Abstract:
A delivery instrument for placing an interbody implant into an intervertebral space of a patient comprises a plurality of elongated plates disposed adjacent one another. Each elongated plate has a proximal portion and a distal portion. The distal portion is sized and shaped to fit into the intervertebral space, and is configured to engage a vertebral body in the intervertebral space. An expandable member is coupled to the plurality of elongated plates so as to form an enclosed tube that is sized and shaped to receive the interbody implant. The expandable member allows for translation of the plurality of elongated plates relative to one another as the interbody implant passes through the tube.

Description:
CROSS-REFERENCE 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 14/322,589 (Attorney Docket No. 44057-705.201), filed Jul. 2, 2014, now U.S. Pat. No. ______, which is a non-provisional of, and claims the benefit of U.S. Provisional Patent Application No. 61/842,879 (Attorney Docket No. 44057-705.101) filed on Jul. 3, 2013; the entire contents of which are incorporated herein by reference. 
         [0002]    The present application is related to U.S. patent application Ser. No. ______ (Attorney Docket No. 44057-706.201) filed the same day as the present application; the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention generally relates to medical devices and methods, and more particularly relates to delivery instruments and methods for deploying an interbody fusion implant into an intervertebral disc space. 
         [0005]    Various interbody fusion implants (also referred to as interbody fusion devices) may be implanted in the intervertebral disc space. These devices facilitate fusion of the adjacent vertebrae together. Depending on the size of the interbody fusion device and the corresponding delivery instrument, a surgeon may have to remove bone from the surrounding vertebrae in order to provide adequate space. Clearly, it would be desirable if bone removal could be minimized or eliminated all together. Moreover, adjacent tissue may also need to be retracted or removed, and it would be desirable to minimize or eliminate this as well. Also, insertion of the implant often requires distraction of the vertebrae, therefore it would be desirable to provide a low profile implant that minimizes the amount of distraction required. 
         [0006]    Newer interbody fusion devices are being developed which have a smaller more compact profile for delivery and a larger expanded profile after deployment. The smaller delivery size facilitates delivery, and the larger deployed configuration facilitates support and fusion of the bone. Therefore, it would be desirable to provide improved delivery instruments which can accurately and safely deliver and deploy interbody fusion devices including those that have collapsed configurations for delivery and expanded configurations after deployment. At least some of these objectives will be satisfied by the devices and methods disclosed below. 
         [0007]    2. Description of the Background Art 
         [0008]    The following US patents and US patent publications are related to interbody fusion devices and their delivery: U.S. Pat. Nos. 6,652,533; 3,486,505; 2011/0071634; 7,896,884; 7,625,379; 6,755,841; 5,431,658; and RE43317. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention generally relates to medical devices and methods, and more particularly relates to delivery instruments and methods for deploying an interbody fusion implant into an intervertebral disc space. 
         [0010]    In a first aspect of the present invention, a delivery instrument for facilitating the placement of an interbody implant into an intervertebral space of a patient comprises a plurality of elongated plates disposed adjacent one another. Each elongated plate has a proximal portion and a distal portion. The distal portion of each elongated plate is sized and shaped to fit into the intervertebral space, and also the distal portion of each elongated plate is configured to engage a vertebral body in the intervertebral space. An expandable member is coupled to the plurality of elongated plates so as to form an enclosed tube for at least a portion of the length of the plurality of elongated plates. The enclosed tube is sized and shaped to receive the interbody implant. The expandable member allows for translation of the plurality of elongated plates relative to one another as the interbody implant passes through the tube. 
         [0011]    The expandable member may be an elastomeric tube that is disposed over the plurality of elongated plates. The expandable member may comprise two or more flexible sheets of resilient material that extend from one elongated plate to another elongated plate. The plurality of elongated plates may have a geometry that is configured to engage the interbody implant passing through the tube, and the plurality of elongated plates may have a geometry that guides the interbody implant into the intervertebral space. The geometry that engages the interbody implant may comprise a plurality of rails extending from the plurality of elongated plates. 
