Abstract:
A precision depth guided instrument, such as a Jamshidi needle, is provided for use in various surgeries related to the vertebrae. The instrument includes an outer cannula, an inner cannula and a stylet. After the cortical bone of a vertebra is penetrated by the outer cannula of the instrument, the depth of penetration of the inner cannula is adjusted by rotation of the inner cannula. The inner cannula is then moved further into the vertebrae, and a stop mounted on the outer cannula controls the depth of penetration of the inner cannula. The correct depth of penetration is determined by radiography prior to the procedure.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    In accordance with 37 C.F.R. 1.76, a claim of priority is included in the Application Data Sheet filed concurrently herewith. Accordingly, the present application claims priority under 35 U.S.C. 119(e) as a continuation-in-part of U.S. Application Ser. No. 61/677,684, filed Jul. 31, 2012, entitled “Depth Controlled Jamshidi Needle”, this application is also a continuation-in-part of U.S. application Ser. No. 13/409,483, filed Mar. 1, 2012, entitled “Depth Controlled Jamshidi Needle” which claims priority under 35 U.S.C. 119(e) to U.S. Application Ser. No. 61/448,030, filed Mar. 1, 2011, entitled “Depth Controlled Jamshidi Needle”, the contents of which are incorporated herein in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to instruments employed for controlling accurate placement of devices, such as Jamshidi needles, used in spinal surgery. In particular, in addition to enabling a surgeon to accurately control the depth of needle penetration into the bone, the present device properly places dilation tubes for percutaneous surgical procedures. 
       BACKGROUND OF THE INVENTION 
       [0003]      100031  Medical procedures involving the vertebrae are normally complicated because of the preciseness and accuracy required to avoid both neural damage and injury to major blood vessels. Precision depth guided instruments are required to perform percutaneous spinal surgery. These surgeries sometimes require penetration of the hard cortical bone of the vertebra and traversal of the softer cancellous bone lying thereunder. A large force is normally required by the surgeon to penetrate the cortical bone. Once the cortical bone is penetrated, extreme care must then be taken to avoid rapidly penetrating through all of the cancellous bone. There is also the danger of rapidly passing through the cancellous bone and then through the cortical bone on the other side of the vertebra. This can result in injury or damage to the spinal cord and/or other organs or blood vessels located adjacent the spine. In some instances, the force required to penetrate the cortical bone is greater than a surgeon can apply by hand. In these instances a hammer or other similar instrument is required to force the instrument through the cortical bone. When a hammer or similar instrument is used, there is a greater danger of the instrument passing rapidly through the cancellous bone and out the other side of the vertebra. Preexisting conditions such as osteoporosis may complicate this problem. 
       DESCRIPTION OF THE PRIOR ART 
       [0004]    U.S. Patent No. 5,458,579 discloses an apparatus for inserting a trocar/cannula assembly through a wall of an anatomical cavity of an individual. The apparatus includes a housing for holding the trocar/cannula assembly, a device for driving the trocar/cannula assembly into the individual, a spine, and a depth stop element mounted on the spine to control the depth which the trocar/cannula assembly is inserted into the individual. 
         [0005]    U.S. Patent No. 6,033,411 discloses a depth guided instrument for use in performing percutaneous implantation of hard tissue implant materials. A depth guided stylet includes a point adapted for piercing hard tissue and self-tapping threads for self tapping into hard tissue. The instrument also includes a cannula surrounding the stylet which employs a pawl and rack of gear teeth to assist passing the cannula through the hard tissue. 
         [0006]    U.S. Patent No. 7,678,077 discloses an instrument for injecting therapeutic and other agents into an individual at a target site. The instrument includes a catheter having a first elongate shaft and a second elongate shaft slidingly disposed within the first shaft. An indicator is secured to an end of the second elongate shaft and moves relative to a scale to indicate the position of the first and second shafts relative to their insertion into an individual. 
         [0007]    None of the above noted prior art devices permit the operator of the device to adjust the depth of penetration of the Jamshidi needle or cannula based on information obtained from a patient prior to surgery. The depth of penetration can be adjusted depending on the point of entry into the body of the Jamshidi needle or cannula. In addition, none of these devices are constructed to place a tap tube or dilation tube simultaneously to placement of the needle. 
       SUMMARY OF THE INVENTION 
       [0008]    A precision depth guided instrument, such as a Jamshidi needle, is provided for use in various surgeries related to the vertebrae. The instrument includes an outer cannula, an inner cannula and a stylet. After the cortical bone of a vertebra is penetrated by the outer cannula of the instrument, the depth of penetration of the inner cannula is adjusted by rotation of a stop mounted to the outer cannula. The inner cannula is then moved further into the vertebrae, and a stop mounted on the outer cannula controls the depth of penetration of the inner cannula. The correct depth of penetration is determined by radiography prior to and during the procedure. In at least one embodiment, the outer cannula is provided with at least one tap or dilation tube which may be placed within the patient for use in subsequent surgical operations after withdrawal of the jamshidi needle. The jamshidi needle may cooperate with the tap or dilation tubes to facilitate controlled withdrawal of the jamshidi from the cortical bone. 
         [0009]    Accordingly, it is an objective of the instant invention to provide a depth controlled jamshidi needle which can be inserted into a patient to a precise location. 
         [0010]    It is a further objective of the instant invention to provide a depth controlled jamshidi needle which can be inserted into a vertebra and then a portion of the device controllably moved to a precise location within the vertebra. 
         [0011]    It is yet another objective of the instant invention to provide a depth controlled jamshidi needle which can be inserted into a vertebra a measured distance, the measured distance having been predetermined by radiography. 
         [0012]    It is a still further objective of the invention to provide a depth controlled jamshidi needle which can be inserted into a vertebra an exact distance without any danger of exceeding the desired distance. 
         [0013]    It is yet a further objective of the invention to provide a depth controlled jamshidi needle that includes at least one dilation tube positioned about the outer cannula which may be placed simultaneously with placement of the jamshidi needle. 
         [0014]    It is still yet a further objective of the invention to provide a depth controlled jamshidi needle that includes at least one tap tube and at least one dilation tube positioned about the outer cannula which may be placed simultaneously with placement of the jamshidi needle. 
         [0015]    Other objects and advantages of this invention will become apparent from the following description taken in conjunction with any accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. Any drawings contained herein constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0016]      FIG. 1  is a perspective view of one embodiment of the present invention with the components partially exploded; 
           [0017]      FIG. 2  is an exploded view of one embodiment of the present invention; 
           [0018]      FIG. 3  is a perspective view of one embodiment of the present invention illustrated with a component placement prior to insertion into a patient; 
           [0019]      FIG. 4  is a perspective view of one embodiment of the present invention illustrated with an inner cannula moved to position for penetration further into a vertebra; 
           [0020]      FIG. 5  is a partial view of the end portion of the embodiment illustrated in  FIG. 3  illustrating the relationship of the two cannulae and needle; 
           [0021]      FIG. 6  is a top view of a handle of the inner cannula into which a needle is inserted, illustrated with a perspective view of the outer cannula; 
           [0022]      FIG. 7  is a cross sectional view of one embodiment of the present invention illustrated positioned in a vertebra; 
           [0023]      FIG. 8  is a perspective view of one embodiment of the present invention illustrated in a position similar to  FIG. 3 ; 
           [0024]      FIG. 9  is a perspective view of one embodiment of the present invention illustrated in a position similar to  FIG. 4 ; 
           [0025]      FIG. 10  is a perspective view of one embodiment of the present invention illustrated with an optional hard stop; 
           [0026]      FIG. 11  is a perspective view of the invention illustrated in  FIG. 1  including an optional hard stop; 
           [0027]      FIG. 12  is a perspective view of one embodiment of the present invention illustrated with a tap tube and a dilation tube positioned about the outer cannula; 
           [0028]      FIG. 13  is a perspective partially exploded view of one embodiment of the present invention illustrating the tap tube partially in section; 
           [0029]      FIG. 14  is a perspective partially exploded view of the embodiment of  FIG. 12  illustrating the tap tube and dilation tube partially in section; 
           [0030]      FIG. 15  is a partial section view taken along lines  15 - 15  of  FIG. 12  illustrating connection between the tap and dilation tubes and the outer cannula; 
           [0031]      FIG. 16  is a perspective view of one embodiment of the present invention illustrated with the tap tube positioned about the outer cannula; 
           [0032]      FIG. 17  is a perspective view of the embodiment shown in  FIG. 16  illustrating partial removal of the outer cannula from the tap tube; 
           [0033]      FIG. 18  is a perspective view of the embodiment illustrated in  FIG. 16  illustrated with the tap tube removed from the outer cannula; 
           [0034]      FIG. 19  is an exploded perspective view of the embodiment illustrated in  FIG. 16 ; 
           [0035]      FIG. 20  is a perspective view of one embodiment of the present invention; and 
           [0036]      FIG. 21  is a partially exploded view of the embodiment illustrated in  FIG. 19 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred, albeit not limiting, embodiment with the understanding that the present disclosure is to be considered an exemplification of the present invention and is not intended to limit the invention to the specific embodiments illustrated. 
