Abstract:
An adjustable pin drill guide and method for using an adjustable pin drill guide to prepare a vertebral body space to receive an implant are disclosed. The method includes providing an adjustable pin drill guide, producing a gap by removing tissue between a first vertebral body and a second vertebral body, inserting into the gap first and second extensions of the guide in a first position, moving the first extension and the second extension to a second position, drilling a first hole in the first vertebral body through a first opening in the guide, drilling a second hole in the second vertebral body through a second opening in the guide, placing a first pin into the first hole, and placing a second pin into the second hole. The first and second extensions are preferably in parallel planes when in the first and second positions.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is directed to an adjustable pin drill guide and methods for inserting pins into adjacent vertebral bodies for use during a spinal surgical procedure. 
     U.S. patent application Ser. No. 11/439,808 (“the &#39;808 application”), which was filed on May 20, 2006 and which is hereby incorporated by reference herein, describes the placement of pins in adjacent vertebral bodies using a pin drill guide. As described in the &#39;808 application, after removal of disc tissue between adjacent vertebral bodies and placement of midline score marks and tack openings in adjacent vertebral bodies, pins are attached to the anterior faces of the bodies, for use in guiding other instruments during the surgical procedure disclosed therein. The pins are inserted using a pin drill guide, as shown as element 194 in at least FIGS. 11A-11D of the &#39;808 application, that is partially inserted into the dissected disc space. 
     Specifically, referring to FIG. 45 of the &#39;808 application, a head or extension 214 at a distal end 196 of pin drill guide 194 is inserted into the disc space between the vertebral bodies until vertebral body stops 222 and 224 abut against the anterior faces of the superior and inferior vertebral bodies. The pin drill guide is preferably aligned with the midline of the vertebral bodies (e.g., as marked by the score line markings) prior to this insertion. At this stage, one of the openings 210 or 212 in a main body 204 of pin drill guide 194 is preferably in alignment with the superior vertebral body and another one of the openings is in alignment with the inferior vertebral body. Referring to FIG. 46 of the &#39;808 application, with pin drill guide 194 in place, holes are drilled in the superior and inferior vertebral bodies using a drill bit and the pins are placed in the holes. 
     Using pin drill guide 194 as described above does not allow for size variations of dissected disc space. That is, the pin drill guide is only applicable for a specific size of dissected disc space. Thus, multiple sizes of pin drill guides 194 may be needed for various patients. Accordingly, a need exists to overcome, inter alia, the above stated limitations. 
     BRIEF SUMMARY OF THE INVENTION 
     Disclosed herein is an adjustable pin drill guide and procedures in accordance with certain embodiments of the present invention. It is contemplated, however, that the instruments and procedures may be slightly modified, and/or used in whole or in part and with or without other instruments or procedures, and still fall within the scope of the present invention. Although the present invention may discuss a series of steps in a procedure, the steps can be accomplished in a different order, or be used individually, or in sub groupings of any order, or in conjunction with other methods, without deviating from the scope of the invention. 
     A first aspect of the present invention is a method of preparing an intervertebral body space to receive an implant. In accordance with certain embodiments of this first aspect, the method includes the steps of providing an adjustable pin drill guide including a first member having a first opening and a first extension and a second member having a second opening and a second extension; removing at least some of the tissue between a first vertebral body and a second vertebral body; inserting the first extension and the second extension of the adjustable pin drill guide in a first position between the first and second vertebral bodies; moving the first extension and the second extension from a first position to a second position, the first and second extensions being in parallel planes with one another in at least the first and second positions; drilling a first hole into the first vertebral body; drilling a second hole into the second vertebral body; placing a first pin in the first hole; and placing a second pin in the second hole. 
     A second aspect of the present invention is another method of preparing a vertebral body space to receive an implant. In accordance with certain embodiments of this second aspect, the method includes the steps of providing an adjustable pin drill guide including a first member having a first extension and a first opening and a second member having a second extension and a second opening wherein the first extension and second extension are provided in a first position; producing a gap between a first vertebral body and a second vertebral body by removing at least some of the tissue between the first vertebral body and the second vertebral body; inserting into the gap the first and second extensions in the first position; displacing the first extension and the second extension into a second position, the first and second extensions being in parallel planes in the second position; drilling through the first opening into the first vertebral body to create a first hole; drilling through the second opening into the second vertebral body to create a second hole; placing a first pin in the first hole; and placing a second pin in the second hole. 
