Patent Publication Number: US-2023145974-A1

Title: Parallel guide for access needle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/932,285, filed Jul. 17, 2020, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to orthopedic surgery. More specifically, techniques, devices, and systems associated with the parallel implantation of a bone screw for joint fusion are described. 
     BACKGROUND 
     Stress across joints and in particular the sacroiliac joint generally is a common cause of pain including lower back pain. Various types of sacroiliac joint stress, including sacroiliac joint disruptions (i.e., separations) and degenerative sacroiliitis (i.e., inflammation) can result from lumbar fusion, trauma, postpartum, heavy lifting, arthritis, or unknown causes. Sacroiliac joint fixation or arthrodesis is sometimes recommended for skeletally mature patients with severe, chronic sacroiliac joint pain or acute trauma in the sacroiliac joint. 
     Conventional solutions for stabilizing joints and relieving pain in joints typically include the insertion of an implant, such as a metal screw, rod or bar, laterally across the joint. As multiple implants may be inserted across the joint, the relative orientation between the implants needs to be controlled. Guides that utilize a sliding mechanism are known. But such guides do not provide both flexibility and the control of discrete placement of the guides used for locating implants. 
     SUMMARY 
     According to an aspect of the present disclosure, a parallel spacer for parallel spacing of a plurality of guiding elements during surgery is provided. The parallel spacer includes a parallel spacer body having a proximal surface and a distal surface. The body defines a first guide aperture extending through the parallel spacer body between an opening in the proximal surface and an opening in the distal surface and defined by an internal wall, the first guide aperture being sized to receive a first guiding element in a first orientation with respect to the parallel spacer body and hold the guiding element at the first orientation. The body further defines a second guide aperture extending through the parallel spacer body between an opening in the proximal surface and an opening in the distal surface and defined by internal walls, sized to receive an access needle. The parallel spacer further includes a first external positioning protrusion extending distally from the distal surface of the parallel spacer body, with the first guide aperture extending through the first external positioning protrusion, and a second external positioning protrusion extending distally from the distal surface of the parallel spacer body, with the second guide aperture extending therethrough. An inner surface of the second guide aperture defines the second guide aperture, the second guide aperture is open from a proximal end of the parallel spacer body to a distal end of the second external positioning protrusion and is configured to receive or extract therefrom the second access needle. 
     According to various embodiments, the first guide aperture aligns to a first axis, and the second guide aperture aligns to a second axis. 
     According to various embodiments, the second guide aperture is open from the proximal end of the parallel spacer body to the distal end of the second external positioning protrusion is a direction radial to the first axis. 
     According to various embodiments, the second guide aperture is open from the proximal end of the parallel spacer body to the distal end of the second external positioning protrusion is a direction radial to the second axis. 
     According to various embodiments, the first axis and the second axis are parallel. 
     According to various embodiments, the second guide aperture is disposed to hold the second guiding element at a distance from the first guiding element. 
     According to various embodiments, the second guide aperture narrows toward the distal end of the second external positioning protrusion. 
     According to various embodiments, the first external positioning protrusion is configured to fit within at least one of a drill guide or tissue protector. 
     According to various embodiments, the inner surface of the second guide aperture includes a proximal portion, a distal portion that is narrower than the proximal portion, and a step between the proximal and distal portions, such that the proximal and distal portions and the step collectively define the narrowing secondary aperture. 
     According to various embodiments, a system is presented for parallel spacing a plurality of guiding elements during surgery. The system includes a tissue protector positioned over a first guiding element, a parallel spacer mounted to the tissue protector, and an access needle having a shape corresponding to the second guide aperture. The first external positioning protrusion is configured to be inserted into a portion of the tissue protector. 
     According to various embodiments, the second guide aperture is configured to align the access needle with an axis of the first aperture. 
     According to various embodiments, the tissue protector defines a bore extending completely therethrough, and the second guide element is receivable within an end of the bore. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several examples in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings, in which: 
         FIG.  1 A  is a perspective view of a parallel guide for joint fusion according to an embodiment; 
         FIG.  1 B  is a rear view thereof; 
         FIG.  1 C  is a distal view thereof; 
         FIG.  1 D  is a proximal view thereof; 
         FIG.  1 E  is a sectional view thereof; 
         FIG.  2    is a perspective view of an access needle being inserted into a bone, in accordance with an embodiment; 
         FIG.  3    is a perspective view of a guiding element of the access needle of  FIG.  2    inserted into a bone after the handle has been removed; 
         FIG.  4    is a perspective view of a soft-tissue dilator positioned over the guiding element of  FIG.  3   ; 
         FIG.  5    is a perspective view of a tissue protector positioned over the dilator of  FIG.  4   ; 
         FIG.  6    is a perspective view of the assembly of  FIG.  5    with the dilator removed; 
         FIG.  7    is a perspective view of a cannulated drill bit drilling into the bone over the guiding element and within the tissue protector of  FIG.  6   ; 
         FIG.  8    is a perspective view of a driver driving an implant into a bone over the guiding element and within the tissue protector of  FIG.  7   ; 
         FIG.  9    is a perspective view of the parallel guide of  FIGS.  1 A-E  guiding a second access needle into a bone; 
         FIG.  10    is a perspective view of a first guiding element and a second guiding element inserted into a bone and spaced via the parallel guide of  FIG.  10   ; and 
         FIG.  11    is a cutaway view of the assembly of  FIG.  9   . 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative examples described in the detailed description, drawings, and claims are not meant to be limiting. Other examples may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are implicitly contemplated herein. 