         [0038]      FIGS. 1-11 , which are now referenced, illustrate various embodiments of the present invention and the manner in which they are assembled. Like reference numerals refer to like components in the various figures. The needle depth controlled Jamshidi assembly  10  comprises a Jamshidi-type needle  12 , and an outer cannula assembly  14 . The Jamshidi-type needle  12  is slidably disposed within the outer cannula assembly  14 . The Jamshidi-type needle  12  includes an inner cannula  16  which is secured to a handle  18 . The handle  18  includes a collar or cylindrical portion  20 . This cylindrical portion  20  is fixedly secured to the cannula  16 . The handle  18  preferably has an ergonomic shape that can comfortably fit into a surgeon&#39;s or medical technician&#39;s hand. The handle includes an upper curved portion  15  which is shaped to conform to an individual&#39;s palm. The lower portion  17  of the handle  18  is also curved. The curve of the lower portion  17  of the handle is designed to be grasped by the fingers of an individual to assist in the control of the Jamshidi-type needle  12 . The handle  18  is used to drive the cannula into, and sometimes through bones of a vertebra. Sometimes the Jamshidi-type needle  12  can be driven through the bone only by using pressure exerted by an individual&#39;s hand. Other times a hammer or other instrument must be employed to drive the needle  12  through a bone. There is a risk that, when a hammer or similar instrument is utilized, the Jamshidi-type needle  12  will pass too far into a vertebra. This can cause damage to nerves located nearby. Sometimes the needle passes completely through the vertebra and injures an adjacent blood vessel or internal organ. To prevent this, the present invention utilizes a second outer cannula  14  which is adjustably secured to the Jamshidi-type needle  12  to provide controlled linear traversal of the Jamshidi-type needle within the outer cannula assembly  14 . 
         [0039]    A needle  22  is slidably positioned within the inner cannula  16  of the Jamshidi-type needle  12 . The preferred embodiment of the present invention illustrates the needle  22  as having a conical tip  24  ( FIGS. 5 ). However, other tips and needles can also be employed. For example, a trocar tip can be utilized. The tip  24  can be tapered, hollow, cannulated, etc. The tip can be utilized to extract a tissue sample. It can also be utilized to penetrate or anchor to a bone. In a preferred embodiment, the needle is detachable from the inner cannula so that a guidewire, Kirschner wire, K-wire or the like can be passed through the inner cannula to the surgical site. Alternatively, the Jamshidi needle can be removed and an orthopedic bone screw or other device can then be passed down the needle  22  and secured to the correct location on a bone. While the preferred embodiment of the present invention discloses a relatively rigid needle  22 , other needles which are flexible can also be employed. 
         [0040]    The outer cannula  14  comprises an upper portion  26  secured to a cannula  28  ( FIG. 2 ). The upper portion  26  comprises a handle or grip  30  and a threaded sleeve  32 . In the preferred embodiment of the outer cannula, the handle  30  and the threaded sleeve  32  are fixedly secured to each other. In other embodiments, these elements can be pivotably or removably secured to each other. The lower or second end  34  of the outer cannula  14  is constructed and arranged to penetrate and pass through bone. While the lower end  34  is normally a hollow tube with an end that tapers to a sharp edge, other edges can also be employed. For example, the edge can be serrated, saw toothed or sinusoidal. The smooth edge is preferably utilized when the needle assembly is driven straight into or through a bone. The serrations or waves are employed when additional effort is required to penetrate a bone. The handle or grip  30  is preferably provided with apertures  31  into which a surgeon&#39;s fingers can be inserted to control the device. 
         [0041]      FIG. 7  illustrates an example of one of the uses of the present invention. The outer cannula  14 , the inner cannula  16  and the tip  24  of the needle  22  are passed through a cortical bone  36  of a vertebra  38  and into the cancellous bone  40 . A sample of the cancellous bone may now be taken. In another situation, the needle  22  may be passed into the cortical bone  36  opposite the point of insertion into the vertebra. In these different situations it is very difficult for a surgeon or medical technician to judge the depth of penetration of the depth controlled Jamshidi type needle  10  into the vertebra. The remedy for this problem lies in the present invention. First, a radiography image of the vertebra being operated upon is taken. Next, the depth into the vertebra that the surgeon wants the needle to penetrate is measured or estimated. The outer cannula includes a first stop member  28 . The outer cannula is driven into the bone until the first stop member  28  contacts the top surface of the bone, providing a reference depth that the outer cannula has penetrated the bone. The Jamshidi-type needle  12  of the present invention includes a threaded nut  42  or similar device which is rotatably secured to the cannula  16  by a bearing. The threads on the nut  42  match the threads on the sleeve  32 . After the surgeon inserts the needle into a patient and through the cortical bone  36  of a vertebra, the cannula  16  is inserted further into the vertebra by rotating the nut  42 . Rotation of the nut  42  moves the cannula and needle  22  further into the vertebra. The distance that these elements are moved can be measured along the threaded sleeve. Alternatively, since the threads have a fixed pitch, the surgeon need only count the rotations of the nut or inner cannula to determine the traversal of the inner cannula through the outer cannula and into the bone. The distance the needle needs to travel into the vertebra, which has been determined by radiography, can be accurately determined. Preferably, marks or indicia are placed on sleeve  32  which allow the surgeon to visually determine the position of the inner cannula with respect to the outer cannula. The surgeon or medical technician can now rotate the nut  42  until it reaches the desired mark of indicia on sleeve  32 . At this point, the cannula  16  and needle  22  are now exactly where they need to be positioned. The nut can be rotated by hand or with a wrench or similar device. The wrench may be utilized if a relatively hard bone is to be penetrated by the device. Because the first stop member  28  is placed a predetermined distance from the distal tip of the outer cannula, the surgeon has a precise knowledge of how far the bone has been penetrated. 
         [0042]    In an alternate embodiment, the nut  42  is fixedly secured to the collar  20  and handle or grip  30 . In this embodiment the handle  30  is rotated, which in turn rotates the collar  20  and nut  42 . This moves the cannula  16  further into the vertebra until the desired position is reached. Rotation of the handle  30  permits additional torque to be applied to the nut  42 , and in certain instances does not required the use of a wrench or similar tool. 
         [0043]      FIG. 3  illustrates the position of the elements of the invention prior to rotation of nut  42 . The end of cannula  16  is adjacent the end  34  of the outer cannula. The tip  24  of the needle  22  protrudes slightly past this point. As illustrated in  FIG. 4 , after nut  42  is rotated, the inner cannula  16  and needle  22  move past the end  34  of cannula  14 . The distance that the inner cannula  16  and needle need to move past the end  34  of cannula  14  has been previously determined by radiography. The end  44  ( FIG. 2 ) of inner cannula  16  can be similar in construction to end  34  of outer cannula  14 . While the end  44  is normally a hollow tube with an end that tapers to a sharp edge, other edges can also be employed. For example, the edge can be serrated, saw toothed or sinusoidal. The smooth edge is preferably utilized when the needle assembly is driven straight into or through a bone. The serrations or waves are employed when additional effort is required to penetrate a bone. 
         [0044]      FIG. 6  illustrates the hollow cannula  16  into which the needle  22  is slidably located. Also visible in  FIG. 6  is funnel  17  which extends from the upper portion  15  of handle  18  to the first end  13  of the inner cannula  16 . The funnel  17  includes an open mouth  19  which tapers substantially to the diameter of the inner bore of the inner cannula. The funnel provides the user with an easily targeted aperture for insertion of the needle  22  or a guidewire, also known as a Kirschner wire (not shown) often used in spinal as well as other types of surgeries. 
         [0045]      FIG. 11  illustrates an optional collar or spacer  150  that can be placed on the sleeve  32 . This spacer or collar  150  enables the surgeon or medical technician to precisely place the cannula  16  and needle  22  within a bone or other portion of a patient. The precise desired location of the cannula  16  and needle  22  is first determined by radiography. A measurement of this location is taken, and then a spacer or collar  150  is selected; the length of the spacer corresponding to this measurement. The spacer or collar is then placed over the sleeve  32  and the procedure is performed. The first stop member  28  determines the depth that the outer cannula  14  enters the bone and the inner cannula or nut  16 ,  42  is rotated to position the distal end of the needle  22  precisely where the surgeon or medical technician has determined it should be. This optional spacer prevents any over-insertion of the cannula  16  and needle  22 . 
         [0046]      FIGS. 8-10  illustrate an alternate embodiment of the present invention. In these figures, a Jamshidi-type assembly  112  is slidably disposed within an outer cannula assembly  114 . The Janshidi-type needle  112  includes a cannula  116  which is secured to a handle  118 . The handle  118  includes a threaded collar portion  120 . This threaded collar portion  120  is fixedly secured or molded to the handle  118 . The handle  118  preferably has an ergonomic shape that can comfortably fit into a surgeon&#39;s or medical technician&#39;s hand. The handle includes an upper curved portion  115  which is shaped to conform to an individual&#39;s palm. The lower portion  117  of the handle  118  is also curved. The curve of the lower portion  117  of the handle is designed to be grasped by the fingers of an individual to assist in the control of the Jamshidi-type assembly  112 . The handle  118  is used to drive the cannula into, and sometimes through bones of a vertebra. Sometimes the Jamshidi-type assembly  112  can be driven through the bone only by using pressure exerted by an individual&#39;s hand. Other times a hammer or other instrument must be employed to drive the Jamshidi-type assembly  112  through a bone. There is a risk, that when a hammer or similar instrument is utilized, the Jamshidi-type assembly  112  will pass too far into a vertebra. This can cause damage to nerves located nearby. Sometimes the needle passes completely through the vertebra and injures an adjacent blood vessel or internal organ. To prevent this, the present invention utilizes a second cannula  114  which is adjustably secured to the Jamshidi-type assembly  112 . 
         [0047]    A needle  122  is slidably positioned within the cannula  116 . The needle, like the other embodiments includes an enlarged head member  123  which includes a boss  25  ( FIG. 2 ) or the like suitable to secure the needle within the inner cannula assembly. In a most preferred embodiment, the boss cooperates with the handle  118  to function as a bayonet type mount. This embodiment of the present invention illustrates the needle as having a conical tip  124 , however, other tips and needles can also be employed. For example, a trocar needle can be utilized. The tip  124  can be tapered, hollow, etc. The tip can be utilized to extract a tissue sample. It can also be utilized to anchor the needle to a bone. An orthopedic bone screw or other device can then be passed down the needle and secured to the correct location on a bone. While the preferred embodiment of the present invention discloses a relatively rigid needle, other needles which are flexible can also be employed. Alternatively, the bayonet mount may be utilized to remove the needle from the inner cannula for placement of a guidewire, K-wire or a Kirschner wire. 