     A third aspect of the present invention is an adjustable pin drill guide for preparing a vertebral body space to receive an implant. In accordance with certain embodiments of the present invention, the guide includes a first member and a second member in a first position, the first member having a first opening and a first extension extending from the distal end of the first member and the second member having a second opening and a second extension extending from the distal end of the second member. The first member and the second member are capable of moving to a second position, the first and second members being in parallel planes in the first and second positions and the first opening and second opening are designed for receiving a drill for creating holes in adjacent vertebral bodies while in the second position. 
     It should be noted that features and methods and functionalities of the present invention, including but not limited to features and methods and functionalities for engaging one tool (or parts thereof) with one or more other tools (or parts thereof) or with the implants (or parts thereof), and vice-versa; for addressing, avoiding, manipulating, or engaging the patient&#39;s anatomy; for aligning one or more tools with anatomic or non-anatomic reference points; and for aligning the tools and implants with one another and/or a treatment space; are not and should not be limited to those embodied in and achieved by the structures and methods of the specific embodiments described and shown, but rather the structures and methods of the specific embodiments described and shown are merely examples of structures and methods that can achieve certain features and methods and functionalities of the present invention. 
     These and other embodiments of the present invention will be described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side perspective view of an adjustable pin drill guide in accordance with one embodiment of the present invention, with a distal portion of the guide in a first position. 
         FIG. 2  is a top perspective view of the adjustable pin drill guide of  FIG. 1 . 
         FIG. 3  is a right-side perspective view of the adjustable pin drill guide of  FIG. 1 . 
         FIG. 4  is a right-side perspective view of the adjustable pin drill guide of  FIG. 1 , with the distal portion in an intermediate position. 
         FIG. 5  is a right-side perspective view of the adjustable pin drill guide of  FIG. 1 , with the distal portion in a second position. 
         FIG. 6  is a perspective view of a portion of a human vertebral column. 
         FIG. 7  is a perspective view of the portion of the vertebral column shown in  FIG. 6 , with a portion of a spinal disc removed between a first vertebral body and a second vertebral body. 
         FIG. 8  is a cross sectional view of two adjacent vertebral bodies having the adjustable pin drill guide of  FIG. 1  inserted therebetween. 
         FIG. 9  is a cross sectional view of the two adjacent vertebral bodies of  FIG. 8  having the adjustable pin drill guide of  FIG. 4  inserted therebetween. 
         FIG. 10  is a cross sectional view of the two adjacent vertebral bodies of  FIG. 8  having the adjustable pin drill guide of  FIG. 5  inserted therebetween. 
         FIG. 11  is another cross sectional view similar to that of  FIG. 10 , subsequent to the drilling of holes in the vertebral bodies. 
         FIG. 12  is a perspective view similar to that of  FIG. 7 , subsequent to the drilling of holes in the vertebral bodies. 
         FIG. 13  is a perspective view similar to that of  FIG. 12 , with pins located in the holes drilled in the vertebral bodies. 
         FIG. 14  is a side perspective view an adjustable pin drill guide in accordance with a second embodiment of the present invention, with a distal portion of the guide in a first position. 
         FIG. 15  is a top perspective view of the adjustable pin drill guide of  FIG. 14 . 
         FIG. 16  is left-side perspective view of the adjustable pin drill guide of  FIG. 14 . 
         FIG. 17  is a side perspective view of the adjustable pin drill guide of  FIG. 14 , with the distal portion in a second position. 
         FIG. 18  is a side perspective view similar to that of  FIG. 17 , with drill elements associated with the adjustable pin drill guide. 
         FIG. 19  is a side perspective view of the distal portion of the adjustable pin drill guide of  FIG. 14 . 
         FIG. 20  is a view of the distal portion taken along line A-A of  FIG. 19 . 
         FIG. 21  is a side perspective view of the distal portion of the adjustable pin drill guide of  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , in accordance with at least one embodiment of the present invention, an adjustable pin drill guide  10  is shown as including a first member  12 , a second member  14 , and a third member  16 . First member  12  includes a first extension  18  and a first opening  20  at its distal end, and a channel  21  (best shown in  FIGS. 3-5 ) near its proximal end. Similarly, second member includes a second extension  22  and a second opening  24  at its distal end, and an open channel  25  (best shown in  FIGS. 3-5 ) at its proximal end. Third member  16  is shown as being movably connected to first member  12  and second member  14 . In particular, third member  16  is attached to first member  12  by a pin connection  23  and to second member  14  by a pin connection  26 . At least a portion of third member  16  is adapted for insertion into channel  21 , while another portion is adapted for insertion into channel  25 . Although described as pin connections, any pivotable coupling between third member  16  and first member  12  and between third member  16  and second member  14  can be used. The operation and use of adjustable pin drill guide  10 , including additional details relating to the interrelationship among the first, second, and third members, are discussed below. 
     Adjustable pin drill guide  10  also includes a displacer  28  (shown as a thumb screw in the drawings), which includes a user interface section  30  and threaded section  32 . Threaded section  32  is sized and configured for cooperation with a displacer receiver  34  connected with first member  12 . Essentially, receiver  34  is a body having a threaded hole that accepts threaded section  32  therein. However, other configurations for this cooperation are contemplated, for instance, a ratchet mechanism or the like. A spring or other resilient member  36  is provided between first member  12  and third member  16 . In the particular embodiment shown in the drawings, spring  36  is provided along threaded section  32  and in contact with receiver  34  and third member  16 . Other configurations are contemplated, for instance, a resilient member that is between first member  12  and third member  16 , and not along threaded section  32 . 
     Moreover, drill guide  10  includes handle  38  which is preferably adapted for gripping by a surgeon. While shown as connected with receiver  34 , it is to be understood that other embodiments may have handle  38  attached to different element(s) or configured differently. In some embodiments, handle  38  is designed for improved gripping by the surgeon (e.g., it may include rubber, surface roughening, or the like). In addition, the handle may also include different ergonomic designs and may be provided in different sizes. Other embodiments of the present invention include handles  38  that are detachable from the remainder of guide  10 , so that different handle designs may be provided and selected from. 
     As is best shown in  FIG. 2 , second member  14  is substantially straight along its length, while portions of first member  12  and third member  16  are curved. Specifically, a portion of first member  12  is curved in a left to right direction in the view of  FIG. 2 , while portions third member  16  are curved in two directions, upwardly in the view of  FIG. 1  and from left to right in the view of  FIG. 2 . Third member  16  also includes a portion that is parallel with first member  12 , and it is in this parallel region that those members are moveably coupled to each other. It is to be understood that the particular configuration shown in the drawings can differ significantly. For example, as is best shown in  FIG. 2 , guide  10  is configured in a manner which allows for handle  38  to be displaced to one side. This preferably aids in the use of guide  10  by allowing the surgeon a clearer line of sight into the area of the spine in which the surgical procedure is being conducted. In the design shown in  FIG. 2 , handle  38  is displaced to the right side of that surgical area. However, it is contemplated that the elements of guide  10  could be designed so as to displace the handle to the left side of the surgical area. This choice may be beneficial depending upon whether the surgeon is left or right handed. Furthermore, displacing the handle above or below the surgical area is also contemplated. 
     In operation, third member  16  moves in the direction toward and away from first member  12  upon threading of displacer  28  into displacer receiver  34 . This threading overcomes the force spring  36  provides upon third member  16 , which preferably acts to hold the third member towards interface section  30  of displacer  28 , as well as to keep guide  10  in the position shown in  FIG. 1 . Upon tightening of displacer  28  and movement of a distal portion of third member  16  towards a distal portion of first member  12  (best shown in the progression of  FIGS. 3-5 ), more and more of a portion of the third member becomes situated in channel  21 . Because of the pivotal connections between third member  16  and both first and second members  12  and  14 , this movement also causes second member  14  to move away from first member  12 . 
     To assure that the first and second members remain in parallel planes with respect to each other, first member  12  is provided with pins  40   a  and  40   b  that are adapted to cooperate with apertures  42   a  and  42   b  formed in a portion of second member  14 . That coupled with the pivotal nature of the connection between second member  14  and third member  16  allows for the desired parallel displacement. While pins  40   a  and  40   b  and apertures  42   a  and  42   b  are shown situated to one side of guide  10  (to remove them from the surgeon&#39;s line of sight), it is noted that other configurations are contemplated, including, but not limited to, the other side of the guide. Likewise, while two circular pins  40   a  and  40   b  are shown cooperating with two circular apertures  42   a  and  42   b , other configurations contemplated. For instance, one pin and one aperture may be provided, and other shapes such as square, rectangular, oval, star shaped, or the like can be employed. Additionally, in other embodiments, first member  12  could include the apertures and second member could include the pins. 
     The above-discussed movement between first member  12  and second member  14  necessary moves first extension  18  and second extension  22  from their first and touching position shown in  FIG. 3 , through the intermediate position shown in  FIG. 4 , and ultimately to their second and spread position shown in  FIG. 5 . Throughout this movement, first member  12  (and first extension  18 ) and second member  14  (and second extension  22 ) remain parallel to each other. This is due to the above-discussed cooperation among the elements of guide  10 . However, it is to be understood that other configurations may be employed that allow for non-parallel movement. For instance, guide  10  may be designed to allow for non-parallel positions in intermediate positions (with the first and second positions being in parallel planes) or for non-parallel first and second positions. 
     Guide  10  may be utilized during a surgical procedure, such as the one disclosed in the aforementioned &#39;808 application. Specifically, guide  10  is useful in drilling pin holes in adjacent vertebral bodies in a similar fashion as is shown in FIGS. 45-49 of the &#39;808 application. However, in some embodiments, guide  10  may be utilized in also performing the steps shown in FIGS. 50-53 of the &#39;808 patent (i.e., placement of the pins). 
     For example,  FIG. 6  of the present application illustrates a typical surgical site in which the present invention is utilized, including a first vertebral body  102 , a second vertebral body  104 , and an intervertebral disc  106 . In a procedure (like the one disclosed in the &#39;808 application), the surgeon first resects a portion of disc  106 , which is often degenerated or in need of replacement for another reason. The surgical site subsequent to this resection step is shown in  FIG. 7 . In order to perform a lot of the surgical steps discussed in the &#39;808 application, pins need to be inserted into vertebral bodies  102  and  104 . Thus, subsequent to a marking step (shown in FIGS. 40-42 of the &#39;808 application), first and second extensions  18  and  22  of guide  10  are inserted between the vertebral bodies. 
     In order to aid in this insertion, first extension  18  may include a tapered nose  44  in addition to a top surface  46  and a bottom surface  48 . Likewise, second extension  22  may include a tapered nose  50  in addition to a top surface  52  and a bottom surface  54 . Thus, when first extension  18  and second extension  22  are in the aforementioned first position (i.e., in parallel planes and touching), they act as one extension with a tapered nose, a top surface  52 , and bottom surface  48 . This construction preferably aids in the insertion of guide  10  into the space between vertebral bodies  102  and  104 . Further still, first extension  18  and second extension  22  are shown as having substantially planar surfaces  46 ,  48 ,  52 , and  54 . However, it is to be understood that they include shapes more akin to the surfaces of the endplates of vertebral bodies  102  and  104 . For instance, top surface  52  and bottom surface  48  may be concave or convex, in whole or in part, in order to better cooperate with the endplates of the vertebral bodies they are placed between. In the embodiment shown in the FIGS, first extension  18  and second extension  22  are each approximately 1.5 millimeters thick. This facilitates their easy insertion when in the first position. 
       FIG. 8  illustrates guide  10  initially inserted between vertebral bodies  102  and  104 . At this point, displacer  28  is operated to move first extension  18  towards vertebral body  102  and second extension  22  towards vertebral body  104 . This movement between the aforementioned first and second positions (which was illustrated earlier in  FIGS. 3-5 ) is shown in  FIGS. 8-10  occurring between bodies  102  and  104 . Ultimately, displacer  28  is operated until top surface  52  comes in contact with vertebral body  104  and bottom surface  48  comes in contact with vertebral body  102  ( FIG. 10 ). In a preferred embodiment, no distraction of the vertebral bodies is caused by the expansion of guide  10 , but rather, the expansion allows for the proper sizing of the space between the bodies. However in other embodiments, or if desired, guide  10  may be utilized to distract the vertebral bodies away from each other. The amount of distraction (or even the ability to) will dictated by the size of the various components of guide  10 . 
