Abstract:
Breast compression devices and methods of operating the same are disclosed. A first breast compression device comprises a back plate, a front paddle comprising two or more fingers, and an adjuster to adjust the space between the back plate and the front paddle. A second breast compression device comprises a back plate, a front paddle comprising two or more fingers, and a bar connecting the back plate and the front paddle. A method for compressing breast tissue with a breast compression device comprises wrapping the breast compression device around the breast tissue from any angle, the breast compression device including a back plate, a front paddle comprising two or more fingers, and a bar connecting the back plate and the front paddle, and adjusting the breast compression device to provide enough compression to render the breast tissue immobile.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims priority to U.S. Provisional Patent Application Ser. No. 62/211,549, filed Aug. 28, 2015, hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to surgical instruments, and more particularly, to a breast compression device. 
       BACKGROUND OF THE INVENTION 
       [0003]    Generally, to date there have been two coring type, excisional breast biopsy devices developed and marketed. These devices are described in the following U.S. Pat. Nos. 5,111,828; 5,197,484; 5,353,804; 6,080,113; 6,267,732; 6,383,145; 6,551,253; 5,782,775; 5,817,034; 5,857,982; 6,036,657; 6,077,231; 6,165,137; and 6,213,957, all of which are hereby incorporated by reference. 
         [0004]    These devices were originally developed for use with stereotactic imaging equipment. Generally, these devices use the same basic technology. The device disclosed in the &#39;253 patent is exemplary. The biopsy device includes a localization needle with a guide wire preloaded into the device. The localization needle and guide wire are used to locate and localize the target area. The methodology of their usage can be summarized as follows: 
         [0005]    1. Localize the target area with needle/wire hook; 
         [0006]    2. Translate device up to the target area using a bladed stylet; 
         [0007]    3. Core out the target specimen using a bladed cannula; and 
         [0008]    4. Transect the tissue using a garrote wire to release the specimen. 
         [0009]    The device can either by a handheld device or may be a fixed device. The below more detailed description of the method of using a prior art device is described with respect to a handheld device. 
         [0010]    First, a localization needle is placed at the center of the target tissue. A localization wire is used to fix the handheld device to the tissue. After the localization wire is deployed, a stylet is manually advanced to a point just proximal of the target. 
         [0011]    One problem associated with the current device is that the localization hook has very little holding power. Another issue related to the prior art devices is the potential of the stylet to push and/or compress, i.e., the tissue in front of the stylet, i.e., “snowplow’. 
         [0012]    After the stylet reaches the target tissue, the cannula is manually advanced over the target tissue. With the cannula advanced over the target tissue, a mechanism, such as a garrote wire is activated to sever the target tissue from the breast. With the target tissue severed from the breast, the device, along with the target tissue with the cannula, may be removed. 
         [0013]    Generally, these prior art devices are purely mechanical devices, i.e., in other words, the coring cannula is advanced by hand. The surgeon or user rotates a knob that activates a gear system to rotate and advances the coring cannula. This results in a relatively slow, intermittent advance of the cannula due to the start/stop motion of the surgeon. The start/stop motion can increase patient discomfort, as well as produce an undesirable irregular specimen shape. 
         [0014]    As discussed above, once the cannula has been advanced over the target tissue, a garrote wire may be used to cut the sample tissue (which is inside the cannula) from the breast so that it may be removed. The garrote wire has several limitations. Typically, the garrote wire traverse (at least partially) along the length of the device, then is bent at a 90 degree angle, after which it encircles an inner surface of the coring cannula. The right angle in the garrote wire results in requiring a large amount of force to pull on the garrote wire to transect the tissue sample. Additionally, the garrote wire is generally located a distance behind the cutting edge of the coring cannula. This results in a core of tissue which is cored by the coring cannula, which is not transected by the garrote wire, and thus remains in the breast. Furthermore, the garrote wire may tear the tissue rather than cutting the tissue. Additionally, dense tissue can be pushed aside rather than cut. 
         [0015]    Another issue related to prior art designs is the size of the cutting edge of the cannula with respect to the stylet. Prior to entry of the device into the breast, a skin incision is made using a scalpel. This incision is generally just slightly wider than the diameter of the cannula. Once the incision is made, the stylet is advanced in the breast, up to the point where the coring blade is ready to enter the incision. At this point, the surgeon will use nerve hooks to grab the skin and open the incision to allow the cutting edge of the cannula to enter the breast. However, the process of using the nerve hooks to grab the skin to make the incision wider can be cumbersome and inefficient and can cause patient discomfort. 
         [0016]    The current devices use a stylet with integral cutting blades. The flat stylet blades are fixed to the stylet which may result in several adverse conditions. First, the close proximity of the cutting edge of the stylet blades to the ramp or stylet tip results in the pushing or compression or other inadvertent movement of the tissue by the stylet. The prior designs also results in a fixed minimal proximal margin equal to the length of the stylet system. 
         [0017]    Improved designs for tissue excision devices and related components include those described in U.S. Pat. Nos. 8,597,200, 8,597,201, 8,597,202, 8,597,203, 8,597,204, 8,597,504, 8,529,467, 8,535,240, 8,444,573, 8,529,466,8,740,809, and 8,484,988. 
         [0018]    The procedure for excising a breast tissue sample with a handheld excision device is performed with the patient lying on her back. In certain cases, it may be beneficial for the surgeon to compress and support the breast from which the tissue sample is being excised. Compressing the breast may help to immobilize the tissue prior to and during excision of the tissue sample, which may result in a more accurate tissue excision. 
         [0019]    The present invention is aimed at one or more of the problems identified above. 
       SUMMARY OF THE INVENTION 
       [0020]    Devices and methods are disclosed for allowing a surgeon to compress and support a breast from which a tissue sample may be excised. 
         [0021]    In a first aspect of the present invention, a breast compression device is disclosed. The breast compression device comprises a back plate, a front paddle comprising two or more fingers, and an adjuster to adjust the space between the back plate and the front paddle. 
         [0022]    In a second aspect of the present invention, a breast compression device is disclosed. The breast compression device comprises a back plate, a front paddle comprising two or more fingers, and a bar connecting the back plate and the front paddle. 
         [0023]    In a third aspect of the present invention, a method for compressing breast tissue with a breast compression device is disclosed. The breast compression device is wrapped around the breast tissue from any angle. The breast compression device includes a back plate, a front paddle comprising two or more fingers, and a bar connecting the back plate and the front paddle. The breast compression device is adjusted to provide enough compression to render the breast tissue immobile. 
         [0024]    In a fourth aspect of the present invention, a tissue excision system is disclosed. The system includes an excision device and a breast compression device. The excision device includes a housing coupled to a coring cannula, a stylet coupled to the housing and having a bladed tip, a hollow central passageway extending through the center of the housing, the coring cannula, and the stylet, and a guide rod assembly removably coupled to the housing. The breast compression device includes a back plate, a front paddle with two or more fingers, and an adjuster to adjust the space between the back plate and the front paddle. The bladed stylet is advanced to a target tissue between the two or more fingers of the front paddle of the compression device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0026]      FIG. 1  is a drawing of a biopsy device with an integrated needle, according to an embodiment of the present invention; 
           [0027]      FIG. 2  includes a series of views of the biopsy device of  FIG. 1  illustrating operation thereof; 
           [0028]      FIG. 3  is an isometric drawing of a biopsy device with an independent needle assembly, according to an alternative embodiment of the present invention; 
           [0029]      FIG. 4A  is a drawing of the independent needle assembly of  FIG. 3 ; 
           [0030]      FIG. 4B  is another drawing of the independent needle assembly of  FIG. 3 ; 
           [0031]      FIG. 5A  is a drawing of a guide element of the independent needle assembly of  FIGS. 3 and 4 ; 
           [0032]      FIG. 5B  is a larger view of a portion of  FIG. 5A ; 
           [0033]      FIG. 6  is a isometric illustration of a handheld breast biopsy device having a housing and a handle, according to an embodiment of the present invention; 
           [0034]      FIG. 7  is a cut-away view of the handle of a breast biopsy device, according to an embodiment of the present invention; 
           [0035]      FIG. 8  is a first cut-away view of a breast biopsy device illustrating the drivetrain components, according to an embodiment of the present invention; 
           [0036]      FIG. 9  is a second cut-away view of the breast biopsy device of  FIG. 8 ; 
           [0037]      FIG. 10  is a drawing of the housing, according to an embodiment of the present invention; 
           [0038]      FIG. 11  is a drawing of the stylet, according to an embodiment of the present invention; 
           [0039]      FIG. 12  a drawing of the cannula, according to an embodiment of the present invention; 
           [0040]      FIG. 13A  is an illustration of a guide element of an independent needle assembly, according to a first embodiment of the present invention; 
           [0041]      FIG. 13B  is an illustration of a partial view of the independent needle assembly of  FIG. 13A , in the unlocking configuration; 
           [0042]      FIG. 13C  is an illustration of a partial view of the independent needle assembly of  FIG. 13A , in the locking configuration; 
           [0043]      FIG. 14  is an illustration of a guide element according to a second embodiment of the present invention, in the unlocking configuration; 
           [0044]      FIG. 15  is an illustration of the guide element of  FIG. 14A  in the locking configuration; 
           [0045]      FIG. 16A  is an illustration of a guide element according to a fourth embodiment of the present invention; 
           [0046]      FIG. 16B  is a front view of the guide element of  FIG. 16A  in the unlocking configuration; 
           [0047]      FIG. 16C  is a side view of the guide element of  FIG. 16A  in the unlocking configuration; 
           [0048]      FIG. 16D  is a side view of the guide element of  FIG. 16A  in the locking configuration; 
           [0049]      FIG. 17  is a side view of a guide element according to a fifth embodiment of the present invention; 
           [0050]      FIG. 18  is a side view of a guide element according to a sixth embodiment of the present invention; 
           [0051]      FIG. 19A  is an illustration of a partial view of an integrated needle assembly with a guide element in the unlocking configuration, according to an embodiment of the present invention; 
           [0052]      FIG. 19B  is an illustration of the integrated needle assembly of  FIG. 19A  with the guide element in the locking configuration; 
           [0053]      FIG. 19C  is an illustration of the integrated needle assembly of  FIG. 19A  with two three wires of the guide element retracted into the localization needle; 
           [0054]      FIG. 19D  is an illustration of a part of the guide element with a single wire which remains in the target tissue to provide orientation of the sample; 
           [0055]      FIG. 20A  is a partial side view of a coring cannula in an initial position and a final position, according to an embodiment of the present invention; 
           [0056]      FIG. 20B  is a front view of the coring cannula of  FIG. 20A ; 
           [0057]      FIG. 21A  is a partial side view of the coring cannula of  FIG. 20B  during initial advanced of a flexible transection blade; 
           [0058]      FIG. 21B  is a front view of the coring cannula and flexible transection blade of  FIG. 21A ; 
           [0059]      FIG. 22A  is a partial side view of the coring cannula and flexible transection blade in a second blade position; 
           [0060]      FIG. 22B  is a front view of the coring cannula flexible transection blade in the second blade position; 
           [0061]      FIG. 23A  is a view of the flexible transection blade in an initial configuration, according to an embodiment of the present invention; 
           [0062]      FIG. 23B  is a top view of the flexible transection blade in a cutting configuration, according to an embodiment of the present invention; 
           [0063]      FIG. 23C  is a front view of the flexible transection blade in the cutting configuration showing a cutting edge, according to an embodiment of the present invention; 
           [0064]      FIG. 24  is a graphical representation of the drivetrain of the device and the flexible transaction blade in the initial position, according to a first embodiment of the present invention; 
           [0065]      FIG. 25A  is a graphical representation of the drivetrain of the device and the flexible transaction blade, of  FIG. 24 , in the final position; 
           [0066]      FIG. 25B  is a front view of the graphical representation of the drivetrain of the device and the flexible transaction blade, of  FIG. 24 , in the final position; 
           [0067]      FIG. 26  is a graphical representation of the drivetrain of the device and the flexible transaction blade in the initial position, according to a second embodiment of the present invention; 
           [0068]      FIG. 27  is a graphical representation of the drivetrain of the device and the flexible transaction blade, of  FIG. 24 , in the final position; 
           [0069]      FIG. 28A  is a first cut away view of the graphical representation of the drivetrain of the device and the flexible transaction blade, of  FIG. 24 , in the final position; 
           [0070]      FIG. 28B  is a second cut away view of the graphical representation of the drivetrain of the device and the flexible transaction blade, of  FIG. 24 , in the final position; 
           [0071]      FIG. 29  is a graphical representation of an alternative drivetrain, according to an embodiment of the present invention; 
           [0072]      FIG. 30  is a graphical representation of a second alternative drivetrain in an initial position, according to an embodiment of the present invention; 
           [0073]      FIG. 31  is a graphical representation of the second alternative drivetrain in a final position; 
           [0074]      FIG. 32A  is a graphical representation of a flexible transection blade and a coring cannula with a circular cutting ring, according to an embodiment of the present invention; 
           [0075]      FIG. 32B  is a front view of the flexible transection blade and coring cannula of  FIG. 32A ; 
           [0076]      FIG. 33A  is a graphical representation of a flexible transection blade and a coring cannula with a partial cutting ring, according to an embodiment of the present invention; 
           [0077]      FIG. 33B  is a front view of the flexible transection blade and coring cannula of  FIG. 33A ; 
           [0078]      FIG. 34A  is a graphical representation of a flexible transection blade which forms the cutting edge of the coring cannula, according to an embodiment of the present invention; 
           [0079]      FIG. 34B  is a front view of the flexible transection blade and coring cannula of  FIG. 34A ; 
           [0080]      FIG. 35  is a graphical representation of a prior art coring cannula with an internal cutting ring; 
           [0081]      FIG. 36A  is a graphical representation of a coring cannula with an angled cutting ring, according to an embodiment of the present invention; 
           [0082]      FIG. 36B  is a front view of the coring cannula and cutting ring of  FIG. 36A ; 
           [0083]      FIG. 37A  is a first view of a garrote wire for use with the cutting ring of  FIGS. 36A and 36B ; 
           [0084]      FIG. 37B  is a second view of a garrote wire for use with the cutting ring of  FIGS. 36A and 36B ; 
           [0085]      FIG. 37C  is a third view of a garrote wire for use with the cutting ring of  FIGS. 36A and 36B ; 
           [0086]      FIG. 38A  is a graphical representation of a coring cannula with an external cutting ring, according to an embodiment of the present invention; 
           [0087]      FIG. 38B  is a view of a portion of the coring cannula and external cutting ring of  FIG. 38A ; 
           [0088]      FIG. 39  is a graphical representation of a coring cannula with an external cutting ring, according to an other embodiment of the present invention; 
           [0089]      FIG. 40  is a graphical representation of a prior art coring cannula with a cutting ring; 
           [0090]      FIG. 41  is a graphical representation of a coring cannula with a cutting ring, according to an embodiment of the present invention; 
           [0091]      FIG. 42A  is a side view of a prior art coring cannula and stylet; 
           [0092]      FIG. 42B  is a front view of the prior art coring cannula and stylet of  FIG. 42A ; 
           [0093]      FIG. 43A  is a side view of a coring cannula and a collapsible stylet in an initial configuration, according to an embodiment of the present invention; 
           [0094]      FIG. 43B  is a first front view of the coring cannula and stylet of  FIG. 43A ; 
           [0095]      FIG. 43C  is a side view of the coring cannula and stylet of  FIG. 43A  in a contracted configuration; 
           [0096]      FIG. 43D  is a second front view of the coring cannula and stylet of  FIG. 43A  with the stylet in the contracted configuration; 
           [0097]      FIG. 44  is a view of a prior art stylet; 
           [0098]      FIG. 45  is a view of a stylet including an independent stylet mechanism, according to an embodiment of the present invention; 
           [0099]      FIG. 46A  is a first view of an expanding localization needle, according to an embodiment of the present invention; 
           [0100]      FIG. 46B  is a second view of the expanding localization needle of  FIG. 46A ; 
           [0101]      FIG. 46C  is a view of the expanding localization needle of  FIG. 46A  with an actuation mechanism, according to a first embodiment of the present invention; 
           [0102]      FIG. 46D  is a view of the expanding localization needle of  FIG. 46A  with an actuation mechanism, according to a second embodiment of the present invention; 
           [0103]      FIG. 47A  is a first view of an expanding localization needle, according to an other embodiment of the present invention; 
           [0104]      FIG. 47B  is a partial view of the expanding localization needle of  FIG. 47A ; 
           [0105]      FIG. 48A  is a first view of a stylet with a rotating blade, according to an embodiment of the present invention; 
           [0106]      FIG. 48B  is a second view of the stylet with the rotating blade of  FIG. 48A ; 
           [0107]      FIG. 49  is an illustration of a stylet with multiple rotating blades, according to an embodiment of the present invention; 
           [0108]      FIG. 50A  is a graphical representation of a portion of a breast biopsy device with a garrote wire and a trigger mechanism includes a pair of cleats; 
           [0109]      FIG. 50B  is a second graphical representation of the breast biopsy device of  FIG. 5A ; 
           [0110]      FIG. 50C  is a third graphical representation of the breast biopsy device of  FIG. 50A ; 
           [0111]      FIG. 50D  is a fourth graphical representation of the breast biopsy device of  FIG. 50A ; 
           [0112]      FIG. 51A  is a graphical representation of another embodiment of the trigger mechanism of  FIG. 50A ; 
           [0113]      FIG. 51B  is a graphical representation of a further embodiment of the trigger mechanism of  FIG. 50A ; 
           [0114]      FIG. 52A  is a top view of a graphical representation of a top view of a breast biopsy device having a rotatable trigger, according to an embodiment of the present invention; 
           [0115]      FIG. 52B  is a side view of the breast biopsy device of  FIG. 52A ; 
           [0116]      FIG. 52C  is a second view of the breast biopsy device of  FIG. 52A ; and 
           [0117]      FIG. 52D  is a third view of the breast biopsy device of  FIG. 52A . 
           [0118]      FIG. 53  is an isometric view of a breast compression device; 
           [0119]      FIG. 54  is a top view of a breast compression device according to a second embodiment; 
           [0120]      FIG. 55  is a top view of a breast compression device according to  FIG. 54  illustrating compression of a breast; 
           [0121]      FIG. 56  is a front view of a breast compression device according to  FIG. 54  illustrating compression of a breast; and 
           [0122]      FIG. 57  is a top view of a breast compression device with a partial side view of a biopsy device. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0123]    Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, the present invention provides a device and method for allowing a surgeon to compress and support a breast from which a tissue sample may be excised. 
         [0124]    An exemplary breast biopsy device  10  and a method of operating the breast biopsy device  10  are disclosed herein. With reference to  FIG. 1 , in one aspect of the present invention, the breast biopsy device  10  is embodied in a handheld device  12 . It should be noted that the present invention may be embodied in a fixed device (not shown). 
         [0125]    The handheld device  12  may include a housing  14  (see  FIG. 10 ) and a handle  16 . In one aspect, the housing  14  is removable from the handle  16 . The handle  16  is reusable. The housing  14  (and all parts contained therein) are disposable and generally provided sterile. In one aspect of the present invention, the device  10  may include an integrated needle assembly  18  (described below). In another aspect of the present invention, the device  10  may include an independent needle assembly  18 ′ (described below). 
         [0126]    With particular reference to  FIGS. 10, 11 and 12 , the housing  14  may include an inner passage  22  (see  FIG. 10 ). A coring cannula  20  is slidably mounted within the inner passage  22  of the housing  14 . The coring cannula  20  has a longitudinal axis  24  and may include a shaft  26  centered on the axis  24 . 
         [0127]    In one embodiment, the coring cannula  20  is coupled to the housing such that rotational movement of the coring cannula  20  about the axis  24  results in linear movement of the coring cannula  20  along the axis  24 . As discussed more fully below, the coring cannula  20  has a cutting edge allowing it to cut through tissue as it is rotated and advanced. 
         [0128]    It should be noted that in other embodiments, the coring cannula  20  may simply rotate within the housing  14 . Linear movement of the coring cannula  20  (to advance the device  10  and the coring cannula  20  into the breast) may be provided by external mechanical means or by the user. 
         [0129]    The breast biopsy device  10  includes a stylet  28 , which includes a stylet housing  38 . With particular reference to  FIG. 11 , the stylet includes a tip  30 . The tip  30  includes at least one blade  32  and a central passage  34 . The tip  30  may also include a slot  31  for the at least one blade  32 . 
         [0130]    In one embodiment of the present invention, the stylet  28  is mounted within the coring cannula  20 . The stylet  28  includes first and second blades  32 A,  32 B integrated between two half portions  38 A,  38 B of a stylet housing  38 . The stylet  28  transects, dilates, and separates tissue as the device  10  is inserted or advanced towards the biopsy site. 
         [0131]    A drive assembly  40  mounted within the housing  14  and the handle  16  (see  FIGS. 7 and 9 ) rotates the cannula  20  and controllably rotates the cannula  20 . In one embodiment, the drive assembly  40  also moves the cannula  20  in a direction parallel to (and along) the axis  24 . In one aspect, the coring cannula  20  has a predetermined linear advancement per revolution of the coring cannula  20 . In one embodiment, the predetermined linear advancement is 0.050 inches per revolution. In an other embodiment, the predetermined linear advancement is 0.084 inches per revolution. 
         [0132]    The drive assembly  40  may include a motor assembly comprised of a DC motor and step down transmission  42  and a drivetrain  44 . The DC motor and step down transmission  42  is coupled to the drivetrain  44  ( FIG. 9 ). The drive assembly  40  and the drivetrain  44  are explained more fully below. 
         [0133]    In one aspect of the present invention, the drive assembly  40  rotates the coring cannula  20  as a single speed, for example, at or around 80 revolutions per minute. Alternatively, the drive assembly  40  rotates the coring cannula  20  at a variable speed (see below). 
         [0134]    The needle assembly  18 ,  18 ′ may include a localization needle  54 . The localization needle  54  has an inner channel  56  and is slidably removable from the central passage of the stylet  28 . The needle assembly  18 ,  18 ′ further includes a guide element  52  (see  FIGS. 4  and  5 A). The guide element  52  is used to secure the tissue while the coring cannula  20  is advanced. 
         [0135]    In one embodiment of the present invention, the guide element  52  has a first end  58  and a second end  60 . The first end  58  of the guide element  52  is slidably disposed within the channel  56  of the localization needle  54 . 
         [0136]    In one embodiment, the guide element  52  is composed, at least in part, of a metal alloy. In one embodiment, the metal alloy is composed of nickel and titanium. In one embodiment, the metal alloy is nitinol. 
         [0137]    A locking member  62  is formed at the second end  60  of the guide element  52 . The locking member  62  has an unlocking configuration and a locking configuration. The locking member  62  is in the unlocking configuration when the guide element  52  is in the first position, i.e., fully contained within the localization needle  54  (see  FIG. 13B ). The locking member  62  is in the locking configuration when the guide element  52  is in the second position, i.e., then the locking member  62  is outside of the localization needle  54  (see  FIG. 13C ). In the illustrated embodiment, the locking wire  62  is formed of multiple wires  64 , e.g., two, which are predisposed toward the locking configuration. When the guide element  52  is slid back into the localization needle  54 , the inner channel  56  of the localization needle  54  constrains and confines the wires  64  in the unlocking configuration. Once the guide element  52  is slid towards and into the second position, the wires  64  are freed from the constraints on the localization needle  54  and allowed to move toward and into the locking configuration. 
         [0138]    In one aspect of the present invention, the locking configuration is defined by a predefined shape of the wires  64 . In one embodiment, the predefined shape is a hook shape. 
         [0139]    In one embodiment, wires (not shown) may be wrapped around the wires  64  to provide rigidity to allow the guide element  52  to be moved within the localization needle  54 . The number of wires  64 , as well as the diameter of the wires  64  (and wires used to provide rigidity) is optimized to provide maximize holding and as a function of the type of targeted tissue, e.g., hard or soft tissue. 
         [0140]    With reference to  FIGS. 14 and 15 , in another embodiment of the present invention, the locking member  62  may include a twisted pair of wires  66 . The guide element  52  is shown in the first position in  FIG. 14  with the twisted pair of wires  66  in the unlocking configuration. The guide element  52  is shown in the second position in  FIG. 15  with the twisted pair of wires  66  in the locking configuration. 
         [0141]    With reference to  FIGS. 16A, 16B, 16C, and 16D , in another embodiment of the present invention, the locking member  62  is formed from braided wire or cable  68 . As shown, in one embodiment, the distal ends of the cables may be straightened and then formed into a predetermined shape, such as a hook shape. The number of wires or cables may vary, e.g., the braided wire or cable may include 4, 7 or any number of individual wires or cables. The guide element  52  is shown in the first position in  FIG. 16C  with the braided cable  68  in the unlocking configuration. The guide element  52  is shown in the second position in  FIG. 16D  with the braided cable  68  in the locking configuration. 
         [0142]    With reference to  FIGS. 17 and 18 , in another embodiment, the guide element  52  may include a pushrod  70  and at least two flexible fingers  72 A,  72 B. In one embodiment, the pushrod  70  and flexible fingers  72 A,  72 B are unitarily formed ( FIG. 17 ). In another embodiment, the flexible fingers  72 A,  72 B are affixed to the pushrod  70  ( FIG. 18 ). 
         [0143]    In one aspect, the flexible fingers  72 A,  72 B may be predisposed towards the locking configuration through a heat treat process. 
         [0144]    Returning to  FIGS. 7 and 9 , in one embodiment of the present invention, the drive assembly  40  may include a variable speed circuit  74  electrically coupled to the motor assembly  42 ,  44 . A forward/reverse switch  76  is electrically coupled to the variable speed circuit  74 . A speed control trigger  78  is electrically coupled to the variable speed circuit  74 . The forward/reverse switch  76  controls the direction of the DC motor  42 , and thus, the direction of movement (forward/reverse) of the cannula  20  along the axis  24 . 
         [0145]    The variable speed circuit  74  controls the speed and rotation of the cannula  20  as a function of the forward/reverse switch  76  and actuation of the speed control trigger  78 . In one aspect, the variable speed circuit  74  has a predetermined speed range, for example 0-100 revolutions per minute. 
         [0146]    The DC motor and transmission  42  is powered by a rechargeable battery  46 , which may be charged via an external power source (not shown) through recharging port  48 . In one embodiment, the rechargeable battery  46  is a lithium ion battery. 
         [0147]    The DC motor and transmission  42  is used to provide low speed and high torque to the drivetrain  44 . A drive gear  50  is directly coupled between the motor  42  and the drivetrain  44 . 
         [0148]    With specific reference to  FIGS. 7, 8, and 9 , the drivetrain  44  may include a spline gear  80 , a spline gear support  82 , a lead screw  84 , a shaft  86 , and a ring gear transmission  88 . The spline gear  80  is contained with the housing  14  and is supported by the spline gear support  82 . The drive gear  50  engages the spline gear  82  to transfer power to the drivetrain  44 , and thus, the coring cannula  20 . 
         [0149]    The speed of the DC motor  42  is controlled by user actuation of the speed control trigger  78 . The variable speed circuit  74  enables variable speed ramp up and slow down. In one embodiment, a speed range of approximately 0-100 rpm at the cannula may be provided. 
         [0150]    The drivetrain  44  is contained within the housing  14 , which is removable coupled to the handle  16 . When the device  10  is assembled, the spline gear  80  engages the drive gear  50  within the handle  16 . Power transferred through the drive gear  50  causes rotation of the spline gear  80 . The spline gear  80  is attached to the spline gear support  82 . The spline gear support  82  is keyed to the shaft  86 . The spline gear support key  82  provides rotation to the shaft  86  while allowing it to move axially (along axis  24 ). The lead screw  84 , which is fixed to the housing  14 , is engaged with threads at the proximal end of the shaft  86 . The coring cannula  20  is attached to the shaft  86 . As the shaft  86  is rotated, the threaded engagement with the lead screw  84  creates axial movement of the coring cannula  20 . 
         [0151]    As the cannula  20  rotates, it continues to move forward for a distance determined by the thread length on the lead screw  84 . As the shaft  86  reaches the end of the threads, it will continue to rotate, but will no longer move forward. The timing is designed such that when the shaft  86  reaches the end of the threaded section of the lead screw  84 , the transmission lockout (lock out button  90 ) engages. With the lock out button  90  engaged, the ring gear assembly  88  is activated and begins to advance a drive dog  92  forward along the drive screw  50 . 
         [0152]    The drive dog  92  is coupled to a severing mechanism  94  which is used to sever the tissue contained within the coring cannula  20 , which is described more fully below. 
         [0153]    The general process of utilization of the device will now be described. First, the localization needle  54  is advanced into the breast under ultrasound guidance. In one aspect of the present invention, this is performed manually. For instance, with the handheld device  10 , the user manually inserts the needle  54  by positioning and manually moving the device  10 . When the needle  54  reaches the target area, the tissue anchor or locking member  62  is advanced to secure the tissue prior to advancement of the device  10 . Next, the localization needle  54  is released allowing the device  10  to move independently of the needle  54 . The device  10  is now advanced into the breast, with the stylet blades  32  separating the tissue up to the target area. When the device  10  has reached the target area, the coring cannula  20  is advanced. The cannula  20  is advanced by depressing the speed control trigger  78  on the handle  16 , with the forward/reverse switch  76  in a forward position. When the cannula  20  reaches its full core length, the severing mechanism  94  is actuated, separating the tissue core from surrounding tissue. In one embodiment, the severing mechanism  94  may include a flexible blade (see below) will automatically advance from the distal end of the coring cannula  20 . After the core of tissue has been cut free, the device  10  is removed from the breast. With the device out of the breast, the forward/reverse switch  76  is placed in a reverse position and the flexible blade is retracted using the speed control trigger  78  allowing the tissue sample to be retrieved from the coring cannula. 
         [0154]    As stated above, in one aspect of the present invention, an integrated needle assembly  18 , as shown in  FIG. 1  and demonstrated in  FIGS. 2A, 2B, 2C, and 2D , may be provided. With the integrated needle assembly  18 , the needle assembly  18  and the coring cannula are integrated into a single unit  18 ,  20  (see  FIG. 2A ). With the integrated needle assembly  18 , the needle assembly  18  is inserted within the central passage  34  of the stylet housing  38  when the localization needle  54  is inserted into the breast ( FIG. 2B ). Once the localization needle  54  reaches the target tissue, a locking member actuation button  96 , located on the top of the housing  14  is slid forward. The actuation button  96  is linked to the locking member  62  resulting in the locking member  62  being slid out of the localization needle  54  securing the target tissue. 
         [0155]    Once the target tissue is secured, the localization needle  54  and locking member  82  are released from the housing  14  by actuation of one of the localization needle release button(s)  98  located thereon. This allows the device  10  to be slid up localization needle  54  (the stylet blades  32  separating the tissue allowing the stylet  28  and coring cannula  20  to pass. Once the coring cannula  20  is adjacent the target tissue, the process proceeds as above. 
         [0156]    Then, the device  10  would be fed down the guide rod  104  and the process would proceed as above (see  FIG. 5A ). 
         [0157]    With respect  FIG. 5B , the central passage  34  is formed by the stylet tube  36 . The stylet tube  36  includes an opening  106  which allows the needle assembly  18 ,  18 B′ to pass into the central passage  34 . The stylet tube  36  also may include a guide portion  108  which extends past the opening  106  to assist in the placement of the guide rod into the central passage  34 . 
         [0158]    In another aspect of the present invention, an independent needle assembly  18 ′ may be provided (see  FIGS. 3, 4A, 4B, 5A, 5B ). The independent needle assembly  18 ′ is separate from the coring cannula  20 . The independent needle assembly  18 ′ includes a localization needle  54 ′, an independent needle handle  100 , and a plunger  102 . The localization needle  54 ′ is inserted into the breast tissue using the handle  100 . Once the target tissue is reached, the plunger  102  is pushed forward. The locking member  62  is pushed forward by the plunger  102 , pushing the wires  64  into the target tissue, thereby securing the target tissue. The localization needle  54 ′ (and handle  100 ), may thereafter be removed, leaving the locking member  62  within the breast with a guide rod  104  extending out of the breast (see  FIG. 4B ). 
         [0159]    The localization needle  54 ′ has a first end  54 A′ and a second end  54 ′. The localization needle includes an internal channel or bore  56 . The handle  100  has first and second ends  100 A,  100 B and an internal bore  268 . The first end  54 A of the needle  54 ′ is fixed to the second end of the handle  100 B. The internal bore  56  of the needle  54 ′ and the internal bore  268  of the handle  100  form an assembly bore  270  therethrough. In the illustrated embodiment, the guide element  52  has a guide rod  104  and a locking member  62 . The guide element  104  has first and second ends  58 ,  60  and is removably contained within the assembly bore  270 . The locking member  62  is fixed to the second end  60  of the guide rod  104 . The plunger  102  includes a pushrod  102 B and an actuation element  102 A coupled to the pushrod  102 B. The plunger  102 A is movable from a first state ( FIG. 4A ) to a second state ( FIG. 4B ) One end of the pushrod  102 B acts on the first end  58  of the guide rod  104 , forcing the locking member  62  out of the needle  18 ′ as the pushrod  102  is moved from the first state to the second state. 
         [0160]    With reference to  FIGS. 19A-19D , in one embodiment one of the wires  64 ′ from the locking member  62  is detachable from the pushrod  70 . It should be noted that although  FIGS. 19A-19D  illustrated this feature with respect to the independent needle assembly  18 , the detachable wire  64 ′ concept may also be used with the integrated needle assembly  18 ′. 
         [0161]    As shown in  FIG. 19A , the locking member  62  is contained within the localization needle  54  when the localization needle is initially inserted into the breast tissue. When the localization needle  54  reaches the target tissue, the locking member  62  is deployed as discussed above ( FIG. 19B ) to secure the target tissue. Then the cannula  20  is advanced over the target tissue and severed using the severing mechanism  94  (see above). Once the device  10  has been removed from the breast, the localization needle  18 ′ may be used to push the severed tissue from the cannula  20 . The tissue anchors or wires  64  may then be retracted. The third hook  64 ′ may either not be attached to the pushrod  70  or may be detachable therefore. The third hook or wire  64 ′ remains attached or secured to the tissue to provide an orientation marker for the sample during pathology (see  FIG. 19D ). 
         [0162]    In another aspect of the present invention, the guide rod  104  may include scale markings  110  to provide an indication to the user the depth of the anchor/guide element  52  within the breast, as shown in  FIGS. 13A and 19B . 
         [0163]    In another aspect of the present invention, the biopsy device  12  includes a flexible transection blade  112 . The flexible transection blade  112  is a flat metal blade with one end sharpened is formatted to the required radius (see below). The blade thickness and material properties as such that the formed flexible transection blade  112  can be flattened out will “spring” back to its formed shape. The blade  112  will be held in a flat position along the side of the coring cannula. 
         [0164]    The coring cannula  20  will use an angled or non-continuous cutting ring (see below) at the completion of the coring process. As shown in  FIGS. 20A and 20B , the coring cannula  20  is movable along the axis  24  from an initial cannula location  118  (shown in dotted lines) to a final cannula location  120  in response to rotation of the coring cannula  20  about the axis  24  in a first direction. 
         [0165]    In one embodiment, once the coring cannula  20  reaches the final cannula location  120 , it will continue to rotate but will not advance axially forward. A mechanism  122  will be engaged to drive the flexible transection blade  112  forward. The flexible transection blade  112  exits the coring cannula  20  at a point slightly distal to the cutting edge of the coring cannula  20  (see  FIGS. 21A and 21B ). As the flexible blade  112  is driven out of the cannula  20 , it will begin to return to its pre-formed curvature. Since this advancement is taking place while the coring cannula  20  is rotating, the result will be a curved, complete cut through the tissue. The path of the blade  112  is designed to intersect with the distal end of the cutting path from the coring cannula  20 , resulting in complete transection and release of the tissue specimen. 
         [0166]    With reference to  FIGS. 23A, 23B, and 23C , in one embodiment the flexible transection blade  112  consists of a thin strip  124  of spring steel or nitinol. The flexible transection blade  112  has a first end  126  and a second or distal end  128 . The flexible transection blade  112  is coupled to the coring cannula  20  at the first end  126 . The distal end  128  of the flexible transection blade  112  is cut to an optimized angle and sharpened to a cutting edge  114  (see  FIG. 23C ). A hole mount  130  may be provided for mounting the blade  112  to the drive assembly  40 . 
         [0167]    In one embodiment as shown in  FIGS. 8 and 9 , the flexible transection blade  112  is stored in a channel  116  built into the coring cannula  20 . The flexible transection blade  112  is held flat in this stored position. At the completion of the coring process, the coring cannula  20  will cease axial advancement, but will continue to rotate. During this rotation the flexible blade  112  is driven forward, advancing past the coring cannula  20 . As the flexible blade  112  advances, it will assume its pre-formed, curved position. Rotation causes the flexible blade  112  to create a semi-circular cut in the tissue. When the flexible transection blade  112  advances past the center of rotation, a complete cut results, releasing the tissue core. The curved blade  112  holds the tissue core inside the cannula  20  until removed from the breast. 
         [0168]    The flexible transection blade  112  has a first blade position and a second blade position. The flexible transection blade  112  is in the first blade position while the coring cannula  20  is between the initial and final cannula locations  118 ,  120 . As shown in  FIG. 20A , in one embodiment, when the flexible transection blade  112  is in the first blade position it is contained within the coring cannula  20 , and thus, not visible. Rotation of the coring cannula  20  in the first direction while the coring cannula  20  is at the final cannula location  120  rotates the flexible transection blade  112  about the axis  24 , moving the flexible transection blade  112  from the first blade position to the second blade position (shown in  FIG. 22B ). 
         [0169]    Testing has revealed a few key elements of the invention. First, the most efficient cutting of tissue is accomplished by creating relative motion between cutting surface, i.e., the cutting edge  114 , and tissue. Second, the relationship between the cutting edge  114  and the rate of advancement of the length and angle of the cutting edge  114  must result in a cutting surface that is greater in length than the linear advancement per revolution. Further, the rate of advancement per revolution should be optimized to minimize cutting forces. This approach will ensure that a thin, flexible blade  112  will follow the desired cutting path. 
         [0170]    With particular reference to  FIGS. 24, 25A, and 25B , in one embodiment the mechanism  122  may include a friction wheel transmission  132 . The friction wheel transmission  132  includes friction wheel  134  which is force fit over the shaft  26 . The shaft  26  is directly coupled to the cannula  20  through a drive ring  20  which is fixed to the housing  14 . A drive screw  136  is fixed to the friction wheel  134 , which is coupled to the flexible transection blade  112 . As the shaft  26  is advanced by the drive assembly  40 , the friction wheel  134 , and thus the flexible transection blade  116  is also advanced. The friction wheel  134  is force fit over the shaft  26  such that the transmission force may be controlled. The relationship between the friction wheel  134  and the drive ring  136  and/or the relationship between the friction wheel  134  and the shaft  26  can be adjusted so that if the force encountered by the flexible transection blade  112  increases to a certain point, the friction wheel  134  will slip on the shaft  26  preventing further advancement of the blade  112 . The blade  112  will continue to rotate until the sample tissue has been cut and the forces reduced. Blade advancement will then automatically resume. 
         [0171]    With particular reference to  FIGS. 26, 27, and 28 , in another embodiment the mechanism  122  may include a gear drive transmission  140 . The gear drive transmission  140  provides continuous drive with maximum power transfer. In one aspect of the present invention, the gears within the gear drive transmission  140  remain meshed but do not rotate during axial advancement of the coring cannula  20 . When advancement of the coring cannula  20  is complete, the gear drive transmission  140  automatically engages and begins to drive the flexible transection blade  112 . 
         [0172]    The gear drive transmission  140  may include a gear housing  146 , a ring gear  150 , and a drive gear  152 . A plunger  144  is slidably coupled to the gear housing  146  and is spring biased in an outward direction. While the coring cannula  20  is between the initial cannula location  118  and the final cannula location  120 , plunger  144  is pressed inwardly by the inner wall of the housing  20  such that one end is inserted a receiving slot  148  on the shaft  26 . Thus, the gear housing  146  is locked relative to the shaft  26 . The shaft gear housing  146  thereby rotates with the shaft  26 , and there is no relative motion between the gears  140 ,  152 . When the gear housing  146  reaches a release slot  154  in the housing  14 , the spring biased plunger  144  slides into the release slot  154 , thereby releasing the shaft  26 , the ring gear  150  is fixed relative to the housing  14  and the drive gear  152  rotates with the shaft  26 , thereby driving the flexible transection blade  112  forward. 
         [0173]    With particular reference to  FIG. 29 , in still another embodiment a lead screw  156  is used to enable the shaft  26  to advance and rotate, stop advancing but continue rotating and then retract to its original position. The shaft  24  includes an opening  158  leading to a shaft threaded section  160 . The lead screw  156  is rotatably fixed to the housing  14  and includes a first end portion  162 , a second end portion  164 , and a lead screw threaded section  166 , which meshes with the shaft threaded section  160 . 
         [0174]    The shaft  26  is driven forward (to the right in  FIG. 29 ) until the back edge of shaft  174  reaches the front edge of lead screw threads  178 . At this position, the shaft  26  will continue to rotate but no longer advances. The shaft threaded portion  160  is supported by shoulder  180 . A first spring  168  makes contact with surface  172  exerting a slight backward force on the shaft  26 . 
         [0175]    When the drive assembly  40  is reversed, the force exerted on surface  172  by the first spring  168  urges re-start of threads between the shaft  26  and the lead screw  156 . The shaft  26  will then move backward until the contact surface  176  clears the surface  172 . A second spring  170  now provides force to urge restart in the forward direction. 
         [0176]    This configuration may also be adopted to drive the flexible transection blade  112 . 
         [0177]    With particular reference to  FIG. 30  in still another embodiment, a drive screw  184  may be used to drive motion of the flexible transection blade  112 . A drive gear  182  is fixed to the drive screw  184  which is threadably coupled to the drive dog  186 . During forward motion of the coring cannula  20 , the drive dog  186  is allowed to slip relative to the drive screw  184 . During activation of the flexible transection blade  112 , the drive gear  182 , and thus, the drive screw  184  rotate. The drive dog  186  has an internal threaded bore (not shown) which is mated with the drive screw  184 . As the drive screw  184  rotates, the drive dog  186  advances (or retracts) along the screw  184 , thereby advancing the flexible transection blade  112 . 
         [0178]    With particular reference to  FIG. 31 , in a further embodiment, a modification is shown. In the illustrated embodiment, the drive dog  186 ′ is fixed to an end of the drive screw  184 ′. The drive gear  182 ′ has in internal threaded bore (not shown) which is mated with the drive screw  184 ′. As the drive gear  182 ′ rotates, the drive screw  184 ′ and the drive dog  186 ′ advances or retracts. 
         [0179]    As discussed more fully below, the cutting edge  114  of the cutting cannula  20  may be formed by a cannula insert  188  and may have different configurations. 
         [0180]    With particular reference to  FIGS. 32A and 32B , the cannula insert  188  forms a circular coring blade  190 . As shown the flexible transection blade  112  advances past the circular coring blade  190 . The flexible blade  112  transects tissue distal to the front edge of cutting ring  190 . 
         [0181]    With particular reference to  FIGS. 33A and 33B , in another embodiment the cannula insert  188  forms a partial cutting ring  192 . The partial cutting ring  192  forms a partial cutting face  194  with an angled edge  196 . As the coring cannula  20  rotates, the angled edge  196  cuts through the tissue. As shown, with the partial cutting ring  192 , the flexible transection blade  112  does not extend past the furthermost edge of the partial cutting rung  192 . Thus, the tissue sample is confined within the cutting ring  192 . 
         [0182]    With particular reference to  FIGS. 34A and 34B , in still another embodiment, the cutting edge  114  of the flexible transection blade  112  is used to core the sample tissue ( FIG. 34A ). The flexible transection blade  112  is then advanced to transect tissue ( FIG. 34B ). 
         [0183]    With particular reference to  FIG. 35 , a prior art cutting ring  200  is shown. The prior art cutting ring  200  is nestled within a bore  202  of the distal end of the cutting cannula  20 . As shown, the coring cannula  20  has an inner diameter of d 1  and the cutting ring  200  has an inner diameter of d 2 . In the prior art device shown in  FIG. 35 , d 1  is substantially equally to d 2 . The outer surface of the coring cannula  205  has a ramping surface  206  from the outer dimension of the coring cannula  205  to the distal end of the coring cannula  205 . As shown, the outer diameter of the coring cannula d 4  is greater than the outer dimension, d 3 , of the prior art cutting ring  200 . 
         [0184]    In the prior art cutting ring  200  of  FIG. 35 , the mechanism for transecting the tissue sample is a garrote wire  204  which transverses the outer wall of the coring cannula  20 . At a location near the distal end of the coring cannula  205  the garrote wire  204  forms a right angle and encircles the inner diameter of the coring cannula  20 . As shown, this occurs at a substantial distance, d 5 , from the distal end of the cutting ring  200 . This arrangement presents two problems. First, the 90 degree bend in the garrote wire  204  significantly increases the force required to pull the garrote wire and transect the tissue. Second, the large distance, d 5 , between the garrote wire  204  and the cutting edge of the cutting ring  200 , results in a core of tissue, or tissue plug, which is cored by the coring cannula  205 , but not transected by the garrote wire. This cored tissue thus remains in the breast. 
         [0185]    With particular reference to  FIGS. 36A and 36B , in one embodiment a partial cutting ring  208  may be provided. The illustrated partial cutting ring  208  may include a face cutting surface  208 A, which has a cutting edge perpendicular to the axis  24 , and a side cutting surface  208 B. The use of the side cutting surface  208 B introduces side cutting. Side cutting is less likely to result in unwanted pushing or movement of tissue. Additionally, the blade angle allows the garrote wire  210  to be installed outside of the coring blade and then clear of the cutting ring when retracting. This also limits the tissue plug problem identified above. Furthermore, the angle in the garrote wire  210  may be increased (as shown), reducing the required transection forces (see  FIGS. 37A, 37B, 37C ). 
         [0186]    With reference to  FIGS. 38A, 38B, and 39  in an other aspect of the present invention, the coring cannula  20  may include an external cutting ring  198 . The external cutting ring  198  has an interior bore  212  within an interior diameter, d 2 . The coring cannula  20  has a reduced diameter portion  214  at its distal end. As shown, the external cutting ring  198  is fitted over the reduced diameter portion of the coring cannula  214 . As shown, the outer diameter (d 4 ) of the coring cannula  20  is substantially equal to the outer diameter of the external cutting ring, d 3 . 
         [0187]    As shown, the transecting mechanism  122  may include a garrote wire  210 . 
         [0188]    With specific reference to  FIGS. 38A and 38B , in one embodiment the garrote wire  210  is removably coupled to the coring cannula  20  by one or more bent tabs  216  formed integrally with the coring cannula  20 . The one or more bent tabs  216  may be integrally formed with the coring cannula  20 . The mechanism  122  is located at the distal end of the coring cannula  20 . The distal end of the coring cannula  20  is within a minimal distance of the distal end of the external cutting ring  198 . This minimizes the tissue plug problem discussed above. In one embodiment, the minimal distance is ≦0.25 inches. 
         [0189]    With specific reference to  FIG. 39 , the distal end of the external cutting ring  198  is spaced from the distal end of the coring cannula  20 . In the illustrated embodiment, the mechanism  122  is located at the distal end of the external cutting ring  198 . The mechanism  122  is within the minimal distance of the distal end of the external cutting ring  198 . The garrote wire may be removably held in place by one or more tabs  218  which may be formed integrally with the cutting ring  198 . 
         [0190]    With particular reference to  FIG. 41 , in one aspect of the present invention, the coring cannula  20  may be provided with a cutting ring in which the inner diameter of the coring cannula  20  has an inner diameter which is smaller than the inner diameter of the cutting ring. Tissue is flexible, malleable and compressible. With the inner diameter of the coring cannula  20  being smaller than the inner diameter of the cutting ring, the tissue sample is compressed as it enters the coring cannula  20  (behind the cutting ring). Compression of the tissue sample results in better retention of the tissue sample in the cannula  20 . Additionally, with the reduced inner diameter of the cannula  20 , the outer diameter of the cannula  20  may also be reduced, until it is the equal to or nearly equal to the outer diameter of the cutting ring. This results in (1) a smaller entry incision and (2) reduction of the required coring cutting force. 
         [0191]    With particular reference to  FIG. 40 , a prior art cannula  222  is shown. The prior art cannula  222  has a cutting ring  224 . The prior art coring cannula  222  has an inner diameter (d 1 ) which is equal to the inner diameter (d 2 ) of the cutting ring  224 . Additionally, the outer diameter (d 4 ) of the prior art coring cannula  222  is greater than the outer diameter (d 3 ) of the cutting ring  224 . 
         [0192]    With particular reference to  FIG. 41 , a coring cannula  226  according to an embodiment of the present invention is shown. The coring cannula  226  has a distal end  228  and is centered on the axis  24  and is coupled to the housing  14 . The coring cannula  226  having an inner surface  230  forming a cannula bore  232 . The cannula bore  232  has an inner diameter (d 1 ) and is rotatable about the axis. A cutting ring  234  has an inner surface  236  which forms a cutting ring bore  238  and is located at the distal end of the coring cannula  226 . The cutting ring bore  238  has an interior diameter (d 2 ). A tapered wall  240  is coupled between the coring cannula  226  and the cutting ring  234 . The tapered wall  240  provides a ramped surface between the inner surface  236  of the cutting ring  234  and the inner surface  236  of the coring cannula  226 . 
         [0193]    As discussed, the inner diameter, d 1 , of the cannula bore  232  is less than the inner diameter, d 2 , of the cutting ring  234 . Furthermore, the outer diameter, d 4 , of the coring cannula  226  is equal to, or only slightly larger than, the outer diameter, d 3 , of the cutting ring  234 . 
         [0194]    In one embodiment, the coring cannula  226  and the cutting ring  234  are unitarily formed. In an other embodiment, the coring cannula  226  and the cutting ring  234  are formed separately. In one embodiment (as described above), the coring cannula  226  may have a reduced diameter portion formed at the distal end  228 . The cutting ring  234  is an external cutting ring which is fitted over the reduced diameter portion of the coring cannula. The distal end of the cutting ring  234  forms a coring cannula cutting edge  238 . 
         [0195]    With reference to  FIGS. 42A, 42B, 43A, 43B, 43C , in another aspect of the present invention a collapsible stylet may be provided (see below). With particular reference to  FIGS. 42A and 42B , a prior art stylet  242  is shown. The prior art stylet  242  is contained within the coring cannula  244 . The prior art stylet  242  has a slot  243  for the stylet blades  246 . The diameter, d 1 , of the prior art stylet  242  is fixed, and smaller than the diameter, d 2 , of the cutting edge  248  of the coring cannula  244 . Thus, in use, after the stylet  242  has cut into the tissue, the skin may need to be opened further to allow the coring cannula  244  to enter the tissue. 
         [0196]    With particular reference to  FIGS. 43A, 43B, and 43C , a collapsible stylet  250  according to one embodiment of the present invention is illustrated. The coring cannula  20  has a distal end  252 , a longitudinal axis  24  and is centered on the axis  24  (see above). The collapsible stylet  250  has a tip  254 , which contains at least one blade  256 , and a central passage  258  and is coupled to the coring cannula  20 . The tip  254  has a recess  260  located near a proximal end  262  thereof. The tip  254  is movable between an initial configuration (shown in  FIGS. 43A and 43B ) and a contracted configuration (shown in  FIGS. 43C and 43D ). When the tip  254  is in the initial configuration, the cutting edge  264  of the coring cannula  20  is within the recess  260 . This allows the coring cannula  20  to enter the incision with the stylet  250 , prior to the coring process, without the need to widen or open the incision any further. The tip  250  remains in the initial configuration as the coring cannula  20  is moved from the initial cannula location towards the final cannula location. Once the coring cannula  20  reaches the final cannula location, the tip may be moved into the contracted configuration ( FIG. 43C ). In the contract configuration, the cutting edge  264  of the coring cannula  20  is exposed when the tip  254  is in the contracted configuration. 
         [0197]    In the illustrated embodiment, the tip  254  has a first half portion  254 A and a second half portion  254 B. As shown in the illustrated embodiment, the first and second half portions  254 A,  254 B have a semi-circular cross-section (see  FIGS. 43B and 43C ) and an inner surface  268 A,  268 B. The inner surface  266 A of the first portion  254 A faces the inner surface  266 B of the second portion  254 B. The first and second half portions  254 A,  254 B have a first part  268 A,  268 B and a second part  270 A,  270 B. The second parts  270 A,  270 B are sloped and curved forming an entry segment  272 . The first and second parts  268 A,  268 B form a linear segment  274 . The linear segment  274  has an associated first diameter, (d 1 ), when the tip is in the initial configuration ( FIG. 43B ). The first diameter associated with the linear segment  274  is greater than or equal to a diameter associated with the cutting edge  248  of the coring cannula  20 . Thus, the cutting edge  248  can sit within the recess  260  prior to the coring process (see above). 
         [0198]    As shown in  FIG. 43C , when the tip  254  is in the contracted configuration the linear segment  274  has a second diameter, (d 2 ). The second diameter is less than diameter associated with the cutting edge  248  of the coring cannula  20 . This allows the coring cannula  20  to be rotated and moved forward (over the stylet) to perform the coring process. 
         [0199]    In one embodiment, the first and second half portions  254 A,  254 B are biased towards the initial configuration. In the illustrated embodiment, the collapsible stylet  250  includes a collet tube  251  and a collet closer  253 . As shown, the tube  251  includes a ramping portion  251 A and a distal end  251 B. The distal end  251 B is fitted between the first and second half portions  254 A,  254 B and bias the first and second half portions  254 A,  254 B into the initial configuration. A collet closer  253  is provided which is movable between a first position (shown in  FIG. 43A ) and a second position (shown in  FIG. 43C ). The collet closer  253  acts on the ramping portion  251 A of the collet tube  251  to compress the distal end  251 B. This allows the first and second half portions  254 A,  254 B of the collapsible stylet  250  to collapse to the contract position. The collet closer  253  may be movable from the first position to the second position by the user through actuation of a button provided on the housing  14  (not shown). 
         [0200]    With specific reference to  FIGS. 44 and 45 , in another aspect of the present invention, an independent stylet mechanism  276  is provided. With particular reference to  FIG. 44 , a prior art stylet  278  is shown. The prior art stylet  278  includes integral cutting blades  280 . Since the integral cutting blades  280  are fixed relating to the stylet tip, the distance between the blades  280  and the stylet  278  is fixed at a minimal distance. This increases the chances of inadvertent movement or compression of the tissue, i.e., “snowplowing”. 
         [0201]    With specific reference to  FIG. 45 , the independent/retractable stylet mechanism  276  includes a tube  282  and at least one stylet blade  284  affixed to the tube  282 . A stylet  286  includes a stylet tip  288  with a central passage  290 . The tube  282  is slidably disposed within the central passage  290  of the stylet  286 . 
         [0202]    In the illustrated embodiment, the stylet mechanism  276  includes first and second blades  284 A,  284 B. 
         [0203]    In one aspect, the tube  282  may include an internal bore  292  for receiving the guide element  52  (see above). 
         [0204]    The independent/retractable stylet mechanism  276  is adjustable within/along the central passage  290  of the stylet  286 . Thus, the user can adjust the distance between the blades  284  and the stylet tip  288  to reduce the chance of snowplowing occurring. 
         [0205]    With reference to  FIGS. 46A-46D and 47A-47C , in another aspect of the present invention, a localization needle with an integral locking member  294  is provided. In one embodiment, the localization needle  294  includes a needle portion  296  and a locking member  304 . The needle portion  296  having a proximal end  298 , a distal end  300  and a channel  302  formed therein. 
         [0206]    The locking member  304  is formed integrally with the needle portion  296 . As shown, the locking member  304  may be formed at the distal end  300  of the needle portion  296  and has an unlocking configuration (shown in  FIG. 46A ) and a locking configuration (shown in  FIG. 46B ). 
         [0207]    In the illustrated embodiment, in the unlocking configuration, the localization needle  294  is straight, i.e., without bends or kinks. In the locking configuration, bends, or barbs, as shown in  FIG. 46B  have been introduced into the localization needle  294 . These bends, barbs, are introduced into the localization needle  294  after the localization needle  294  has been inserted into the breast, thereby locking the localization needle  294  relative to the target tissue (see above). 
         [0208]    In one embodiment, the localization needle  294  includes an actuation device  306 . The actuation device  306  is coupled to the distal end  300  and is used to apply a force thereto (see  FIG. 46B ). The force acts to bring the distal end  300  closer to the proximal end  298 . With the proximal end  298  fixed to, for example, the housing  14  of the biopsy device  10 , the localization needle  294  collapses at the locking member  304  creating the barbs, or extensions, as shown, thereby controllably moving the locking member from the unlocking configuration to the locking configuration. 
         [0209]    In one aspect of the present invention, the actuation device  306  includes a member  308  coupled to an inner surface of the distal end  300  of the needle portion  296 . 
         [0210]    With particular reference to  FIG. 46C , in one embodiment the member  308  may include a wire  310  fixed to the inner diameter of the localization needle  294 . The wire  310  may be attached to a lever (not shown) on the housing, or some other suitable mechanism, which pulls the wire  310  back toward the proximal end  298 . 
         [0211]    In another embodiment, the member  308  is a threaded rod  312  which is received by a threaded receiving member  314  which is coupled to the inner surface of the distal end  300  of the needle portion  296 . This arrangement allows the localization needle  294  to be moved back into the unlocking configuration if the placement needs to be corrected. 
         [0212]    In another aspect of the present invention, the locking member  304  is formed by at least one pair of opposed slots  316  within the needle portion  296 . In one embodiment, the slots  316  may be laser cut from the needle portion  296 . As shown in  FIGS. 46A-46D , in one embodiment, the slots  316  may have a general rectangular shape with rounded ends. The slots  316  may include one or may directional cutouts  317  which assist in forming the extensions or barbs. The directional cutouts  317  may be triangular shaped. 
         [0213]    In another aspect of the present invention the slots  316  may have a general diamond shape, as shown in  FIGS. 47A-47C . 
         [0214]    With particular reference to  FIGS. 48A, 48B, and 49 , in another aspect of the present invention, one or more rotating circular blades  318 ,  318 A,  318 B may be used. The use of the rotating circular blades  318 ,  318 A,  318 B improves the efficiency of the stylet and reduces the risk of compression and/or tearing of the tissue as the stylet in pushed into the breast. 
         [0215]    The rotating circular blade(s)  318 ,  318 A,  318 B may be powered (see below) or may rotating freely. The rotation of the blade (s)  318 ,  318 A,  318 B whether from an external source or as a result of friction between the blade  318 ,  318 A,  318 B and the tissue, creates relative motion therebetween. 
         [0216]    With particular reference to  FIG. 48A , in one embodiment a stylet  320  is provided with a single rotating circular blade  318 . The stylet  320  is coupled to a coring cannula  322 . The coring cannula  322  has a longitudinal axis  324  and is centered on the axis  324 . The stylet  320  is coupled to the coring cannula  322 . The stylet  320  includes a stylet tube  326 . The rotating circular blade  318  is rotatably coupled to a distal end  328  of the stylet tube  326 . 
         [0217]    With particular reference to  FIG. 48B , in another embodiment, the rotating circular blade  318  is not mechanically driven, but is allowed to freely rotate. As the device  10  is advanced into the tissue, force exerted by the tissue will tend to rotate the circular blade  318 , eliminating the tendency to push/tear tissue and improving cutting efficiency. 
         [0218]    In both embodiments, the singular rotating circular blade  318  is mounted on its center point  334 . As shown, the center point  334  is centered over the stylet tube  326 . 
         [0219]    The rotating circular blade  318  defines a first plane which is parallel to the axis  324 . The axis defines a second plane. The first and second planes intersect at a right angle. The center point  334  of the rotating circular blade  318  is located on both the first and second planes. 
         [0220]    A blade drive mechanism  330  is coupled to the rotating circular blade  318  for controllably rotating the circular blade  318 . In one embodiment, the blade drive mechanism  330  may include a motor (not shown) and drive cable  332 . Alternatively, the blade drive mechanism  330  may include a rod and gearing system (not shown). 
         [0221]    With particular reference to  FIG. 49 , the stylet  320  may include a pair of offset blades  318 A,  318 B. The second blade  318 B defines a third plane which is parallel to the first plane. As shown in  FIG. 39 , the center  334 A,  334 B of the blades  318 A,  318 B are offset a predetermined distance. The first and second blades  318 A,  318 B may be mechanically driven or may be allowed to rotate freely. 
         [0222]    Returning to  FIGS. 2A-2D, 5A and 5B , in another aspect of the present invention the biopsy device  10  includes at least one retractable stylet blade  336 . The at least one retractable stylet blade  336  is part of a stylet blade mechanism  338 . The stylet blade mechanism  338  may include first and second retractable blades  336 A,  336 B, as shown. 
         [0223]    The stylet blade mechanism  338  is coupled to the coring cannula  20  via the stylet tip  30 . In one embodiment, the stylet blade mechanism  338  includes the stylet tube  36 . The at least one retractable stylet blade  336  is fixed to the stylet tube  36 . The stylet tube  36  is slidably disposed within the stylet housing  38 . The central passage  34  is formed by the stylet tube  36 . 
         [0224]    The stylet blade mechanism  338  is movable between a cutting position and a retracted position. In the cutting position, the at least one stylet blade is located a distance in front of the stylet tip  30  (as shown). In the retracted position, the at least one stylet blade  336  is located within the stylet tip  30 . 
         [0225]    In one embodiment, the stylet blade mechanism  338  may be manually moved from the retracted position to the cutting position. In one embodiment, the stylet blade mechanism  338  is spring biased towards the cutting position. 
         [0226]    As discussed above, the biopsy device  10  may further comprise a guide portion  108  formed at the end of the stylet tube  30 . The guide portion  108  extends past an opening of the stylet tube  30 . The guide portion  108  having an interior curved surface  340 . The interior curved surface  340  assists in guiding the end of the guide element  52  into the central passageway  108 . 
         [0227]    It should be noted that the stylet blade mechanism  338  and the retractable stylet blades  336  may be used with either integrated localization needle or the independent needle (see above). With respect to  FIGS. 5A and 5B , the stylet blade mechanism  338  is used with the independent needle handle assembly  18 ′. As discussed above, the independent needle handle assembly  18 ′ is inserted into the breast, the guide element  52  is extended outside of the needle  54  and the locking member  62  is affixed to the target tissue. Once the locking member  62  is locked into the target tissue, the guide element  52  is removed from the needle  54 . The guide element  52  is then inserted into central passageway  108 . 
         [0228]    With the guide element  52  within the central passageway  108  and the stylet blade mechanism  338  in the cutting position, the biopsy device  10  is slid up the guide element  52 , the stylet blades  336  cutting the tissue and allowing the device  10  to reach the target tissue. Once the target tissue is reached, the stylet blade mechanism  338  can be retracted such that the blade(s)  336  are contained within the tip  30 . The coring cannula  20  can then be advanced over the target tissue. 
         [0229]    With reference to  FIGS. 50A, 50B, 50C, 50D, 51A and 51B , in still another aspect of the present invention, a garrote wire  210  is used to transect the tissue sample. 
         [0230]    The prior art devices, which employ a garrote wire, use a linear pull “trigger” system to activate the garrote wire. A limitation of the design is the travel required to fully pull the garrote wire. This limitation becomes an issue for larger cannula sizes. As the cannula diameter increases, the length of garrote wire required to transect tissue increases resulting in an increase in required travel. The travel length is limited by the overall length of the device. Continuing to increase the device length is not a viable option. 
         [0231]    As discussed below, the breast biopsy device  10  may include a trigger mechanism  342  which includes a trigger  344  (shown diagrammatically in  FIGS. 50A-51B ). The trigger  344  is generally pulled backward to pull garrote wire  210  backward, thereby transecting the tissue sample within the coring cannula  20 . 
         [0232]    As shown in  FIG. 50A , the breast biopsy device  10  includes a pair of rotatable cleats  346  which are coupled to the housing  14  (through a trigger body  350 ) and are rotatable between a first cleat position (shown in  FIG. 50A ) and a second cleat position (shown in  FIG. 50B ). As shown, in one embodiment, the rotatable cleats  346  include a plurality of teeth  348  which grip the garrote wire  210 . The cleats  346  are coupled to the trigger mechanism  342  and when the trigger mechanism  342  is actuated, i.e., pulled backward relative to the housing  14 . Friction causes the cleats  346  to rotate, thereby engaging the teeth  348  into the garrote wire  210 . Then, as the trigger mechanism  342  is pulled backward, the cleats  346  move therewith, pulling the garrote wire  210  as well. 
         [0233]    With specific reference to  FIG. 50A , when the garrote wire  210  is in a first position, the wire  210  forms a loop  352  which is external to the coring cannula  20 . After the coring cannula  20  is extended and surrounds the sample tissue, the trigger mechanism  342  is used to complete separate the sample tissue from the breast. 
         [0234]    In one embodiment, a single actuation of the trigger mechanism  342 , e.g., a single pull of the trigger  342 , moves the garrote wire  210  from the first wire position to a second wire position in which the garrote wire  210  is within the coring cannula  20  (and the sample completely separated from the breast). 
         [0235]    In another embodiment, multiple actuations of the trigger mechanism  342 , or multiple pulls of the trigger  344 , are required. In the illustrated embodiment, two pulls of the trigger  344  are required. Each pull of the trigger  344 , moving the garrote wire a distance defined by the distance between X 1  and X 2 . 
         [0236]      FIG. 50A  shows the garrote wire  210  in an initial position with the loop  352  in its largest configuration.  FIG. 50B  shows the garrote wire  210  in an intermediate location, after the first pull of the trigger  344  (the trigger  344  and trigger body  350  are shown at full travel). 
         [0237]      FIG. 50C  shows the garrote wire  210  at the intermediate location, with the trigger body  350  returned to the initial position. In one aspect, the trigger body  350  is spring biased back to the initial position. In another aspect, the trigger body  350  may be manually moved back to the initial position. 
         [0238]      FIG. 50D  shows the garrote wire  210  at the final location, fully actuated and within the coring cannula  20 . At this point, the sample is completely severed from the breast. 
         [0239]    This improvement to the linear pull system will enable the use of larger cannula sizes to provide for multiple pulls of the trigger  344  on the garrote wire  210 . Multiple pulls can be accomplished using the breakaway cleat system. The cleat system works as follows: When the trigger  348  is pulled, cleats  346  with separated edges or teeth  348  grip the garrote wire  210 , allow the trigger  344  to pull the wire  219  the full length of travel. At the end of travel, the trigger  344  is pushed forward back to the start position. When the trigger  344  is moved in this direction, the cleat  346  (cam) disengages the wire so that the trigger  344  slides forward without affecting the wire  210 . As the trigger  344  is pulled back, the cleats  346  re-engage the wire  210 , pulling it to further transect tissue. This process is repeated until transection is completed. 
         [0240]    With reference to  FIG. 51A  in a further embodiment, a second pair rotatable cleats  354  may be fixed directly to the device  10 , e.g., directly to the housing  14 . The second pair of rotatable cleats  354  are not fixed to the trigger body  350 . The second pair of cleats  354  prevented undesirable forward motion of the garrote wire  210 . 
         [0241]    With reference to  FIG. 51B  in another embodiment, the garrote wire  210  may have a number of beads  356  fixed thereto (crimped or welded thereon) to assist in grabbing of the wire by the cleats  346 ,  354 . 
         [0242]    As discussed above, the prior art utilizes a linear pull trigger system, in which the trigger is pulled straight back to actuate the garrote wire. The trigger rides in a track and is supported by guide rods to maintain the desired linear pull. When the trigger is pulled back it engages a support ring attached to the garrote wire. This support ring moves backward with the trigger, pulling the garrote wire across the cannula, transecting the core of tissue at the distal end. However, there are a significant number of cases which encounter “tough” breast tissue. When tough tissue is encountered, transection force increases significantly, at times resulting in incomplete transection. The user cannot provide enough input force to fully actuate the trigger system. Occurrences of this problem increases as cannula diameter increases. 
         [0243]    Constriction and transection of breast tissue by the garrote wire can best be described by separating it into two phases. Phase  1  includes 0% to 70-95% constriction of the tissue by the garrote wire. The 70-95% range is dependent on cannula size and tissue density. The requirements of Phase  1  are long travel and low/medium input force. The current linear pull system works well during Phase  1 . Phase  2  covers up to the final 30% of tissue constriction and eventual transection. The requirements of Phase  2  are limited travel with potentially high input forces required. The linear pull system does not always meet these requirements. 
         [0244]    With reference to  FIGS. 52A, 52B, 52C, and 52D , in another aspect of the present invention, the garrote wire  210  actuation by a trigger mechanism  358 . The trigger mechanism  358  is coupled to the housing  14  and the garrote wire  210  (via support ring  370 ). In the illustrated embodiment, the trigger mechanism  358  includes a trigger  360  slidably mounted in a trigger channel  362  in the housing  14 . In the illustrated embodiment the trigger channel  362  is formed by a linear support track  368  within the housing  14 . The trigger  360  is movable from a first trigger position (shown in  FIGS. 52A and 52B ) to an intermediate trigger position (shown in  FIG. 52C ) within the trigger channel  362 . 
         [0245]    The garrote wire  210  is coupled directly to the trigger  360 . In response to the trigger  360  being moved from the first trigger position to the intermediate trigger position, the garrote wire is moved from the first wire position to an intermediate wire position. In the illustrated embodiment, the triggers  360  drops into a cam channel  366  once it reaches the intermediate trigger position. 
         [0246]    Once the trigger  360  reaches the intermediate trigger position it can move no further within the trigger channel  362 . The trigger  360  is further rotatably movable about a trigger axis  364  from the intermediate trigger position to a second trigger position (shown dotted lines in  FIG. 52D ). In response to movement of the trigger  360  to the second trigger position, the garrote wire  210  is moved from the intermediate wire position to the second wire position in response thereto. 
         [0247]    The addition of a rotational cam mechanism, i.e., the rotatable trigger  360 , to the trigger mechanism  358  will address Phase  2 . The rotational cam provides a mechanical advantage to the user allowing greater input force with limited travel. The concept described here is a “hybrid” system, using the linear pull system for the first 70-95% wire travel and then switching to the rotational cam system for the final phase of transection. 
         [0248]    In use, the user will pull the trigger  360  along the linear track. At an optimized position, the trigger  360  will reach the end of the trigger channel and engage the cam activation system. In this position the trigger will no longer translate, but will now rotate so that the input force is transferred through the cam to the support ring  370 . 
         [0249]    A compression device described below compresses and supports the breast during a breast biopsy procedure. Although designed for use in conjunction with the exemplary excision devices described herein, the compression device can be used with any excisional or incisional biopsy device. 
         [0250]    Referring now to  FIG. 53 , an isometric view of a breast compression device  372  according to a first embodiment is shown. Breast compression device  372  includes a back plate  374  to support the breast. Breast compression device  372  further includes a front paddle  376 . The breast is compressed by front paddle  376  when the breast is placed between back plate  374  and front paddle  376 . Front paddle  376  is comprised of at least two fingers  378 , with a U-shaped space in between that provides access to the breast tissue by a biopsy device. The fingers  378  are independently adjustable to allow fine adjustment of the compression as necessary. Breast compression device  372  further includes an adjuster  380  to adjust the interior spacing of the device, shown in  FIG. 53  as adjustment sleeve  382 . 
         [0251]    Referring now to  FIG. 54 , a top view of a breast compression device  384  according to a second embodiment is shown. In one embodiment, breast compression device  384  does not include an adjuster to adjust the interior spacing of the device. Rather, breast compression device  384  includes a bar  386  that connects back plate  374  and front paddle  376 . Breast compression device  384  may be comprised of a single sheet of material that has elastic or spring-like properties. In the second embodiment, the material itself provides the compressive force against the breast  388 . 
         [0252]    In a third embodiment, breast compression device  384  includes both bar  386  and adjuster  380  to adjust the interior spacing of the device. In the third embodiment, breast compression device  384  may be comprised of a single sheet of material that has elastic or spring-like properties to provide the compressive force against the breast  388 . 
         [0253]    Referring now to  FIG. 55 , a top view of a breast compression device  384  according to  FIG. 54  illustrating compression of breast  388  is shown. The breast compression device  384  may be wrapped around the breast  388  from any direction or angle and allow for access of both an ultrasound probe and a biopsy device, as needed for a biopsy procedure. 
         [0254]    Referring now to  FIG. 56 , a front view of a breast compression device  384  according to  FIG. 54  illustrating compression of a breast  388  is shown. In this illustration, the breast compression device  384  has been wrapped around the breast  388  from the front of the breast  388 . 
         [0255]    Referring now to  FIG. 57 , a top view of a breast compression device  384  with a partial side view of a biopsy device  390  is shown. The biopsy device  390  has access to the breast  388  through the U-shaped space in between fingers  378 . The open space in the area above the breast  388  and the breast compression device  384  provides unrestricted access for an ultrasound probe (not shown). 
         [0256]    Additional components that may be used in conjunction with the devices disclosed herein are described in U.S. patent application Nos. [Attorney Docket No. 068264.00093], [Attorney Docket No. 068264.00094], and [Attorney Docket No. 068264.00095], filed on Dec. 11, 2015, all of which are hereby incorporated by reference. 
         [0257]    Any modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims.