Abstract:
An apparatus for implanting a locatable marker at a target site within a tissue mass comprises an insertion device and a marker introducer system that is received within the insertion device. The marker introducer system is anchored in a compressed tissue mass and a locatable marker is deployed from the introducer system after the tissue mass is decompressed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 10/904,666, filed Nov. 22, 2004, and further claims the benefit of U.S. Provisional Patent Application No. 60/596,467, filed Sep. 26, 2005, both of which are incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to a medical device for marking a target site within a tissue mass and more specifically to a medical device having a marker for marking a biopsy site in breast tissue that is deployed after the breast tissue has been decompressed. 
     2. Description of the Related Art 
     A biopsy is a well-known medical procedure that involves taking a sample of tissue from a person and examining it for diagnostic purposes. This is often done when an abnormality is found in a tissue mass, for example when a lump is found in breast tissue or when an imaging system, such as mammography or ultrasonography detects a suspicious area. Examining a sample of tissue from an abnormal site or lesion is currently the only way to accurately diagnose cancer. 
     A vacuum-assisted biopsy (VAB) uses an imaging system, such as ultrasonography or mammography, to locate a lesion in the breast tissue and to guide a biopsy probe to the site. An example of a known VAB device  200  is shown in  FIG. 1 . Such a VAB device is described in U.S. Pat. No. 6,712,774 and is incorporated by reference in its entirety. The details of the VAB device are not germane to the invention and thus will only be briefly described. The probe  70  has a pointed tip  76  to facilitate its insertion through the tissue mass, an opening  78  in the side wall of the probe near the pointed tip, and a vacuum chamber  72 . Once the probe  70  is in position at the lesion site, a vacuum pump creates a vacuum in chamber  72  and draws the tissue through the opening  78  and into a sampling chamber where a cutting device is advanced through the probe  70  to cut and remove a tissue sample. Other instruments can be inserted through the probe  70  in addition to the cutting device. 
     The position of the patient during VAB depends on the imaging system used to locate the lesion and position the probe. If ultrasonography is used, the patient will be in a supine position. If mammography is used, the patient typically lies prone on a specialized table such that the breast protrudes through a hole in the table. The breast is compressed between two plates while an image of the lesion is produced on a monitor by a mammography unit. Once the lesion is imaged, the VAB probe, which is mounted to the table or the mammography unit, is inserted into the breast tissue and the tissue sample is gathered as described above. 
     In some cases, it is desirable to mark the location of the lesion site in case a future biopsy or surgery is necessary. This is done with a marker that is made of any suitable material that can be imaged by an imaging system, such as ultrasonography, magnetic resonance, or mammography, or that is palpable through the skin and tissue of the patient. The marker must be accurately placed at the lesion site in the breast tissue and must remain at the site so that the lesion can be located and identified at a later time, if necessary. However, there sometimes is a need for a marker to be repositioned after its initial placement, such as if the marker was not placed at the desired location or if the marker shifts upon decompression of the tissue. Thus, the marker must be able to remain anchored in the breast tissue, yet permit its repositioning. 
     One type of marker is a biocompatible clip that can be placed at the lesion site to facilitate locating the lesion during later procedures. The clip has the advantage of being implanted entirely within the tissue mass, so that there is no possibility of accidental repositioning by pulling or tugging the clip. The clip is placed after the tissue sample has been gathered from the lesion site and while the breast is still compressed. The clip is inserted into the tissue mass through the VAB probe and thus does not require the tissue mass to be repierced. Since the clip is deployed when the breast tissue is compressed, upon decompression the clip may be found to be implanted away from the lesion site, leading to inaccurate marking of the lesion site. An illustrative example of the post-decompression shifting problem is a rubber ball that is normally 5 cm in diameter, but compressed to 2 cm. If a clip is to be placed 1 cm from the edge of the ball, the clip would be placed at the center of the ball. However, if upon decompression of the ball the clip stays at the center of the ball or shifts away from the target site, the clip is misplaced by up to several centimeters. Coopers ligaments in the breast exacerbate the problem of inaccurate marking by acting to pull the clip away from the site of implantation when the breast is uncompressed. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a method for implanting a locatable marker in a tissue mass, comprises compressing the tissue mass, locating a target site within the tissue mass, inserting the locatable marker into the tissue mass at the target site, decompressing the tissue mass, and repositioning the locatable marker to the target site if the locatable marker is not at the target site after decompressing the tissue mass. 
