Abstract:
A marking apparatus includes a rigid cannula having a peripheral wall forming a lumen that carries an imaging marker, a proximal end coupled to a handle, a lateral opening in the peripheral wall that is open to the lumen, and a closed-off distal portion having a ramp adjacent the lumen. The closed-off distal portion extends distally from the ramp to terminate at a tissue piercing pointed tip. The ramp of the rigid cannula is curved to transition from the peripheral wall of the rigid cannula to the lateral opening of the rigid cannula. The ramp of the rigid cannula is adapted to engage the distal end of the stylet as the stylet is advanced through the lumen of the rigid cannula to guide the distal end of the stylet to a position to substantially close off the lateral opening of the rigid cannula having the tissue piercing tip.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 11/275,918 filed Feb. 3, 2006, which is a continuation of U.S. application Ser. No. 10/710,587 filed Jul. 22, 2004 and a continuation-in-part of U.S. application Ser. No. 10/707,044 filed Nov. 17, 2003, now U.S. Pat. No. 7,424,320, issued Sep. 9, 2008, all of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates generally to an apparatus for the percutaneous positioning of an imaging marker for identifying the location of a lesion in a biopsy procedure. More particularly, the invention relates to a self-contained marking apparatus that expels the imaging marker through the side of the marking device. 
         [0004]    2. Description of the Related Art 
         [0005]    Tissue biopsies are commonly performed on many areas and organs of the body where it is desirable to ascertain whether or not the biopsied tissue is cancerous. Often, a lesion or other tissue to be biopsied is identified through use of an imaging technique such as a computerized axial tomography (CAT) scan, ultrasonography, magnetic resonance imaging, and mammography. 
         [0006]    One problem commonly encountered, especially in breast biopsies, is that the lesion is so small that the biopsy reduces its size to the extent that it is no longer visible by the imaging method employed. In such circumstances, it is desirable to place an imaging marker at the site of the biopsy to enable the medical practitioner subsequently to locate the lesion quickly and accurately in the event complete removal of the affected tissue is indicated. This problem is currently met by placing an imaging marker at the biopsy area by means of a cannula or similar device housing the marker. 
         [0007]    There are currently two primary types of marking devices. One of the primary types is referred to as vacuum assisted biopsy devices (VAB&#39;s). The VAB devices are many times integrated with a mammography imaging system. They include a large diameter cannula, approximately 9 to 12 gage, or probe that is inserted into the breast tissue. Instruments, such as a biopsy device and a marking device, are introduced into the breast tissue through the large diameter cannula to take biopsy samples or mark a biopsy location. 
         [0008]    The other primary type is self-contained marking devices comprising a small diameter, approximately 14 to 17 gage, open-end cannula and a stylet slidably received within the cannula. A marker is located in the cannula and expelled out the open-end upon the advancing of the stylet relative to the cannula. 
         [0009]    One disadvantage of the VAB system is the biopsy and marking tools are integrated with the mammography imaging system. The capital investment of this type of system is substantial. Also, the biopsy and marking tools are typically designed to work only with the large diameter probe, which tends to lock the hospital or medical professional into the same source for the imaging system and the biopsy and marking tools. The VAB systems are also intended for the same components to be reused, which requires sterilization after each step. The various components are also typically flexible to help insert them through the probe. The VAB systems also have a relatively large diameter probe, which, all things being equal, the larger the diameter, the greater trauma to the surrounding tissue and the greater the pain or discomfort for the patient. 
         [0010]    The self-contained marking devices address these disadvantages of the VAB systems. Since the self-contained marking device is not integrally incorporated with a particular imaging system, the self-contained marking devices can be used with any suitable imaging system and are not limited to just mammography. This permits the hospital or medical professional to mix and match the available imaging systems and self-contained marking devices to obtain the desired performance and cost-effectiveness. 
         [0011]    The self-contained marking devices are typically disposable, which negates the need to sterilize them after each use. They also have a much smaller diameter, resulting in much less trauma to the surrounding tissue and pain to the patient. 
         [0012]    A disadvantage of the self-contained systems is that the cannula has an open tip through which the marker is expelled. The open tip is generally closed by the marker residing in the cannula. However, the marker does not completely close off the open tip and it is possible for tissue to enter the open end of the cannula during the positioning of the marking device. The presence of tissue inside the open end of the cannula can interfere or make more difficult the expelling of the marker from the cannula. 
         [0013]    The possibility for tissue being present in the open end of the cannula is, to some extent, related to the distance that the cannula is inserted through the tissue to the marking site. Thus, the manner in which the marking device is located at the biopsy site can impact the presence of tissue in the open end of the cannula. For example, the self-contained systems are sometimes used in combination with a positioning cannula that is inserted into the tissue mass with a stylet closing the end of the positioning cannula. In such a configuration, the stylet is removed once the positioning cannula is properly located relative to the biopsy site. Both the biopsy device and the marking device can be inserted and withdrawn through the positioning cannula. The use of the positioning cannula reduces the distance that the open end of the marking device cannula must travel through the tissue. 
         [0014]    Alternatively, the marking device can be inserted without the positioning cannula. This is most common when it is desirable to place a marker without taking a biopsy. Under such circumstances, it is more likely that tissue will be received within the open end of the cannula. Therefore, it is more likely that the tissue will interfere with the expelling of the marker. 
         [0015]    Therefore, it is desirable to have a self-contained marking device that can be used with or without a positioning cannula and which does not receive tissue within the open end of the cannula that might interfere with the expelling of the marker. 
       SUMMARY OF THE INVENTION 
       [0016]    The invention relates to a marking apparatus for the percutaneous placement of an imaging marker at a predetermined location in a tissue mass to facilitate subsequent determination of the predetermined location. The marking apparatus comprises a handle, cannula, and plunger. The handle is to be grasped by a user to aid in the placement of the marker. 
         [0017]    The cannula comprises a peripheral wall forming a lumen, with a proximal end carried by the handle, and a distal end terminating in a self-piercing tip. A lateral opening is formed in the peripheral wall and is open to the lumen. 
         [0018]    A plunger having a distal end is slidably received within the lumen for movement between a ready position, where the distal end is spaced inwardly from the self-piercing tip to form a marker recess in communication with the lateral opening and sized to receive an imaging marker, and an expelled position, where the distal end is advanced a sufficient distance into the marker recess to expel a marker contained therein through the lateral opening. 
         [0019]    One or more imaging markers can be positioned within the marker recess. 
         [0020]    The handle, cannula, plunger are operably coupled such that they form a self-contained marking apparatus that can be easily and conveniently handled by a user to effect operation of the marking apparatus from the ready position to an expelled position. 
         [0021]    The cannula is preferably sufficiently rigid and a distal end of the cannula is pointed to form the self-piercing tip. The cannula is 13 gage or less. 
         [0022]    A ramp can be provided on at least one of the plunger and cannula to aid in expelling an imaging marker. The ramp can be located in the lumen adjacent the lateral opening. The distal end of the plunger can be flexible to be deflected toward the lateral opening by the ramp when the plunger is moved to the expelled position. The ramp can also be located on the distal end of the plunger. 
         [0023]    The invention, in one form thereof, is directed to a marking apparatus for the percutaneous placement of an imaging marker in a tissue mass. The marking apparatus includes a handle to be grasped by a user, a rigid cannula and a stylet. The rigid cannula has a peripheral wall forming a lumen that carries the imaging marker, a proximal end coupled to the handle, a lateral opening in the peripheral wall that is open to the lumen, and a closed-off distal portion having a ramp adjacent the lumen. The closed-off distal portion extends distally from the ramp to terminate at a tissue piercing pointed tip. The ramp of the rigid cannula is curved to transition from the peripheral wall of the rigid cannula to the lateral opening of the rigid cannula. A stylet has a distal end, with at least the distal end of the stylet being flexible. The stylet is slidably received within the lumen of the rigid cannula for movement in the lumen. The ramp of the rigid cannula is adapted to engage the distal end of the stylet as the stylet is advanced through the lumen of the rigid cannula to guide the distal end of the stylet to a position to substantially close off the lateral opening of the rigid cannula having the tissue piercing tip. 
         [0024]    The invention, in another form thereof, is directed to a marking apparatus for the percutaneous placement of an imaging marker in a tissue mass. The marking apparatus includes a handle to be grasped by a user, a cannula, and a stylet. The cannula has a peripheral wall forming a lumen that carries the imaging marker, a proximal end coupled to the handle, a lateral opening in the peripheral wall that is open to the lumen, and a closed-off distal portion having a ramp adjacent the lumen. The closed-off distal portion extends distally from the ramp to terminate at a tissue piercing pointed tip. The stylet has a distal end with an angled surface. The stylet is disposed in the lumen and movable in the lumen between a ready position and an expelled position, such that when the stylet is advanced through the lumen to the expelled position the ramp deflects the distal end of the stylet toward the lateral opening such that at the expelled position the angled surface is flush with the peripheral wall of the cannula at the lateral opening of the cannula. 
         [0025]    The invention, in another form thereof, is directed to a marking apparatus for the percutaneous placement of an imaging marker in a tissue mass. The marking apparatus includes a handle to be grasped by a user, a cannula, and a stylet. The cannula has a peripheral wall forming a lumen that carries the imaging marker, a proximal end carried by the handle, a closed-off distal portion terminating in a self-piercing tip, a ramp integrated with the closed-off distal portion, and a lateral opening in the peripheral wall. The lateral opening extends in a region between the proximal end and the closed-off distal portion of the cannula. The lateral opening has a proximal extent and a distal extent, the distal extent being closer to the self-piercing tip than the proximal extent. The stylet includes a distal end. The stylet is slidably received within the lumen for movement between a ready position, wherein the distal end of the stylet is spaced inwardly from the self-piercing tip to form a marker recess in communication with the lateral opening, and an expelled position, wherein the distal end of the stylet is advanced a sufficient distance into the marker recess to expel the imaging marker contained in the lumen through the lateral opening of the cannula. When the distal end of the stylet is at the expelled position the distal end of the stylet is deflected by the ramp to close off the lateral opening of the cannula between the proximal extent and the distal extent of the lateral opening. 
         [0026]    The invention also relates to a method for percutaneously placing a marker at a predetermined location in a tissue mass using a self-piercing, side-ejecting, self-contained marking apparatus comprising a cannula defining a lumen and terminating in a self-piercing tip, with a lateral opening in communication with the lumen, and a plunger slidably received within the lumen for expelling a marker in the lumen through the lateral opening. The method comprises: inserting the cannula into the tissue mass by puncturing an exterior of the tissue mass with the self-piercing tip, and expelling the marker through the lateral opening by sliding the plunger within the lumen. 
         [0027]    The inserting step can comprise locating the lateral opening near a predetermined location in the tissue mass where it is desired to be marked. Preferably, the lateral opening is located beneath the predetermined location. 
         [0028]    The expelling step comprises expelling multiple markers into the tissue mass. 
         [0029]    At least one of the multiple markers can be expelled at a different location in the tissue mass than another of the multiple markers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    In the drawings: 
           [0031]      FIG. 1  is a plan view of a self-contained, self-piercing, and side-expelling marking apparatus comprising an actuator, a cannula with a side opening, and a stylet for laterally expelling a marker through the side opening in accordance with the invention. 
           [0032]      FIG. 2  is an enlarged sectional view of the area II of  FIG. 1 , illustrating the relationship between the cannula, stylet and marker prior to the expelling of the marker. 
           [0033]      FIG. 3 . is an enlarged top view of the cannula tip of  FIG. 2 . 
           [0034]      FIG. 4 . is an enlarged sectional view of a portion of the actuator. 
           [0035]      FIG. 5  is a sectional view of the marking device inserted into a tissue mass such that the cannula side opening is adjacent an area to be marked, with the stylet shown in a ready position and the marker still retained within the cannula lumen. 
           [0036]      FIG. 6  is an enlarged sectional view of the cannula tip of  FIG. 5 . 
           [0037]      FIG. 7  is a sectional view of the marking device inserted into a tissue mass such that the cannula side opening is adjacent an area to be marked, with the stylet shown in a expelled position and the marker expelled through the side opening into the surrounding tissue mass. 
           [0038]      FIG. 8  is an enlarged sectional view of the cannula tip of  FIG. 7 . 
           [0039]      FIG. 9  is a sectional view of an alternative design for the cannula and stylet according to the invention, with the stylet having a flexible tip and shown in the ready position. 
           [0040]    FIG. 10  is a sectional view of the cannula and stylet of  FIG. 9  with the stylet shown in the expelled position. 
           [0041]    FIG. 11  is a sectional view of a second alternative design for the cannula and stylet according to the invention, with the stylet having a ramped tip and shown in the expelled position. 
       
    
    
     DETAILED DESCRIPTION 
       [0042]      FIGS. 1-4  illustrate a self-contained, self-penetrating, side-expelling marking apparatus  10  according to the invention, which is capable of the percutaneous placement of a imaging marker at a desired location, such as at a tissue biopsy site or a lesion site in a breast. The marking apparatus  10  comprises an introducer  12  and an imaging marker  14  ( FIG. 2 ) contained within the introducer  12 . The introducer  12  includes an actuator  16  having a hollow interior  18 . The actuator  16  comprises a grip portion  20  from which extends a tapered nose portion  22 . The grip portion  20  defines a rear opening  24  that provides access to the hollow interior  18 . A pair of detents  26  are formed in the grip portion  20  near the rear opening  24 . Channels  28  are formed on the interior surface of the grip portion  20  and extend from the rear opening  24  to the detents  26 . 
         [0043]    The nose portion  22  comprises a guide passage  30  extending from the tip of the nose portion  22  to the hollow interior  18  of the actuator  16 . The guide passage  30  decreases in diameter inwardly from the tip of the nose portion to form a cannula seat  32  ( FIG. 5 ). 
         [0044]    A plunger  50  comprises a cylindrical body  52  from which extend a pair of catches  54  at diametrically opposed positions. The cylindrical body  52  is sized so that it is slidably received within the rear opening  24  of the actuator  16  where it is so oriented with respect to the actuator such that the catches  54  are aligned with the guide channels  28 . The plunger is free to reciprocate within the grip portion  20  of the actuator  16 . 
         [0045]    A cannula  60  is mounted to the introducer  12 . The cannula  60  defines a hollow interior in the form of a lumen  62  and comprises a proximal end  64  and a distal end  66 . The proximal end  64  ( FIG. 5 ) is mounted within the cannula seat  32  to secure the cannula  60  to the introducer  12 . The distal end  66  terminates in a closed-off tip  68  to provide the marking apparatus with self-piercing functionality. The closed-off tip  68  is illustrated as being pointed, but other suitable shapes are possible. 
         [0046]    The cannula  60  is preferably  13  gage or less in size. The cannula  60  is also preferably rigid. That is, the cannula does not substantially flex. The rigidity of the cannula aids in inserting the cannula into a tissue mass, without the aid of a guide needle or guide cannula. 
         [0047]    A side opening  70  is formed in the cannula  60  and extends entirely through the cannula such that the lumen  62  is in communication with the exterior of the cannula  60  through the side opening  70 . The side opening is preferably located behind the closed-off tip  68 . 
         [0048]    A ramp  72  is provided on the interior of the cannula  60 . The ramp  72  is illustrated as being integrally formed with the closed-off tip  68 . Such a configuration can result in a solid distal end  66  as illustrated. However, the distal end can be hollow and the ramp  72  can be formed by separately from the distal end  66 . 
         [0049]    The ramp  72  extends diametrically across the lumen  62  and terminates at the side opening  70 . With this configuration, the ramp  72  aids in directing an imaging marker  14  stored in the lumen through the side opening  70  and beyond the exterior of the cannula. 
         [0050]    A stylet  80  comprising a shaft  82  and a base  84  is received within the hollow interior  18  of the actuator  16  in a manner such that the shaft  82  extends through the guide passage  30  and into the cannula interior  62  and the stylet base  84  lies within the hollow interior  18  and is mounted to the plunger  50 . Thus, the reciprocation of the plunger  50  relative to the grip portion  20  results in a reciprocation of the stylet  80  within the cannula  60 . 
         [0051]    The stylet  80  terminates in a distal end  86 , which, when the marking apparatus is in the ready position, is spaced from the distal end  66  of the cannula  60  to form a marker recess therebetween. As illustrated, a single marker  14  is stored within the marker recess. It is within the scope of the invention for multiple markers to be received within the marker recess. 
         [0052]    As is shown, the foregoing construction provides a marking apparatus that is preassembled as a self-contained unit and prepackaged, all under sterile conditions, thereby affording the practitioner substantially greater convenience and reliability, while eliminating the need for sterilizing the self-contained unit after use. Preferably, the self-contained unit is disposed of after it is used. 
         [0053]    Referring to  FIGS. 5-8 , in operation, the introducer  12  begins in the ready condition shown in  FIGS. 5 and 6 . In this condition, the distal end  86  of the stylet  80  is received within the cannula and spaced from the closed-off distal end  66  of the cannula to define a marker recess in which a marker  14  is stored. The plunger  50  is in a position relative to the grip portion  20  in which the catches are outside the grip portion; that is, they are not received within the detents  26 . However, the plunger  50  is so oriented with respect to the grip portion that the catches  54  are aligned with the guide channels  28 . 
         [0054]    With the introducer in the ready condition, the cannula is positioned within the tissue mass such that the side opening  70  is at or near the location of a tissue mass where it is desired to place the marker. In the case of marking a biopsy site, the side opening is preferably placed adjacent the biopsy site. 
         [0055]    To place the side opening adjacent the site to be marked, the medical professional grasps the grip portion  20  of the actuator and presses the closed-off tip  68  against the exterior of the tissue mass to puncture the tissue mass. The medical professional continues applying force to the grip portion  20  to drive the cannula  60  to the desired location within the tissue mass. 
         [0056]    The closed tip  68  helps separate the tissue of the tissue mass to make it easier to insert the cannula within the tissue mass to the desired location. A starter incision can be made in the exterior of the tissue mass to reduce the initial force need to start the insertion. 
         [0057]    The used of a side opening  70  instead of a tip opening found in the prior art self-contained devices helps prevent the accumulation of tissue within the lumen  62  upon the insertion of the cannula  60  into the tissue mass. The closed tip  68  also helps in that it separates the tissue to form a path through which the side opening passes. Since the side opening is parallel to the path, there is much less tendency for the insertion of the cannula to force tissue into the side opening as could occur in the prior-art front opening cannulae. 
         [0058]    Typically, a suitable imaging system will be used by the medical professional to help guide the cannula to the desired location within the tissue mass. Examples of contemporary imaging systems include: stereotactic, x-ray, ultrasound, CAT scan, or MRI. The invention is not limited to any particular type of imaging system. 
         [0059]    Once the cannula is positioned at the desired location, the plunger  50  is moved from a first or ready condition as illustrated in  FIGS. 5 and 6  to a second or expelled condition as illustrated in  FIGS. 7 and 8 . As the plunger is moved, the stylet  80  is advanced into the marker recess to drive the marker  14  up the ramp  72 . The continued advancement of the stylet  80  ultimately drives the marker  14  through the side opening  70  and into the adjacent tissue. 
         [0060]    Once the stylet is in the expelled position, the cannula can be withdrawn to leave the marker in the tissue. To withdraw the cannula, the medical professional pulls on the actuator to withdraw the cannula from the tissue mass. After use, the marking apparatus is disposed of, negating the need for sterilization. 
         [0061]    As illustrated, the rigid cannula in combination with the closed-off tip  68  provides an ideal structure for inserting the device directly into the tissue without the need for a guide needle or cannula. This is advantageous in that it reduces the size of the opening formed in the tissue and thereby reducing the trauma to the patient. The closed-off tip is used to puncture the exterior of the tissue mass. While the marking apparatus of the invention can be used with a guide needle or cannula, there is no need to do so because of the self-piercing nature of the invention. 
         [0062]      FIGS. 9 and 10  illustrate an alternative design for the stylet in the ready and expelled conditions, respectively. The alternative stylet  80 ′ is essentially identical to the stylet  80 , except that the distal end  66 ′ is made from a resilient material and has an angled surface  90 ′. The resilient material permits the distal end  66 ′ to deflect when contacting the ramp  72 ′, such that the distal end  66 ′ generally follows the shape of the ramp  72 ′. The angle of the angled surface  90 ′ is preferably selected such that the angled surface substantially closes off the side opening  70 ′ when the stylet is in the expelled condition, which will ensure that the marker is completely expelled through the side opening  70 ′. It will also ensure that no portion of the marker  14  will be pulled back into the side opening  70 ′ due to the vacuum forces created upon the withdrawal of the cannula. The angled surface  90 ′ functions like the ramp  72  in that it helps to deflect the marker  14  through the side opening. 
         [0063]      FIG. 11  illustrates another alternative design for the stylet and cannula. In this alternative design, the distal end  66 ″ of the stylet  80 ″ includes a ramp  72 ″. A resilient end wall  92 ″ is used instead of the ramp  72  of the cannula. The space between the ramp  72 ″ and the resilient end wall  92 ″ defines the marker recess in which multiple markers  14 ″ are stored. The advancement of the stylet from the ready condition to the expelled condition drives the markers up the ramp  72 ″. When contacted by the ramp  72 ″, the resilient end wall  92 ″ deflects to permit the ramp  72 ″ to slide beneath and into the distal end closed tip  68 ″ of the cannula. 
         [0064]    In all of the embodiments, multiple markers can be located within the cannula and expelled at the same or different locations within the tissue mass. 
         [0065]    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.