         [0048]    The outer cannula  114  comprises an upper portion  126  secured to a cannula  128  ( FIG. 8 ). The upper portion  126  comprises a handle or grip  130 . In this embodiment, the outer or second cannula  114  and the handle  130  are fixedly secured to each other. In other embodiments, these elements can be pivotably secured to each other. The lower end  134  of the outer cannula  114  is constructed and arranged to penetrate and pass through bone. While the end  134  is normally a hollow tube with an end that tapers to a sharp edge, other edges can also be employed. For example, the edge can be serrated, saw toothed or sinusoidal. The smooth edge is preferably utilized when the needle assembly is driven straight into or through a bone. The serrations or waves are employed when additional effort is required to penetrate a bone. 
         [0049]    The Jamshidi-type assembly  112  of this embodiment includes a threaded collar portion  120 . The second cannula  114  includes a housing  132  at a top end thereof. The housing is relatively hollow and includes threads which match the threads on sleeve portion  120 . After the surgeon inserts the needle into a patient and through the cortical bone  36  of a vertebra, the cannula  116  is inserted further into the vertebra by rotating the handle  118  and sleeve portion  120 . Rotation of sleeve  120  moves the cannula  116  and needle further into the vertebra. The distance that these elements are moved can be measured along the sleeve portion  120  which is provided with windows  162  and/or indicia  164 . The distance the needle needs to travel into the vertebra, which has been determined by radiography, will be measured along sleeve portion  120 . The surgeon or medical technician can now rotate handle  118  and sleeve  120  until it reaches the desired mark of indicia on sleeve  120 . At this point, the cannula  116  and Jamshidi-type assembly  112  are now exactly where they need to be positioned. 
         [0050]      FIG. 10  illustrates an optional collar or spacer  160  that can be placed on the sleeve  120 . This spacer or collar  160  enables the surgeon or medical technician to precisely place the cannula  116  and Jamshidi-type assembly  112  within a bone or other portion of a patient. The precise desired location of the cannula  116  and Jamshidi-type assembly  112  is first determined by radiography. A measurement is taken and then a spacer or collar  160  is selected which corresponds to this measurement. The spacer or collar is then placed over the sleeve  120  and the procedure is performed. This optional spacer prevents any over-insertion of the cannula  116  and Jamshidi-type assembly  112 . 
         [0051]    Now referring to  FIGS. 12-15 , an alternative embodiment of the depth controlled jamshidi is illustrated. This embodiment includes at least one dilator tube  166  positioned about the outer cannula  114 . In a most preferred embodiment, a pair of dilation tubes in the form of a tap tube  168  and a dilation tube  166  is positioned about the outer cannula  114 . The tap tube includes a first end  170 , a second end  172 , an inner diameter  174  and an outer diameter  176 . The tap tube generally includes a length that is slightly shorter than the outer cannula. In this manner, the tap tube can function as a stop member for the outer cannula, whereby the progression of the outer cannula through bone is stopped when the second end  172  of the tap tube contacts the outer surface of the bone. The inner diameter  174  of the tap tube  168  is sized to allow passage of a drill or tap member (not shown), thus the inner diameter also allows the tap tube to over the outer surface of the outer cannula. The first end  170  of the tap tube  168  preferably includes a connection to the outer cannula illustrated herein as internal threads  178  ( FIG. 15 ). The second end  172  of the tap tube  168  is preferably tapered or radiused to allow for traversal through tissue in vivo. Thus, in operation, a surgeon can tap the depth controlled jamshidi needle  10  into a position wherein the second end  172  of the tap tube  168  contacts the bone. The surgeon can then rotate the handle  118  until the inner cannula  116  reaches the desired depth. The cap  123  of the needle  22  can be rotated to release the needle from the inner cannula  116 . The needle is then withdrawn and a guidewire can be passed through funnel  17  and the inner cannula to the surgical site. The tap tube  168  can then be rotated to release it from the outer cannula  114 . Gripping surface  178  provides the surgeon with sufficient friction to allow the tap tube to be released from the outer cannula. While the gripping surface  178  is illustrated as a knurled surface, other grippable surfaces may be utilized without departing from the scope of the invention; such gripping surfaces may include, but should not be limited to, wrench flats, an enlarged diameter, polygons and the like. The dilation tube  166  may be utilized in some embodiments over the outer diameter of the tap tube  168 . The dilation tube includes a first end  180 , a second end  182 , an inner diameter  184  and an outer diameter  186 . The first end  180  includes an attachment, illustrated herein as external threads  188  ( FIG. 15 ) for attachment to the outer cannula. This construction allows the dilation tube  166  to be released as desired by the surgeon to leave the dilation tube in place. It should also be noted that while threads are illustrated, other types of attachments may be utilized without departing from the scope of the invention; such attachments may include, but should not be limited to, adhesives, friction, thumbscrews, locking tapers, and the like. The inner bore of the dilation tube  166  is sized to cooperate with the tap tube  168  and may be sized for passage of an implant such as a pedicle screw or the like. The second end of the dilation tube is preferably tapered or radiused to allow traversal through tissue in vivo. The tap tube  168  and the dilation tube  166  are preferably constructed from a polymeric plastic material. However, it should be noted that metals, rubbers and suitable combinations thereof may be utilized without departing from the scope of the invention. 
         [0052]      FIGS. 16-19  illustrate an alternate embodiment of the present invention. In these figures, a Jamshidi-type assembly  112  is slidably disposed within an outer cannula assembly  114 . The Janshidi-type needle assembly  112  includes a cannula  116  which is secured to a handle  118 . The handle  118  includes a threaded collar portion  120 . This threaded collar portion  120  is fixedly secured or molded to the handle  118 . The handle  118  preferably has an ergonomic shape that can comfortably fit into a surgeon&#39;s or medical technician&#39;s hand. The handle includes an upper curved portion  115  which is shaped to conform to an individual&#39;s palm. The lower portion  117  of the handle  118  is also curved. The curve of the lower portion  117  of the handle is designed to be grasped by the fingers of an individual to assist in the control of the Jamshidi-type assembly  112 . The handle  118  is used to drive the cannula into, and sometimes through bones of a vertebra. Sometimes the Jamshidi-type assembly  112  can be driven through the bone only by using pressure exerted by an individual&#39;s hand. Other times a hammer or other instrument must be employed to drive the Jamshidi-type assembly  112  through a bone. There is a risk, that when a hammer or similar instrument is utilized, the Jamshidi-type assembly  112  will pass too far into a vertebra. This can cause damage to nerves located nearby. Sometimes the needle passes completely through the vertebra and injures an adjacent blood vessel or internal organ. To prevent this, the present invention utilizes a second cannula  114  which is adjustably secured to the Jamshidi-type assembly  112  so that the Jamshidi assembly can pass through the second cannula assembly  114  in a precisely controlled manner once the second cannula assembly is embedded into the desired bone for anchoring. 
         [0053]    A needle  122  is slidably positioned within the cannula  116 . The needle, like the other embodiments includes an enlarged head member  123  which includes a boss  25  ( FIG. 21 ) threads or the like suitable to secure the needle  122  within the cannula  116 . In a most preferred embodiment, the boss  25  cooperates with the handle  118  to function as a bayonet type mount. This embodiment of the present invention illustrates the needle as having a conical tip  124 , however, other tips and needles can also be employed. For example, a trocar needle or point formed from a plurality of flat surfaces etc. can be utilized. The tip  124  can be solid, tapered, hollow, etc. The tip can be utilized to extract a tissue sample. It can also be utilized to anchor the needle to a bone. A drill, tap and/or orthopedic bone screw or other device (not shown) can then be passed down the needle and secured to the correct location on a bone. While the preferred embodiment of the present invention discloses a relatively rigid needle, other needles which are flexible can also be employed. Alternatively, the bayonet mount may be utilized to remove the needle from the inner cannula for placement of a guidewire, K-wire or a Kirschner wire. 
         [0054]    The outer cannula  114  comprises an upper portion  126  secured to a cannula  128  ( FIG. 8 ). The upper portion  126  comprises a handle or grip  130 . In this embodiment, the outer or second cannula  114  and the handle  130  are fixedly secured to each other. In other embodiments, these elements can be pivotably secured to each other. The lower end  134  of the outer cannula  114  is constructed and arranged to penetrate and pass through bone. While the end  134  is normally a hollow tube with an end that tapers to a sharp edge, other edges can also be employed. For example, the edge can be serrated, saw toothed or sinusoidal. The smooth edge is preferably utilized when the needle assembly is driven straight into or through a bone. The serrations or waves are employed when additional effort is required to penetrate a bone or tissue. 
         [0055]    The Jamshidi-type assembly  112  of this embodiment includes a threaded collar portion  120 . The second cannula  114  includes a housing  132  at a top end thereof. The housing is relatively hollow and includes internal threads which match the external threads on sleeve portion  120 . After the surgeon inserts the needle into a patient and through the cortical bone  36  of a vertebra ( FIG. 7 ), the cannula  116  is inserted further into the vertebra by rotating the handle  118  and sleeve portion  120 . Rotation of sleeve  120  moves the cannula  116  and needle further into the vertebra. The distance that these elements are moved can be measured along the sleeve portion  120  which is provided with windows  162  and/or indicia  164 . The distance the needle needs to travel into the vertebra, which has been determined by radiography, will be measured along sleeve portion  120 . The surgeon or medical technician can now rotate handle  118  and sleeve  120  until it reaches the desired mark of indicia on sleeve  120 . At this point, the cannula  116  and Jamshidi-type assembly  112  are now exactly where they need to be positioned. 
         [0056]    Still referring to  FIGS. 16-19 , the preferred embodiment of the present invention incudes at least one tap tube  168  positioned about the outer cannula  114 . In a most preferred embodiment, the tap tube  168  is positioned about the stop member  28  of the outer cannula  114 . The stop member  28  is preferably molded around the outer cannula  128  however, press fits, shrink fits, adhesives, fasteners and the like may also be utilized to secure the stop member in place without departing from the scope of the invention. In a most preferred embodiment, threads  129  are formed into the stop member for threaded cooperation with the tap tube  166 . The tap tube includes a first end  170 , a second end  172 , an inner diameter  174  and an outer diameter  176 . The tap tube generally includes a length that is slightly shorter than the outer cannula  128 . In this manner, the tap tube or the stop member can function as a stop member for the outer cannula, whereby the progression of the outer cannula through bone is stopped when the second end  172  of the tap tube or distal end of the stop member contacts the outer surface of the bone. The inner diameter  174  of the tap tube  168  includes threads sized to cooperate with the threads on the stop member and is sized to allow passage of a drill or tap member (not shown). The second end  172  of the tap tube  168  is preferably tapered or radiused to allow for traversal through tissue in vivo. Thus, in operation, a surgeon can tap the depth controlled jamshidi needle  10  into a position wherein the second end  172  of the tap tube  168  contacts the bone. The surgeon can then rotate the handle  118  until the inner cannula  116  reaches the desired depth. The cap  123  of the needle  22  can be rotated to release the needle from the inner cannula  116 . The needle is then withdrawn and a guidewire can be passed through funnel  17  and the inner cannula to the surgical site. The tap tube  168  can then be rotated to release it from the outer cannula  114  and for backing the outer cannula out of the bone while leaving the tap tube in position. Gripping surface  178  provides the surgeon with sufficient friction to allow the tap tube to be released from the outer cannula. While the gripping surface  178  is illustrated as a knurled surface, other grippable surfaces may be utilized without departing from the scope of the invention; such gripping surfaces may include, but should not be limited to, wrench flats, an enlarged diameter, polygons and the like. A dilation tube  166  may be utilized in some embodiments over the outer diameter of the tap tube  168 . The dilation tube includes a first end  180 , a second end  182 , an inner diameter  184  and an outer diameter  186 . The first end  180  includes an attachment, illustrated herein as external threads  188  ( FIG. 15 ) for attachment to the outer cannula. This construction allows the dilation tube  166  to be released as desired by the surgeon to leave the dilation tube in place. It should also be noted that while threads are illustrated, other types of attachments may be utilized without departing from the scope of the invention; such attachments may include, but should not be limited to, adhesives, friction, thumbscrews, locking tapers, and the like. The inner bore of the dilation tube  166  is sized to cooperate with the tap tube  168  and may be sized for passage of an implant such as a pedicle screw or the like. The second end of the dilation tube is preferably tapered or radiused to allow traversal through tissue in vivo. The tap tube  168  and the dilation tube  166  are preferably constructed from a polymeric plastic material. However, it should be noted that metals, rubbers and suitable combinations thereof may be utilized without departing from the scope of the invention. 
         [0057]    Referring to  FIGS. 20-21 , an alternative embodiment of the present invention is illustrated. In these figures, a Jamshidi-type assembly  112  is slidably disposed within an outer cannula assembly  114 . The Jamshidi-type needle assembly  112  includes a cannula  116  which is secured to a handle  118 . The handle  118  includes a threaded collar portion  120 . This threaded collar portion  120  is fixedly secured or molded to the handle  118 . The handle  118  preferably has an ergonomic shape that can comfortably fit into a surgeon&#39;s or medical technician&#39;s hand. The handle includes an upper curved portion  115  which is shaped to conform to an individual&#39;s palm. The lower portion  117  of the handle  118  is also curved. The curve of the lower portion  117  of the handle is designed to be grasped by the fingers of an individual to assist in the control of the Jamshidi-type assembly  112 . The handle  118  is used to drive the cannula into, and sometimes through bones of a vertebra. Sometimes the Jamshidi-type assembly  112  can be driven through the bone only by using pressure exerted by an individual&#39;s hand. Other times a hammer or other instrument must be employed to drive the Jamshidi-type assembly  112  through a bone. There is a risk, that when a hammer or similar instrument is utilized, the Jamshidi-type assembly  112  will pass too far into a vertebra. This can cause damage to nerves located nearby. Sometimes the needle passes completely through the vertebra and injures an adjacent blood vessel or internal organ. To prevent this, the present invention utilizes a second cannula  114  which is adjustably secured to the Jamshidi-type assembly  112  via the threaded collar portion  120  so that the Jamshidi assembly can pass through the second cannula assembly  114  in a precisely controlled manner once the second cannula assembly is abutted to the desired bone for anchoring. Alternatively, the cannula  116  may be extended past a tap tube portion  166  of the second cannula  114  before be driven into the bone to limit the distance that the cannula  116  can penetrate the bone. Once the distal end  175  of the tap tube contacts the bone traversal of the cannula through the bone is stopped. Rotation of the jamshidi assembly in a first direction will cause further progression of the needle  122  through the bone or tissue while rotation in a second direction will pull the jamshidi assembly from the bone leaving the tap tube in position over the aperture created in the bone by the needle  122  and cannula  116 . 