     Techniques for joint fusion are described, including systems, apparatuses, and processes for fusing a joint. Some embodiments of systems and apparatuses for fusing a joint include a cage (i.e., a cannulated cage), a tissue protector assembly, a guide, a soft-tissue dilator, a cannulated drill bit (e.g., an adjustable cannulated drill bit that employs a stop collar), a driver, a parallel guide, and a plunger distance tool. As used herein, the term “cannulated” refers to having a cannula, or a hollow shaft. In some examples, the cage may be inserted or implanted into tissue (e.g., bone, cartilage, or other tissue in the joint). As used herein, the term “implant” or “implantation” refers to inserting or insertion into a part of a body. For example, a bone cage may be implanted into a joint (e.g., a sacroiliac joint). In some examples, the cage may have a cannula and radial fenestrations in which therapeutic materials may be packed. Such therapeutic materials may include osteogenic compounds (e.g., bone morphogenetic protein, or other osteogenic compounds that may ossify tissue in the joint), osteoconductive materials (e.g., demineralized bone, hydroxyapatite, or other material that promotes bone growth), antibiotics, steroids, contrast materials, or other materials that may beneficial to fusing the joint, treating inflammation or other conditions in the joint, or enabling the visualization of the area within and adjacent to an implanted bone cage. In some examples, the bone cage may be a screw or screw-type device having threads. In some examples, the screw may have one or more rows or groups of helical fenestrations along the wall (i.e., the shaft of the cage defining the cannula) of its shaft to allow the material packed inside the cannula of the cage to contact (e.g., touch, seep into, affect, communicate with, or otherwise physically contact) tissue adjacent to, surrounding, or even within, the cage. In some examples, various tools may be used to insert a cage into a location on a joint, and to prepare the location for the insertion procedure. Such tools may include, for example, an implantation assembly, which may comprise a tissue protector; a guide; a soft-tissue dilator; a cannulated drill bit; a driver; a parallel guide; a packing plunger, which may comprise a packing tube, a plunger and a loading port; a plunger distance tool; and other tools. 
     In some examples, a guide may be inserted first into a joint at a desired location. In some examples, a tissue protector assembly may be used, along with the guide, to guide the preparation (i.e., drilling) of a pilot hole as well as to guide insertion of a cannulated cage or other implant while forming a barrier between the preparation site and the surrounding tissue. In some examples, a cannulated drill bit may be used with the tissue protector and/or guide to drill the pilot hole. In some examples, a driver or screw driver may be used to insert the cage into the pilot hole. The term “driver” is used herein to refer to a tool configured to engage the head of a screw or similar device, typically via a tip of the driver, the tool being useful for rotating a screw or otherwise manipulating the screw to drive the screw or, in this case, cage into place in a joint. In some examples, a parallel spacer device may be used to space another guide in preparation for insertion of another cage. In some examples, a packing plunger assembly may be used to pack the cage with the above-mentioned materials. The packing plunger may be used to pack materials into the cage either or both pre- and post-insertion of the cage into the joint, and may be used with or without the tissue protector assembly. 
       FIGS.  1 A-E  are various views of a parallel guide  100  for joint fusion. Here, the parallel guide  100  includes a parallel spacer body  110  and an external positioning protrusion  120 . The parallel spacer body  110  of this embodiment includes a primary or first guide aperture  130  suitable to receive one or more guiding elements  150  (shown in  FIGS.  2 - 10   ) configured to guide the direction of one or more components including a drill bit. The guiding elements may include pins and wires (for example, Kirschner wires). The external positioning protrusion  120  extends from the parallel spacer body  110  and is suitable to engage with a tissue protector  180 . The external positioning protrusion  120  is configured to have a diameter  157  suitable to enable the external positioning protrusion  120  to pass through the tissue protector  180 . In some embodiments, the diameter of guide pins is approximately 1.5 and 6.5 mm. The diameter of Kirschner wires is approximately 0.9-1.5 mm. In the embodiment shown in  FIGS.  1 A-E , the external positioning protrusion  120  includes one or more deformation openings  121  and retention protrusions  123  configured to aid the external positioning protrusion  120  to enter the tissue protector and secure, through tension, to the inner surface of the tissue protector  180 . In some examples, the parallel guide  100  may be configured to place another or a next guiding element  170  at a predetermined distance from a previously placed implant (i.e., a previously implanted screw or cage  200 ). Like-numbered and named elements in this view describe the same or substantially similar elements as in previous or subsequent views. 