         [0012]    The plurality of elongated plates may be expandable to allow the delivery instrument to expand in one or multiple directions in order to accommodate various sizes of interbody implants. The plurality of elongated plates may have a longitudinally oriented slit located therealong, and the slit may be configured to allow the plurality of plates to expand and contract. The longitudinally oriented slit may comprise a stress relief feature. The plurality of plates may be coupled together adjacent their proximal portion. 
         [0013]    At least one of the plurality of elongated plates may comprise a finger loop adjacent a proximal end thereof, and the finger loop may be configured to facilitate grasping by an operator&#39;s finger. The delivery instrument may further comprise a stop element disposed adjacent a distal portion of at least one of the plurality of elongated plates. The stop element may be configured to limit insertion of the delivery instrument into the intervertebral space. 
         [0014]    In another aspect of the present invention, a system for delivering an implant to an intervertebral space of a patient comprises the delivery instrument previously described above as well as an interbody implant. 
         [0015]    In still another aspect of the present invention, a method for delivering an interbody implant into an intervertebral space between adjacent vertebral bodies of a patient comprises providing a delivery instrument having a plurality of elongated plates disposed adjacent one another and coupled together with an expandable member, and advancing the interbody implant along a tube formed by the plurality of elongated plates and the expandable member. The method also comprises translating the plurality of elongated plates relative to one another as the interbody implant advances along the tube, ejecting the interbody implant from the delivery device, and returning the elongated plates to an unbiased configuration after the interbody implant has been ejected. 
         [0016]    Translating the plurality of elongated plates may comprise moving the plurality of plates away from one another, or expanding or collapsing the expandable member. The expandable member may comprise an elastomeric tube that is disposed over the plurality of elongated plates. 
         [0017]    Advancing the interbody implant may comprise guiding the interbody implant along the tube with a plurality rails extending from the plurality of elongated plates. A stress relief feature may be included in one or more of the plurality of elongated plates, and the method may further comprise relieving stress in the delivery instrument as the interbody implant is translated therealong. 
         [0018]    Translating the plurality of elongated plates may comprise expanding or contracting a slit disposed in at least one of the plurality of elongated plates. The plurality of elongated plates may be coupled to one another adjacent a proximal portion thereof, and translating the plurality of elongated plates may comprise pivoting the plurality of elongated plates relative to the proximal portion. Ejecting may comprise disposing the interbody implant in the intervertebral space. The method may further comprise engaging a distal portion of the plurality of elongated plates with the vertebral bodies. 
         [0019]    The method may further comprise grasping the delivery device by inserting one or more fingers in a finger loop disposed on a proximal portion of at least one of the plurality of elongated plates. The method may also further comprise advancing the plurality of elongate plates into the intervertebral space, and limiting penetration of the plurality of elongate plates into the intervertebral space. This may be accomplished by engaging a stop element disposed on at least one of the plurality of elongate plates against an edge of at least one of the adjacent vertebral bodies. 
         [0020]    These and other embodiments are described in further detail in the following description related to the appended drawing figures. 
       INCORPORATION BY REFERENCE 
       [0021]    All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which: 
           [0023]      FIG. 1  is a perspective view of an elongated plate component; 
           [0024]      FIG. 2  is a perspective view of an insertion guide device, using the elongated plate in  FIG. 1 , in the collapsed state; 
           [0025]      FIG. 3  is a perspective view of the insertion guide device in  FIG. 2  in an expanded state; 
           [0026]      FIG. 4  is a perspective view of an elongated plate component; 
           [0027]      FIG. 5  is a perspective view of an insertion guide device, using the elongated plate in  FIG. 4 , in the collapsed state; 
           [0028]      FIG. 6  is a perspective view of the insertion guide device in  FIG. 5  in an expanded state; 
           [0029]      FIG. 7  is a perspective view of an elongated plate component; 
           [0030]      FIG. 8  is a perspective view of an insertion guide device, using the elongated plate in  FIG. 7 , in the collapsed state; 
           [0031]      FIG. 9  illustrates an interbody implant coupled to the insertion guide device; 
           [0032]      FIGS. 10A-10F  illustrate insertion of the insertion guide device into the intervertebral disc space and delivery of an interbody implant; and 
           [0033]      FIGS. 11A-11B  illustrate a pusher element for pushing an interbody implant from the insertion guide device. 
           [0034]      FIG. 12A  illustrates a perspective view of another exemplary embodiment of an elongated plate used in an insertion guide device. 
           [0035]      FIG. 12B  is a side view of  FIG. 12A . 
           [0036]      FIG. 13A  illustrates a perspective view of an insertion guide device using the elongated plate in  FIG. 12A  and in the collapsed configuration. 
           [0037]      FIG. 13B  illustrates the embodiment of  FIG. 13A  in the expanded configuration. 
           [0038]      FIG. 14  is a perspective view of the insertion guide device of  FIG. 13A  inserted into the intervertebral space. 
           [0039]      FIG. 15A  illustrates a perspective view of another exemplary embodiment of an elongated plate that may be used in an insertion guide device. 
           [0040]      FIG. 15B  is a side view of  FIG. 15A . 
           [0041]      FIG. 16A  illustrates a perspective view of an insertion guide device using the elongated plate in  FIG. 15A  and  FIG. 12A , and in the collapsed configuration. 
           [0042]      FIG. 16B  illustrates the embodiment of  FIG. 16A  in the expanded configuration. 
           [0043]      FIG. 17  illustrates the insertion guide device of  FIG. 16A  inserted into the intervertebral disc space. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0044]    Specific embodiments of the disclosed device, delivery system, and method will now be described with reference to the drawings. Nothing in this detailed description is intended to imply that any particular component, feature, or step is essential to the invention. 
         [0045]      FIG. 1  shows the elongated plate  20  with optional rails  21  extending outward from the elongated plate, to guide the implant into the disc space. The rails  21  extend up to the distal portion  22  of the elongated plate  20  that enters the disc space. The rails  21  end prior to the distal portion  22  of the elongated plate  20  in order to decrease the width of the elongated plate  20  that has to pass by the neural elements and into the disc space. The rails  21  are set at a distance apart to match the width of the implant being passed through it further optimizing the width of the elongated plate  20  so that it is as narrow as possible (low profile) as it passes by the neural elements. Notch  23 , is an optional feature in the elongated plate  20  to allow for the engagement of the expandable member  30 . This notch  23  prevents the axial migration of the expandable member  30  along the length of the elongated member  20 . The elongated plate  20  may be made out of a variety of materials including, but not limited to, metals such as stainless steel or aluminum, carbon fiber, other composite materials, polymers such ABS, and Radel™. 
         [0046]    Two of the elongated plates  20  are shown in  FIG. 2  joined by an expandable member  30  in one exemplary embodiment of the device. In this configuration the distal portion of the device  31  that enters the disc space is in a collapsed configuration with each distal portion  22  of the elongated plates  20  adjacent or engaged with one another and being positioned such that they can engage the endplates of the adjacent vertebral bodies in a collapsed disc space. In this embodiment the expandable member  30  has a distal end  32  that doesn&#39;t enter into the disc space, in addition, the proximal end  33  of the expandable member  30  does not extend to the proximal end  24  of the elongated member  20 . The expandable member  30  may be made of a variety of different materials including, but not limited to, polyurethane, polyisoprene, and latex. 
         [0047]    In  FIG. 3 , the device is shown in an expanded state with the distal end of the device  31  aiding in distraction of the disc space and the expandable member  30  being stretched to accommodate the increased distance between the elongated plates  20 . The distal ends of elongated members  20  are separated from one another by a gap and displaced apart relative to the collapsed configuration. 
         [0048]      FIG. 4  shows another exemplary embodiment of the elongated plate  40 . In this iteration there are rails  41  extending outward from the plate  40  and that run the length of the elongated plate  40  terminating only where the distal end  42  enters the disc space. The major addition in this embodiment of the design is the ability of the elongated plate  40  to expand to accommodate varying width implants. This expansion is accommodated by the split or slot  43  in the elongated plate  40  that runs from the proximal end  47  to the distal end  42 . The split  43  runs out of the lateral edge  45  of the elongated plate  40  allowing for a solid surface within the disc space at the distal end  42  for better distraction of the disc space and a decreased potential for subsidence of the elongated plate  40  into the endplate. The rails  41  have a tapered portion  44  that allow for the insertion of a wide implant at the proximal end  47  prior to the expansion of the elongated plate  40 . Additionally, the split  43  in the elongated plate  40  has a stress relief cut  46  near the proximal end  47 . In this embodiment, the stress relief  46  is a circular through hole in the elongated plate. This version of the elongated plate  40  is shown as part of an assembled device in  FIG. 5 . In this embodiment of the device, two elongated plates  40  are joined by the expandable member  50 . 
         [0049]      FIG. 5  shows the device in its collapsed state with the little distance between the elongated plates  40  at the distal end of the device  51 . This same embodiment of the device is shown in  FIG. 6  in an expanded state with a distracted distal end of the construct  51 . The top elongated plate is substantially the same as the bottom elongated plate. 
         [0050]      FIG. 7  shows another preferred embodiment of the elongated plate  60 . In this embodiment, the elongated plates are joined at the proximal end  61 . Similar to the previous embodiment  40 , this embodiment has a split  62  or slot to allow for expansion in width, a tapered portion  60 , a lateral run out  65  of the split  62 , and a flat surface that contacts the vertebral end plates at the distal end  66 . This embodiment of the elongated plate  60  also has a step  64  to help constrain the expanding member  70  as seen in  FIG. 8 . 
         [0051]      FIG. 8  shows the embodiment of the elongated plate  60  with the expanding member  70  covering the distal portion of the device to protect the neural elements and terminating just prior to the distal end of the device  71  that enters the disc space. 
         [0052]      FIG. 9  illustrates an interbody implant  92  coupled to the insertion guide device  94 . The interbody implant is in its collapsed configuration, and it may be any of the embodiments disclosed herein, or disclosed in U.S. patent application Ser. No. ______ (Attorney Docket No. 44057-706.201) filed the same day as the present application and previously incorporated herein by reference. The insertion guide device may be any of the embodiments disclosed in this specification. 
         [0053]      FIGS. 10A-10F  illustrate an exemplary method of delivering an interbody implant using an insertion guide device such as those described in this specification. In  FIG. 10A , the insertion guide device  102  is inserted into the intervertebral disc space between adjacent vertebrae V. The elongated plates are in their collapsed configuration. The expandable member is advanced toward the vertebrae, but is not inserted into the intervertebral space. 
         [0054]    In  FIG. 10B , the interbody implant  104  is advanced distally out of the insertion guide device  102  until it is exposed from the expandable portion of the insertion guide device and positioned in a desired location between the vertebrae, as illustrated in  FIG. 10C .  FIG. 10D  is similar to  FIG. 10C  but illustrates a longer portion of the insertion guide device. In  FIG. 10E , the interbody implant and the insertion guide device have been rotated preferably 90 degrees so that the textured surfaces of the interbody implant are in engagement with the endplates of the vertebrae.  FIG. 10F  is a top view of the interbody implant and insertion guide device with the upper vertebra removed for ease in viewing. Additionally, the interbody implant has been laterally expanded to increase its width. The interbody implant and the insertion guide device may be any of the embodiments disclosed herein. Additional details on the interbody implant are disclosed in U.S. patent application Ser. No. ______ (Attorney Docket No. 44057-706.201) filed the same day as the present application, and previously incorporated herein by reference. 
         [0055]      FIGS. 11A-11B  illustrate the pusher element which may be advanced or retracted by an operator to move the interbody implant through the insertion guide device disclosed above. In  FIG. 11A , the pusher element  1102  includes an elongate shaft with a handle on the proximal end for ease in manipulation. A lever  1104  helps lock the pusher to the interbody implant.  FIG. 11B  illustrates the interbody implant  1106  coupled to the pusher element  1102 . A leaf spring is disposed under the actuation lever thereby biasing the lever in the up position so that the pusher remains locked with the interbody implant. When the lever is moved, the implant may be decoupled from the pusher. The pusher/implant assembly is preferably inserted into the elongated plate assembly for delivery to the intervertebral space. 
         [0056]      FIGS. 12A-12B  illustrate another exemplary embodiment of elongated plates that may be used in an insertion guide device.  FIG. 12A  shows an exemplary embodiment of an elongated plate  80  with rails  81  that extend outward from the plate and guide the implant into the disc space. Pre-formed finger loops  82  on the proximal end of the plate allow a user to more easily control the insertion guide device position. Rails  81  end prior to the distal portion  83  of the elongated plate and extend up to the transition  84  to finger loop  82 .  FIG. 12B  illustrates a side view of  FIG. 12A . 
         [0057]      FIGS. 13A-13B  illustrate an insertion guide device using the elongated plates of  FIG. 12A . In  FIG. 13A , the insertion guide device is illustrated in the collapsed configure. Two of the elongated plates  80  are shown joined by an expandable member  90  which may be any of the embodiments of expandable member disclosed herein. Expandable member  90  is preferably attached to the top surfaces  91  of elongated plates  80  via an adhesive. Expandable member  90  also has a bead  92  to help resist tearing of the expandable member during use. The bead may be a rolled up section of the expandable member to increase thickness and resistance to tearing, or it may be a separate material coupled to the expandable member to provide the reinforcement. 
         [0058]      FIG. 13B  illustrates the embodiment of  FIG. 13A  in the expanded configuration. 
         [0059]      FIG. 14  illustrate the insertion guide device of  FIG. 13A  inserted into the intervertebral disc space. The insertion guide device is positioned such that the distal portions  83  of the elongated plates  80  engage the endplates of the adjacent vertebral bodies  95  and  96 . The expandable member  90  remains outside of the intervertebral space. 
         [0060]      FIGS. 15A-15B  illustrate still another exemplary embodiment of elongated plates that may be used in an insertion guide device.  FIG. 15A  shows an elongated plate  100  with stop feature  101  to prevent the insertion guide device from being inserted too far anteriorly into the disc space. The stop  101  is preferably a protrusion which extends out of the plane of the elongated plate. Other aspects of the elongated plate are generally the same as the embodiment illustrated in  FIG. 12A-12B .  FIG. 15B  is a side view of  FIG. 15A . 
         [0061]      FIG. 16A  illustrates an exemplary embodiment of an insertion guide device using one elongated plate as illustrated in  FIG. 15A  with a stop, and another elongated plate as illustrated in  FIG. 12A  without a stop. The embodiment in  FIG. 15A  is in the collapsed configuration. Expandable member  90  joins elongated plates  80  and  90  together. Other aspects of the insertion guide device are generally the same as previously described above. An alternative embodiment of the insertion guide device may have two elongated plates both having stops. Thus, the insertion guide may have two elongated plates such as those described in  FIG. 15A . Other aspects of this alternative embodiment may be the same as those previously described.  FIG. 16B  illustrates the insertion guide device in  FIG. 16A  in the expanded (also referred to as distracted) configuration. 
         [0062]      FIG. 17  shows the insertion guide device of  FIG. 16A  inserted into the intervertebral disc space. Stop feature  101  engages the edge of superior vertebral body  110  to prevent the insertion guide device from moving further anterior. In alternative embodiments, the stop feature may engage the edge of the inferior vertebral body  96 , or in embodiments with two stops, an edge of the inferior and superior vertebral body may be engaged by a stop feature. 
         [0063]    While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.