Abstract:
A biopsy device configured to rotate a needle about a longitudinal axis when resecting tissue, and a method of performing a biopsy using the same. Also disclosed is a needle configured to resect tissue by a rotational motion, for example, when operating in conjunction with the device herein.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims the benefit of priority to U.S. Provisional Application No. 61/128,740, filed May 23, 2008, the contents of which are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This application relates to a biopsy device, more particularly to a biopsy device configured to rotate a needle about a longitudinal axis when resecting tissue; the application also relates to a needle configured to resect tissue by a rotational motion. 
       BACKGROUND 
       [0003]    In the practice of medical biopsy, samples obtained may utilize either the so called fine needle aspiration (FNA) technique or the core biopsy technique. In FNA, a semi-liquid specimen is aspirated, usually through a small gauge needle (for example 22 g to 25 g) and subsequently expressed onto slides for examination of individual cells, or into a container with fixative for centrifugation and later cytologic analysis. By contrast, core biopsy typically utilizes larger gauge needles (for example 14g to 18 g) to yield a cohesive specimen which is placed in a fixative agent and later sliced, stained and microscopically examined for histologic analysis. 
         [0004]    Often regions of tissue of interest may be quite small, for example a lesion 5 mm or less in one dimension. Such lesions may not be observable to the naked eye and are demonstrated only with the use of an imaging modality (such as ultrasound, computed tomography, or magnetic resonance imaging). Given the small size of such lesions it is of critical importance that the biopsy device samples only the region of interest in the immediate proximity of the lesion. 
       SUMMARY 
       [0005]    In general, in one aspect of the technology described herein includes a biopsy device configured to perform a biopsy by rotating a needle. 
         [0006]    The technology described herein further includes a biopsy device comprising: a proximal casing having a longitudinal axis; and a distal needle as further described herein affixed to the casing, and configured to rotate about the longitudinal axis. 
         [0007]    In another aspect, the technology includes a biopsy device comprising: a casing having a proximal end and a distal end, and defining a longitudinal axis running between the proximal and distal ends; a first chamber disposed within the casing and opening to the distal end; a second chamber disposed within the casing between the first chamber and the proximal end; a hub disposed coaxially within the first chamber and including a feature on its external surface; a needle assembly mounted on and disposed coaxially with the hub, the needle having a lumen, the lumen in fluid connection with the second chamber; and a control configured to engage the feature on the external surface of the hub, and to cause a rotation of the hub and needle assembly about the longitudinal axis. 
         [0008]    The technology herein also includes a method of performing a biopsy of a tissue, the method comprising: controlling a device as further described herein so that the needle is inserted into the tissue; rotating the needle about the longitudinal axis of the device, thereby cutting tissue; reducing pressure in the lumen; and withdrawing the needle from the tissue, thereby removing a portion of cut tissue. 
         [0009]    The technology further includes a biopsy needle comprising: a tubular body having a centrally disposed longitudinal axis running between distal and proximal ends of the body, the body further comprising a lumen disposed along the longitudinal axis, and a distal opening; and one or more elongated members extending distally from the distal opening and contiguous with the tubular body, each of the one or more elongated members having a first edge and an opposed second edge, the first edge configured to perform a cutting action as the needle is rotated about the longitudinal axis in a first direction, the second edge optionally configured to perform a cutting action as the needle is rotated about the longitudinal axis in a second direction, the second direction being in an opposite rotational sense to the first direction. 
         [0010]    Certain embodiments may have one or more of the following advantages. The device, needle, and rotational cutting method described herein can prevent sampling of adjacent non-target tissue such that tissue sampled is precisely from the locus of interest. 
         [0011]    The details of one or more embodiments are set forth in the accompanying drawings and the description herein. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a longitudinal cross-sectional view of one embodiment of a biopsy device as further described herein. 
           [0013]      FIG. 2A  is a longitudinal cross-sectional view of a hub isolated from the device shown in  FIG. 1 . 
           [0014]      FIG. 2B  is a plan view of the hub shown in  FIG. 2A . 
           [0015]      FIG. 2C  is a transverse cross-sectional view of the hub shown in  FIGS. 2A-B . 
           [0016]      FIG. 3A  is a longitudinal cross-sectional view of a casing of the biopsy device shown in  FIG. 1 . 
           [0017]      FIG. 3B  is a elevation view of the casing shown in  FIG. 3A . 
           [0018]      FIG. 3C  is a transverse cross-sectional view of a distal region of the casing shown in  FIGS. 3A-B , and a control. 
           [0019]      FIG. 3D  is a transverse cross-sectional view of a proximal region of the casing shown in  FIGS. 3A-B . 
           [0020]      FIG. 3E  shows an exemplary control disassembled from the device. 
           [0021]      FIGS. 4A-B  are cross-sectional views of a diaphragm assembly isolated from the device shown in  FIG. 1 . 
           [0022]      FIG. 5  is a longitudinal cross-sectional view of an end cap isolated from the device shown in  FIG. 1 . 
           [0023]      FIGS. 6A-N  are cross-sectional and perspective views of various embodiments of a needle for rotating while carrying out a biopsy. 
           [0024]      FIGS. 7A-B  are cross-sectional views of the device shown in  FIG. 1 , illustrating movement of the control and hub, and movement of the diaphragm assembly. 
           [0025]      FIGS. 7C-D  are transverse cross-sectional views of a proximal region of the casing and diaphragm assembly shown in  FIGS. 7A-B , illustrating a ratcheting mechanism of the second chamber. 
           [0026]      FIG. 8A  is a longitudinal cross-sectional view of an alternative embodiment of an device as further described herein. 
           [0027]      FIG. 8B  is a transverse cross-sectional views of a proximal region of the casing and diaphragm assembly of the embodiment shown in  FIG. 8A . 
           [0028]      FIG. 9  is a longitudinal cross-sectional view of another embodiment of an device. 
       
    
    
       [0029]    The figures represent only certain embodiments of the disclosure. They are not necessarily drawn to scale, and may emphasize or exaggerate certain features to facilitate illustration and explanation. Like reference numbers in the drawings refer to like parts. 
       DETAILED DESCRIPTION 
     Biopsy Device 
       [0030]      FIG. 1  generally illustrates, in cross-sectional view, principal features of an exemplary embodiment of a biopsy device  100   a . Biopsy device  100   a  comprises hub  200 , casing  300   a , diaphragm assembly  400 , and end cap  500 . A first chamber  315  is disposed at distal end  302  of casing  300   a , and includes a distal opening of the device. A longitudinal axis  301  runs centrally through the length of the device. The axis passes through the centroid of a transverse cross-section of the body at each point along its length. Hub  200  is disposed coaxially within receiving chamber  315  and encloses a lumen. Hub  200  is shown as fitting snugly within chamber  315 , though this need not be the case. Hub  200  is shown with a helical groove inscribed on its outer surface, though other surface features are possible. 
         [0031]    A control is configured to engage with hub  200  and to cause a rotational motion of hub  200  about the longitudinal axis. In the exemplary embodiment of  FIG. 1 , a distal slot  340  is disposed at distal end  302  of casing  300   a  and runs parallel to the longitudinal axis. A handle  220 , is connected to stem  221 , which slidably inserts through distal slot  340  and engages hub  200  at helical groove  209 . 
         [0032]    Casing  300   a  also includes a barrel portion  310  that connects first chamber  315  and a second chamber, at proximal end  303  of the casing  300   a . The second chamber is divided into a proximal portion  350  and a distal portion  360 . A channel  330  is also disposed at proximal end  303 . In certain embodiments, distal portion of the second chamber  350  and proximal portion of second chamber  360  may surround channel  330 , as shown. In some embodiments, a spring  122  may be included in the distal portion of the second chamber. Diaphragm assembly  400 , in its various parts and as explained further herein, is disposed within second chamber  350 , within casing  300   a , and at the exterior of casing  300   a . End cap  500  is reversibly inserted into channel  330 . 
         [0033]    Needle assembly  600 , comprising a needle and a connecting member that attaches the needle to hub  200 , may be reversibly attached to hub  200  (e.g., via a luer connection) as shown, and is disposed coaxially with longitudinal axis  301 . A lumen of needle  600  can align with barrel portion  310  so as to create a continuous channel through device  100   a  via the lumen of hub  200 . As referred to throughout this application, needle  600  may be a conventional biopsy needle, including those used for both fine biopsies and core biopsies, or any of needles  610 ,  620 , or  630  illustrated in  FIGS. 6A-M , as further described herein. Other needles may also be used. 
         [0034]    As described further herein, the operation of exemplary device  100   a  is as follows. During use (e.g., after needle  600  is attached to the device and inserted into a tissue of interest in a subject), an operator may move control  220  back and forth along slot  340  (e.g., in the proximal and distal directions), engaging helical groove  209  with stem  221 . As a result, the translational motion of the control is converted into rotational motion of hub  200  so that the hub and attached needle assembly  600  will rotate around longitudinal axis  301 . Such rotation can be effected to cut tissue in a precise manner and with single-hand operation of the device, freeing the other hand, for example to control other instrumentation, such as an ultrasound probe, or another device. 
         [0035]    Other manners of causing a rotational motion of the needle and hub can be envisaged and are within the scope of the present description. For example, the hub may have a series of parallel circumferential grooves on its outer surface, or a set of teeth, that may be held directly by an operator and turned manually via a point of access. 
         [0036]    A user may also apply suction by pulling back (e.g. in the proximal direction) on diaphragm assembly  400 . Optionally, a spring  122  can be used to facilitate the proximal translation of diaphragm assembly  400 . Proximal movement of assembly  400  applies suction upon the fluid in barrel portion  310 , channel  330 , and second chamber  350  and through needle  600  to create suction on the target tissue. Subsequently, the needle may be removed from the patient and the sample obtained may be extruded from the device, again with controlled, one-hand operation. 
         [0037]      FIGS. 2-5  illustrate individual components of the exemplary biopsy device of  FIG. 1 . For clarity, shading of the various components has been removed in some illustrations. 
       Hub and Control of Rotational Motion 
       [0038]      FIG. 2A  illustrates hub  200  in the same cross-sectional view as shown in  FIG. 1 . Hub  200  includes, at its distal end  202 , needle mount  230  which is sized and configured (e.g., with a luer-lock fitting) so that a needle may be reversibly attached to it. Hub  200  includes a housing  208 , which defines helical groove  209  as well as lumen  210 . Lumen  210  may be optionally extended past housing  208  (toward proximal end  203 ) by a stem  211 . The optional proximal stem  211  may insert into channel  330  on proximal portion of device  303  thereby increasing the effective lumen length  210  and limiting spillage of the aspirated content into the distal portion of the second chamber  350 . Should such spillage occur, however, it is retrievable by reciprocal motion of assembly  400  as detailed elsewhere herein. 
         [0039]      FIG. 2B  shows hub  200  in an elevated view. In this view, needle mount  230  (shown in dashed lines) is occluded by housing  208 . Helical groove  209  (of which a portion is shown) extends around the perimeter of needle hub housing  208 . Helical groove  209  is canted at angle α with respect to a plane perpendicular to axis  301 . Angle α may be selected to facilitate rotation of the hub during operation of the device. For example, angle α may be between approximately 5 degrees and approximately 60 degrees, such as between approximately 15 and approximately 30 degrees. From its beginning to its end, helical groove  209  may extend partially or completely around housing  208  and around longitudinal axis  301 , depending on the length of housing  208  and the orientation of helical groove  209 . The extent to which helical groove  209  extends around housing  208  determines the amount of rotation of the hub as control  220  is moved proximally or distally. Helical groove  209  may extend, in various embodiments, approximately 360° about axis  301 . In some embodiments, helical groove  209  may extend up to or less than approximately 360° around longitudinal axis  301 , e.g., between approximately 90° and approximately 360°. In other embodiments, it may extend more than approximately 360° around longitudinal axis  301 , e.g., between approximately 360° and approximately 540°, and may encompass multiple, such as 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, or 20 revolutions around  301 . Helical groove  209  may extend in either a clockwise or counterclockwise direction when viewed down the longitudinal axis in a distal direction. 
         [0040]      FIG. 2C  illustrates a transverse cross-sectional view of hub  200  from  FIG. 1 . In this view, a cross section of helical groove  209  can be seen. In the embodiment shown, helical groove  209  has a rounded (e.g. “u” shaped) cross section (e.g., in order to decrease friction between helical groove  209  and stem  221 , not shown here), but it may take other shapes in other embodiments. As shown in this embodiment, lumen  210  and needle hub  208  have circular cross sections, and lumen  210  is concentric with needle hub  208 . 
         [0041]      FIG. 3A  illustrates casing  300   a  in a longitudinal cross-sectional view through its center. Disposed at distal end  302  is first chamber  315 , which is configured to receive hub  200  (not shown). Leading from first chamber  315  toward the proximal end,  303 , is a center portion  310 , referred to also as a barrel portion  310 , which separates the first chamber from the second chamber and contains a lumen that, continuing in the proximal direction, leads to second chamber  350  and channel  330 . The distal portion of second chamber  350  and channel  330  are in fluid communication with one another, and with the lumen in barrel portion  310 . When hub  200  is attached to the device, barrel portion  310  is in fluid communication with lumen  210 . When a needle is attached to the device, lumen  210  is in fluid communication with the lumen of the needle, so that the distal portion of the second chamber  350  is in fluid communication with the lumen of the needle. 
         [0042]    Referring still to  FIG. 3A , distal slot  340  is disposed at the distal end  302  of casing  300   a , and configured to allow stem  221  to slidably move therein. In this embodiment of the device, end  222  of stem  221  engages helical groove  209  of hub  200 , as described elsewhere herein. 
         [0043]    Referring still to  FIG. 3A , proximal slot  370  is disposed at the proximal end  303  of casing  300   a , and configured to allow part of the diaphragm assembly  400  (not shown) to slidably move within distal portion of the second chamber. Distal portion of second chamber  350  includes distal end-stops  351 , and proximal end-stops  353 . As explained elsewhere herein, these end-stops provide distal and proximal endpoints for the slidable movement of diaphragm assembly  400  in the distal and proximal directions, respectively. In some embodiments, the proximal portion of second chamber  360  also includes a ratcheting mechanism for providing intermediate stopping points for the slidable movement of diaphragm  400 , via a control member. For example, in the embodiment illustrated (see also  FIG. 8A ), intermediate stops  365  are disposed within casing  300   a . These intermediate stops may be, e.g., perforations, or other types of depressions or recessions in casing  308   a , and disposed alongside proximal groove  370 . As described elsewhere herein (e.g.,  FIG. 7D ), these intermediate stops may engage an arm  414  on the diaphragm assembly, enabling a user to temporarily and controllably interrupt the slidable movement of the diaphragm assembly  400  between its distal and proximal endpoints. While the illustration in  FIG. 3B  shows three intermediate stops, casing  300   a  may contain any number of intermediate stops consistent with the construction and operation of this device. Note also that other ways for providing a ratcheting effect to diaphragm assembly  400  can be envisaged, for example, the inner surface of the proximal portion of the second chamber  360  may contain bumps or ridges or be rough, thereby providing a friction-based way to interrupt the movement of the diaphragm assembly by engagement of arm  414 . 
         [0044]    Referring still to  FIG. 3A , in certain embodiments, the proximal portion of the second chamber  360  may include a vent, such as vent  361 . As described elsewhere herein, vent  361  allows air to pass in and out of the proximal portion of the second chamber  360  to maintain atmospheric pressure when diaphragm assembly  400  is moved in the distal or proximal directions. 
         [0045]      FIG. 3B  shows an elevation view of casing  300   a . Visible in this view is distal slot  340 , at distal end  302 , extending parallel to longitudinal axis  301 . Proximal slot  370 , at proximal end  303 , (accommodating parts of diaphragm assembly  400 , as discussed herein) also extends parallel to longitudinal axis  301 . Also in this view are intermediate stops  365 , disposed laterally from proximal slot  370  and which are engaged by side arm  414 . Other components, corresponding to those shown in  FIG. 3A , may be shown in dashed lines, indicating they are occluded by casing  300   a  in this view. 
         [0046]      FIG. 3C  illustrates a transverse cross-section of a distal region of casing  300   a , as indicated in  FIGS. 3A-B . This part of casing  300   a  is shown here to have a circular cross section, but in other embodiments may have a cross section of a different shape (e.g., elliptical). Casing  300   a  encloses receiving chamber  315 , which generally will have a circular cross section, as shown, to enable smooth rotation of hub  200  within it. Control handle  220  is connected to stem  221 , which inserts through distal slot  340  to engage in a helical groove on an external surface of hub  200  (not shown). In some embodiments, stem  221  may be slidably connected to casing  300   a , for example, by bars  223  (see also  FIG. 3E ) which engage rails (not shown) in casing  300   a  along the sides of distal slot  340 . In another embodiment, stem tip  222  may represent a ball bearing fabricated of a metal such as stainless steel or plastic such as polycarbonate. Distal slot  340  and stem tip  222  may be covered with a lubricious substance such as silicone or polytetrafluoroethylene to facilitate movement. Other means of connecting the control to the casing of the device may be envisaged. 
         [0047]      FIG. 3D  illustrates a transverse cross-section of a proximal region of casing  300   a , as indicated in  FIGS. 3A-B . Casing  300   a , second chamber  350 , and channel  330  are shown in this implementation to have circular cross-sections, and are disposed concentrically around a central axis (longitudinal axis  301 , not shown). In other embodiments, they may have other cross-sectional shapes and configurations. As also shown in this embodiment, the distal portion of second chamber  350  surrounds channel  330 . Other arrangements can be envisaged, however. For example, the second chamber may be disposed only on one side of the channel. 
         [0048]      FIG. 3E  shows a cross-sectional view shown in  FIG. 3C  of control  220  isolated from casing  300   a , for clarity. 
       Diaphragm Assembly 
       [0049]      FIGS. 4A-B  illustrate two views of an exemplary diaphragm assembly  400 , comprising a partition  410 , a rod  412 , and a handle  420 .  FIG. 4A , viewed from the same cross-sectional view as shown in  FIG. 1 , shows two regions of partition  410 . In the exemplary device shown, partition  410  is a disc that forms an airtight seal with the walls of the distal portion of the second chamber  350 . Partition  410  is configured to move along the longitudinal axis within the distal portion of the second chamber  350  so that a volume of the distal portion of the second chamber distal to the partition is in fluid communication with lumen  310 . Partition  410  is connected to handle  420  via flexible rod  412 . Flexible rod  412  is configured so that in the device, part of flexible rod  412  slidably inserts through casing  300   a , such as through distal slot  370 . (See  FIGS. 3A-B .) Flexible rod is typically made from a sprung material that permits a user to reversibly deflect it. Since flexible rod  412  extends within the proximal portion of the second chamber  360  only to the proximal wall of partition  410 , and since the slot in casing  300   a  through which the rod extends does not overlap with the distal portion of the second chamber, the integrity of the vacuum or partial vacuum within barrel portion  310  and the distal portion of second chamber  350  is never compromised. This allows a vacuum or positive pressure to be generated, which might otherwise be compromised if groove  370  lay distal to the distal surface of partition  410 . In the exemplary embodiment of FIGS.  1  and  3 A-B, member  412  extends proximal to partition  410  and travels in groove  370  which lies proximal to partition  410  at all positions of  410 . 
         [0050]      FIG. 4B  shows diaphragm assembly  400  and its component parts in transverse cross-section. Bar  414  extends laterally from flexible rod  412 . Bar  414  may engage intermediate stops  365  (see description of  FIG. 3A , and elsewhere herein). Bar  414  represents one way to arrest proximal or distal motion of the partition: by catching a member such as bar  414  on a lug or protrusion or indentation on the interior of the casing. In another embodiment, flexible rod travels longitudinally in a slot in the casing but the slot additionally has lateral, or transverse, notches in it, such that by a sideways motion of handle  420 , the connector between handle  420  and rod  412  engages in a notch thereby arresting proximal or distal motion of the diaphragm assembly. 
         [0051]      FIG. 5  shows end cap  500 . End cap  500  may be inserted (e.g., by friction fit, luer screw connection, etc.) into channel  330  (see  FIGS. 1 and 3 ). End cap  500  may be solid, or may have an internal lumen allowing a rod such as a stylet, tube, or other instruments to be inserted through it and into the second chamber to assist in the controlled extrusion of contents aspirated into lumens  210 ,  310  and  330 . When inserted into channel  330 , end cap  500  will form an air-tight seal with the wall of the chamber. As noted elsewhere herein, channel  330  is in fluid communication with distal portion of second chamber  350 , and channel  310 . A syringe (not shown) containing fluid such as fixative or saline may be connected in lieu of cap  500  and used to evacuate the lumens as well as any contents which may have accumulated in chamber  550 . 
       Needle 
       [0052]    The technology herein includes a biopsy needle comprising: a tubular body having a centrally disposed longitudinal axis running between distal and proximal ends of the body, the body further comprising a lumen disposed along the longitudinal axis, and a distal opening; and one or more, such as two, elongated members extending distally from the distal opening and contiguous with the tubular body, each of the one or more elongated members having a first edge and an opposed second edge, the first edge configured to perform a cutting action as the needle is rotated about the longitudinal axis in a first direction, the second edge optionally configured to perform a cutting action as the needle is rotated about the longitudinal axis in a second direction, the second direction being in an opposite rotational sense to the first direction. The first and second edges of each of the one or more elongated members meet at an apex. 
         [0053]    In certain embodiments, a transverse cross-section of the needle body has a perimeter and the one or more elongated members lie entirely on the perimeter when the needle is viewed in cross-section along the longitudinal axis. In certain other embodiments, the first and second edges of each of the one or more elongated members curve inwards from the perimeter and meet at an apex. In still other embodiments, the apices of the respective two or more, such as two, elongated members meet at the centrally disposed longitudinal axis. In another embodiment, there is just one elongated member whose apex lies on the longitudinal axis. 
         [0054]    Typically the needle is such that the first edge has a bevel on its surface interior to the needle, and the second edge has a bevel on its surface exterior to the needle. This means that in certain embodiments the first edge is a leading edge, and the second edge is a trailing edge, during the cutting action as the needle is rotated about its longitudinal axis. 
         [0055]    Typically, the needle body is cylindrical, in which case a transverse cross-section of the body has a circumference and the one or more elongated members protrude from an arc of the circumference. In some embodiments, the arc has an angular extent between π/8 (“Pi/8”) and π (“Pi”) radians, such as π/4 (“Pi/4”), π/6 (“Pi/6”) or π/3 (“Pi/3”), of the circumference. 
         [0056]    In other embodiments, the one or more, such as four, elongate members are mounted flexibly at their respective points of contact with the cylindrical tube, and wherein the first and second edges of each elongate member are contiguous with one another, such as form together an arc of a circle or an oval. In such embodiments, the elongate members flare outwards from a centrally disposed longitudinal axis as the needle is inserted into a subject, but the elongate members revert to their respective original positions as the needle is withdrawn from the subject. In certain such embodiments, the one or more elongate members are hinged or sprung at their respective points of contact with the cylindrical tube, thereby providing flexibility. 
         [0057]      FIGS. 6A-6N  illustrate cross-sectional and perspective views of the distal ends of various exemplary embodiments of a needle for carrying out a rotational biopsy as further described herein. Needle  600 , shown in other illustrations of this application, may refer to any of needles  610 ,  620 ,  630 ,  640 , or  650 , as well as to any other needle useable with this device. Edges, e.g., sharp or beveled edges, on needle  600  allow for rotational cutting action. Sharp distal tips on the beveled needle  600  also facilitate distal advancement of said needles into tissue to reach the locus of interest. 
         [0058]    Referring to  FIG. 6A , needle  610  includes a tubular body  615  and a sharpened distal end  611  and a lateral opening located proximal to the distal end, leading to a hollow lumen. Needle  610  also defines longitudinal axis  601 . Leading edge  612  and trailing edge  613  curve around and extend along the perimeter of needle body  615  (i.e., they do not bend inward towards axis  601 .) As used herein the terms “leading edge” means the edge leading towards the distal tip that cuts tissue as the needle rotates. The term “trailing edge” is the other edge, i.e., the edge that follows the leading edge when the needle rotates as above. Note that the trailing edge may also cut tissue.  FIG. 6B  is a view of needle  610  looking proximally from the distal end of the longitudinal axis. Note that leading edge  612  and trailing edge  613  lead along the same perimeter as needle body  615 . When inserted into the body and rotated about the longitudinal axis, the leading and trailing edges  612 ,  613  will cut surrounding tissue.  FIG. 6C  shows a perspective view of needle  610 . Needle  610  may be beveled, and may be beveled such that leading edge  612  is beveled on the inside (e.g. the side nearer the lumen of the needle), and trailing edge  613  is beveled on the outside. This beveling arrangement promotes the movement of cut tissue toward the lumen of the needle. 
         [0059]      FIG. 6D  shows an alternative embodiment, needle  620 . As in the embodiment of  FIG. 6A , needle  620  has a tubular body  625  which defines longitudinal axis  601  and includes a sharpened distal end  621  and a lateral opening located proximal to the distal end, leading to a hollow lumen. The outer edge of the needle may curve inward at distal end  621 , toward longitudinal axis  601 .  FIG. 6E  shows a view of needle  620  looking proximally from the distal end of the longitudinal axis. In this view, it can be seen that leading edge  622  and trailing edge  623  bend inwards toward axis  601 . Distal end  621  may end at axis  601 , or at any point between the circumference of needle body  625  and axis  601 . Also shown in  FIG. 6E , the curvatures of leading edge  622  and trailing edge  623  may be different from one another, (i.e., the portion leading to distal end  621  is asymmetric in this view, i.e. asymmetric about a mirror plane including axis  601  and tip  621 ). Needle  620  may also have symmetric leading portions, i.e., symmetric in such a mirror plane. Similarly, the leading portion may curve or twist in a clockwise or counterclockwise direction around axis  601  as it extends towards distal end  621 . When inserted into the body and rotated about the longitudinal axis  601 , the leading and trailing edges  622 ,  623  can cut the surrounding tissue.  FIG. 6F  shows needle  620  in a perspective view. Leading end  622  and trailing end  623  may be beveled, as described above. 
         [0060]    Although the distal tip of the needle, as shown in the embodiments of  FIGS. 6A-6F , appears blunt, it is typical for the curvature on the most distal point to be shallower than depicted in the figures so that the distal tip of the needle is a sharp point. 
         [0061]      FIG. 6G  shows an alternative embodiment, needle  630 . Needle  630  defines longitudinal axis  601  through needle body  635 . In this embodiment, two regions extend toward, and, optionally, converge at, distal end  631 . A lateral opening is located proximal to the distal end, and leads to a hollow lumen. Needle  630  includes first and second leading edges  632   a  and  632   b , respectively, and first and second trailing edges  633   a  and  633   b , respectively.  FIG. 6H  shows a view of needle  630  looking proximally down the longitudinal axis from a distal position. Here, it can be seen that curvature of leading edges  632   a - b  is the same as those of trailing edges  633   a - b  (i.e. portions leading to distal end  621  are symmetric in this view, i.e. symmetric about a mirror plane including axis  601 ). Needle  630  may also have asymmetric leading portions, and each such portion may itself be asymmetric, as described for  FIG. 6E . Similarly, these leading portions may curve or twist in a clockwise or counterclockwise direction around axis  601  as they extend towards distal end  631 . When inserted into the body and rotated about the longitudinal axis, the leading and trailing edges  632   a ,  632   b ,  633   a ,  633   b  can cut surrounding tissue. As above, leading edges  632   a - b  may be beveled on the inside, and trailing edges  633   a - b  may be beveled on the outside, e.g., to direct cut tissue towards the lumen of the needle. 
         [0062]      FIG. 6J  shows an alternative embodiment, needle  640 . Needle  640  defines longitudinal axis  601  through needle body  645 . In this embodiment, multiple regions  641 , e.g., three, four, five, or six, are located at the distal end of the needle  640  and extend slightly inwardly. Regions  641  include sharp leading edges  642 . Further, the inner surface  643  of each region  641  can be beveled.  FIG. 6K  shows a view of needle  640  looking proximally down the longitudinal axis from a distal location. Here, it can be seen that regions  641  extend slightly inward toward a hollow lumen (not drawn to scale for illustrative purposes). Such needle tip may be fabricated from a shaped memory alloy such as nitinol (NiTi). When needle  640  is advanced into tissue, the sharp edges  642  can cut tissue. Further, as shown in  FIG. 6L , if the needle  640  is both advanced distally and rotated around axis  601 , the accumulation of tissue within the lumen can create an outward force on regions  641 , causing the regions  641  to move outward. Once tissue sampling is complete, the construct of region  641  again extends slightly inward and because the inner surfaces  643  are beveled, the cut tissue can be trapped within the lumen as the needle  640  is removed.  FIG. 6M  shows a top-down view of needle  640  in such a position. When rotation of the needle  640  is completed, the structural force of regions  641  overcomes that of the entrapped tissue, resulting in return of regions  641  to their original position (as shown in  FIG. 6K ), thereby preventing tissue inside the lumen from being lost as the device is removed from the patient. In another embodiment, a vacuum apparatus may be attached proximally (not shown) thus allowing immediate retrieval of the specimen while the device remains in the patient. 
         [0063]    An example of another embodiment of a needle having a single elongated member is needle  650  shown in  FIG. 6N . It can be seen that such an embodiment can be obtained from a standard needle, as used in medicine and surgery, by cutting away portion at one side  653  of the distal tip, thereby creating a beveled edge. If the edge so created is beveled in the opposite sense to the beveling at the opposite edge  652 , the rotational cutting efficacy of the needle is enhanced and contrasts with the beveling of a standard needle, which is in the same sense along all edges. In this embodiment, distal tip  651  is flush with the perimeter of the body  655  of the needle when viewed down a longitudinal axis  659 . 
         [0064]    For reference, when needle  600  (which includes any of needles  610 ,  620 ,  630 ,  640  and  650 ) is attached to a biopsy device such as biopsy device  100   a  by luer or other connection, the longitudinal axis of the needle (e.g. axis  601 ) will typically be collinear with longitudinal axis  301 . See, e.g.  FIG. 1 . As noted herein, vacuum may be applied to the lumen of the needle so that cut tissue may be removed by aspiration. 
         [0065]    The geometries and orientations of needles  610 ,  620 ,  630 ,  640 , and  650  illustrated in  FIGS. 6A-N  are exemplary, and it is understood that certain modifications may be made, including the following. The distal ends of the needles may be modified (e.g., by sharpening, pointing, etc.) to promote advancement of the needle into tissue. Referring to the examples illustrated in  FIGS. 6A-F , more than one leading and trailing edges (i.e. more than one portion leading to a distal end) may be present on a single needle. Similarly, referring to  FIGS. 6G-I , more than two leading and trailing edges (i.e., more than two portions leading to a distal end) may be present on a single needle. Curving or twisting portions leading to the distal end may curve or twist in a clockwise or counterclockwise direction. Leading and trailing edges may be straight or curved. Curvature of the leading and trailing edges may be the same (i.e., symmetric about a mirror plane including axis  601 ) or different (i.e. asymmetric about a mirror plane including axis  601 ), and may be concave (as illustrated) or convex. The distal end or ends may lie at the same circumference as that of the needle casing, may curve inwards and lie on axis  601 , or may lie on any point or points in between. Referring to the examples illustrated in  FIGS. 6J-M , sharpened leading edges  642  may be shaped with a saw tooth or irregularly and/or asymmetrically sharp configurations. Other modifications may also be made consistent with the teachings of this disclosure. 
         [0066]    Needle  600  (which includes any of needles  610 ,  620 ,  630 , and  640 ) may be used for any type of biopsy or similar technique, including fine biopsy, including, without limitation, biopsy of the thyroid, salivary gland, lung, pleura, liver, spleen, kidney, pancreas, adrenal, lymph node, breast, prostate, muscle, brain, intestine and any neoplastic solid mass, and core biopsy, including, without limitation, biopsy of the thyroid, salivary gland, liver, spleen, kidney, pancreas, adrenal, lymph nodes, breast, prostate, muscle, brain, intestine and any neoplastic intravisceral or extravisceral solid mass. Examples include needles of 22 to 27 gauge for fine biopsy, and 8 to 14 gauge for core biopsy. Such needles may be made from materials used to make conventional biopsy needles, including, without limitation, stainless steel, various alloys such as nickel titanium and certain high tensile strength plastics, such as polycarbonate, and carbon composites. 
       Operation 
       [0067]    Operation of the aspiration biopsy device  100   a  is illustrated by  FIGS. 7A-B . First, rotation of hub  200  is described. Referring to  FIG. 7A  (and as described elsewhere herein) hub  200  is disposed in casing  300   a , and slide  208  is disposed within receiving chamber  315 . Handle  220  is connected to stem  221 , which slidably inserts through distal slot  340 . Stem  221  terminates at end  222 , which engages helical groove  209 .  FIG. 7A  shows control  220  in a fully retracted position, that is, control  220  is as far in the proximal direction as possible. A user may manually (e.g. by using a thumb or finger) extend handle  220  in the distal direction indicated by arrow  701 . During such extension, the movement of end  222  engaging helical groove  209  causes hub  200  to rotate around axis  301  relative to casing  300   a , as shown by arrow  702 . 
         [0068]      FIG. 7B  shows needle biopsy device  100   a  when control  220  has been moved partway along the slot in the manner described above. A user may now continue to move the control  220  in the distal direction, or may retract it by pulling it back in the proximal direction as indicated by arrow  703 . Retraction of the control in this manner will cause hub  200  to rotate in the opposite direction as it did during the distal movement, as indicated by arrow  704 . 
         [0069]    When a needle (not shown here) is attached to the hub, the needle will also rotate. By repeatedly moving the control  220  in the distal and proximal directions, a user may cut tissue for biopsy with fine control. 
         [0070]    In certain implementations, the distance between full extension and retraction of control  220  may be from about 0.5 cm to about 2.0 cm. In other implementations, the device may be dimensioned and oriented for other distances. This distance will be determined in part by the length and orientation of helical groove  209  and slot  340 . 
         [0071]      FIGS. 7A-B  also illustrate operation of diaphragm assembly  400 . Diaphragm assembly  400 , including partition  410  disposed in the distal portion of second chamber  350 , may be slidably moved in the proximal and distal directions relative to the second chamber.  FIG. 7A  shows diaphragm assembly  400  in a fully extended position, that is, disc  410  is as far in the distal direction as possible, stopped by distal end-stops  351 . Distal position of disc  410  effects compression of optional spring  122 . As such, spring  122 , between casing  300   a  is fully compressed between casing  300   a  and diaphragm assembly  400 . Diaphragm assembly  400  may be retracted in the proximal direction indicated by arrow  705  by moving handle  420 , e.g. by a thumb or other finger. Such retraction proximally of diaphragm  410  will create a reduced pressure, such as a partial vacuum, in the distal portion of second chamber  350 . The distal portion of the second chamber  350  is in fluid communication with central barrel  310 , which is in fluid communication with the lumen of the hub  210 . When a needle is attached, hub chamber  210  is in fluid communication with the lumen of the needle. Thus, retraction of handle  420  will create a reduced pressure, such as a partial vacuum, in the lumen of the needle, allowing the user to remove cut tissue by aspiration. 
         [0072]      FIG. 7B  shows biopsy device  100   a  when diaphragm assembly  400  has been partially retracted in the manner described elsewhere herein. Also, diaphragm assembly  400  is at an intermediate stopping point, since bar  414  (not shown in this view) on flexible rod  412  has engaged an intermediate stop  365  (see  FIGS. 7C-D ). Spring  122  is thus partially expanded. A user may now continue to move diaphragm assembly  400  by withdrawing handle  420  away from casing  300   a . Handle  420  is connected to diaphragm  410  by flexible rod  412 . Other manners of controlling motion of partition  410  are consistent with the devices herein. Depression of handle  420  disengages a lateral member  414  from stops  365 . The release of this locking mechanism allows optional spring  122  to release tension, thereby abetting the proximal motion of diaphragm  410 . The user may then continue to retract diaphragm assembly  400 , or may extend it in the distal direction by pushing handle  420  in the distal direction, as indicated by arrow  705 . When handle  420  is extended in the distal direction, positive pressure will be generated in the distal portion of the second chamber  350  and, correspondingly, in the lumen of the attached needle. Such positive pressure may be used to extrude the sample for analysis, after the needle has been withdrawn from the subject. The optional spring  122  serves to resist rapid emptying and prevent sudden undesirable extrusion of all tissue from the vacuum chamber  310  and needle at once. As partition  410  is moved in the distal direction, negative pressure may be generated in the proximal portion of second chamber  360 . As described above, such pressure can be minimized by vent  361 , which fluidly communicates venting chamber  360  with the surrounding atmosphere. 
         [0073]      FIGS. 7C and 7D  illustrate a ratcheting mechanism of diaphragm assembly  400 . In these expanded transverse cross-sectional views, bar  414  is seen to extend from flexible rod  412 . In  FIG. 7C , bar  414  engages intermediate stop  365 , preventing the diaphragm assembly from being drawn in the proximal or distal direction.  FIG. 7D  illustrates that by pushing handle  420  towards casing  300   a , flexible rod  412  will depress, disengaging bar  414  from intermediate stop  365 . 
         [0074]    Once a sample has been extruded, needle  600  (which includes any of needles  610 ,  620 ,  630 , and  640 ) may be removed from hub  200 . The device may be cleaned, and any residual tissue or liquids may be removed, by injecting cleaning liquid or air into the device using a syringe attached at proximal end, once cap  500  is removed. 
         [0075]    Advantageously, the rotational cutting method using the needle and/or the device described herein can prevent sampling of adjacent non-target tissue such that tissue sampled is precisely from the locus of interest. For example, using ultrasound or some other visualization tool for guidance, the tip of the biopsy needle may be advanced to the locus of interest within a lesion such as a thyroid lesion. Traditional fine needle aspiration methodology employs a to-fro motion on the needle, often with simultaneous suction provided by an attached syringe. The acquisition of a sample in this manner may include irrelevant material outside the locus of interest. This can be minimized using the biopsy device with a rotational needle as described herein, whereby the aspiration occurs using rotary cutting of the needle tip without the need for proximal or distal translation. 
         [0076]    Additionally, in some embodiments, a solid stylet may be advanced to the leading edge of needle tip  600  (which includes any of needles  610 ,  620 ,  630 ,  640 , and  650 ) through proximal end hole in lieu of cap  500 . Having such a stylet in place prevents, or substantially hinders, the accumulation of unwanted non-target tissue within the needle lumen as the assembly is advanced in the body to the locus of interest. Once the tip of the needle has reached the locus (as defined by imaging with or without robotic instrumentation), the stylet can be removed and the sample obtained as described herein. 
         [0077]    Additionally, the device described herein, with a sharp distal needle tip, may be utilized in some embodiments for core biopsy in which larger gauge needles utilize rotational cutting while forward translation of the needle assembly is additionally effected by manual or mechanical means. This may be particularly useful in the setting of robotic assisted biopsy, where the locus of interest has been determined three dimensionally from imaging data. It is proposed that cutting tissue simultaneously using rotary as well as forward translational movement may allow for a greater degree of cutting efficiency and exactitude when compared with other biopsy methods that use needle translation only without simultaneous rotary cutting action. When such core specimens are obtained, they may be left within needle lumen for later retrieval (after the device has been removed from the patient) or such specimens may be instantaneously retrieved by the application of a vacuum or mechanical suction device peripheral to the biopsy device. 
         [0078]      FIGS. 8A-B  illustrate alternative embodiments of a biopsy device  100   b  with needle  600  attached to hub  200  (e.g., by a luer connection). As shown in  FIG. 8A , casing  300   b  assumes an ergonomic shape, being dimensioned to feel comfortable in the hand of a user. Casing  300   b  may include one or more finger grooves or indentations  309  that may be shaped to accept one or more fingers and thumb. Also shown in this embodiment, the diameter of central chamber  330  may be the same or about the same as that of barrel  310 .  FIG. 8B  shows a transverse cross-sectional view of a proximal region of device  100   b . In this view, it is seen that control  220  and handle  420  may be angularly offset from one another with respect to longitudinal axis  301 . The degree of offset may be arbitrary and may be altered to maximize comfort and usability of the device. Other aspects of the exemplary embodiment depicted in  FIGS. 8A-B  correspond to those of other embodiments described herein. 
         [0079]      FIG. 9  illustrates alternative embodiments of a device wherein a vacuum or partial vacuum is created by use of a motor rather than by manual movement of a handle. As shown, biopsy device  100   c  includes motor  900 , powered by power source  902 . Motor  900  moves rod  413 . Rod  413  moves disc  410  in the proximal direction to create a vacuum or partial vacuum in the distal portion of second chamber  350 . Rod  413  may also be moved in the proximal direction to create positive pressure to eject a tissue sample. Motor  900  can be controlled by one or more buttons, e.g., buttons  910   a  and  910   b , for turning the motor on and off, and controlling the direction of movement of disc  410 . This embodiment may be constructed with or without spring  122 . 
         [0080]    In an additional embodiment, a biopsy device such as biopsy device  100   c  shown in  FIG. 9 , may be equipped with a motor to rotate hub  200 .  FIG. 9  shows motor  920  (which may also be powered by power source  902 ) which may drive shaft  913 , connected to gear  915 . Gear  915  may engage teeth on needle mount hub  200  so that rotation of gear  915  may rotate needle mount hub  200 . Motor  920  may be controlled by one or more buttons, e.g., buttons  930   a  and  930   b.    
         [0081]    Other known techniques and materials may be used to rotate hub  200  and move disc  410  by motor. Also, while  FIG. 9  shows both the hub and the disc moved by a motor, such motorized movements are independent, and can be present in separate implementations, with an alternative being manual movement of both as described elsewhere herein. 
       Materials 
       [0082]    In certain embodiments, components of biopsy device  100   a ,  100   b , or  100   c  (including, but not limited to casing  300   a - c  and hub  200 ) may be made of a suitable plastic material (e.g., polycarbonate). In some embodiments, casing  300   a - c  may have solid portions and hollow portions, e.g., in order to reduce weight or cost of materials. Also, as described elsewhere herein, the part of casing  300   a - c  surrounding vacuum chamber  350  and venting chamber  360  may be hollow to accommodate part of diaphragm assembly  400 . In certain implementations, various components may be transparent, e.g., to enable the user to visualize fluid, tissue, instrumentation, etc., within the device. In other implementations, they may be colored and either opaque or transparent. 
         [0083]    End  222  may be constructed to reduce friction as it engages helical groove  209 , and to facilitate linear movement of control  220  and corresponding rotation of hub  200 . For example, in implementations, end  222  may be rounded or ball-shaped. Stem  221  and/or end  222  may be made from a suitable plastic or polymer (e.g. polycarbonate) and/or coated with Teflon, silicone, or a similar material with low coefficient of friction. In other implementations, end  222  may be a metallic ball bearing, similar to the end of a conventional ballpoint pen. Other constructions and materials of stem  221  and end  222  can easily be envisaged. 
         [0084]    The gripping surfaces of the device (e.g. outer surfaces of casing  300   a - c ) can be covered with a thermoplastic elastomer, including those under trade names Megol, Santoprene and Multibase, as well as silicone elastomers. The casing may comprise a unitarily moulded skeleton onto which the elastomer areas are moulded in a separate injection moulding step (see, e.g. International Application PCT/US 1999/020606 of Volpenhein et al.). The points of contact between the stationary and active portions of the device may be coated with Teflon, silicone, or a similar material with low coefficient of friction. 
         [0085]    Disc  410  and end cap  500  may be made from lightweight plastic, and, for the airtight seals to vacuum chamber  350  and central chamber  330 , disc  410  may be made of lightweight plastic constructed with a peripheral rim of rubber or a deformable resilient plastic such as a silicone. 
         [0086]    Control  220  and handle  420  may, in certain embodiments, pivot laterally for better ergonomic control. These items may be ridged, so as to facilitate grip, and composed of an elastomeric compound bound to lightweight durable plastic. 
         [0087]    In addition, larger gauge embodiments for core biopsy, although not shown, are envisioned. In such embodiments, the entire assembly may be advanced using manual or mechanical methods (including spring, hydraulic, pneumatic and motorized methods) for translation. In addition, computer assisted robotic methods of controlling a biopsy performed by the device and/or needle herein may be envisaged. 
         [0088]    A number of embodiments have been described. Nevertheless, it will be understood that any single device may include features of the particular devices illustrated, and various modifications may be made, including modifications to shape, size, and arrangement of parts, without departing from the spirit and scope of the disclosure, including the aforementioned nonvascular applications and others. Accordingly, other embodiments are within the scope of the following claims.