Abstract:
A selectively lockable introducer assembly is disclosed that comprises an introducer cannula and a needle guide. The introducer cannula is defined by a proximal end and a distal end and includes a lumen extending therebetween. The needle guide is defined by a body portion that includes at least one channel extending therethrough. The introducer cannula is configured to be selectively receivable within the at least one channel and the introducer cannula may be selectively lockable with respect to the needle guide such that the introducer cannula is selectively prevented from moving laterally with respect to the needle guide.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates generally to needle guides used for biopsy systems, and in particular to a needle guide configured for guiding an introducer device into a patient. 
       BACKGROUND 
       [0002]    During certain biopsy procedures, a needle guide may be used through which a portion of an introducer cannula passes. The needle guide serves to minimize non-axial movement or deflection of the introducer during a biopsy to ensure that the introducer is inserted into the correct location of a patient&#39;s tissue adjacent a target lesion. 
         [0003]    In breast biopsy procedures, for example, an MRI biopsy procedure, needle guides are often used in connection with a compression plate. The compression plate may include a plurality of grid-like openings. Prior to the start of the breast biopsy procedure, the compression plate is pressed against the breast, thereby compressing it, and a needle guide is inserted into one of the grid-like openings where the lesion to be biopsied may be found. The needle guide includes at least one channel extending therethrough. The channel is used through which a portion of an introducer passes. A biopsy needle is then inserted into the introducer. 
         [0004]    As the biopsy is being taken, the introducer may unintentionally move in the direction of the z-axis. That is, the introducer cannula may advance further into the breast than intended, or, alternatively, the introducer may partially pull out from the breast as well. One known device for securing the introducer in place is a retaining ring located around an outer diameter of the introducer. The ring includes an outer diameter that is greater than an inner diameter of the channel. Therefore, the introducer is unable to advance further into the breast. However, the ring is unable to restrain the introducer in the opposite direction, away from the breast, and therefore the introducer is still able to partially pull out from the breast. 
         [0005]    Accordingly, there exists a need for a device that will secure the introducer such that the introducer is unable to pull out from the breast as the biopsy is being taken. 
       SUMMARY 
       [0006]    A selectively lockable introducer assembly is disclosed that comprises an introducer cannula and a needle guide. The introducer cannula is defined by a proximal end and a distal end and includes a lumen extending therebetween. The needle guide is defined by a body portion that includes at least one channel extending therethrough. The introducer cannula is configured to be selectively receivable within the at least one channel and the introducer cannula may be selectively lockable with respect to the needle guide such that the introducer cannula is selectively prevented from moving laterally with respect to the needle guide. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an elevational perspective view of a compression plate, a needle guide, and an introducer with a stylet inserted therein; 
           [0008]      FIG. 2A  is an elevational perspective view of the needle guide and a portion of the introducer in a first uncompressed position; 
           [0009]      FIG. 2B  is an elevational perspective view of the needle guide and the introducer of  FIG. 2A  in a second compressed position; 
           [0010]      FIG. 2C  is a partially sectioned plan view of the needle guide and the portion of the compression plate; 
           [0011]      FIG. 3A  is an elevational perspective view of an alternative illustration of the needle guide including a flange; 
           [0012]      FIG. 3B  is a partially sectioned plan view of the needle guide in  FIG. 3A  and a portion of the compression plate; 
           [0013]      FIG. 4A  is an elevational perspective view of another alternative illustration of the needle guide including a pair of outwardly extending arms; 
           [0014]      FIG. 4B  is a partially sectioned plan view of the needle guide in  FIG. 4A  with a force being acted on the arms, and a portion of the compression plate; 
           [0015]      FIG. 5A  is an elevational perspective view of yet another alternative illustration of the needle guide including a moveable ring; and 
           [0016]      FIG. 5B  is a partially sectioned plan view of the needle guide in  FIG. 5A  and a portion of the compression plate. 
           [0017]      FIG. 6  is an elevational view of an embodiment of an introducer assembly. 
           [0018]      FIG. 7  is an end view of the introducer assembly of  FIG. 6 . 
           [0019]      FIG. 8  is a plan view of an embodiment of a needle guide. 
           [0020]      FIG. 9A  is an enlarged a side elevational view of a portion of the introducer assembly of  FIG. 6 , disposed in an engaged configuration within the needle guide of  FIG. 8 . 
           [0021]      FIG. 9B  is an enlarged and partial cross-sectional view of the introducer assembly of  FIG. 6 , in a disengaged configuration within the needle guide of  FIG. 8 . 