     The inserting step can comprise inserting a sheath containing the locatable marker into the tissue mass at the target site. The inserting step can further comprise anchoring the sheath containing the locatable marker at the target site. Anchoring the sheath can comprise embedding an anchor wire in the tissue mass. 
     The repositioning step can comprise locating the locatable marker and the target site using an imaging system to determine the position of the locatable marker relative to the target site. The repositioning step can further comprise implanting the locatable marker at the tissue site after the locatable marker is determined to be at the target site. The repositioning step can further comprise relocating the locatable marker to the target site before implanting the locatable marker. 
     The repositioning step can further comprise locating the sheath and the target site using an imaging system to determine the position of the sheath relative to the target site. The repositioning step can further comprise implanting the locatable marker at the tissue site after the locatable marker is determined to be at the target site. The repositioning step can further comprise one of advancing and retracting the sheath to the target site before implanting the locatable marker. 
     The method can further comprise inserting an insertion device into the compressed tissue mass prior to inserting the locatable marker. The inserting step can further comprise inserting a sheath containing the locatable marker through the insertion device. The method can further comprise withdrawing the insertion device from the tissue mass prior to the repositioning step. 
     The target site can be one of a lesion site and a biopsy site. 
     According to another aspect of the invention, a method for implanting a locatable marker in a tissue mass comprises compressing the tissue mass, locating a target site within the tissue mass, anchoring a sheath containing the locatable marker at the target site, decompressing the tissue mass, and deploying the locatable marker at the target site after decompressing the tissue mass. 
     The anchoring step can comprise inserting the sheath containing the locatable marker and an anchor wire into the tissue mass at the target site. The anchoring step can further comprise embedding the anchor wire at the target site. Embedding the anchor wire can comprise extending the anchor wire from within a lumen of the sheath to the target site. 
     The deploying step can comprise implanting the locatable marker at the tissue site after decompressing the tissue mass. Implanting the locatable marker can comprise pushing the locatable marker from a lumen of the sheath using a pushrod. The deploying step can further comprise deploying a hemostatic agent with the locatable marker. The deploying step can further comprise locating the sheath and the target site using a locatable system before implanting the locatable marker to determine the position of the locatable marker relative to the tissue site. The deploying step can further comprise relocating the locatable marker to the target site before implanting the locatable marker. Relocating the locatable marker can comprise retracting the sheath a predetermined distance to the target site. Relocating the locatable marker can comprise inserting a cannula over the sheath and advancing the cannula, with the sheath contained therein, a predetermined distance to the target site. 
     The method can further comprise inserting an insertion device into the compressed tissue mass prior to the anchoring step. The anchoring step can further comprise inserting a sheath containing the locatable marker through the insertion device. The method can further comprise withdrawing the insertion device from the tissue mass prior to the deploying step. 
     The target site can be one of a lesion site and a biopsy site. 
     According to yet another aspect of the invention, an apparatus for implanting a locatable marker at a target site within a tissue mass comprises an insertion device comprising a first lumen having an exit opening, a sheath slidably received within the first lumen and comprising a second lumen having a distal opening, a locatable marker received within the second lumen and deployable through the distal opening, and an anchor operably coupled to the sheath to fix the location of the sheath in the tissue mass, wherein the insertion device can be located within the tissue mass and the sheath can be inserted into the tissue mass through the exit opening of the insertion device, and the anchor can fix the position of the sheath in the tissue mass for deployment of the locatable marker at the target site. 
     The insertion device can be a biopsy probe. The probe can be a vacuum-assisted biopsy probe. The exit opening can comprise a ramp. 
     The sheath can comprise a third lumen having a distal opening, with the anchor received within the third lumen and deployable through the distal opening. The sheath can comprise a distal terminal end and the distal terminal end can comprise an insertion tip. At least one of the sheath distal openings can be formed in the distal terminal end of the sheath. At least one of the sheath distal openings can be formed in a side wall of the sheath. At least one of the sheath distal openings formed in the side wall can comprise a ramp to guide the locatable marker through at least one of the sheath distal openings formed in the side wall. 
     The sheath can be flexible. The sheath can comprise distance markings. 
     The apparatus can further comprise a pushrod slidably received within the second lumen that deploys the locatable marker through the distal opening. 
     The locatable marker can be one of an imaging marker and a palpable marker. The locatable marker can be a clip. 
     The anchor can comprise an anchor wire. The sheath can comprise a third lumen having a distal opening and the anchor wire can be received within the third lumen. The anchor wire can be operable between a straight configuration where the anchor wire is contained within the third lumen and a curved configuration where the anchor wire is extended through the distal opening of the third lumen. The anchor wire can be embedded in the tissue mass in the curved configuration. 
     The apparatus can further comprise a cannula received within the first lumen, the cannula comprising a fourth lumen having a distal opening, with the sheath received within the fourth lumen. The cannula distal opening can comprise a ramp to guide the sheath through the cannula distal opening. 
     The apparatus can further comprising a pair of compression plates for compressing the tissue mass prior to location of the insertion device into the tissue mass at the target site and for decompressing the tissue mass prior to implantation of the locatable marker. 
     The apparatus can further comprise a hemostatic agent received within the second lumen and deployable through the distal opening 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic illustration of a prior art VAB device. 
         FIG. 2  is a schematic illustration of a VAB probe containing an introducer system according to the first embodiment of the present invention comprising a sheath having a first lumen containing a marker clip and a pushrod and a second lumen containing an anchor wire. 
         FIG. 3  is an enlarged view of the first embodiment of the introducer system from  FIG. 2 . 
         FIG. 4  is a sectional view of the introducer system taken along line  4 - 4  from  FIG. 3 . 
         FIG. 5  is a drawing similar to  FIG. 3  illustrating the anchor wire extended from the second lumen. 
         FIG. 6  is a drawing similar to  FIG. 5  illustrating the pushrod extended from the first lumen to push the marker clip out of the introducer system. 
         FIG. 7  is a schematic illustration of the VAB probe from  FIG. 2  inserted into a tissue mass comprising a breast that is compressed between compression plates. 
         FIG. 8  is a close-up view of area VIII from  FIG. 7  illustrating the insertion of the introducer system into the VAB probe. 
         FIG. 9  is a drawing similar to  FIG. 8  illustrating the introducer system extended from the VAB probe and into the tissue mass. 
         FIG. 10  is a drawing similar to  FIG. 9  illustrating the anchor wire extended from the second lumen and anchored in the tissue mass. 
         FIG. 11  is a drawing illustrating the tissue mass in an uncompressed state with the introducer system anchored in the tissue mass and the retraction of the VAB probe from the tissue mass. 
         FIG. 12  is a close-up view of area XII from  FIG. 11  illustrating the pushrod extended from the first lumen to push the marker clip out of the introducer system and into the tissue mass. 
         FIG. 13  is a drawing similar to  FIG. 12  illustrating the marker clip implanted in the tissue mass and the retraction of the introducer system from the tissue mass. 
         FIGS. 14-16  are schematic illustrations showing a method of relocating the introducer system within the tissue mass. 
         FIG. 17  is a schematic illustration of an introducer system having distance markings on the first and second lumens. 
         FIG. 18  is an enlarged view of a second embodiment of the introducer system. 
         FIG. 19  is a sectional view of the introducer system taken along line  19 - 19  from  FIG. 18 . 
         FIG. 20  is an enlarged view of a third embodiment of the introducer system showing the anchor wire extended from the second lumen. 
         FIG. 21  is an enlarged view of the introducer system from  FIG. 20  showing the anchor wire in a compressed configuration within the second lumen. 
         FIG. 22  is an enlarged view of the introducer system from  FIG. 20  showing the anchor wire in a straight configuration within the second lumen. 
         FIG. 23  is an enlarged view of a fourth embodiment of the introducer system. 
         FIG. 24  is an enlarged view of a second embodiment of the VAB probe. 
         FIG. 25  is a drawing similar to  FIG. 2  illustrating the introducer system contained within an outer cannula that is contained within the VAB probe. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and particularly to  FIG. 2 , an embodiment of the marker introducer system  10  is illustrated contained within a VAB probe  70  of a VAB system ( FIG. 1 ). The VAB probe  70  comprises a vacuum chamber  72 , a lumen  74 , a closed insertion tip  76 , and a proximal opening (not shown) into which the introducer system  10  can be inserted. An opening  78  in the cannula  72  allows a tissue sample to be taken from a tissue mass as previously described. 
     Referring additionally to  FIG. 3 , the introducer system  10  comprises a first sheath  12  and a second sheath  14  which respectively define a first lumen  16  and a second lumen  18 . The first sheath  12  comprises an open distal insertion tip  22  and an open proximal end (not shown). The second sheath  14  comprises an open distal tip  32  and an open proximal end (not shown). An anchor wire  40  is contained within the second lumen  18  and a marker in the form of a clip  50  and a pushrod  60  are contained within the first lumen  16 . 
     The sheaths  12 ,  14  are preferably independently fabricated from a biocompatible plastic that is flexible and bonded together as shown in  FIG. 4 . The gap between the sheaths  12 ,  14  and the corresponding pushrod  60  and anchor wire  40  is exaggerated in  FIG. 3  to better discern the elements. One or both of the sheaths  12 ,  14  could also be formed from a coiled wire or any other biocompatible material that is sufficiently flexible such that the introducer system  10  can be inserted through the VAB probe and out of the opening  78 . 
     Referring to  FIG. 5 , the anchor wire  40  comprises a hook  42  and a thread  44 . When mounted in the sheath  14  prior to implantation in the tissue mass, the hook  42  is contained within the second lumen  18  and a portion of the thread  44  extends exteriorly from the proximal end of the sheath  14 . The thread  44  is of sufficient length such that the proximal end of the thread  44  is exterior to the proximal end of the sheath  14  to manipulate the anchor wire  40  relative to the sheath  14 . 
     The hook  42  is fabricated from a resilient, biocompatible material, for example a shape-memory alloy such as Nitinol. This allows the hook to assume a straight first configuration in the lumen as illustrated in  FIG. 3 , and a curved second configuration outside the lumen as illustrated in  FIG. 5 . 
     The hook  42  is preferably formed from the same wire as the thread  44  such that the hook is a continuation of the thread with the end of the hook  42  being connected to the thread  42  to complete hook  42 . Alternately, the hook  42  and the thread  44  can be formed from different wires and or different materials. In either case, the hook  42  can be bonded or welded to the thread  44  to form the connection. 
     While the anchor wire  40  is shown having a hook  42  that engages the tissue mass, the anchor wire  40  can be formed with any one of a number of different anchors. For instance, as disclosed in U.S. patent application Ser. No. 10/904,666, the anchor wire  40  can be formed with a diamond or square shaped anchor, a triangular shaped anchor, a circular shaped anchor, or any other anchor shape or type that provides a secure implantation of the introducer system  10  in the tissue mass. The shape of the anchor can be selected upon, for example, the density of the tissue into which the wire is to be placed, the size of the lesion, and/or the anchoring force required to implant the introducer system  10  in the tissue mass. 
     While only one anchor wire  40  is illustrated in the embodiments shown herein, it is understood that the introducer system  10  can comprise more than one anchoring device. For example, the introducer system  10  can have multiple anchor wires  40  loaded in the second sheath  14 , or the introducer system  10  can have multiple sheaths that each hold one anchor wire  40 . In either case, the anchor wires  40  can be configured to engage the tissue mass at different angles to provide for a more secure implantation of the introducer system  10 . 
     Referring to  FIG. 6 , the pushrod  60  comprises a distal end  62  and a proximal end (not shown). The distal end  62  is used to force the clip  50  out of the sheath  12  and into the tissue mass. The pushrod  60  is of sufficient length such that the proximal end of the pushrod is exterior to the proximal end of the sheath  12  to manipulate the pushrod  60  relative to the sheath  12 . The pushrod  60  can be made of any material that is sufficiently flexible in order to be threaded through the sheath  12 , yet stiff enough to push the clip  50  out of the open tip  22  of the sheath  12 . 
     The clip  50  can be any suitable type of marker that can be detected and located. The clip  50  can be imaged by an imaging technique or palpable through the skin and tissue. Types of imagable markers include markers that are echogenic, radiopaque, or a combination of these types. The imaging technique used locate the clip  50  can be a standard imaging system such as ultrasonography, mammography or magnetic resonance imaging. 
     Referring to  FIGS. 7-13 , the clip  50  is deployed into the tissue mass as follows. The VAB probe  70  is inserted into the tissue mass  80  illustrated as a breast that is compressed between two plates  82  and containing a target site  84 . The target site can comprise a lesion or biopsy site. Referring to  FIG. 8 , after a VAB procedure has been performed during which a sample of tissue is taken from the target site  84 , the introducer system  10  is inserted through the open proximal end of the VAB probe  70 . Referring to  FIG. 9 , the introducer system is threaded through lumen  74  and through opening  78  so that the distal tips  22 ,  32  of the sheaths  12 ,  14  protrude into the tissue mass  80 . 
     The introducer system  10  is then secured in the tissue mass  80  using the anchor wire  40 . Referring to  FIG. 10 , the anchor wire  40  is embedded at the target site  84  by moving the thread  44  through lumen  18  relative to the sheath  14  such that the anchor wire  40  emerges from tip  32 . As anchor wire  40  emerges from tip  32 , hook  42  expands from the straightened first configuration to the curved second configuration. As it expands into the surrounding tissue, the hook  42  pierces the adjacent tissue to imbed the anchor wire  40  at the target site  84 . 
     After anchoring the introducer system  10 , the tissue mass  80  is uncompressed by removing the compression plates  82 . The VAB probe is next retracted from the tissue mass  80  as illustrated by an arrow in  FIG. 11 . An image is taken of the tissue mass  80  to determine if the introducer system  10  has been correctly positioned at the target site  84 . Correct positioning of the introducer system constitutes a placement that allows the clip  50  to be deployed at the target site  84  and thus is determined by the position of tip  22 . 
     If the introducer system  10  is correctly positioned, the clip  50  is implanted in the tissue mass  80  to mark the target site  84 . Referring to  FIG. 12 , the pushrod  60  is moved through lumen  16  relative to the sheath  12  such that the distal end  62  pushing the clip  50  emerges from tip  22  thus deploying clip  50  at the target site  84 . The pushrod  60  and the anchor wire  40  are then retracted back into their respective sheaths  12  and  14 , and the introducer system  10  is retracted from the tissue mass  80 , leaving the clip  50  implanted at the target site  84  as illustrated in  FIG. 13 . 
     If it is determined by the image taken after the tissue mass  80  is uncompressed that the introducer system  10  has been incorrectly placed, the introducer system  10  can be repositioned within the tissue mass  80  as shown in  FIGS. 14-16 . Repositioning is normally accomplished with the aid of an ultrasound. In the event of misplacement, it is most often the case that the introducer system  10  is too deep or beyond the target site  84  as illustrated in  FIG. 14 . Referring to  FIG. 15 , to reposition the introducer system, the anchor wire  40  is pulled back into lumen  18  by moving the thread  44  relative to the sheath  14 . The introducer system  10  is next retracted back an appropriate distance such that the tips  22 ,  32  are at the target site  84 . The introducer system is then secured in the tissue mass  80  using the anchor wire  40  and another image can be taken to confirm that the introducer system  10  is correctly positioned at the target site  84 . The introducer system  10  can be repositioned as many times as necessary until the introducer system  10  is correctly positioned as illustrated in  FIG. 16 . The clip  50  is then implanted in the tissue mass  80  to mark the target site  84  as previously described. 
     Referring to  FIG. 17 , to facilitate the repositioning of the introducer system  10 , the sheaths  12 ,  14  could be provided with distance markings  96 , for example centimeter markings that would enable the introducer system to be moved a distance determined from the image taken after the breast is uncompressed. Distance markings on the sheaths  12 ,  14  allow the introducer system  10  to be repositioned more accurately and reduces the possibility that the introducer system  10  has to be repositioned more than once to achieve correct placement of the introducer system  10 . 
     Although a rare occurrence, the introducer system  10  can be misplaced shallow to or before the target site. To reposition the introducer system  10  in this case, a hollow cannula can be inserted over the introducer system  10  and then the cannula and introducer system  10  are advanced an appropriate distance to the target site  84 . The cannula is next removed and the clip  50  is deployed. 
       FIG. 17  also illustrates the optional placement of a hemostatic agent  97  in addition to the placement of the clip  50 . The hemostatic agent  97  can comprise a soil hemostatic agent such as a plug of collagen, chitosan, thrombin, Factor Xa, fibrinogen, nonsoluble polysaccharide, cellulose and dried gelatin; or a hemostatic agent in liquid form that is coated or impregnated in a bioabsorbable material. The hemostatic agent  97  can be loaded into the first sheath  12  along with the clip  50  and can be positioned relative to the clip  50  to be expelled prior to or just after the clip  50  as the push rod  60  is advanced. In another contemplated embodiment, the clip  50  can be coated with or encompassed by the hemostatic agent  97 . The presence of the hemostatic agent  97  can prevent the clip  50  from being displaced due to bleeding at the target site  84 . 
     While the VAB probe  70  is illustrated as the structure for providing a passageway into the tissue mass for the insertion of the introducer system, it should be noted that other insertion devices can be used and the introducer system is not limited to the VAB probe  70 . For example, another insertion device can be a cannula with an axial opening or an opening in the side wall. 
     A second embodiment of the introducer system is shown in  FIGS. 18 and 19  where like elements are identified with the same reference numerals. In this embodiment, the first sheath  12  has a partition  86  that extends the length of the sheath and divides the sheath  12  into first lumen  16  and second lumen  18 . Such a configuration has a smaller cross-sectional size as illustrated in  FIG. 19  and the clip  50  is deployed in the same manner as described for the first embodiment of the introducer system  10 . 
     A third embodiment of the introducer system is shown in  FIGS. 20-22  where like elements are identified with the same reference numerals. In this embodiment, the tip  32  of the sheath  14  is closed and an opening  36  is provided in a side wall of the sheath  14 , near the distal end of the sheath  14 . As the anchor wire  40  is inserted into the sheath  14  it assumes the straight first configuration as shown in previous illustrations. When the hook  42  reaches the opening  36 , it will assume the curved second configuration as it protrudes from the lumen  18  into the tissue mass to anchor the introducer system  10 . Referring to  FIG. 21 , if it is then necessary to reposition the introducer system  10 , the thread  44  is pushed forward, forcing the hook  42  through opening  36  and against the closed tip  32 . Because of the forwardly-directed force on the wire  40 , the hook  42  remains in the curved second position but is slightly compressed. After repositioning the introducer system  10 , the thread  44  is pulled back, and the hook  42  exits the opening  36  to anchor the system into the tissue mass. Referring to  FIG. 22 , when the introducer system  10  is removed, the thread  44  is pulled back farther such that the hook  42  abuts the proximal edge of the opening  36  and assumes the straight first configuration as the hook  42  enter the second lumen  18 . 
     A fourth embodiment of the introducer system is shown in  FIG. 23  where like elements are identified with the same reference numerals. In this embodiment, both tips  22 ,  32  are closed and openings  26 ,  36  are provided near the proximal end  24 ,  34  of the sheaths  12 ,  14 , respectively. A ramp  28  is provided on the distal side of the opening  26  that occludes lumen  16  and prevents advancement of the clip  50  and the pushrod  60  beyond opening  26 . The ramp  28  is angled to guide the clip  50  and the pushrod  60  upward and through the opening  26 . 
     The VAB probe  70  can be altered in a similar fashion to facilitate the movement of the introducer system  10  out of the probe  70 . A second embodiment of the probe  70 , shown in  FIG. 24  where like elements are identified with the same reference numerals, has a ramp  88  formed on the distal side of the opening  78  such that it occludes lumen  74  and prevents the introducer system  10  from advancing beyond the opening  78 . The ramp  80  is angled to guide the introducer system  10  upwards and through opening  78 . While the second embodiment of probe  70  is shown in conjunction with the first embodiment of the introducer system  10 , it is understood that any embodiment of the introducer system  10  can be used with the second embodiment of the probe  70 . 
     Referring to  FIG. 25 , the introducer system  10  can also be inserted through an outer cannula  90  to facilitate the movement of the introducer system  10  out of the probe  70 . The cannula  90  defines a lumen  92  and comprises a closed distal end  94  and a proximal end (not shown). An opening  98  near the distal end  94  is provided with a ramp  100 . The opening  98  is located on the cannula  90  such that when the cannula  90  is fully inserted, the opening  98  is aligned with opening  78 . The cannula  90  is considered to be fully inserted into the probe  70  when the closed end  94  contacts the closed insertion tip  76 , thus aligning opening  98  with opening  78 . The cannula  90  has an outer diameter sized so that is can easily fit through the lumen  74  of the probe  70  and an inner diameter sized so that the introducer system  10  can easily fit through lumen  92 . 
     To deploy the clip  50 , the outer cannula  90  is first inserted into the probe  70  and pushed forward until it is fully inserted. Full insertion of the cannula  90  can be determined when resistance is felt against the further forward movement of the cannula  90 . Then, the introducer system  10  is inserted into the cannula  90  such that the introducer system  10  is guided up the ramp  100  and out of the opening  98 . Next, the introducer system  10  is anchored by the anchor wire  40  and the probe  70  and cannula  90  are simultaneously retracted leaving the introducer system  10  in the tissue mass. The clip  50  is then deployed following the same steps as previously described. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.