     The parallel spacer body  110  includes a proximal surface  112  and a distal surface  114 . While shown as opposing flat parallel surfaces, it is appreciated that these surfaces  112 ,  114  can have other suitable profiles, such as concave, convex and irregular surfaces. The parallel spacer body  110  of this embodiment has a sufficient depth to hold a guiding element  150  in a substantially constant angular position relative to the parallel guide  100 . The parallel spacer body  110  has a suitable shape to keep each of the various apertures therethrough in a fixed relationship with each other. 
     The first guiding element aperture  130  extends through the parallel spacer body  110 . The first guiding element aperture  330  has an axis  130   a  that orients the parallel guide  100  relative to the first guiding element  150  received through the aperture  130 . The external positioning protrusion  120  includes a length  153  suitable for enabling the one or more guiding elements to be approximately aligned along axis  130   a.  In some embodiments, the length  153  is approximately 50-60 mm. The first guiding element aperture  130  includes an opening on the proximal end of the parallel guide  100 . The opening extends into the parallel spacer body  110  from the proximal surface  112 . In other examples, the opening may extend into the parallel spacer body  110  from a suitable surface on the proximal end of the parallel guide  100 , such as a protrusion on the proximal end or like feature. The first guiding element aperture  130  includes an opening on the distal end of the parallel guide  100 . The opening extends into the parallel spacer body  110  from a suitable surface on the distal end of the parallel guide  100 . The aperture  130  extends from the proximal side opening to the distal side opening  122  on the distal surface on the external positioning protrusion  120 . In other examples, the opening extends from a similar suitable feature, such as from the distal surface  114 . The first guiding element  150  aperture  130  is defined by an interior surface that extends between the distal and proximal openings. 
     The parallel guide  100  includes a second guide aperture (i.e., second aperture functioning as an access needle guide port  140 ) configured to receive a subsequent access needle  160 . The guide port  140  is a second aperture and is fixedly located relative to the first guiding element aperture  130 , thereby defining a set distance and/or orientation between the guide port  140  and the aperture  130 . In the embodiment of  FIGS.  1 A-E , the guide port  140  is configured to position the new access needle  160  (and accompanying guiding element  170 ) in relation to the previous guiding element  150  at fixed distance and orientation, which is preferably parallel. The guide port  140  is configured to enable an access needle  160  to be inserted into the guide port  140  and align the access needle  160  along an axis  140   a  that defines the orientation of the guiding element  170  of the access needle  160  relative to the parallel guide  100  as the guiding element  170  passes through the guide port  140 . The guide port  140  includes an external positioning protrusion  144  that extends from the spacer body  110  in the direction of axis  140   a.  The external positioning protrusion  144  is configured to receive an access needle. The external positioning protrusion  120  and the external positioning protrusion  144  extend past the distal end  114  of the parallel spacer body  110 . In the embodiment shown in  FIGS.  1 A-E , the external positioning protrusion  120  and the external positioning protrusion  144  are separated by a gap  247  configured to enable the external positioning protrusion  144  to be inserted into the tissue protector  180 . When the external positioning protrusion  144  is inserted into the tissue protector  180 , the external positioning protrusion  120  and the external positioning protrusion  144  extend past a proximal end  251  of the tissue protector  180 . 
     The distance  151  between axis  130   a  and axis  140   a  is determinant upon the distance between implants. In the embodiment of  FIGS.  1 A-E , axis  130   a  and axis  140   a  are parallel. In the embodiment of  FIGS.  1 A-E , the distance  151  between axis  130   a  and axis  140   a  is approximately 20 mm. In some embodiments, the distance  151  is greater than 20 mm. In some embodiments, the distance  151  is less than 20 mm. In other examples, the distance between the axes is dependent upon the desired or required distance between implants. 