           [0022]      FIG. 10  is an elevational view of another embodiment of an introducer assembly. 
           [0023]      FIG. 11  is a plan view of an embodiment of a needle guide. 
           [0024]      FIG. 12  is an enlarged side elevational view of an encircled area  12  of the introducer assembly of  FIG. 10 , with the introducer assembly disposed in an engaged configuration within the needle guide of  FIG. 11 . 
           [0025]      FIG. 13  is an elevational view of another embodiment of an introducer assembly. 
           [0026]      FIG. 14  is plan view of an embodiment of a needle guide. 
           [0027]      FIG. 15  is an enlarged and partial cross-sectional view of the introducer assembly of  FIG. 13 , with the introducer assembly disposed in an engaged configuration within the needle guide of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present invention. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
         [0029]    According to various exemplary illustrations described herein, a needle guide is provided that includes a body portion. The body portion is configurable between an uncompressed position and a compressed position. The body portion further includes at least one channel extending therethrough. At least one slot extends outwardly from the channel. The slot permits at least a portion of the body portion to compress inwardly between the uncompressed position and the compressed position. The channel includes a first diameter and a second diameter, the first diameter defined by the uncompressed position and the second diameter defined by the uncompressed position. The first diameter is greater than the second diameter. 
         [0030]    Turning now to the drawings and in particular to  FIG. 1 , an exemplary compression plate  20  is shown, including a plurality of grid-like openings  22 . In the illustration of  FIG. 1 , the compression plate  20  is used with a needle guide  30 . Prior to the start of a biopsy procedure, the compression plate  20  is pressed against a body area of interest. In a breast biopsy procedure, for example, the compression plate is pressed against the breast, thereby compressing the breast. An introducer  32  with a stylet is inserted into one of the openings  40  of the needle guide  30  where the lesion to be biopsied may be found. The needle guide  30  includes a series of slots  64  that allow for the needle guide  30  to compress inwardly such that the introducer  32  is unable to move inwardly and outwardly from the opening  40  when locked, as discussed in greater detail below. 
         [0031]      FIG. 2A  is an illustration of the needle guide  30  and the introducer  32  in a first, uncompressed position. The needle guide  30  includes a body portion  44 , an outer periphery  46 , and a proximate face  60 . The needle guide also includes at least one channel  62  extending therethrough. Although  FIGS. 2A-2B  illustrate the needle guide  30  including nine channels  62 , it should be noted that any number of channels  62  may be used. 
         [0032]    The series of slots  64  are located along the proximate face  60  of the needle guide  30 . The slots  64  extend outwardly from each of the channels  62 , and towards either of the outer periphery  46  or an adjacent channel  62 , depending on the placement of the slots  64 . That is, if the slot  64  is located adjacent the outer periphery  46 , then the slot  64  extends from the channel  62  to the outer periphery  46 . If the slot  64  is adjacent to another channel  62 , then the slot  64  extends from one of the channels  62  towards another channel  62 . In the illustration as shown, the slots  64  are each located along a middle section M of each of the channels  62 , however the slots  64  may be located along any point of the channels  62 . 
         [0033]    As illustrated in  FIG. 2A , the slots  64  extend along a length L of the body portion  44 . The length L is parallel with an axis A-A of the needle guide  30 . The slots  64  permit at least a portion of the body portion  44  to compress inwardly between the uncompressed position and a compressed position, which is discussed in greater detail below. In the embodiment shown, each of the channels  62  include two generally opposing slots  64 , with one of the slots  64  located along an upper portion  54  of the channel  62  and the other slot  64  located along a bottom portion  56  of the channel  62 . Although  FIG. 2A  illustrates the channels  62  having two generally opposing slots  64  along the upper portion  54  and the bottom portion  56 , the slots  64  may also be located at other positions, such as, for example, along opposing sides  58  of the channel  62  as well. 
         [0034]    In the uncompressed position, the needle guide  30  is loosely engaged with the introducer  32 . More specifically, when the needle guide  30  is in the uncompressed position, an inner surface  66  of the channel  62  is unable to closely engage with an outer diameter OD of the introducer  32 . As seen in  FIG. 2A , the channel  62  includes a first unlocked diameter D 1 . The unlocked diameter D 1  is greater than the outer diameter OD of the introducer  32 . Thus, when in the uncompressed position, the introducer  32  is able to freely move in a direction D towards the needle guide  30  as well as in a direction R that is away from the needle guide  30 . 
         [0035]    However, as the needle guide  30  is inserted into one of the openings  22  of the compression plate  20 , a compressive force F is exerted along the outer periphery  46  of the needle guide  30 . That is, when the compressive force F is exerted along the outer periphery  46 , the needle guide  30  is urged inwardly from the first uncompressed position ( FIG. 2A ) into the second compressed position ( FIG. 2B ). Because the needle guide  30  can be selectively compressed inwardly by the compressive force F when in the uncompressed position, the needle guide  30  is unlocked. 
         [0036]      FIG. 2B  illustrates the needle guide  30  in the compressed position, after the compressive force F has been applied. For clarity, the compression plate  20  has been omitted. The body portion  44  of the needle guide  30  is urged inwardly by the compressive force F when placed inside the opening  22  of the compression plate  20  (not shown in  FIG. 2B ). In the compressed position, the slots  64  are urged together. In one embodiment, the slots  64  are urged together such that the slots  64  close and the needle guide  30  is unable to compress further inwardly. The needle guide  30  is also unable to expand outwardly because the outer periphery  46  is restrained by the opening  22  of the compression plate  20 . Thus, the needle guide  30  is effectively locked in the compressed position. 
         [0037]    When the needle guide  30  is in the compressed position, as in  FIG. 2B , the channel  62  is defined by a second diameter D 2 . The second diameter D 2  is less than the first diameter D 1 . Moreover, the second diameter D 2  is about equal to or slightly less then the outer diameter OD of the introducer  32 . Therefore, when in the compressed position, the outer diameter OD of the introducer  32  is closely engaged with the inner surface  66  of the channel  62 . Thus, when in the compressed position, the introducer  32  is unable to move inwardly in the direction D and outwardly in the direction R from the channel  62 . 
         [0038]    In the illustrations as shown in  FIGS. 2A-2B , the body portion  44  includes an optional support member  68 . The support member  68  is connected to the body portion  44  at a proximate end  70  of the body portion  44 . The support member  68  includes the proximate face  60 . In one illustration as seen in  FIG. 2C , the support member  68  includes a width W′ that is greater than a width W of the opening  22  of the compression plate  20 . Thus, when inserted into the compression plate  20 , the needle guide  30  is seated such that a back surface  80  of the support member  68  is flush with the opening  22 . The back surface  80  of the support member  68  retains the needle guide  30  within the opening  22  of the compression plate  20  such that the needle guide  30  is unable to advance further into the opening  22 , and in the direction D. Including the support member  68  may also provide a grip that the user can easily hold on to when a user removes the needle guide  30  from the opening  22 . 
         [0039]    When the introducer  32  is slid into the channel  62  the needle guide  30  is in the uncompressed position. Then, once the introducer  32  is positioned to the desired depth, the needle guide  30  is placed within one of the openings  22  of the compression plate  20 . As seen in  FIGS. 2A-2B , the introducer  32  may also include a series of graduated markings  90  that indicate the depth of the introducer  32  within a breast. 
         [0040]    When placed within the opening  22 , the needle guide  30  compresses from the uncompressed position ( FIG. 2A ) to the compressed position ( FIG. 2B ). This is because the compressive force F urges the needle guide  30  to move inwardly from the uncompressed position to the compressed position. As discussed in greater detail below, the needle guide  30  may also include a snapping movement between the compressed and uncompressed configuration, therefore providing a tactile feedback to a user. The tactile feedback allows the user to know when the needle guide  30  is in the locked versus the unlocked position. 
         [0041]    In one example of the needle guide  30 , the slot  64  snaps between the uncompressed position and the compressed position. More specifically, the slot  64  only has two positions, a first open position as seen in  FIG. 2A , and a second closed position as seen in  FIG. 2B . Thus, when the needle guide  30  is pushed into the opening  22  of the compression plate  20 , the slots  64  will snap shut with an abrupt movement. A sharp sound may also be used to indicate to a user that the needle guide  30  is in the locked position within the compression plate  20 . 
         [0042]      FIGS. 3A-3B  are alternative embodiments of a needle guide  130  where the proximate face  160  includes a flange  172  located along at least a portion of the outer periphery  146 . The flange  172  extends outwardly from the proximate face  160 , in the direction R. The flange  172  provides a grip such that when the needle guide  130  is placed within the opening  22  of the compression plate  20 , a user will have a surface along the needle guide  130  that is easy to grasp. 
         [0043]    As best seen in  FIG. 3B , the flange  172  protrudes from the opening  22  of the compression plate  20 . A back surface  174  of the flange  172  is in contact with the compression plate  20 , and the outer periphery  176  of the flange  172  is slightly larger than the opening  22 . Therefore, when inserted within the opening  22 , the needle guide  30  is unable to travel past the back surface  174 , and the needle guide  30  is unable to advance further into the opening  22  in the direction D. The flange  172  provides a handle that a user may hold on to when the needle guide  130  is removed from the opening  22  of the compression plate  20 . 
         [0044]    In yet another alterative illustration of a needle guide  230 , as seen in  FIGS. 4A-4B , a pair of outwardly extending arms  270  are included that extend from opposing sides of the outer periphery  246 . A pivot member P is mounted to a portion of each arm  270 . When the arms  270  are pushed by an inwards force F′ towards the needle guide  230  and in the direction D, the pivot member P contacts a portion of the compression plate  20  and needle guide  230  is urged into the uncompressed configuration and unlocks. That is, as seen in  FIG. 4B , when the inward force F′ is exerted upon the arms  270 , the pivot member P cooperates with arms  270  such that needle guide  230  is pushed outwardly and away from the opening  22  of the compression plate  20  and in the direction R. Thus, the arms  270  and pivot member P facilitate removal of the needle guide  230  from the opening  22  of the compression plate  20  by a user. 
         [0045]    Yet another alternative illustration of a needle guide  330  is shown in  FIG. 5A . The needle guide  330  includes a moveable ring  370  that encircles the outer periphery  346 . The ring  370  is moveable along a length L′ that is measured from the back surface  380  of the support member  368  towards a distal end  358  of the body portion  344  of the needle guide  330 . In the illustration as shown, the ring  370  is placed behind the support member  368 . The support member  368  retains the ring  370  along the outer periphery  346  of the needle guide  330 . The ring  370  urges the needle guide  330  into the compressed configuration. More specifically, when the moveable ring  370  is advanced to the proximate face  360  of the needle guide  330 , the slots  364  are urged together, thereby compressing the needle guide  330  into the compressed and locked configuration. 
         [0046]      FIG. 5B  illustrates a needle guide  330  inserted into an opening  22  of the compression plate  20 . The needle guide  330  is tapered inwardly, and includes a distal end outer periphery DP and a proximate end outer periphery PP. The distal end outer periphery DP is less than the proximate end outer periphery PP. The moveable ring  370  includes an inner diameter  392  that is smaller than the proximate end outer periphery PP but greater than the distal end outer periphery DP. 
         [0047]    The needle guide  330  is urged inwardly and into the compressed position when the ring  370  is advanced towards the proximate face  360  of the needle guide  330  in the direction R. That is, the inner diameter  392  of the ring  370  compresses the needle guide  330  inwardly, and urges the slots  364  together. When the ring  370  is retracted away from the proximate face  360 , and pushed in the direction D, the needle guide  330  will unlock into the uncompressed position. 
         [0048]      FIGS. 6-9  illustrate an arrangement of a selectively lockable introducer assembly  400  that cooperates with a needle guide  402  to maintain a desired position for introducer assembly  400 . Introducer assembly  400 , best seen in  FIGS. 6 and 7 , includes a generally hollow introducer cannula  404  defined by a proximal end  406  and a distal end  408 . An introducer hub  410  may be secured to proximal end  406  of introducer cannula  404 . Introducer hub  410  includes an opening therethrough that is in communication with an inner lumen  411  extending through introducer cannula  404  and may also include a haemostatic valve (not shown). 
         [0049]    Positioned on an outer portion of introducer cannula  404  is a plurality of retaining members  412 . Retaining members  412  extend upwardly from an outer surface of introducer cannula  404 . In one arrangement, retaining members  412  are positioned along a substantial portion of the length of introducer cannula  404 . In another arrangement, retaining members  412  are also positioned so as to be spaced at equi-distance intervals. In another arrangement, two sets of retaining members  412  are positioned on introducer cannula  404 , with the sets being positioned 180° apart from one another, as seen in  FIG. 7 . Retaining members  412  will be explained in further detail below. 
         [0050]    Referring now to  FIG. 8 , needle guide  402  will be described. Needle guide  402  includes a body portion defined by an outer periphery  414  and at least one channel  416  extending therethrough. Although  FIG. 8  illustrates the needle guide  402  including nine channels  416 , it should be noted that any number of channels  416  may be used. 
         [0051]    Disposed within each channel  416  is at least one retaining tang  418  positioned on an internal surface  420  of each channel  416 . Retaining tangs  418  are positioned so as to extend inwardly into each channel  416 , and away from inside surface  420  of each channel  416 . In one arrangement, a plurality of retaining tangs  418  extend along the length of inside surface  420  of each channel  416 . In another arrangement, there are at least a pair of retaining tangs  418 , with each retaining tang  418  being positioned 180° apart from one another, as shown in  FIG. 8 . In one arrangement, retaining tangs  418  are formed so as to have a complimentary shape to retaining members  412 , to be explained below. 
         [0052]    Turning now of  FIGS. 9A-9B , the interaction between introducer cannula  404  and needle guide  402  will now be explained. Once a site of interest for performing a biopsy or treatment has been determined, and needle guide  402  has been appropriately positioned with a compression plate  20  (see  FIG. 1 ), introducer cannula  404  is inserted into a desired channel  416 . In one exemplary arrangement, to permit introducer cannula  404  to enter needle guide  402 , introducer cannula  404  is appropriately rotated such that retaining members  412  are positioned approximately 90° from retaining tangs  418 . In this configuration, introducer cannula  404  may freely slide within channel  416  to a desired depth. To assist with ascertaining the appropriate depth, the outer surface of introducer cannula  404  may be provided with markings or other indicia to indicate depth. 
         [0053]    After a desired depth for insertion of introducer cannula  404  has been reached, introducer cannula  404  may be selectively locked into position by rotating introducer cannula  404  within channel  416  by approximately 90.° Once rotated, retaining members  412  engage with retaining tangs  418  in a complementary manner. More specifically, retaining members  412  are rotated so as to place a retaining tang  418  between adjacent retaining members  412 . Once so engaged, introducer cannula  404  is locked into position with needle guide  402  in the x, y, and z axes. Such locking action prevents accidental dislodgement of introducer cannula  404  during a surgical or therapeutic procedure, including accidental sliding of introducer cannula  404  along the z axis. Thus, a stable pathway to a site of interest is maintained. Once a procedure is complete, introducer cannula  404  may be disengaged from needle guide  402  by simply rotating introducer cannula  404  sufficiently such that retaining members  412  become disengaged with retaining tangs  418  and introducer cannula  404  may be slid out of needle guide  402 . 
         [0054]    Referring to  FIGS. 10-12 , another arrangement of a selectively lockable introducer assembly  500  is shown. Similar to the arrangement shown in  FIGS. 6-9 , introducer assembly  500  cooperates with a needle guide  502  to maintain a desired position for introducer assembly  500 . Introducer assembly  500 , best seen in  FIG. 10 , includes a generally hollow introducer cannula  504  defined by a proximal end  506  and a distal end  508 . An introducer hub  510  may be secured to the proximal end  506  of introducer cannula  504 . Introducer hub  510  includes an opening therethrough that is in communication with an inner lumen extending through introducer cannula  504 . Introducer hub  510  may also include a haemostatic valve (not shown) to minimize blood flow. 
         [0055]    Positioned on an outer portion of introducer cannula  504  is at least one central groove  512 . In one arrangement, a central groove  512  extends along a substantial portion of the length of introducer cannula  504 . Extending away from central groove  512  is a plurality of spaced apart engagement grooves  514  that extend radially along the outer surface of introducer cannula  504 . In one arrangement, engagement grooves  514  are spaced apart at equi-distance intervals and are arranged in pairs disposed on either side of central groove  512 , as shown in  FIG. 10 . In another arrangement, a second central groove may be formed on the outside surface of introducer cannula  504 , approximately 180° from the first central groove  512 . Like the first central groove  512 , the second central groove also includes a plurality of engagement grooves. Engagement grooves  514  will be explained in further detail below. 
         [0056]    Referring now to  FIG. 11 , needle guide  502  will be described. Needle guide  502  includes a body portion defined by an outer periphery  516  and at least one channel  518  extending therethrough. Although  FIG. 11  illustrates the needle guide  502  as having nine channels  518 , it should be noted that any number of channels  518  may be used. 
         [0057]    Disposed within each channel  518  is at least one retaining tang  520  positioned on an internal surface  522  of each channel  518 . Retaining tangs  520  are positioned so as to extend inwardly into each channel  518 , and away from inside surface  522  of each channel  518 . In one arrangement, a plurality of retaining tangs  520  may be provided that extend along the length of inside surface  522  of each channel  518 . In another arrangement, there are at least a pair of retaining tangs  520 , with each retaining tang being positioned 180° apart from one another, as shown in  FIG. 11 . 
         [0058]    Turning now to  FIG. 12 , the interaction between introducer cannula  504  and needle guide  502  will now be explained. Once a site of interest for performing a biopsy or treatment has been determined, and needle guide  502  has been appropriately positioned within compression plate  20 , introducer cannula  504  is inserted into a desired channel  518 . To permit introducer cannula  504  to enter needle guide  502 , introducer cannula  504  is rotated such that central groove  512  is aligned with retaining tang  520 . Retaining tang  520  is appropriately sized to enter central groove  512  such that introducer cannula  504  may freely slide within channel  518  to a desired depth. To assist with ascertaining the appropriate depth, the outer surface of introducer cannula  504  may be provided with markings or indicia to indicate the depth. After a desired depth of introducer cannula  504  has been reached, introducer cannula  504  may be locked into position by slightly rotating introducer cannula  504 . The rotation of introducer cannula  504  causes an engagement groove  514  to slide over retaining tang  520  (shown in phantom in  FIG. 12 ). Once retaining tang  520  has been captured in engagement groove  514 , introducer cannula  504  is locked into position within needle guide  502  such that introducer cannula is effectively prohibited from being displaced during a surgical or other therapeutic procedure. 
         [0059]    Once a procedure is complete, introducer cannula  504  may be easily disengaged from needle guide  502 . For example, introducer cannula  504  is rotated in such a manner so as to place retaining tang  520  in central groove  512 . Once in central groove  512 , introducer cannula  504  may be slid out of needle guide  502 . 
         [0060]    Referring to  FIGS. 13-15 , another arrangement of a selectively lockable introducer assembly  600  is shown. Introducer assembly  600  cooperates with a needle guide  602  to maintain a desired position, in the x, y, and z axes, for introducer assembly  600 . Introducer assembly  600 , best seen in  FIG. 13 , includes a generally hollow introducer cannula  604  defined by a proximal end  606  and a distal end  608 . An introducer hub  610  may be secured to proximal end  606  of introducer cannula  604 . Introducer hub  610  includes an opening therethrough that is in communication with an inner lumen extending through introducer cannula  604 , and may also include a haemostatic valve (not shown) to control blood flow from the body. 
         [0061]    Outer surface of introducer cannula  604  is threaded  612  along at least a portion of its length. In one arrangement, outer surface of introducer cannula  604  is threaded along a substantial portion of introducer cannula  604 . In one arrangement, spaced along threads  612  at predetermined intervals are depth indicators  614 , such as indicia or markings. Use of depth indicators  614  will be explained in further detail below. 
         [0062]    Referring now to  FIG. 14 , needle guide  602  will be described. Needle guide  602  includes a body portion defined by an outer periphery  616  and at least one channel  618  extending therethrough. Although  FIG. 14  illustrates the needle guide  602  including nine channels  618 , it should be noted that any number of channels  618  may be used. Each channel  618  is threaded  620  (see  FIG. 15 ) so as to cooperate with threads  612  of introducer cannula  604  (to be explained below). 
         [0063]    Referring now of  FIG. 15 , the interaction between introducer cannula  604  and needle guide  602  will now be explained. Once a site of interest for performing a biopsy or treatment has been determined, and needle guide  602  has been appropriately positioned within compression plate  20 , introducer cannula  604  is directed into a desired channel  618 . Introducer cannula  604  is then rotated in a first direction into the desired channel  618 , such that threads  612  of introducer cannula  604  engage with threads  620  of channel  618 . After a desired depth of introducer cannula  604  has been reached, which may be visually indicated by depth indicators  614 , rotation of introducer cannula  604  is stopped. However, due to the interaction of threads  612  and  620 , introducer cannula  604  is effectively prevented from being displaced during a surgical or other therapeutic procedure. 
         [0064]    Once a procedure is complete, introducer cannula  604  may be easily disengaged from needle guide  602  simply by rotating introducer cannula  604  in a second direction so as to disengage threads  612  and  620  from one another until introducer cannula  604  is free of needle guide  502 . 
         [0065]    While the present disclosure has been particularly shown and described with reference to the foregoing preferred embodiments, it should be understood by those skilled in the art that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure embodiments within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing embodiment is illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.