     Once guide  10  is in the second position between bodies  102  and  104  (shown in  FIG. 10 ), first opening  20  and second opening  24  are utilized to drill holes in the bodies to receive pins. The result of this drilling step is best illustrated in  FIGS. 11 and 12 . The configuration of guide  10  is such that after its expansion to the second position, openings  20  and  24  are aligned with the vertebral bodies to guide a drill to properly situate holes  106  and  108 . First opening  20  and second opening  24  are sized so as to receive a drill bit, portion of a drill, or the like, similar to that disclosed in the &#39;808 application (e.g., a stepped drill bit). Openings  20  and  24  may also be sized to accept pins therethrough and guide them into holes  56  and  58 . In other words, act in a similar fashion as does reference pin guide 236 of the &#39;808 application. In this regard, reference is made to both the placement of pins as described in the &#39;808 patent, and  FIG. 13  of the present invention (which shows pins  110  and  112  in first vertebral body  102  and second vertebral body  104 , respectively). It is to be understood that the placement of pins through guide  10  may or may not involve the use of a pin sleeve or the like, as is described as element 290 in the &#39;808 application. 
     In accordance with the present invention, it is noted guide  10  can be utilized to aid in the placement of pins in vertebral bodies of varying sizes, as well as in vertebral bodies being situated different distances from each other. For instance, as is discussed above, in the first position first extension  18  and second extension  22  may have a combined thickness of approximately 3 millimeters. As guide  10  is expanded, first extension  18  and second extension  22  move away from each other until they reach the second position, which may result in a total distance between top surface  52  and bottom surface  48  (i.e., the thickness) of approximately 7 millimeters. Of course, there are various intermediate positions in which this distance may be any one of the values between 3 and 7 millimeters. Depending upon the size and configuration of guide  10 , an infinite amount of thicknesses may be provided by the guide. 
     Referring to  FIGS. 14-21 , a second embodiment adjustable pin drill guide  310  is shown. Because of the similarities of many of the elements of guide  310  and that of above-discussed guide  10 , similar elements are labeled with like reference numerals within the 300-series of numbers. For instance, guide  310  includes a first member  312  and second member  314 . First member  312  includes a first extension  318  and a first opening  320  at its distal end, and second member includes a second extension  322  and a second opening  324  at its distal end. First and second members  312  and  314  are connected to each other via a pin connection  323 , thereby allowing for pivotal movement of the members with respect to each other. As is best shown in  FIG. 15 , the first and second members cooperate with each other in a somewhat different fashion as do the first, second, and third members of guide  10 . First and second members  312  and  314  of guide  310  are designed to include portions which oppose one another and portions which lie side by side with one another. These side by side portions (i.e., the distal portions of members  312  and  314 ) are connected by pin connection  323 . Of course, as is the case with guide  10 , any similar connection can be utilized and connected to the members. 
     Also like guide  10 , adjustable pin drill guide  310  includes a displacer  328  including a first threaded end  332  and a second end  334  attached via a pin  335  to second member  314 . A user interface section or nut  330  is provided for cooperation with first threaded end  332 . Thus, upon threading of nut  330  on threaded section  332 , first member  312  is displaced towards second member  314 . The cooperation between second end  334  and pin  335  allows for at least the partial rotation of displacer  328  with respect to second member  314 . This ensures the proper application of forced to first and second members  312  and  314 . Essentially, displacer remains in a vertical position while the first and second members move towards on another. This is best shown in  FIGS. 16-18 . Other configurations for displacer  328  are contemplated. For instance, first end  332  and user interface second  330  could be cooperating ratchet mechanisms or the like. A leaf spring or other resilient member  336  is provided between first member  312  and second member  314 . Spring  336  acts to push the proximal portions of first and second members  312  and  314  away from one another absent a force being applied to overcome its force. 
     The aforementioned proximal portions of first and second members  312  and  314  make up a handle which is similar to handle  38  of above-discussed guide  10 . Specifically, first member  312  includes handle portion  338   a  and second member  314  includes a handle portion  338   b . Like in guide  10 , the handle of guide  310  may include elements designed for improved gripping by the surgeon (e.g., it may include rubber, surface roughening, or the like). For instance, portions  338   a  and  338   b  are shown in the drawings to include surfaces designed to improve gripping of the device. In other embodiments, only one of the handle portions may include such a surface and/or the surfaces can be differently designed. In addition, the handle may also include differently sized handle portions  338   a  and  338   b  to therefore provide in different overall handle sizes. Any combination of the various handle portions is contemplated. As is best shown in  FIG. 15 , guide  310  provides a similar curved profile as in the above-discussed guide  10 . Specifically, portions of first and second members  312  and  314  are curved in a right to left direction, thereby aiding in the use of guide  310  by allowing the surgeon a clearer line of sight into the area of the spine in which the surgical procedure is being conducted. Also similar to guide  10 , guide  310  may include other configurations in which the handle or other elements of guide  310  are displaced in different directions. This includes in the opposite left to right direction, as well as above and below the surgical area. 
     In operation, movement of first member  312  towards second member  314  causes movement of first extension  318  and second extension  322  away from each other. The movement of the first and second members towards one another is preferably created by the threading of displacer  328  into displacer receiver  334 , but may be created through the simple squeezing of handle portions  338   a  and  338   b  towards each other. Either of these operations would overcome the force spring  336  provides upon first and second members  312  and  314 , with the former retaining the first and second members in this position. Because of the pivotal connections between first and second members  312  and  314 , handle portions  338 A and  338 B move towards one another, while more distal portions of the first and second members move away from each other. This is best shown in  FIG. 17 . 
     To assure that first extension  318  and second extension  322  remain in parallel planes with respect to each other, guide  310  is provided with a detailed linkage assembly best shown in  FIGS. 19 and 21 . In particular, this linkage assembly includes a first bar  360  pivotably connected to a distal portion of first member  312  via a pin connection  361  and a proximal portion of second extension  322  via a pin connection  367 . The assembly also includes a second bar  362  pivotably connected with to a distal portion of second member  314  via a pin connection  363  and a proximal portion of first extension  318  via a pin connection  365 . Furthermore, first and second bars  360  and  362  are connected to one another via a pivot point  364 . Pin connections  361  and  363  only allow for simple rotation of first bar  360  with respect to first member  312  and second bar  362  with respect to second member, respectively. On the other hand, first bar  360  is connected to second extension  322  via a pin connection  367  which is permitted to slide within a slot  371  formed on a proximal portion of second extension  322  and second bar  362  is attached to first extension  318  via a pin connection  365  which is also permitted to slide within a slot  369  formed on a proximal portion of first extension  318  (best shown in  FIG. 21 ). These similar pin and slot connections allow for both rotational and sliding movements. As is best shown in  FIGS. 19 and 21 , upon movement of first and second handle portions  338 A and  338 B towards one another, these configurations causes the first and second extensions  318  and  322  to move away from each other in parallel planes.  FIG. 20  shows a cross-section taken through pivot point  364 . 
     The above-discussed movement between first member  312  and second member  314  necessarily moves first extension  318  and second extension  322  from their first and touching position shown in  FIGS. 14 ,  15 ,  16 ,  19 , and  20 , to their second and spread position shown in  FIGS. 17 ,  18 , and  21 . Throughout this movement, and because of the linkage assembly discussed above, at least first extension  318  and second extension  322  remain parallel to each other. However, it is understood that other configurations may be employed that allow for non-parallel movement. For instance, guide  310  may be designed to allow for non-parallel positions in intermediate positions (with or without the first and second positions being in parallel planes) or for non-parallel first and second positions. Guide  310  may be utilized in a similar fashion as is discussed above in connection with guide  10 . However, it is noted that guides  10  or  310  may be utilized in different circumstances, depending upon various factors, including patient anatomy, etc. 
     Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.