     The external positioning protrusion  144  is open from the proximal end of the parallel guide  100  laterally to the distal end and is configured to receive a stabilizing portion of a sheath of an access needle. The protrusion  150  aids in the alignment of access needle  160  along axis  140   a.  The guide port  140  includes a channel  142  configured to receive access needle  160 . The external positioning protrusion  144  has a length  149  sufficient to enable the access needle to be approximately aligned with the access  130   a  through the channel  142 . In some embodiments, length  149  is approximately 20-25 mm. In some embodiments, the length  149  is greater than 20 mm. In some embodiments, the length  149  is less than 20 mm. In the embodiment of  FIGS.  1 A-E , the channel  142  tapers from the proximal end toward the distal end (having a narrower width at the distal end than the proximal end), to increase contact between the new access needle  160  and the channel  142 , increasing the alignment of the new access needle  160  along axis  140   a.  The length and dimensions of the tapered channel are configured to enable the access needle  160  to access the bone while inserted into the channel  142 . In the embodiment of  FIGS.  1 A-E , the external positioning protrusion  144  tapers in a step-type fashion, which includes a series of narrowing steps  141 ,  143 . The steps  141 ,  143  taper the channel  142  from a first width  146  to one or more decreasing widths  147 ,  148 . In the embodiment shown in  FIGS.  1 A-E , the channel  142  includes three sections of varying widths, including a proximal section  252 , having width  146 , a middle section  253 , having width  147 , and a distal section  254 , having width  148 . The proximal section  252  may include a height to width ratio of approximately 2:1. In other embodiments, the height to width ratio of the proximal section  252  is approximately 3:1. In other embodiments, other suitable ratios may be used. 
     The middle section  253  may include a height to width ratio of approximately 1:1. In other embodiments, the height to width ratio of the middle section  253  is approximately 2:1 or approximately 3:1. In other embodiments, other suitable ratios may be used. The height to width ratio of the middle section  253  is configured to enable the access needle  160  to be aligned when the proximal section  231  of the sheath  175  is inserted into the middle section  253  of the channel  142 . 
     The distal section  254  may include a height to width ratio of approximately 5:1. In other embodiments, the height to width ratio of the distal section  254  is approximately 4:1 or approximately 3:1. In other embodiments, other suitable ratios may be used. 
     The channel  142  has a length  255  from the proximal end of middle section  253  to the distal end of proximal section  254 . In some embodiments, width  146  is approximately 5-10 mm, width  147  is approximately 5-10 mm, and width  148  is approximately 5 mm. In some embodiments, width  146  is less than 5 mm. In some embodiments, width  146  is greater than 10 mm. In some embodiments, width  147  is less than 5 mm. In some embodiments, width  147  is greater than 10 mm. In some embodiments, width  148  is less than 5 mm. In some embodiments, width  148  is greater than 5 mm. In other embodiments, the tapering may conform to other shapes such as, for example, gradual linear tapering or curved tapering. In yet other embodiments, the width and/or diameter of the external positioning protrusion  144  is consistent from the proximal end to the distal end. In the embodiments of  FIGS.  1 A-E , the widths of the steps  141 ,  143  range from 5-8 mm. In other embodiments, the widths of the steps  141 ,  143  include other dimensions. The width  146  enables a handle connection section of the access needle to be inserted into the channel  142  above the first step  141 . The steps  141 ,  143  cause the diameter of the channel  142  to narrow, preventing the handle connection section from passing through the channel, limiting how far the access needle can pass through the channel  142  and, therefore, how far the access needle can be inserted into the bone. In the embodiments of  FIGS.  1 A- 1 E , the channel  142  includes a plurality of depths  161 ,  162 ,  249 . In some embodiments, depth  161  is approximately 15-20 mm, depth  162  is approximately 10-15 mm, and depth  249  is approximately 10-15 mm. In some embodiments, depth  161  is less than 15 mm. In some embodiments, depth  161  is greater than 20 mm. In some embodiments, depth  162  is less than 10 mm. In some embodiments, depth  162  is greater than 15 mm. In some embodiments, depth  249  is less than 10 mm. In some embodiments, depth  249  is greater than 15 mm. The decrease in depth further prevents the handle connection section from passing through the channel  142 . 
     In the embodiment of  FIGS.  1 A-E , the channel  142  extends through the aperture  140  from the proximal end  112  of the parallel spacer body  110  to the distal end of the external positioning protrusion  144  faces away from the first guiding element aperture  130 . In the embodiment of  FIGS.  1 A-E , the aperture  140  is open from the proximal end  112  of the parallel spacer body  110  to the distal end of the external positioning protrusion  144  in a direction radial to axis  130   a.  In various embodiments, the aperture  140  is open from the proximal end  112  of the parallel spacer body  110  to the distal end of the external positioning protrusion  144  in a direction radial to axis  140   a.    
     The external channel  142  enables an access needle  160  to be inserted and/or removed from the channel  142  radially with respect to the axis  140   a  by tilting the tissue protector  180  with the parallel guide  100  still mounted in the tissue protector with the guiding element  150  or other protrusion received in the bone  237 . In other embodiments, the channel  142  faces a different direction in relation to the first guiding element aperture  130 , and in some embodiments the different direction is also suitable for radial insertion or removal of the access needle into or from the channel  142  of the second aperture  140 , such as by tilting the tissue protector and parallel guide. 
     In the embodiment of  FIGS.  1 A-E , the inner surface  145  of the channel  142  is rounded. The inner surface  145  defines the second aperture  140 . The rounded inner surface  145  are configured to enable a close fit of a portion of an exterior of one or more portions of the access needle within the channel  142 , enabling rotational movement of the access needle  160  while the access needle  160  is positioned within the channel  142 , which aids in the insertion of the access needle  160  into the bone. In other embodiments, the inner surface of the channel  142  may conform to other shapes, such as matching the shape of an intended, corresponding access needle. For example, in other embodiments, the inner surface of the channel  142  may be flat and/or may include one or more corners. 
     The external positioning protrusion  120  is suitably connected to the parallel spacer body  110  so as to constrain and/or position the tissue protector  180  relative to the parallel spacer body  110 . For example, the external positioning protrusion  120  may be of unitary construction with the parallel spacer body  110 . The external protrusion has an outer diameter suitable to be received into the tissue protector  180  and a length configured to further stabilize and more precisely align the access needle  160 . In the embodiments of  FIGS.  1 A-E , the external protrusion has an inner diameter (e.g. along the aperture  130  which could be stepped in diameters to accommodate both the guiding element and the tissue protector) suitable to receive the tissue protector  180 . 
     As illustrated in  FIGS.  2 - 10   , the procedure for placing a series of implants into bone are illustratively depicted. As shown in  FIG.  2   , a first access needle  152 , having a sheath  154 , handle  156 , and guiding element  150 , is inserted into bone, at  155 . According to various embodiments, the guiding element  150  protrudes from the sheath  154  on the end opposite the handle  156  and extends through the sheath  154  and into the handle portion  156 . The handle portion  156  is removable, exposing the guiding element  150 , which is inserted into the bone, as shown in  FIG.  3   . Subsequent to the handle portion  156  being removed, the sheath  154  is removed, leaving the guiding element  150  positioned within the bone. 
     A soft-tissue dilator  190  is placed over the exposed guiding element  150 , as shown in  FIG.  4   . The soft-tissue dilator  190  is configured to determine the depth of a guide  150  to be inserted into the bone. In the embodiment of  FIGS.  4  and  5   , the soft-tissue dilator  190  includes depth markings  195  and a channel  197  through which the guiding element  150  can pass. The channel  197  is formed along an exposed wall of the depth gage  190 . The channel  197  transitions into an enclosed channel through a lower body portion of the soft-tissue dilator  190 . The contact surface is located on the distal end of the lower body portion and is suitable to contact the bone. The guiding element  150  can then be slid into the soft-tissue dilator  190  to the desired depth as measured on the depth markings  195 . The soft-tissue dilator  190  is configured to determine the depth in which the guiding element  150  is inserted into a bone and/or joint. The depth markings  195  can measure the depth in which the guiding element  150  is driven into the bone. Typically, the depth markings  195  range from around 25-65 mm depths, but in other embodiments, different range markings can be provided. The number in depth markings  195  that corresponds to the location of the end of guiding element  150  indicates the depth of the guide  150 . In other examples, the depth markings can indicate a different depth that may correspond and be calibrated to the depth of the guiding element  150  (e.g., the depth markings may indicate a desired drilling depth for a pilot hole, a depth of a cage to be implanted, and/or other depth that is associated with the depth of the guiding element  150 , and may thus be measured against the depth of guiding element  150 ). Other embodiments include a soft-tissue dilator that does not have depth markings, and in some embodiments, the process can be practiced without using the soft-tissue dilator, depending on the location of the surgery. 
     In  FIG.  5   , a tissue protector assembly  180  is shown placed over the guiding element  150  and the soft-tissue dilator  190 . The tissue protector  180 , in this example, includes a tissue protector sleeve  188 , handle  182 , tissue protector head  185 , tissue protector tip  186  and the depth gage  190  (functioning as a guide sleeve for a pin or wire), but other types of tissue protectors can alternatively be used. The sleeve  188  of tissue protector assembly  188  has a hollow shaft having a close fit to one or more of the soft-tissue dilator  190 , the cage or screw  200 , and/or a drill  210 . In some examples, the outer diameter of sleeve (e.g., soft-tissue dilator  190 ) shaft is shaped to fit inside the cannula of the tissue protector  180 , which has an internal diameter that may be configured to accommodate tools and implants (e.g., cages  200 , and the like) having a larger diameter than a guide. For example, the diameter of tissue protector&#39;s cannula may correspond to (i.e., be sized to fit) the head or outer diameter on an implant (e.g., cages  100 ). In some examples, the internal surface of tissue protector  180  may be configured to guide an implant (e.g., cage  200 ) inserted into the tissue protector  180  from the tissue protector head  185  and through to tissue protector tip  186 . 
     In some examples, the tissue protector tip  186  includes spikes, teeth, wedges, and/or other structures, to engage a bone. In the embodiment shown in  FIG.  5   , the tissue protector tip has relatively blunt teeth or other feature that are not embedded into the bone, but merely increases friction such that the tissue protector tip  186  does not slip on the exterior of the bone. Some embodiment has a tissue protector with a smooth, non-serrated distal end. 