         [0058]    A needle  122  is slidably positioned within the cannula  116 . The needle, like the other embodiments includes an enlarged head member  123  which includes a boss  25  ( FIG. 21 ) threads or the like suitable to secure the needle  122  within the cannula  116 . In a most preferred embodiment, the boss  25  cooperates with the handle  118  to function as a bayonet type mount. This embodiment of the present invention illustrates the needle as having a conical tip  124 , however, other tips and needles can also be employed. For example, a trocar needle or point formed from a plurality of flat surfaces etc. can be utilized. The tip  124  can be solid, tapered, hollow, etc. The tip can be utilized to extract a tissue sample. It can also be utilized to anchor the needle to a bone. A drill, tap and/or orthopedic bone screw or other device (not shown) can then be passed down the needle and secured to the correct location on a bone. While the preferred embodiment of the present invention discloses a relatively rigid needle, other needles which are flexible can also be employed. Alternatively, the bayonet mount may be utilized to remove the needle from the inner cannula for placement of a guidewire, K-wire or a Kirschner wire. 
         [0059]    The outer cannula  114  comprises an upper portion  126  secured to a cannula  128  ( FIG. 20 ). The upper portion  126  comprises a handle or grip  130 . In this embodiment, the outer or second cannula  114  and the handle  130  are fixedly secured to each other. In other embodiments, these elements can be pivotably secured to each other. The lower end  134  of the outer cannula  114  is constructed and arranged to function as a tap tube  166  having an inner bore sized for the traversal of a tap member or drill bit (not shown) for sizing the aperture in the bone and/or forming threads therein for cooperation with a bone fastener (not shown). 
         [0060]    The Jamshidi-type assembly  112  of this embodiment includes a threaded collar portion  120 . The second cannula  114  includes a housing  132  at a top end thereof The housing is relatively hollow and includes internal threads which match the external threads on sleeve portion  120 . After the surgeon inserts the needle into a patient and through the cortical bone  36  of a vertebra ( FIG. 7 ), the cannula  116  is inserted further into the vertebra by rotating the handle  118  and sleeve portion  120 . Rotation of sleeve  120  moves the cannula  116  and needle further into the vertebra. The distance that these elements are moved can be measured along the sleeve portion  120  which may be provided with windows and/or indicia. 
         [0061]    Still referring to  FIGS. 20-21 , the preferred embodiment of the present invention incudes at least one tap tube  168  positioned about the outer cannula  114 . In a most preferred embodiment, the tap tube  168  is positioned to function as a stop member to prevent over insertion of the jamshidi assembly. In this manner, the tap tube can function as a stop member for the outer cannula, whereby the progression of the outer cannula through bone is stopped when the second end  172  of the tap tube or distal end of the stop member contacts the outer surface of the bone. The inner diameter  174  of the tap tube  168  is sized to allow passage of a drill or tap member (not shown). The second end  172  of the tap tube  168  is preferably tapered or radiused to allow for traversal through tissue in vivo. Thus, in operation, a surgeon can tap the depth controlled jamshidi needle  10  into a position wherein the second end  172  of the tap tube  168  contacts the bone. The surgeon can then rotate the handle  118  until the inner cannula  116  reaches the desired depth. The cap  123  of the needle  22  can be rotated to release the needle from the inner cannula  116 . The needle is then withdrawn and a guidewire can be passed through funnel  17  and the inner cannula to the surgical site. The tap tube  168  can then be rotated to release it from the outer cannula  114  and for backing the inner cannula out of the bone while leaving the tap tube in position. Gripping surface  130  provides the surgeon with sufficient friction to allow the tap tube to be released from the inner cannula. While the gripping surface  178  is illustrated as a handle  130 , other grippable surfaces may be utilized without departing from the scope of the invention; such gripping surfaces may include, but should not be limited to, wrench flats, an enlarged diameter, polygons and the like. A dilation tube  166  ( FIG. 14 ) may be utilized in some embodiments over the outer diameter of the tap tube  168 . The dilation tube includes a first end  180 , a second end  182 , an inner diameter  184  and an outer diameter  186 . The first end  180  includes an attachment, illustrated herein as external threads  188  ( FIG. 15 ) for attachment to the outer cannula. This construction allows the dilation tube  166  to be released as desired by the surgeon to leave the dilation tube in place. It should also be noted that while threads are illustrated, other types of attachments may be utilized without departing from the scope of the invention; such attachments may include, but should not be limited to, adhesives, friction, thumbscrews, locking tapers, and the like. The inner bore of the dilation tube  166  is sized to cooperate with the tap tube  168  and may be sized for passage of an implant such as a pedicle screw or the like. The second end of the dilation tube is preferably tapered or radiused to allow traversal through tissue in vivo. The tap tube  168  and the dilation tube  166  are preferably constructed from a polymeric plastic material. However, it should be noted that metals, rubbers and suitable combinations thereof may be utilized without departing from the scope of the invention. 
         [0062]    All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. 
         [0063]    It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and any drawings/figures included herein. 
         [0064]    One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.