the distal end of slot  31 . With the push arm  22  rigidly connected to the flexible body  24 , this change in angle applies a force that bends the flexible body  24  and translates it along the flexible body guide pins  28  until they terminate their slot  33 .