     The soft-tissue dilator  190  is removed from the tissue protector  180 , as shown in  FIG.  6   , and replaced with a cannulated drill bit  210 , as shown in  FIG.  7   , for drilling a pilot hole for insertion of a cage for joint fusion  200 . Here, the cannulated drill bit  210  may include a cutting tip  212 , body  214 , and shank. As used herein, “drill bit” refers to a cutting tool configured to create substantially cylindrical holes, and “shank” refers to an end of the drill bit, usually the end opposite the cutting tip, configured to be grasped by a chuck of a drill, handle  216  or other torque applying device. In some examples, the cannulated drill bit  210  is configured to drill a pilot hole to a predetermined depth. For example, cutting tip  212  is configured to cut cylindrical holes into a bone and/or joint when torque and axial force is applied to rotate cutting tip  212  (i.e., by a drill). In other examples, the cannulated drill bit  210  is adjustable, and thereby configured to drill a range of depths using depth markings. In the embodiment of  FIG.  7   , the outside diameter of the cannulated drill bit  210  is configured to fit within a tissue protector (e.g., tissue protector  180 ). In other examples, the outside diameter is significantly smaller than the tissue protector  180 , such that the tissue protector does not provide significant support to the drill bit  210  or function as the primary locating tool for the drill bit  210 . In other examples, the tissue protector  180  functions as the drill guide, providing significant support and locating functionality to the drill bit  210  by having an inner diameter that is substantially the same size as the outer diameter of the drill bit  210 , the variance in sizes being sufficient to allow the drill bit  210  to slide and rotate within the tissue protector  180 . 
     In some examples, a desired drilling depth (i.e., depth of a pilot hole) is the same or similar to the depth of a guide that has been inserted into a bone and/or joint. In other examples, the desired drilling depth may be offset (i.e., less deep) by a predetermined amount (e.g., a few millimeters or other offset amount). For example, if a guide has been inserted 40 mm deep into the sacroiliac joint, a corresponding desired drilling depth for the pilot hole may be 40 mm, or it may be 40 mm minus the predetermined offset may be selected (i.e., if the predetermined offset is 3 mm, then the desired drilling depth in this example would be 37 mm). 
     The cannulated drill bit  210  includes cannula. In some examples, the cannula is sized to fit over a guiding element (e.g., guiding element  150 ). A driver handle  216  receives the shank, allowing a user to apply a torque to the drill bit  210 . The drill bit  210  is slid down over the guiding element  150 , thereby accurately locating the drill bit  210  based on the insertion location of the guiding element  150  into the bone. The tissue protector  180 , particularly the sleeve  188  thereof protects the tissue surrounding the drill site from being damaged by the drilling action. The drill forms hole through one or more bones (e.g., ilium and/or Sacrum. 
     The cannulated drill  210  is replaced with a driver  220 , as shown in  FIG.  8   , for inserting an implant  200  into the joint for fusion. As used herein, a cage  200  is provided as an example, but it is noted that bone screws for joint fusion can also be used. The cage  200  includes head, tip, one or more groups of helical fenestrations (e.g., fenestration groups), threads, and tapered end. In some examples, cage  200  is fabricated, manufactured, or otherwise formed, using various types of medical grade material, including stainless steel, plastic, composite materials, or alloys (e.g., Ti-6Al-4V ELI, another medical grade titanium alloy, or other medical grade alloy) that may be corrosion resistant and biocompatible (i.e., not having a toxic or injurious effect on tissue into which it is implanted). In some examples, threads include a helical ridge wrapped around an outer surface of cage  200 &#39;s shaft. In some examples, cage  200  is cannulated, having a cannulated opening formed by a hollow shaft that extends from head to tip. Cage  200  may vary in length (e.g., ranging from approximately 25 mm to 50 mm, or longer or shorter) to accommodate size and geometric variance in a joint. Other dimensions of cage  200 , including major and minor diameters of threads, also may vary to accommodate size and geometric variance in a joint. In some examples, an outer surface of cage  200 &#39;s shaft tapers from head to tapered end, and thus threads also may taper (i.e., be a tapered thread) from head to tapered end (e.g., having a range of major and minor diameters from head to tapered end). In some examples, the tapering of threads, as well as tapered end, aids in guiding the cage through a pilot hole. In other examples, head and threads are sized to fit within a tool or instrument, for example, a tissue protector  180 , as described herein. 
     In some examples, cage  200 &#39;s hollow shaft, or cannula, is accessed (i.e., for packing material into) through an opening in head. In some examples, head may have a flat or partially flat surface (e.g., pan-shaped with rounded edge, unevenly flat, or other partly flat surface). In other examples, head has a different shape (e.g., dome, button, round, truss, mushroom, countersunk, oval, raised, bugle, cheese, fillister, flanged, or other cage head shape). In some examples, the opening in head has a receiving apparatus for a torque applying tool, such as driver. The driver may be a flat head, Phillip&#39;s head, square head, hexagonal, head or other shape suitable to receive a tool and apply torque therefrom. In one example, the torque applying tool may be a driver having a TORX® or TORX®-like shape (i.e., six-point or six-lobed shape) configured to receive the tip of a TORX® or TORX®-like screwdriver (e.g., driver  220 ). For example, cage  200  may include head grooves which may start at head and extend linearly into the cannula of cage  200  to receive complementary lobes on the end of a screwdriver. For a TORX® or TORX®-like opening there may be six (6) total head grooves, including, for example, head grooves, to receive the complementary lobes on the tip of a TORX® or TORX®-like driver. In some examples, the opening in head may be contiguous with, and form a proximal end of, cage  200 &#39;s cannula. For example, the opening may provide access to the cannula, for example, to pack material into the cage. The opening may also include a chamfer providing a lead-in for a tool into the head grooves. 
     As described herein, therapeutic materials include osteogenic compounds (e.g., bone morphogenetic protein, or other osteogenic compounds that may ossify tissue), osteoconductive materials (e.g., demineralized bone, hydroxyapatite, or other material that promotes bone growth), antibiotics, steroids, contrast materials, or other materials that may be beneficial to fusing the joint, treating inflammation or other conditions in the joint, or enabling the visualization of the area within and adjacent to the cage. For example, an osteogenic compound, such as bone morphogenetic protein or other compounds, may be packed into cage  100 &#39;s cannula such that when cage  100  is inserted into a joint or traverses through a joint (e.g., a sacroiliac joint), the osteogenic compound, for example through fenestrations, may come into contact with tissue in the joint adjacent to or surrounding cage, and ossify the tissue to fuse the joint across and through the cage. In some examples, the osteogenic compound may enter the joint and may fill the joint, partially or entirely. In other examples, an osteoconductive material, such as demineralized bone or hydroxyapatite or other materials may be packed into cage&#39;s cannula. When cage is inserted into a joint (e.g., the joint between ilium I and sacrum S), the osteoconductive material may come into contact with tissue in the joint adjacent to or surrounding cage, for example through fenestrations, and promote bone growth into the cage and the joint to fuse the joint across and through the cage. In still other examples, a substance for treating sacroiliitis, such as steroids or antibiotics or other substances, may be packed into cage&#39;s cannula such that when cage is inserted into the joint, the substance may come into contact with tissue in the joint adjacent to or surrounding cage, for example through fenestrations, and treat the inflamed joint tissue. In yet other examples, a contrast material may be packed into cage&#39;s cannula such that, when cage is inserted into the joint, the contrast material within cage, and in some examples absorbed by tissue adjacent to or surrounding cage, may be viewed using visualization techniques (e.g., x-ray, fluoroscope, ultrasound, or other visualization technique). In still other examples, different materials may be packed into cage for different purposes. In yet other examples, the above-described materials may also come into contact with tissue adjacent to, or surrounding, cage through an opening at tip. As described herein, cage may be packed with material prior to being inserted into the joint, and may also be packed after insertion into the joint. Also as described herein, such materials may be packed into cage using a packing plunger. 
     In some examples, fenestrations may provide therapeutic openings in cage&#39;s shaft to enable material packed inside cage to come into contact with surrounding or adjacent tissue (e.g., bone, cartilage, or other tissue in the joint) when cage is implanted. Additionally or alternatively, in various examples, the fenestrations may be shaped to provide additional cutting edges or edges suitable to clean threads formed by the tip. In various examples, fenestrations are substantially circular. In other examples, the fenestrations are oblong (e.g., substantially oval, substantially elliptical, or other suitable shapes). In other examples, fenestrations are shaped differently (e.g., rectangular, rounded rectangular, squared, triangular, or other suitable shapes). In accordance with various embodiments and discussed herein. 
       FIG.  9    illustrates a view of an exemplary parallel guide  100  for placement of a new access needle  160  as placed on a drill guide. A partially sectional view of the components as shown in  FIG.  9    is illustrated in  FIG.  11   . As shown, external positioning protrusion  120  may fit into tissue protector  180 , which has a length  228 , an outer diameter  227 , an inner diameter  226  configured to receive the external positioning protrusion  120 , which has a diameter  225 . The inner diameter  226  of the tissue protector  180  is configured to enable the external positioning protrusion  120  to fit snugly within the tissue protector  180 . In some embodiments, the diameter  225  of the external positioning protrusion  120  is approximately 10-20 mm. In some embodiments, the inner diameter  226  of tissue protector  180  produces a snug fit between the inner surface of the tissue protector  180  and the outer surface of the external positioning protrusion  120 . In the embodiment shown in  FIG.  11   , protrusion  123  maintains contact with the inner surface of the tissue protector  180 . The length  228  of the tissue protector  180  is sufficient to fully encapsulate the external positioning protrusion  120 . In some embodiments, the length  228  of the tissue protector  180  is approximately 120-130 mm. In some embodiments, the length  228  is less than 120 mm. In some embodiments, the length  228  is greater than 130 mm. In the embodiments of  FIGS.  9  and  11   , part of the parallel guide  100  rests against the tissue protector  180 . 
