Abstract:
Disclosed is a deflectable biopsy device that includes a cannula having a preformed bend, wherein the shape of the cannula can be temporarily altered with the cannula returning to its original shape afterward. The deflectable biopsy device also includes a sampling member slidably disposed within the cannula and operable therewith to collect a tissue biopsy.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/US2010/054420, filed Oct. 28, 2010, which is hereby incorporated by reference. PCT/US2010/054420 claims the benefit of provisional Application No. 61/261,857 filed Nov. 17, 2009. 
    
    
     BACKGROUND 
     It is often desirable to perform a biopsy to sample selected tissue from a patient for medical evaluation. For example, biopsies can be useful in diagnosing various forms of cancer and other diseases affecting a localized area of tissue. However, access to some anatomical regions using present apparatus and methods can be difficult and/or dangerous due to obscure location(s) of the localized area. For example, a localized area could be obscured by obstacles such as bone, an artery or vein, ducts, nerves or organs. Such obstacles pose the possibility for unnecessary iatrogenic trauma during biopsy procedures. 
     Accordingly, there is a need for a biopsy apparatus and method that provide alternative modes of access to anatomical sites. 
     SUMMARY 
     Disclosed in one aspect is a deflectable biopsy device that includes a cannula having a preformed bend, wherein the shape of the cannula can be temporarily altered with the cannula returning to its original shape afterward. The deflectable biopsy device also includes a sampling member movably disposed within the cannula. The sampling member can include a wire slidably disposed within the cannula, the wire including a sampling cavity and a flexible portion, wherein the cannula and sampling member are slidable relative to one another between respective positions in which the sampling cavity is covered by or uncovered from the cannula. 
     This cannula can be inserted through an introducer laterally offset from the biopsy area with the preformed bend providing lateral displacement of the sampling cavity from the insertion site. This provides an alternate, indirect route to obtain the biopsy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a deflectable biopsy device including a cannula, a wire and a firing mechanism. 
         FIG. 2  is an elevational view of the cannula of  FIG. 1 . 
         FIG. 3  is an elevational view of the wire of  FIG. 1 . 
         FIG. 4  is an exploded assembly view of the deflectable biopsy device of  FIG. 1 . 
         FIG. 5  is a perspective view of the deflectable biopsy device of  FIG. 1 . 
         FIG. 6   a  is a top plan view of distal end of the cannula and wire of  FIG. 1  in a cocked position. 
         FIG. 6   b  is a side elevational view of  FIG. 6   a.    
         FIG. 7  is an elevational view of an introducer. 
         FIG. 8  is an elevational view of an introducer inserted into a body with a deflectable biopsy device partially inserted into the introducer. 
         FIG. 9  is an elevational view of the  FIG. 8  arrangement with the deflectable biopsy device completely inserted into the introducer with the distal end of the deflectable biopsy device positioned in a sample site. 
         FIG. 10  is an elevational view of the  FIG. 9  arrangement in a cocked configuration. 
         FIG. 11  is an elevational view of the  FIG. 9  arrangement in an initial triggered configuration. 
         FIG. 12  is an elevational view of an alternative embodiment of the  FIG. 11  configuration. 
         FIG. 13  is an elevational view of the  FIGS. 9 ,  10  and  11  arrangement in a final fired configuration. 
         FIG. 14   a  is a partial elevational view of an alternative embodiment of a wire. 
         FIG. 14   b  is a partial elevational view of an alternative embodiment of a wire. 
         FIG. 14   c  is a partial elevational view of an alternative embodiment of a wire. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to certain embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure and the claims is thereby intended, such alterations, further modifications and further applications of the principles described herein being contemplated as would normally occur to one skilled in the art to which this disclosure relates. In several figures, where there are the same or similar elements, those elements are designated with the same or similar reference numerals. 
     Referring to  FIG. 1 , one embodiment of a deflectable biopsy device  110  is illustrated including coring cannula  40 , sampling member  60  and firing mechanism  80 . 
     Cannula  40 , as illustrated in  FIGS. 1 and 2 , includes wall  42  defining a lumen between proximal end  50  and distal end  52  and including a preformed bend  46 , straight walled portion  48  and tip  44 . Cannula  40  may also optionally include visualization markers  45  as discussed below. In some embodiments, tip  44  is constructed and arranged to penetrate tissue, for example with a cutting edge. In the illustrated embodiment, tip  44  is pointed and bevel sharpened entirely around cannula  40  for cutting tissue. Needle cannula  40  can be soldered or otherwise affixed to hub  54  using one of selected well-known techniques, including that of Hall described in U.S. Pat. No. 5,354,623. Cannula  40  can be comprised of any suitable material, such as a plastic and/or metal material. In certain embodiments, cannula  40  comprises a superelastic alloy, for example, nitinol (Ni—Ti alloy), that permits elastic manipulation of cannula  40  beyond the point at which other metals would experience plastic deformation. 
     In embodiments where cannula  40  is formed of nitinol, preformed bend  46  can be imparted in the nitinol cannula  40  by deforming the cannula under heat for a prescribed period of time, which can produce a cannula entirely in the austenitic state, or by cold working the cannula. Cold working can convert a portion of crystalline structure of the bending zone of the cannula  40  into at least a partial martensitic condition while the unworked portions of the cannula, for example substantially straight portions proximal and/or distal of the bending zone, remain in the austenitic state. Cold worked Ni—Ti alloys are discussed in “Linear Superelasticity in Cold-Worked Ni—Ti”, (Zadno and Duerig) pp. 414 to 419, in Engineering Aspects of Shape Memory Alloys, Butterworth-Heineman, Boston, Mass. (Duerig et al, editors). In addition to nitinol, superelastic or pseudoelastic copper alloys, such as Cu—Al—Ni, Cu—Al-Zi, and Cu-Zi are available as alternative cannula materials. Flexible polymeric materials with sufficient rigidity for both deployment and shape memory to assume a preformed bend may also be used in certain applications, either alone or in combination with reinforcing metal components, such as a metal braid or tip. 
     In the illustrated embodiment, preformed bend  46  curves cannula  40  approximately 90° relative to the longitudinal axis of cannula  40  proximate to proximal end  50 . In alternative embodiments, preformed bend  46  can be configured to bend cannula  40  at least about 40°, typically about 40° to about 270°, and in certain embodiments between approximately 40° and approximately 90° relative to the longitudinal axis of cannula  40  proximate to proximal end  50 . While the illustrative embodiment has a constant bend radius, other non-linear paths such as a variable bend radius can be used in other embodiments, for example, an increasing or decreasing bend radius. Furthermore, it is possible to introduce more than one preformed bend into cannula  40  for applications requiring a special configuration. The distal portion of cannula  40  can include straight walled portion  48  between distal end  52  and preformed bend  46 . Straight walled portion  48  can be substantially straight or linear when in an unstressed condition. 
     Sampling member  60 , as illustrated in  FIG. 3 , includes sample cavity  62 , tip  64  at distal end  72 , shoulder  67 , flexible portion  66  and hub  68  at proximal end  70 . Sampling member  60  may also optionally include visualization markers  65  as discussed below. In one embodiment, sampling member  60  is constructed and arranged to transmit compressive, tensile and torsional forces between tip  64  and hub  68  with flexible portion  66  providing little resistance to bending so as to slidably navigate preformed bend  46  of cannula  40  without kinking or binding. Sampling member  60  can be comprised of any suitable material, such as a plastic and/or metal material. In certain embodiments, sampling member  60  comprises a superelastic alloy, for example, a superelastic Ni—Ti alloy. In other embodiments, sampling member  60  comprises a stainless steel alloy. As shown in  FIG. 1 , sampling member  60  is disposed in the lumen of cannula  40 . 
     As noted above, cannula  40  and/or sampling member  60  may optionally include visualization markers  45  and/or  65  near tips  44  and/or  64  and/or sampling cavity  62  to provide enhanced visualization during insertion and use. For example, when utilizing ultrasonic visualization techniques, visualization markers  45  and/or  65  could comprise an echogenic marker such as a series of small dimple-like indentations on the outer surface of cannula  40  and/or sampling member  60 , for example those used on ECHOTIP® Echogenic Needles available from Cook Medical, Bloomington, Ind., USA, to provide enhanced ultrasonic return. In other embodiments, a radiopaque marker, such as a band of bismuth or titanium, could be used to provide enhanced x-ray response during fluoroscopy or other x-ray visualization techniques. Visualization marker  45  and/or  65  may improve the ability of an interventionalist to monitor the position of tips  44  and/or  64  and/or sampling cavity  62  within a patient&#39;s body during use. 
     Firing mechanism  80 , as illustrated in  FIGS. 4 and 5 , includes housing  82 , actuator  84 , drive carriage  86 , spring  88 , indicator  89  and cover  94 . Housing  82  includes finger grips  90  and actuator  84  includes grip  82 . Firing mechanism  80  is coupled to cannula hub  54  and wire hub  68  as part of deflectable biopsy device  110 . Cannula hub  54  is coupled to drive carriage  86  and wire hub  68  is coupled to actuator  84 . When assembled, firing mechanism  80  is “cocked” by pulling grip  92  (and actuator  84 ) away from housing  82 . Actuator  84  interfaces with drive carriage  86  so that when actuator  84  is pulled away from housing  82 , drive carriage  86  compresses spring  88  between housing  82  and drive carriage  86 . The housing includes a resilient latch that engages the underside of drive carriage  86  in the cocked position. Spring  88  can be subsequently released by pushing grip  92  toward housing  82  generating forward movement of actuator  84  which causes spring  88  to push drive carriage  86  which in turn thrusts cannula  40  over sample cavity  62  of wire  60 . Cover  94  fits onto housing  82 , covering and protecting spring  88  and sliding engagement between drive carriage  86  and housing  82  from debris and interference. Indicator  89  optionally points in the direction of preformed bend  46 . A suitable firing mechanism is disclosed in U.S. Pat. No. 6,056,760 to Koike. (The mention of this firing mechanism is not intended to be limiting or restrictive, it is simply provided as an example of a suitable firing mechanism.) 
     As described in greater detail below, actuation of firing mechanism  80  propels coring cannula  40  over sampling member  60  to sever and trap tissue within sample cavity  62  of the sampling member  60 . The disclosed embodiment of firing mechanism  80  is a single action biopsy device which is effective when used to obtain tissue samples. Alternative embodiments can, for example, utilize double action firing device such as the device disclosed in U.S. Pat. No. 5,538,010 to Darr which may be used in other embodiments in place of the single action device disclosed herein. 
     As assembled, deflectable biopsy device  110  includes sampling member  60  disposed in the lumen of cannula  40  with hubs  54  and  68  engaged with firing mechanism  80  as described above. Firing mechanism  80  has two positions (cocked and uncocked) which provide two relative positions between cannula  40  and sampling member  60 . In the uncocked position, tip  64  protrudes slightly outside of cannula  40  and tip  44  but with sample cavity  62  substantially covered by cannula  40  with sample cavity  62  substantially lined up with straight wall portion  48 . In the cocked position, as illustrated in  FIGS. 6   a  and  6   b , cannula  40  and tip  44  are retracted back over sampling member  60 , exposing sample cavity  62  outside of cannula  40  and tip  44 . 
       FIG. 7  illustrates introducer  20  that is operable to insert and direct deflectable biopsy device into a body. Introducer  20  includes wall  22  defining lumen  24 , tip  26  at distal end  34 , handle  28  at proximal end  32  and fitting  30 . In one mode of construction and operation, during insertion of introducer  20  into the body, deflectable biopsy device  110 , in the uncocked position, can be received in introducer  20  with tip  64  of sampling member  60  protruding slightly from tip  26 , desirably a needle tip, of introducer  20 . This can prevent undesired coring by or occlusion of the introducer  20 . Alternatively, while not illustrated, introducer  20  may include a removable trocar received within lumen  24  and connected to fitting  30  during insertion of introducer  20 . Such a trocar can block distal end  34  of lumen  24  and prevent undesired coring or occlusion and may further assist in creating access for introducer  20 . In some embodiments, the outside of introducer  20  may include depth markers  21  that are directly viewable by a user to determine the depth of insertion through the skin to indicate the approximate depth of insertion. In addition, depth markers  21  can be spaced at regular intervals (such as centimeters) for use as a scale to measure the relative size of internal structures (such as tumors, etc.). 
     As noted, lumen  24  is arranged and configured to pass cannula  40  therethrough. In this regard, preformed bend  46  of cannula  40  is elastically deformable sufficiently for preformed bend  46  to pass through lumen  24  without substantial plastic deformation. When preformed bend  46  passes into and through lumen  24  it is constrained to conform to the shape of lumen  24 . As preformed bend  46  exits lumen  24  through tip  26 , preformed bend  46  substantially returns to its unconstrained shape. In the illustrated embodiment, introducer  20  is substantially straight and preformed bend  46  of cannula  40  is constrainable to the substantially straight shape of introducer  20 . In alternative embodiments, introducer  20  can be curved. In certain embodiments, introducer  20  or a component attached thereto (e.g. housing  28 ) can include indicator  29  that remains external to the patient when using introducer  20  and that indicates to the user the open direction of the bevel of tip  26 . In some embodiments, it is desired that preformed bend  46  exits through the open portion of tip  26  such that cannula  40  does not impinge against tip  26 . (Note: other embodiments of introducer  20  may use other configurations of tip  26  that may or may not have a beveled profile. In yet other embodiments, it may be desirable to alter the relative positioning of the bevel of tip  26  to slightly modify the profile of preformed bend  46  as it exits tip  26 .) 
       FIGS. 8-13  illustrate one embodiment of deflectable biopsy device  110  taking a tissue sample from a sample site within a body. Introducer  20  has been inserted into body  100  through insertion site  108  in skin  102  at a position laterally offset from sample site  104  and obstacle  106 . Obstacle  106  broadly encompasses objects or features of body  100  that would be difficult or undesirable to insert introducer  20  through. Obstacle  106  may be between the most direct route between skin  102  and sample site  104 . For example, obstacle  106  could include bone, an artery or vein, a duct, a nerve, an organ or obstacle  106  could represent a portion of skin  102  that it would be undesirable to pass introducer  20  into or through. 
     In  FIG. 8 , deflectable biopsy device  110  is partially inserted into introducer  20  with cannula  40  beginning to emerge from introducer  20 . The arrow indicates the direction of travel of deflectable biopsy device  110 . While not shown, note that, at the point illustrated, the direction that cannula  40  will curve when preformed bend  46  emerges from introducer  20  is controllable by rotating housing  82  (and cannula  40 ) with respect to handle  28  (and introducer  20 ). Deflectable biopsy device  110  can be rotated through a full 360° (around the axis of introducer  20 ). In certain embodiments, cannula  40  or a component attached thereto (e.g. housing  82 ) can include indicator  89  that remains external of the patient when using device  110  and that indicates to the user the direction in which tip  44  (and preformed bend  46 ) of the cannula will advance as cannula  40  emerges from distal end  34  of introducer  20 . Illustratively, as shown in  FIGS. 8-11 , this can be accomplished by aligning a recognizable portion of housing  82  with the plane of curvature of bend  46  and, to the extent needed (e.g. as with a symmetrical grip  82  as shown), providing a further marking on the housing  82  (e.g. indicator  89  as the illustrated arrow) to indicate the direction in which the cannula tip  44  will proceed due to the emergence of bend  46  from distal end  34  of introducer  20 . When desired, indicator  29  may also be aligned with indicator  89  so that preformed bend  46  exits through the bevel of tip  26 . 
     In  FIG. 9 , deflectable biopsy device  110  is inserted into introducer  20  with preformed bend  46  fully emerged from introducer  20 . Tips  64  and  44  are positioned within sample site  104  and cannula  40  covers sample cavity  62 . As preformed bend  46  emerged from introducer  20  it returned to its unconstrained bent shape so that tip  64  substantially passed through the space filled by cannula  40 . Therefore, in the  FIG. 9  configuration, cannula  40  (and preformed bend  46 ) are in a substantially unstressed state. 
     In  FIG. 10 , firing mechanism  80  is in the cocked position with grip  92  pulled away from housing  82  simultaneously compressing spring  88 . Cannula  40  and wire  60  substantially remain substantially fixed in relationship to each other when firing mechanism  80  is cocked 
     In  FIG. 11 , grip  92  has been partially depressed toward housing  82  thereby pushing wire  60  out of cannula  40  thereby exposing sample cavity  62  inside sample site  104  with tip  44  perched on shoulder  67 . As sample cavity  62  is exposed inside sample site  104 , a portion of the tissue from sample site  104  moves into sample cavity  62  due to interstitial pressure. 
     Referring to  FIG. 12 , an alternative configuration of wire  60  and cannula  40  is illustrated with sampling cavity  62  rotated approximately 180° as compared to the configuration illustrated in  FIG. 11 . In other embodiments, sampling cavity  62  can be oriented in any desired direction. 
     In  FIG. 13 , grip  92  has been completely depressed toward housing  82  thereby releasing the spring in firing mechanism  80  causing cannula  40  to cover sample cavity  62 . This generates a cutting action in which tip  44  cuts through and severs a portion of tissue from sample site  104  that moved into sample cavity  62  prior to the firing of firing mechanism  80 . In certain embodiments, during the cutting action that occurs between sampling member  60  and cannula  40 , sampling member  60  remains constrained by cannula  40  to a condition bent from its relaxed (unconstrained) configuration while preformed bend  46  of cannula  40  remains in its relaxed (unconstrained) configuration. That portion of sample site  104  is then retained inside sample cavity  62  and cannula  40  and can be recovered for further investigation and testing by removing deflectable biopsy device  110  from introducer  20  and cocking firing mechanism  80  to once again retract cannula  40  over sampling member  60  to expose sample cavity  62 . 
       FIGS. 14   a - 14   c  illustrate alternative embodiments of sampling member  60 . In  FIG. 14   a , wire  60 A is formed by centerless grinding to create a more flexible portion  66 A from one continuous wire (that also includes a tip and sample cavity formed from or attached to the wire). In  FIG. 14   b , wire  60 B is formed by grinding flexible portion  66 B on one side of one continuous wire, cannula or other suitable elongate member (that also includes a tip and sample cavity formed therein or attached thereto). In  FIG. 14   c , wire  60 C is assembled from separate large gauge wire  61 , small gauge wire  63  and sample cavity  62   c . Assembly can be by soldering, welding or otherwise permanently attaching the components together with flexible portion  66 C generally corresponding with small gauge wire  63 . Illustrative elongate materials that can be used to create sampling member  60  include wire and/or cannula as noted above as well as cable-tube, multi-filar cable, or any combination of these or potentially other materials. 
     In various embodiments of sampling member  60 , flexible portion  66  provides substantially no resistance to bending and member  60  can be rotated with respect to cannula  40  to vary the angle at which sampling cavity  62  is presented when cannula  40  is retracted. However, in alternative embodiments of sampling member  60 , including where member  60  comprises a superelastic alloy, flexible portion  66  can provide substantial resistance to bending. In such embodiments, the bending characteristics of member  60  can be used to alter the bending characteristics of cannula  40  (and thereby deflectable biopsy device  110 ). For example, if member  60  includes a preformed bend in flexible portion  66  that is oriented corresponding to preformed bend  46 , then sampling member  60  can assist cannula  40  in returning to its unstressed curved state after exiting lumen  20 . Alternatively, bending characteristics of cannula  40  could be varied by rotating sampling member  60 , having a preformed bend, with respect to cannula  40 . This could vary the effective angle of preformed bend  46 . In yet another embodiment, sampling member  60  can comprise a superelastic alloy without a preformed bend (providing a generally straight member  60  when unconstrained) such that member  60  is in a stressed condition when located within preformed bend  46  of cannula  40  outside of introducer  20 . 
     While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain specific embodiments have been shown and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.