Patent Publication Number: US-2010114031-A1

Title: Introducer localization assemblies

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. Nos. 61/111,604 filed Nov. 5, 2008, and 61/122,172 filed Dec. 12, 2008, which applications are hereby incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to introducer stylets and cannulas used for biopsy systems. 
     BACKGROUND 
     Medical procedures have advanced to stages where less invasive or minimally invasive surgeries, diagnostic procedures and exploratory procedures have become desired and demanded by patients, physicians, and various medical industry administrators. To meet these demands, improved medical devices and instrumentation have been developed, such as cannulae or micro-cannulae, medical introducers, vacuum assisted biopsy apparatus, and other endoscopic related devices. 
     During certain biopsy procedures, an introducer stylet may be used to create a pathway to access the biopsy site. The introducer stylet is inserted into body tissue with a cannula mounted thereon. After the pathway is created, the introducer stylet is removed, but the cannula is left within the tissue pathway providing access to the biopsy area and further minimizing movement of the biopsy device adjacent a target lesion. To further locate the introducer stylet near an excision site, different systems have been used, such as open surgical procedures, mammography or magnetic resonance imaging (MRI). Ultrasonography may also be used to further assess target areas found and further used as a guidance method to better guide the introducer stylet adjacent suspect tissue. 
     In recent years, ultrasound-guided biopsy of breast lesions has been used for diagnostic purposes, partially replacing open surgical intervention. Ultrasound guidance is also often used for needle localization of some lesions prior to biopsy, as well as for cyst aspiration. Ultrasound guidance for such interventions, however, is difficult to learn and perform. One needs good hand-eye coordination and three-dimensional visualization skills to guide the biopsy needle to the target tissue area with the aid of ultrasound imagery. Devices have been developed that try to create a higher reflective property for viewing with the ultrasonic wave. However, these devices do not allow the operator to pinpoint exactly where the device sampling aperture is in relation to the lesion site nor do they afford the operator the ability to place the introducer stylet with the biopsy aperture up prior to inserting the biopsy device providing exact location to the tissue to be sampled. 
     Therefore, what is needed is an introducer stylet having an imagable feature capable of replicating the biopsy tool&#39;s aperture image signature, thus effectively identifying the location of the excision site while maintaining the ability to remove the introducer stylet. There is also a separate need for an introducer stylet having an orientation indicator with a selectively lockable and removable cannula introducer capable of receiving and orienting a biopsy device after removal of the introducer stylet. Finally, there is also a need for a selectively lockable cannula that may be selectively used with different types of medical devices. 
     SUMMARY 
     In one exemplary arrangement, an introducer stylet is disclosed. The introducer stylet comprises an introducer stylet body defined by a proximal end and a distal end. The distal end further includes an imagable feature. The imagable feature may be configured with a predetermined size that generally corresponds to a portion of a medical device. 
     Also disclosed are various embodiments of introducer cannulas for use with various introducer stylets, including, but not limited to, the imagable introducer stylet also disclosed herein. The introducer cannulas disclosed also include various configurations of introducer hubs for attaching to various medical devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an introducer stylet; 
         FIG. 2  is a perspective view of the introducer stylet inserted into an introducer cannula and engaged in a locked position; 
         FIG. 3  is a perspective view of the introducer stylet and introducer cannula of  FIG. 2  with the introducer stylet in an unlocked position; 
         FIG. 4A  is a perspective view of the introducer cannula having a connecting hub. 
         FIG. 4B  is a perspective view of the introducer cannula of  FIG. 4A  with syringe attached thereto; 
         FIG. 5A  is a perspective view of an imagable feature on the introducer stylet representing the aperture of a biopsy device; 
         FIG. 5B  is a perspective view of a turned diameter imagable feature on the introducer stylet representing the aperture of a biopsy device; 
         FIG. 5C  is a perspective view of a machined faces imagable feature on the introducer stylet representing the aperture of a biopsy device; and 
         FIG. 6A  is a side view of a spring loaded introducer stylet in a pre-fire position; 
         FIG. 6B  is a side view of the spring loaded introducer stylet of  FIG. 6A  in a fired positioned. 
         FIG. 7A  is a side perspective view of an alternative embodiment of a spring loaded introducer stylet in a pre-fire position. 
         FIG. 7B  is a side perspective view of the spring loaded introducer stylet assembly of  FIG. 7A  in a fired position. 
         FIG. 8A  is a partial cross-sectional and perspective view of the spring loaded introducer stylet assembly of  FIG. 7A  in the pre-fire position. 
         FIG. 8B  is a partial cross-sectional and perspective view of the spring loaded introducer stylet assembly of  FIG. 7A  in the fired position. 
         FIG. 9A  is an enlarged cross-sectional view of the spring loaded introducer stylet assembly of  FIG. 8A  in the pre-fire position. 
         FIG. 9B  is an enlarged cross-sectional view of the spring loaded introducer stylet assembly of  FIG. 8B  in the fired position. 
         FIG. 10A  is a perspective view of an introducer assembly with a multiple fitting introducer hub attached to a luer lock syringe. 
         FIG. 10B  is a perspective view of the introducer assembly of  FIG. 10A  attached to a luer taper syringe. 
         FIG. 11A  is a side view of the introducer assembly of  FIG. 10A  attached to a luer lock syringe. 
         FIG. 11B  is a side view of the introducer assembly of  FIG. 10B  attached to a luer taper syringe. 
         FIG. 12A  is a side cross-sectional view of the introducer assembly of  FIG. 10A  attached to a luer lock syringe. 
         FIG. 12B  is a side cross-sectional view of the introducer assembly of  FIG. 10B  attached to a luer taper syringe. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, illustrative and exemplary embodiments of the present disclosure are shown in detail. Although the drawings represent some embodiments of the present disclosure, the drawings are not necessarily to scale and certain characteristics may be exaggerated to better illustrate and explain the present disclosure. Further, the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the disclosure to the precise forms and configurations disclosed in the following detailed description. 
     Turning now to the drawings, and in particular to  FIG. 1 , an exemplary introducer stylet body  22  of an introducer assembly is shown. In the arrangement of  FIG. 1 , introducer stylet body  22  is configured so as to be generally cylindrical and is defined by a proximal end  24  and a distal end  32 . Introducer stylet body  22  may be configured to be generally solid. Distal end  32  includes a tissue piercing tip  34 , such as, for example, a trocar tip, sized for introduction into a patient&#39;s body. In addition to a trocar tip, it will be appreciated that the piercing tip  34  may include other devices for piercing the patient&#39;s tissue, including without limitation, devices that use a laser or radio frequencies (RF) to pierce the tissue. 
     In the embodiment illustrated, introducer stylet body  22  extends from a handle  26  positioned opposite distal end  32 . The handle  26  may include a latching tab interference portion  30 , to be explained below in further detail. In one exemplary arrangement, handle  26  is fixed with respect to introducer stylet body  22  such that rotation of handle  26  causes introducer stylet body  22  to rotate as well. 
     In one exemplary arrangement, introducer stylet body  22  is provided with an imagable feature  36 , disposed adjacent to distal end  32 . In certain arrangements, imagable feature  36  (to be discussed in further detail below) may be, but is not required to be, configured so as to represent the size, as well as an orientation of an aperture of a biopsy device. In embodiments where an imagable feature  36  is provided that is configured to represent an orientation of an aperture of a biopsy device, an imagable feature orientation indicator  28  may be provided. In one specific, but exemplary arrangement, the imagable feature orientation indicator  28  may be configured as an ergonomic thumb pad. Imagable feature orientation indicator  28  provides a visual position of the imagable feature  36  (to be discussed in further detail below) on the introducer stylet body  22 , relative to the handle  26  position. Alternatively, the imagable feature orientation indicator  28  may be configured by printing a mark on the handle (not shown) that allows the operator to orient the imagable feature  36  to a target tissue area prior to removal of the introducer stylet body  22  and insertion of a core biopsy device within an introducer cannula  42 , to be explained in further detail below. An exemplary core biopsy apparatus may be seen by way of example in U.S. Pat. Nos. 6,638,235 and 6,744,824, which are commonly owned by the assignee of the present disclosure and are incorporated herein by reference in their entirety. 
     Turning now to  FIGS. 2-3 , an exemplary introducer assembly  20 , which includes the introducer stylet body  22  received within and latched to an introducer cannula  42 , is shown. In the illustration of  FIGS. 2-3 , introducer cannula  42  is configured so as to be generally cylindrical and is defined by a distal end  40  and a proximal end  44 . Proximal end  44  further includes a latching hub  46 . A lumen shaft extends between distal end  40  and proximal end  44 . 
     As will be described in detail, introducer assembly  20  is particularly, but not necessarily, suited for use in biopsy procedures that identify a target biopsy site using various imaging modalities such as ultrasonography or magnetic resonance imaging (MRI). Indeed, in one exemplary arrangement, the imagable feature  36  is an echogenic feature, particularly suitable with ultrasonography. In another alternative arrangement, the imagable feature  36  is a radio-opaque feature particularly suitable with mammography. The assembly  20  may also be made of a MRI compatible, medical grade material, such as 316 stainless steel or Inconel™ 625. In one specific embodiment, the introducer stylet body  22  and the introducer cannula  42  are made of stainless steel. 
     In one exemplary configuration, latching hub  46  includes a generally annular hub portion  47  and a latch portion  48 . The annular hub portion  47  includes a hub outer surface  82 , a hub mating surface  84 , (best seen in  FIG. 3 ) a hub proximal end  86 , and a hub distal end  88 . The latch portion  48  includes a release button  85  and a latch  87  having a latch tab  89  (as seen best in  FIG. 3 ). In one configuration, the latch  87  may extend generally parallel to the lumen shaft of the introducer cannula  42 . In one embodiment, the latch tab  89  extends perpendicular to and toward the center line of the lumen shaft of the introducer cannula  42 . The latch tab  89  cooperates with the latching tab interference portion  30  to secure the introducer cannula  42  to introducer stylet  22  and to prevent the introducer cannula  42  from rotating or laterally moving with respect to the introducer stylet  22  during use. 
     The latching hub  46  of the introducer cannula  42  defines an entrance opening  49  for receiving the introducer stylet  22  (and other medical devices). 
     In one configuration, the distal end  40  of the introducer cannula  42  may include a sharpened tapered edge  41  defining an exit opening  43 . In one embodiment, (best seen in  FIG. 2 ) sharpened tapered edge  41  starts at an inner diameter of the lumen and extends outwardly radially to an outer diameter surface to create the tapered edge  41 . Tapered edge  41  provides for a smooth entry into the tissue area. The lumen shaft extends longitudinally starting at the proximal end  44  and terminating at the distal end  40  tapered edge  41 . To maintain visibility of the imagable feature  36  when the introducer stylet  22  is received within the introducer cannula  42 , the length of the introducer cannula  42 , from the hub  46  to the tapered edge  41 , does not exceed the length of introducer stylet shaft  21  from the handle  26  to a proximal edge  36   a  of the imagable feature  36 . 
     In one embodiment, entry into the tissue area begins when the introducer cannula  42  is attached to the introducer stylet  22  with the latch hub  46 . Because the introducer stylet  22  is positively latched to the latch hub  46  of the introducer cannula  42 , the assembled assembly  20  provides for a predetermined length that permits more accurate location identification of treatment area. More specifically, as the imagable feature  36  is visible under one or more imaging modalities, once inserted, the operator will be able to visual verify the location of the imagable feature  36  prior to inserting a medical device into a patient. 
     After the introducer cannula  42  is positively attached to the introducer stylet  22 , the operator grasps the handle  26  and presses the piercing tip  34  into the tissue. The piercing tip  34  enters the tissue and the operator applies further pressure sliding the assembly  20  into the tissue. The introducer cannula  42  enters skin and the operator applies further pressure while watching an imaging device as the assembly  20  creates an entry path to the targeted tissue area. The operator will complete the entry by applying continuous pressure to the assembly  20  until the imagable feature  36  reaches the target tissue. As stated above, in one specific configuration, the imagable feature  36  is sized to generally represent the size of an aperture of a biopsy device. Accordingly, the imagable feature  36  will provide visual confirmation of the location from which biopsy samples will be taken, i.e., the depth into which a distal end of a medical device will extend through the introducer cannula  42 . 
     Once the operator verifies that the imagable feature  36  has reached the target area, the operator may release the introducer stylet  22  from the introducer cannula  42 . Separation of the assembly  20  is accomplished when the operator holds the latching hub  46  and presses the release button  85 , causing disengagement of the latch tab  89  from the latch tab interference portion  30 . The operator then grasps the handle  26  and slides introducer stylet  22  out of the introducer cannula  42  and ultimately out of the tissue leaving the introducer cannula  42  within the patient&#39;s body. Thus, the introducer cannula  42  creates a direct pathway for the introduction of other medical devices, such as a biopsy device, for example. Upon completion of the medical procedure the operator will then slide the introducer cannula  42  and the medical device out of the body. 
     In some embodiments, the imagable feature  36  may be configured to also represent an orientation of an aperture of a medical device, such as a biopsy device. For example, as seen in  FIGS. 1 and 2 , the imagable feature  36  is configured with a generally planar surface, flanked by a proximal end  36   a  and a distal end  36   b . In one particular embodiment, proximal end  36   a  and distal end  36   b  are disposed at an angle that tapers inwardly towards the generally planar surface from an outer surface  37  of the introducer stylet body  21 . The generally planar surface is reflective, which will serve as an orientation indicator. More specifically, as the introducer stylet  22  is positioned in the targeted tissue, paying particular attention to the orientation indicator  28  as related to the imagable feature  36 . Once the distal end  32  of the introducer stylet  22  reaches the targeted tissue, the operator will rotate the handle  26  to orient the imagable feature  36  in the direction of the sample to be taken. The orientation handle  28  will reflect the orientation of the imagable feature  36 . Thus, once the orientation is set, and the introducer stylet  22  is removed, the orientation of the medical device will be set when the medical device is inserted into the introducer cannula  42  and locked thereto. 
       FIG. 3  is an illustration of the introducer assembly  20  with the latch hub  47  unlocked from the latch tab interference portion  30  of the introducer stylet  22 . The illustration of  FIG. 3  further demonstrates the interaction between the introducer cannula  42  and the introducer stylet  22 . More specifically  FIG. 3  demonstrates, as detailed above, the effect of releasing the latching hub  46  by pushing down on the release button  85 , thereby releasing the latch  87  and the latch tab  89  so as to allow the introducer stylet  22  to be removed from the introducer cannula  42 . Once released, the introducer cannula  42  may be left within the tissue with the proper orientation set for the addition of a core biopsy device, a syringe or other required device, as previously explained above. 
       FIGS. 4A and 4B  illustrate an alternative embodiment of the introducer cannula  42 . In the illustration of  FIG. 4A , introducer cannula  42  includes a hub  50  for sealingly connecting to a medical device. One such exemplary medical device is a syringe  54 . In one embodiment, hub  50  may be configured with a luer type fitting that engages with a complimentary luer-type fitting positioned on a distal end  52  of syringe  54 . 
       FIG. 5A  illustrates further detail of the imagable feature  36 , which is defined by the proximal end  36   a  and a distal end  36   b . In one embodiment, the imagable feature  36  is a ground notch formed in a portion of the cylindrical introducer stylet  22 . The imagable feature  36  is sized so as to represent an aperture size and shape of the biopsy device as referenced above in  FIG. 1 . The imagable feature  36 , at a predetermined orientation and under a suitable imaging modality, creates a reflective surface as a result of the change in surface area or an applied surface treatment. This change creates a larger image reflection signature when using a suitable imaging device to guide the introducer stylet  22  into the target tissue area. Once the introducer stylet  22  is introduced into the target tissue area, the operator rotates the handle  26 , setting the radial orientation of the ground notch of the imagable feature  36  on the introducer stylet  22  to the desired biopsy area. The radial orientation of the imagable feature  36  represents the aperture of the biopsy device relative to the target tissue once the biopsy device is disposed within the introducer cannula  42 . 
       FIGS. 5B and 5C  illustrate different embodiments of the imagable feature  36 . As seen in  FIG. 5B , an introducer stylet  122  having a turned diameter  136  is shown. The turned diameter  136  creates a signature visible from all orientations during imaging, though no aperture orientation will be visible in this particular embodiment.  FIG. 5C  includes an introducer stylet  222  having machined (and generally planar) surfaces  236 , again creating a highly reflective signature visible from a specific orientation such that an aperture orientation would be visible. 
     The imagable features  36 ,  136  and  236  are all created using material removal techniques, including but not limited to, rough surface grinding with a carbon nitride grinding wheel, milling or turning the diameter on a lathe or other suitable material removal device. The imagable feature  36  may also be created through surface treatments such as but not limited to, grit blast, bead blast, laser abrasion, dimpling, or by applying an imagable coating or any other suitable method creating a surface capable of displaying a larger imagable reflective signature when using a suitable imaging device. 
       FIGS. 6A and 6B  illustrate an exemplary spring loaded introducer stylet body  522 . The introducer stylet body  522  is suited for use in an X-ray arrangement, as will be explained in further detail below. In the illustration of  FIGS. 6A and 6B , introducer stylet body  522  is configured as generally cylindrical and defined by a distal end  532  and a proximal end  524 . Distal end  532  includes a tissue piercing tip  534  sized for introduction into a patient&#39;s body. In one embodiment, piercing tip  534  is configured as a trocar tip. However, it will be appreciated that the piercing tip  534  may include other devices for piercing the patient&#39;s tissue, including without limitation, devices that use a laser or radio frequencies (RF) to pierce the tissue. 
     In the embodiment illustrated, introducer stylet body  522  extends from a handle  526 . The introducer stylet body  522  may include an introducer stylet shaft  521  moveably received within the handle  526  and a firing mechanism  552  fixedly attached to a portion of the introducer stylet shaft  521 . The handle  526  may include a latching tab interference portion  530  that operatively connects to the firing mechanism  552 . The handle  526  may also include an imagable feature orientation indicator  528  so as to provide a visual orientation position of an imagable feature  536  on the distal end  532  of introducer stylet body  522  relative to the handle  526  (for those embodiments that include a generally planar reflective surface). In one exemplary arrangement, the imagable feature orientation indicator  528  may be configured as an ergonomic thumb pad. Alternatively, the imagable feature orientation indicator  528  may also be attained by printing a mark on the handle (not shown) that allows the operator to orient the imagable feature  536  to a target tissue area prior to the removal of the introducer stylet body  522  and the insertion of a core biopsy device within an introducer cannula  42  such as shown in  FIGS. 2 and 3 . 
     The firing mechanism  552  includes a generally annular hub portion  547  that carries latch portion  548 . The annular hub portion  547  includes a hub outer surface  582 , a hub mating surface  584 , a hub proximal end  586 , and a hub distal end  588 . A first spring locator (shown in phantom as  590 ) is mounted on a proximal end  524  of the introducer stylet body  521 . A second spring locator (also shown in phantom as  590 ) is mounted to an inside surface of the handle  526 . A spring  550  is secured to the spring locators  590 . A retaining collar  591  is fixedly secured to the introducer stylet body  521  and disposed with the handle  526  to prevent the proximal end  524  of the introducer stylet body  521  from disengaging from the handle  526 . The latch portion  548  includes a release button  585  and a latch  587  having a latch tab  589  (as seen best in  FIG. 3 ). The latch tab  589  may extend generally perpendicular to the introducer stylet shaft  521  of the introducer stylet body  522 . In one embodiment, the latch  587  extends parallel to and toward the center line of the introducer stylet shaft  521  of the introducer stylet body  522 . The annular hub portion  547  is mounted to the introducer stylet shaft  521  and travels outwardly from the handle  526  with the introducer stylet shaft  521  upon release of a spring  550 . 
     The firing mechanism  552  prevents the introducer stylet body  522  from extending into a tissue area prematurely during a procedure. During a procedure, the introducer stylet  522  is mounted within a sterotactic cradle (not shown) having an upwardly extending wall portion (not shown), against which a proximal end of handle  526  is mounted. Once mounted, the introducer stylet  522  enters into the tissue area when the spring  550  is released from a pre-fire, compressed position ( FIG. 6A ) to an extended, fired position ( FIG. 6B ) and the introducer stylet shaft  521  is thrust into the tissue. The wall portion of the cradle will prevent the handle  526  from moving in the proximal direction when the spring  550  is released from the compressed position, thereby forcing the introducer stylet  521  to move in the distal direction and into the tissue. 
     Indeed, in operation, the operator grasps the handle  526 , paying particular attention to the orientation indicator  528  as related to the imagable feature  536 , and forces the piercing tip  534  into the tissue. The piercing tip  534  enters the tissue and the operator presses the release button  585 , causing disengagement of the latch tab  589  from the latch tab interference portion  530 . The force from the spring  550 , releasing from a compressed position, (best seen in  FIG. 6A ) causes the introducer stylet shaft  521  to force itself through the tissue creating a path for the later introduction of other medical devices. 
     Once the operator has released the spring  550  to the fully extended position the operator will apply further pressure, while watching the imaging device, to guide the imagable feature  536  adjacent the targeted tissue. After the imagable feature  536  reaches the targeted area the operator will rotate the handle  526  to orient the imagable feature  536  in the direction of the sample to be taken. Upon proper orientation the operator may remove the introducer stylet  522  or leave the introducer stylet  522  in place while evaluating other procedures. To remove the introducer stylet  522  the operator grasps the handle  526  and slides the introducer stylet  522  out of the tissue leaving a path for the introduction of other medical devices, as stated above. 
     Referring now to  FIGS. 7-9 , an alternative embodiment of a spring loaded introducer stylet assembly  600  is shown. Referring first to  FIGS. 7A and 7B , introducer stylet assembly  600  includes an introducer stylet body  622 . In one exemplary arrangement, introducer stylet body  622  is configured as generally cylindrical and defined by a distal end  632  and a proximal end  624 . Distal end  632  may include a tissue piercing tip  634  sized for introduction into a patient&#39;s body. It will be appreciated that the piercing tip  634  may include other devices for piercing the patient&#39;s tissue, including, without limitation, devices that use a laser or radio frequencies (RF) to pierce the tissue. An imagable feature  636  may be positioned adjacent to distal end  632  of introducer stylet  622 . While shown as a generally planar surface, it is appreciated that imagable feature  636  may be formed in a variety of configurations, including, but not limited to, those configurations shown and described above in connection with  FIGS. 5A-5C . 
     In the illustrated arrangement, introducer stylet body  622  is positioned in sliding arrangement through a handle  626 . A firing button  652  (to be explained in further detail below) is provided that extends through an opening  651  (best seen in  FIG. 9B ) in handle  626  when introducer stylet assembly  600  is in a “pre-fire” configuration (as shown in  FIGS. 7A ,  8 A, and  9 A). In one exemplary arrangement, firing button  652  is positioned so as to be adjacent to an imagable feature orientation indicator  628 . As with the other embodiments disclosed herein, imagable feature orientation indicator  628  may be configured as an ergonomic thumb pad. Alternatively, the imagable feature orientation indicator  628  may also be configured by printing a mark on handle  626  (not shown) that allows the operator to selectively orient the imagable feature  636  to a target tissue area prior to the removal of the introducer stylet body  622  and the insertion of a biopsy device. 
     Introducer stylet assembly  600  may also be used with an introducer assembly  20  (described in greater detail in connection with  FIGS. 2-3 ). As may be seen, introducer stylet assembly  20  includes an introducer cannula  42  and a latching hub  46 . Latching hub  46  includes a generally annular hub portion  47  and a latch portion  48 . The latch portion  48  includes a release button  85  and a latch  87  having a latch tab  89  (as seen best in  FIGS. 9A-9B ). The latch tab  89  cooperates with a latching tab interference portion  630  formed on a surface of handle  626  to prevent the introducer cannula  42  from rotating or laterally moving with respect to the introducer stylet body  622  during use. 
     As best shown in  FIGS. 8 and 9 , introducer stylet assembly  600  further includes a slidable carriage  688  and a biasing member  650 . Slidable carriage  688  has a body member  682  and an arm member  685 . Arm member  685  extends outwardly from body member  682  and carries firing button  652 . 
     Slidable carriage  688  is fixedly secured to a portion of introducer stylet body  622   a  and disposed within a chamber  690  formed within handle  626 . Biasing member  650  is also positioned within chamber  690 , adjacent a proximal end  692  of handle  626 . Biasing member  650  is positioned between body member  682  of carriage  688  and an internal surface  694  of chamber  690 . 
     In operation, when introducer stylet assembly  600  is in the “pre-fire” configuration ( FIGS. 8A and 9A ), carriage  688  is retracted and held in the pre-fire configuration by firing button  652  that extends upwardly through opening  651 . Body member  682  serves as a stop member for biasing member  650  (which may be a spring), such that when introducer stylet assembly  600  is in the “pre-fire” configuration, biasing member  650  is compressed between body member  682  and internal surface  694  of chamber  690 . 
     To move introducer stylet assembly  600  into a “fired” configuration (see  FIGS. 8B and 9B ), firing button  652 , which is selectively compressible, is depressed thorough opening  651 . Once cleared from opening  651 , biasing member  650  acts against body member, thereby “firing” carriage  688 , which is carrying introducer stylet body  622 , forward. The firing button  652  cooperates with a forward wall member  696  to limit the forward extent that introducer stylet body  622  may fire. 
     Further, proximal end  624  of introducer stylet body  622  may also be configured with a stop member  698  that serves to prevent introducer stylet body  622  from exiting handle  626  during the firing process. For example, as may be seen in  FIGS. 8-9 , proximal end  624  of introducer stylet body extends outwardly from an opening  700 . In one exemplary arrangement, a stop member  698  is attached to proximal end  624 . When introducer stylet assembly  600  is positioned within the fired configuration ( 7 A,  8 A, and  9 A), a portion of stop member  698  contacts an outside surface  702  of proximal end  692  of handle  626 . Stop member  698  may be configured integrally with introducer stylet body  622  or a separate piece. 
     Referring now to  FIGS. 10-12 , an alternative embodiment of an introducer cannula assembly  800  is shown. Introducer cannula assembly  800  comprises an introducer cannula  802  and an introducer hub  804 . Introducer cannula  802  is configured so as to be generally cylindrical and is defined by a distal end  806  and a proximal end  808  (best seen in  FIGS. 12A and 12B . Proximal end  808  of introducer cannula  802  is fixedly secured within a channel  810  formed in a distal portion  812  of introducer hub  804 . 
     Introducer hub  804  further includes a proximal portion  814 . Proximal portion  814  further includes a gripping member  816  that is disposed around a mounting groove  818 . In one exemplary embodiment, gripping member  816  is configured as an annular member that extends around mounting groove  818 . In another embodiment, gripping member  816  may be configured as a series of projections positioned around mounting groove  818 . Gripping member  816  is constructed of a compressible material, as will be explained in further detail below. 
     Introducer hub  804  is designed to allow selective fixed engagement with a variety of medical devices. More specifically, gripping member  816  is sized to engage both luer lock type syringes  900 , as well as luer taper type syringes  950 . However, unlike traditional fittings for introducers that are threaded or require a twist-type engagement (such as bayonet fittings), gripping member  816  is designed to fit multiple types of medical devices with a quick interference-type fit. 
     For example, referring to  FIG. 12A , introducer hub  804  gripping members  816  may be engaged with an internal mounting groove  920  formed in a distal end  902  of luer lock type syringe  900  in an interference fit. To facilitate such engagement, an end portion  820  of gripping member  818  may be configured with a taper. To effect engagement between introducer hub  804 , end portion  820  of gripping member  816  is press fit into internal mounting groove  920 . The compressible material is compressed within mounting groove  920 , thereby providing an interference fit between introducer hub  804  and mounting groove  920 , without requiring any twisting motion. 
     Referring to  FIG. 12B , introducer hub  804  gripping members  816  may be engaged with an external surface  952  of luer taper type syringe  950 . More specifically, a distal end  954  of syringe  950  is received within mounting groove  818  of introducer hub  804 . The compressible material expands around distal end  954  and gripping members  816  engage external surface  952  in an interference fit without requiring any twisting motion. 
     In addition to gripping members  816  and mounting groove  818 , introducer hub  804  may also be optionally provided with a latch portion  822 , similar to those described above in connection with  FIGS. 1-3 . In such an embodiment, introducer hub  804  may also selectively engage those devices that include a latch interference portion. 
     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 characteristic or element is essential to all possible combinations that may be claimed in this or a later application.