     The access needle  160  is configured to enable insertion of a guiding element  170  within bone  237 . In various embodiments, the access needle may be a commercially available access needle such as, for example, the Jamshidi™ Needle, the Medtronic PAK Needle, the Preston™ Bone Access Needle, the Laurane® Vertebroplasty/Cementoplasty Introducer, or other suitable access needle. 
     The access needle  160  may include a guiding element  170 , sheath  175 , handle connection section  229 , and handle  177 . The handle connection section  229  is configured to secure the handle  177  to the access needle  160  and is configured to enable introduction and removal of the handle  177  from the access needle  160  (to enable access to the guiding element  170  within the access needle  160 ). The handle connection section  229  may be rounded and/or include a plurality of sides. In the embodiment of  FIGS.  9  and  11   , handle connection section  229  has a diamond-shaped cross-section. In some embodiments, the handle connection section  229  includes one or more shapes such as, for example, rounded or circular shapes, rectangular shapes, triangular shapes, etc. In some embodiments, a width of the protruding section is approximately matching to a width of the channel  142 . The handle connection section  229  has a width  238  of sufficient size to prevent the handle connection section  229  from passing through proximal section  252  of the channel  142 . In some embodiments, the handle connection section  229  has a width  238  of approximately 10-20 mm. In other embodiments, the diameter  238  of the handle connection section  229  may be less than 10 mm or greater than 20 mm. 
     In the embodiment shown in  FIG.  11   , the access needle  160  includes a sheath  175  having a length  230  and a proximal section  231 , a middle section  232 , and a distal section  234 . The proximal section  231  has a width  248 . In some embodiments, the width is approximately 5-15 mm. In some embodiments, width  248  is less than 5 mm. In some embodiments, width  248  is greater than 15 mm. In some embodiments, the proximal section  231  of the sheath  175  functions as a guiding section. The width  248  of the proximal section  231  is configured to be approximately the same as the width  147  of the middle section  253  of the channel  142 . In various embodiments, the proximal section  231  of the sheath  175  is sized to enable insertion into and/or rotation within the middle section  253  of the channel  142 . 
     The middle section  232  of the sheath  175  has a diameter  233  and is configured to remain external to the bone  237 . The middle section  232  is configured to be inserted within the distal section  254  of the channel  142 . In some embodiments, the proximal section  232  has a diameter  233  of approximately 1-5 mm. In other embodiments, the diameter may be greater than 5 mm. The proximal section  234  has a diameter  235  and is configured to be partially or entirely inserted into the bone  237 . The guiding element  170  extends from the proximal section  234 . In the embodiment of  FIG.  11   , the guiding element  170  ends with an insertion point  236 . The proximal section  234  is inserted into the bone  237  by threading, hammer, pressing or similar method. In some embodiments, the diameter  235  of the distal section  234  is approximately 1-2 mm. In the embodiment shown in  FIG.  11   , the access needle  160  tapers between sections  231 ,  232 , and  234 . The taper may be linear, curved, gradual, immediate, or other suitable form of taper. 
     In some examples, the tissue protector  180  is slid over the soft-tissue dilator  190  to locate the tissue protector  180 . In other examples, the tissue protector  180  is located first and then the guide  150  and soft-tissue dilator  190  are inserted into the tissue protector  180 . In the embodiment of  FIG.  9   , the handle portion  182  of the tissue protector  180  includes a guiding hole  240  configured to be used as an access needle guide separate and apart from the parallel guide  100 . The guiding hole  240  includes an inner surface  250  at a distance  246  from guiding element  150 . In some embodiments, the distance  246  is approximately 5 mm. In some embodiments, the distance is less than 5 mm. In some embodiments, the distance  246  is greater than 5 mm. In the embodiment of  FIG.  6   , the handle portion  182  of the tissue protector  180  includes one or more additional holes  241 ,  242 ,  243 ,  244 ,  245 , each having a center axis at a set distance from the guiding element  150  and which can be used to guide an access needle into bone at a set distance from the guiding element  150 , causing the handle portion  182  of the tissue protector  180  to act as a second guiding element spacer. The external positioning protrusion  120  fits over the first guiding element  150  via aperture  130 . The parallel guide  100  enables the new wire guide  170  to be placed a set distance from the primary wire guide  150 , as shown in  FIG.  10   . 
     Although the foregoing examples have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention.