Abstract:
Transbronchial needle aspiration (TBNA) device. In one embodiment, the device comprises a handle and a flexible catheter, the handle having a bore, the proximal end of the catheter being fixed within the handle bore. A protective tubular hub having a flared distal end is press-fit coaxially within the distal end of the catheter, the distal end of the catheter being sealed around the distal end of the hub so as to define a distal opening. A hollow needle having a sharp tip at its distal end is disposed within the catheter, the needle tip being sized for insertion through the distal opening of the catheter. The distal end of a flexible wire is coupled to the proximal end of the needle, the proximal end of the wire extending through the handle bore and coupled to a button slide accessible through a slot in the handle. The button slide is movable between a distal position in which the needle tip extends through the distal opening of the catheter and a proximal position in which the needle tip is disposed within the hub. When in either its distal position or its proximal position, a pawl on the button slide releasably engages a corresponding notch on the handle to lock the button slide in place.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is a divisional of U.S. patent application Ser. No. 10/449,826, inventors Sergey S. Grigoryants et al., filed Dec. 11, 2006, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates generally to tissue sampling devices and relates more particularly to transbronchial needle aspiration devices.  
         [0003]     In order to diagnose and to stage lung cancer in a patient, it is often necessary to biopsy a tissue sample from a nearby lymph node of the patient. One type of technique that has been used in the past to obtain such a tissue sample involves percutaneously inserting a sampling needle through the patient&#39;s chest into the patient&#39;s lung and then through the bronchial wall of the lung into a nearby lymph node. Examples of devices adapted for percutaneous tissue sampling are disclosed in the following U.S. patents, all of which are incorporated herein by reference: U.S. Pat. No. 5,971,939, inventors DeSantis et al., which issued Oct. 26, 1999; U.S. Pat. No. 5,713,368, inventor Leigh, which issued Feb. 3, 1998; U.S. Pat. No. 4,799,494, inventor Wang, which issued Jan. 24, 1989; and U.S. Pat. No. 4,766,907, inventors de Groot et al., which issued Aug. 30, 1988.  
         [0004]     Although the above-described percutaneous sampling technique has proven satisfactory in terms of time and expense, such a technique does have its shortcomings. One such shortcoming is the risk of uncontrollable bleeding if the biopsy needle, which may be quite large in diameter, pierces or shears a blood vessel. Another shortcoming is the risk of pneumothorax, i.e., lung collapse, resulting from the puncturing of the lung by the biopsy needle, causing air to leak from the lung and to accumulate between the lung surface and the chest cage. In fact, if pneumothorax is severe enough, the patient may require a chest tube to drain air from the chest cavity. Moreover, in extreme cases, the condition may be fatal. Still another shortcoming is the risk of infection resulting from the percutaneous insertion of the needle into the patient.  
         [0005]     Accordingly, another technique that has been used to obtain a lymph node tissue sample is transbronchial needle aspiration (sometimes referred to as “TBNA”). In transbronchial needle aspiration, the distal end of a bronchoscope is inserted through a patient&#39;s mouth and to a neutral location within the patient&#39;s lung, the proximal end of the bronchoscope not being inserted into the patient and, instead, extending externally thereto. The distal end of a TBNA device is then inserted through a working channel of the bronchoscope, the proximal end of the TBNA device not being inserted into the bronchoscope and, instead, extending externally to the patient. The TBNA device typically comprises a catheter, a wire longitudinally disposed within the catheter, a histology sampling needle coupled to the distal end of the wire, a cap coupled to the proximal end of the wire and accessible externally to the patient for moving the wire relative to the catheter so as to alternately extend the needle beyond the distal end of the catheter and retract the needle into the catheter, and a port accessible externally to the patient for coupling a syringe to the proximal end of the catheter so that the syringe may provide suction to the catheter.  
         [0006]     The TBNA device is typically loaded into a bronchoscope with its needle in a retracted position and with a syringe attached to the port. Once confirmation is received that the distal end of the TBNA device has passed entirely through the bronchoscope (such confirmation typically being provided using a video channel of the same bronchoscope), the bronchoscope and the TBNA device are advanced together to the target site, and the needle is advanced to its extended position. The needle is then inserted through the bronchial wall of the patient and into a nearby lymph node. At this time, the syringe is used to apply suction. In the unfortunate event that the needle errantly penetrates a blood vessel, instead of a lymph node, the application of suction causes blood to be aspirated into the catheter and the syringe, where it is detected. In such a case, the application of suction is discontinued and the bloodied TBNA device is removed from the bronchoscope and the patient. A fresh TBNA device is then loaded into the bronchoscope and the patient in the manner described above, and another attempt is made to penetrate the lymph node.  
         [0007]     If, while suction is applied, it appears that the sampling needle has penetrated a lymph node, as is desired, the catheter is agitated to help shear tissue from the penetrated lymph node into the sampling needle. With a tissue sample thus disposed within the sampling needle, the needle is retracted into the catheter. The TBNA device is then removed from the bronchoscope and the patient. The needle is then advanced out of the catheter, and negative suction is then used to expel the tissue from the sampling needle onto a slide or the like for histological examination.  
         [0008]     Examples of TBNA devices are disclosed in the following patents, all of which are incorporated herein by reference: U.S. Pat. No. 5,056,529, inventor de Groot, which issued Oct. 15, 1991; U.S. Pat. No. 4,966,162, inventor Wang, which issued Oct. 30, 1990; U.S. Pat. No. 4,890,626, inventor Wang, which issued Jan. 2, 1990; U.S. Pat. No. 4,791,937, inventor Wang, which issued Dec. 20, 1988; U.S. Pat. No. 4,766,906, inventor Wang, which issued Aug. 30, 1988; U.S. Pat. No. 4,702,260, inventor Wang, which issued Oct. 27, 1987 U.S. Pat. No. 4,693,257, inventor Markham, which issued Sep. 15, 1987; U.S. Pat. No. 4,617,940, inventor Wang, which issued Oct. 21, 1986; U.S. Pat. No. 4,532,935, inventor Wang, which issued Aug. 6, 1985; and U.S. Pat. No. 4,249,541, inventor Pratt, which issued Feb. 10, 1981.  
         [0009]     Referring now to  FIGS. 1 and 2 , there are shown perspective and enlarged fragmentary section views, respectively, of a conventional, commercially available embodiment of a TBNA device, said TBNA device being represented generally by reference numeral  11 .  
         [0010]     Device  11  comprises a handle or body  13 . Body  13  is a branched or T-shaped, tubular member shaped to include a first port  15  at its proximal end, a second port  17  at its distal end, and a third port  19  extending perpendicularly to and between said first port  15  and said second port  17 . Each of first port  15 , second port  17  and third port  19  is in fluid communication with the other two ports. Third port  19  is adapted to receive a syringe for use in providing suction to device  11 .  
         [0011]     Device  11  also comprises a flexible catheter  21 . Catheter  21  has a proximal end and a distal end  23 , the proximal end of catheter  21  being fixedly mounted within second port  17 .  
         [0012]     Device  11  additionally comprises a metal hub or tip  25 . Tip  25  is a generally tubular member having a proximal end  27  and a distal end  29 . A plurality of external barbs  31  are formed on tip  25  intermediate to proximal end  27  and distal end  29 . Proximal end  27  and barbs  31  are mounted within catheter  21  proximate to distal end  23 , with distal end  29  of tip  25  not being inserted into catheter  21 , but rather, externally abutting distal end  23  of catheter  21 .  
         [0013]     Device  11  further comprises a flexible wire  35 , wire  35  having a proximal end  37  and a distal end  39 . Proximal end  37  of wire  35  is fixed to a cap  41 , cap  41  being adapted to be screwed onto first port  15  of body  13 . The remainder of wire  35  is threaded through ports  15  and  17  of body  13  and into catheter  21 , with distal end  39  of wire  35  being disposed within catheter  21  proximate to distal end  23 . A stop (not shown) is provided on wire  35 , said stop being engageable with body  13  to delimit proximal movement of wire  35 .  
         [0014]     Device  11  also comprises a histology sampling needle  51 , needle  51  having a proximal end  53  and a distal end  55 . Proximal end  53  of needle  51  is fixed to distal end  39  of wire  35 . Distal end  55  of needle  51  is shaped to include a sharp tip. A bore  57  extends proximally from distal end  55  of needle  51  to a side opening  59  proximate to proximal end  53 . An annular seal  61  is mounted over needle  51  just distal to side opening  59 , seal  61  being adapted to abut proximal end  27 .  
         [0015]     Device  11  may be used essentially in the fashion described above to obtain a tissue sample. To place needle  51  in its advanced position, i.e., so that distal end  55  of needle  51  extends beyond tip  25 , one moves cap  41  distally and screws cap  41  onto port  15 . Conversely, to withdraw or to retract needle, i.e., so that distal end  53  of needle  51  is disposed within tip  25 , one unscrews cap  41  from port  15  and moves cap  41  proximally relative to body  13  until restrained by the aforementioned stop.  
         [0016]     Although device  11  is satisfactory in many respects, the present inventors have identified certain shortcomings therewith. One such shortcoming is that, whereas device  11  includes means for retaining needle  51  in its extended position (namely, by screwing cap  41  onto port  15 ), device  11  does not include corresponding means for retaining needle  51  in a retracted position. Consequently, if one wishes to ensure that needle  51  is not advanced through distal end  23  of catheter  21  at an inopportune moment, one must constantly pull cap  41  proximally relative to body  13 . However, as can readily be appreciated, such a requirement substantially complicates the manipulation of device  11 , especially by an individual operator.  
         [0017]     Another shortcoming identified by the present inventors with device  11  is the branched shape of body  13  and the resultant orientation of a syringe coupled thereto through port  19 . More specifically, the present inventors have found that the perpendicular orientation of a syringe relative to the longitudinal axis of catheter  21  makes device  11  cumbersome and difficult to manipulate by an individual operator.  
         [0018]     Yet another shortcoming identified by the present inventors with device  11  is that, when needle  51  is in its extended position and a load force is applied to the distal end  53  of needle  51  (such as is the case when needle  51  is used to penetrate a tissue), needle  51  tends to be moved proximally relative to catheter  21 , thereby effectively shortening the usable length of needle  51  for penetrating the tissue. Such a loss in the usable length of needle  51  occurs because wire  35  has an outer diameter that is considerably smaller than the inner diameter of catheter  21 , giving wire  35  room to move laterally within catheter  21 . Consequently, when catheter  21  is bent, as is the case when device  11  is deployed in a patient, and a load force is applied to needle  51 , wire  35  tends to take the longest possible path through catheter  21 .  
         [0019]     Conversely, when cap  41  is pulled back relative to catheter  21  to its fully retracted position and catheter  21  is bent to a substantial degree, needle  51  may not fully retract relative to catheter  21 . This is because of the aforementioned difference between the outer diameter of wire  35  and the inner diameter of catheter  21  and the tendency of wire  35  to take the shortest possible path through catheter  21 . As can readily be appreciated, if needle  51  cannot be fully retracted when sampling is not being performed, damage may occur to equipment, operators and/or the patient.  
         [0020]     Still another shortcoming identified by the present inventors with device  11  is that tip  25  is susceptible to becoming dislodged distally from catheter  21 . As can readily be appreciated, if tip  25  were to become separated from catheter  21 , the risks to the patient would be considerable. Such a susceptibility of tip  25  to becoming dislodged is due, in part, to the fact that tip  25  is held within catheter  21  only by the friction-fit of catheter  21  over barbs  31  and proximal end  27 . This susceptibility is exacerbated by the fact that, when needle  51  is advanced to its extended position, seal  61  applies a distally directed force against tip  25 . In addition, because catheter  21  has a tendency to bulge radially outwardly in the area where it overlies barbs  31 , this bulged area of catheter  21  is susceptible to becoming snagged on the distal end of a bronchoscope when device  11  is retracted into the bronchoscope. Such snagging results in additional distally directed force being applied to tip  25  relative to catheter  21 .  
         [0021]     Still yet another shortcoming identified by the present inventors with device  11  is that distal end  29  of tip  25 , which is not disposed within catheter  21 , but rather, lies externally thereto, has a tendency to scratch and, thus, to damage the working channel of a bronchoscope.  
         [0022]     Still a further shortcoming identified by the present inventors with device  11  is that, when needle  51  is retracted, distal end  55  of needle  51  has a tendency to be withdrawn proximally from hub  25 . This requires needle  51  to be re-aligned properly with hub  25  in order for needle  51  to be re-inserted into hub  25 .  
         [0023]     Still yet a further shortcoming identified by the present inventors with device  11  is that seal  61  often does not create an air-tight seal against tip  25  when needle  51  is placed in its fully extended position; as a result, the full extent of the vacuum force applied to bore  57  of needle  51  by the syringe is frequently not experienced.  
       SUMMARY OF THE INVENTION  
       [0024]     It is an object of the present invention to provide a tissue sampling device suitable for use in transbronchial needle aspiration (TBNA).  
         [0025]     It is another object of the present invention to provide a tissue sampling device as described above that overcomes at least some of the shortcomings associated with existing TBNA devices.  
         [0026]     It is still another object of the present invention to provide a device as described above that can be mass-produced relatively inexpensively, that has a minimal number of parts, and that is easy to operate.  
         [0027]     In furtherance of the above and other objects to be described or to become apparent from the description below, there is provided, according to one aspect of the invention, a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a flexible catheter, said flexible catheter having a proximal end and a distal end; (b) a sampling needle, said sampling needle being insertable into said flexible catheter and being shaped to include a distal tip; (c) means coupled to said sampling needle for moving said sampling needle between a first position wherein said distal tip of said sampling needle is disposed within said flexible catheter and a second position wherein said distal tip of said sampling needle extends distally beyond said distal end of said flexible catheter; and (d) means for retaining said sampling needle at said first position in a releasably locked fashion.  
         [0028]     According to another aspect of the invention, there is provided a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a flexible catheter, said flexible catheter having a proximal end and a distal end; (b) a sampling needle, said sampling needle being disposed at said distal end of said flexible catheter and having a distal tip; and (c) a handle assembly, said handle assembly being secured to said proximal end of said flexible catheter, said handle assembly including a port adapted to receive a syringe in such a manner as to fluidly interconnect said syringe to said flexible catheter, said port being oriented parallel to said proximal end of said flexible catheter.  
         [0029]     According to yet another aspect of the invention, there is provided a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a flexible catheter, said flexible catheter having a proximal end, a distal end and an inner diameter; (b) a wire, said wire extending substantially coaxially within said flexible catheter, said wire having a proximal end, a distal end and an outer diameter, said outer diameter of said wire being substantially less than said inner diameter of said flexible catheter; (c) a sampling needle, said sampling needle being positioned at said distal end of said flexible catheter and being coupled to said distal end of said wire; (d) means inserted over at least a portion of said wire for centering said wire within said flexible catheter while still providing a space for fluid flow; and (e) a handle assembly, said flexible catheter being fixed at said proximal end to said handle assembly.  
         [0030]     According to still yet another aspect of the invention, there is provided a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a flexible catheter, said flexible catheter having a proximal end and a distal end; (b) a hub, said hub being substantially tubular and having a proximal end and a distal end, said hub being disposed within said flexible catheter, with said distal end of said flexible catheter being inverted so as to retain said hub distally within said flexible catheter; (c) a sampling needle, said sampling needle having a tip; and (d) means coupled to said sampling needle for moving said sampling needle between a first position wherein said tip of said sampling needle is disposed within said hub and a second position wherein said tip of said sampling needle extends distally beyond said distal end of said flexible catheter.  
         [0031]     According to a further aspect of the invention, there is provided a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a flexible catheter, said flexible catheter having a proximal end, a distal end and an inner diameter; (b) a wire, said wire extending within said flexible catheter, said wire having a proximal portion and a distal portion, said distal portion having a decreased thickness as compared to said proximal portion; (c) a sampling needle, said sampling needle being positioned at said distal end of said flexible catheter and being coupled to said wire; and (d) a compressed spring surrounding and secured to at least a portion of said distal portion of said wire.  
         [0032]     According to still a further aspect of the invention, there is provided a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a handle, said handle comprising a body and a cover, said body and said cover together defining a top, a bottom and a distal end, said top having a slot, said distal end having a bore; (b) a button slide, said button slide being slidably mounted in said handle and including a button, said button extending upwardly through said slot for manipulation by an operator; (c) a flexible catheter, said flexible catheter having a proximal end and a distal end, said proximal end being mounted within said bore in said handle; (d) a wire, said wire having a proximal end and a distal end, said proximal end of said wire being coupled to said button slide; and (e) a sampling needle, said sampling needle being coupled to said distal end of said wire, said sampling needle having a distal tip; (f) wherein said button slide is movable between a first position in which said distal tip of said sampling needle is positioned within said flexible catheter and a second position in which said distal tip of said sampling needle extends distally past said proximal end of said flexible catheter.  
         [0033]     According to still yet a further aspect of the invention, there is provided a tissue sampling device suitable for use in transbronchial needle aspiration, said tissue sampling device comprising (a) a flexible catheter, said flexible catheter having a proximal end and a distal end; (b) a hub, said hub being substantially tubular and having a proximal end and a distal end, said hub being disposed within said flexible catheter proximate to said distal end thereof; (c) a sampling needle, said sampling needle having a distal tip and a shoulder; and (d) means coupled to said sampling needle for moving said sampling needle between a first position wherein said distal tip of said sampling needle is disposed within said hub and a second position wherein said distal tip of said sampling needle extends distally beyond said distal end of said flexible catheter; (e) wherein said shoulder of said sampling needle is adapted to directly abut said proximal end of said hub to form a seal therewith when said sampling needle is placed in said second position.  
         [0034]     For purposes of the present specification and claims, various relational terms like “top,” “bottom,” “proximal,” “distal,” “upper,” “lower,” “front,” and “rear” are used to describe the present invention when said invention is positioned in a given orientation. It is to be understood that, by altering the orientation of the invention, certain relational terms may need to be adjusted accordingly.  
         [0035]     Additional objects, as well as features and advantages, of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. In the description, reference is made to the accompanying drawings which form a part thereof and in which is shown by way of illustration various embodiments for practicing the invention. The embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0036]     The accompanying drawings, which are hereby incorporated into and constitute a part of this specification, illustrate various embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings wherein like reference numerals represent like parts:  
         [0037]      FIG. 1  is a perspective view of a conventional transbronchial needle aspiration (TBNA) device;  
         [0038]      FIG. 2  is a fragmentary, section view of the TBNA device of  FIG. 1 , showing the distal portion thereof;  
         [0039]      FIG. 3  is a side view of one embodiment of a TBNA device constructed according to the teachings of the present invention, the TBNA device being shown with its needle in the retracted position;  
         [0040]      FIG. 4  is a fragmentary longitudinal section view of the TBNA device of  FIG. 3 , the TBNA device being shown with its needle in the retracted position;  
         [0041]      FIG. 5  is an exploded perspective view of the TBNA device of  FIG. 3 ;  
         [0042]     FIGS.  6 ( a ) and  6 ( b ) are fragmentary section views of the TBNA device of  FIG. 3 , showing the distal portion thereof with the needle in its retracted and extended positions, respectively;  
         [0043]     FIGS.  7 ( a ) through  7 ( f ) are perspective, side, top, proximal, distal and longitudinal section views, respectively, of the handle body shown in  FIG. 3 ;  
         [0044]     FIGS.  8 ( a ) through  8 ( e ) are perspective, top, bottom, left longitudinal section and right longitudinal section views, respectively, of the handle cover shown in  FIG. 3 ;  
         [0045]     FIGS.  9 ( a ) through  9 ( e ) are perspective, top, bottom, right side and left longitudinal section views, respectively, of the button slide shown in  FIG. 3 ;  
         [0046]      FIG. 10 ( a ) through  10 ( e ) are perspective, proximal, distal, right side and left longitudinal section views, respectively, of the syringe connector shown in  FIG. 3 ;  
         [0047]     FIGS.  11  ( a ) through  11  ( d ) are perspective, proximal, right side and right longitudinal section views, respectively, of the strain relief member shown in  FIG. 3 ;  
         [0048]     FIGS.  12 ( a ) and  12 ( b ) are perspective and right longitudinal section views, respectively, of the hub shown in  FIG. 3 ;  
         [0049]      FIG. 13  is a fragmentary right side view of the wire shown in  FIG. 3 ;  
         [0050]     FIGS.  14 ( a ) and  14 ( b ) are proximal and side views, respectively, of the jacket shown in  FIG. 3 ;  
         [0051]     FIGS.  15 ( a ) and  15 ( b ) are right side and enlarged right longitudinal section views, respectively, of the spring shown in  FIG. 3 ;  
         [0052]     FIGS.  16 ( a ) through  16 ( c ) are fragmentary right side, fragmentary right longitudinal section and fragmentary enlarged right longitudinal section views, respectively, of the combination of the wire, the jacket and the spring shown in  FIG. 3 ;  
         [0053]      FIG. 16 ( d ) is an enlarged right side view showing the distal ends of the spring and the wire shown in  FIG. 16 ( a );  
         [0054]     FIGS.  17 ( a ) through  17 ( d ) are perspective, left side, top and enlarged fragmentary left longitudinal section views, respectively, of the needle shown in  FIG. 3 ;  
         [0055]     FIGS.  18 ( a ) through  18 ( c ) are perspective, top and left side views, respectively, of a first alternate needle; and  
         [0056]     FIGS.  19 ( a ) through  19 ( c ) are perspective, top and left side views, respectively, of a second alternate needle.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0057]     Referring now to  FIGS. 3, 4 ,  5 ,  6 ( a ) and  6 ( b ), there are shown various views, respectively, of one embodiment of a transbronchial needle aspiration (TBNA) device constructed according to the teachings of the present invention, said TBNA device being represented generally by reference numeral  101 .  
         [0058]     Device  101  comprises a handle assembly  103 , a wire  105 , a flexible catheter  107 , a sampling needle  109 , a hub  111 , a jacket  113  and a spring  115 .  
         [0059]     Handle assembly  103 , in turn, comprises a body  117 , a cover  119 , a button slide  121 , a syringe connector  123  and a strain relief member  125 .  
         [0060]     Referring now to FIGS.  7 ( a ) through  7 ( f ), body  117  is a unitary, generally C-shaped member, preferably made of a durable molded plastic or another similarly suitable material, comprising a top portion  131 , a distal end portion  133  and a bottom portion  135 , the sides and proximal end of body  117  being open. Top portion  131 , distal end portion  133  and bottom portion  135  collectively define a longitudinally-extending cavity  139 , which, as will be described below, is shaped to accommodate a syringe or similar aspirating device.  
         [0061]     Top portion  131  is shaped to include a pair of rails  141 - 1  and  141 - 2 , rails  141 - 1  and  141 - 2  being separated by a slot  142  whose purpose will become apparent below. A first pair of detents  143 - 1  and  143 - 2  are formed on the outer side surface of rail  141 - 1 , and a second pair of detents  145 - 1  and  145 - 2  are formed on the outer side surface of rail  141 - 2 , second detents  145 - 1  and  145 - 2  being staggered relative to first detents  143 - 1  and  143 - 2 . As will be described below, detents  143 - 1 ,  143 - 2 ,  145 - 1  and  145 - 2  are used in the coupling together of body  117  and cover  119  to form a handle.  
         [0062]     Distal end portion  133  includes a proximal surface  147 , proximal surface  147  being shaped to receive syringe connector  123 . Distal end portion  133  also includes a distally extending post  149 . A bore  151  (which is seen best in  FIG. 7 ( f )) extends longitudinally through post  149  and continues through the remainder of distal end portion  133  to cavity  139 . Bore  151  includes a distal portion  151 - 1  of comparatively greater cross-sectional diameter and a proximal portion  151 - 2  of comparatively lesser cross-sectional diameter, distal portion  151 - 1  extending for most of the length of bore  151 . As will be described further below, distal portion  151 - 1  is sized to securely receive the proximal end of catheter  107 , with the proximal end of wire  105  passing through proximal portion  151 - 2 . A transverse opening  153  is also provided in distal end portion  133 , transverse opening  153  intersecting distal portion  151 - 1  of bore  151  at an intermediate location thereof.  
         [0063]     Bottom portion  135  has a top surface  155  and a bottom surface  157 . Top surface  155  is contoured to receive a syringe or similar aspirating device thereon. Bottom surface  157  is contoured to fit ergonomically within the hand of an operator.  
         [0064]     Referring now to FIGS.  8 ( a ) through  8 ( e ), cover  119  is a unitary, generally trough-shaped member, preferably made of a durable molded plastic or another similarly suitable material, comprising a top portion  161 , a pair of side portions  163 - 1  and  163 - 2 , and a proximal end portion  165 , the bottom and the distal end of cover  119  being open. Top portion  161  is shaped to include an elongated, longitudinally-extending slot  167 , through which, as will be further described below, the button portion of button slide  121  is adapted to extend. Top portion  161  is also shaped to include a proximal pair of notches  169 - 1  and  169 - 2  and a distal pair of notches  171 - 1  and  171 - 2 , notches  169 - 1  and  169 - 2  being disposed on opposite sides of slot  167  near the proximal end thereof, notches  171 - 1  and  171 - 2  being disposed on opposite sides of slot  167  near the distal end thereof. As will be described further below, proximal notches  169 - 1  and  169 - 2  and distal notches  171 - 1  and  171 - 2  are alternately adapted to receive, in a releasably locking fashion, a pair of pawls formed on button slide  121 , notches  169 - 1  and  169 - 2  being adapted to receive said pawls in such a manner as to retain button slide  121  at a proximal position (as in  FIGS. 3, 4  and  6 ( a )), notches  171 - 1  and  171 - 2  being adapted to receive said pawls in such a manner as to retain button slide  121  at a distal position (as in  FIG. 6 ( b )).  
         [0065]     A first pair of recesses  175 - 1  and  175 - 2  are formed on the inside surface of side portion  163 - 1 , and a second pair of recesses  177 - 1  and  177 - 2  are formed on the inside surface of side portion  163 - 2 . Recesses  175 - 1  and  175 - 2  are adapted to securely receive detents  143 - 1  and  143 - 2 , respectively, of rail  141 - 1 , and recesses  177 - 1  and  177 - 2  are adapted to securely receive detents  145 - 1  and  145 - 2 , respectively, of rail  141 - 2 . In this manner, body  117  and cover  119  may be secured to one another to form a handle. With body  117  and cover  119  thus coupled together, proximal end portion  165  of cover  119  is situated within the open proximal end of body  117 , the open distal end of cover  119  terminates just proximally of post  149 , and top portion  161  of cover  119  is spaced, for reasons to become apparent below, from the top surfaces of rails  141 - 1  and  141 - 2 .  
         [0066]     Referring now to FIGS.  9 ( a ) through  9 ( e ), button slide  121  is a unitary, generally rectangular member, preferably made of a durable molded plastic or other similarly suitable material, comprising an outer frame portion  181  and an inner tab portion  183 . Frame portion  181 , which is generally planar, is shaped to include a proximal end  185 , a distal end  187 , and a pair of sides  189 - 1  and  189 - 2 , all of which collectively define an interior cavity  190 . For reasons to become apparent below, frame portion  181  is appropriately dimensioned so that sides  189 - 1  and  189 - 2  are adapted to ride along the top surfaces of rails  141 - 1  and  141 - 2 , respectively, and below a pair of ribs  188 - 1  and  188 - 2 , respectively, formed on cover  119  (see FIGS.  8 ( c ) through  8 ( e )).  
         [0067]     Proximal end  185  of frame  181  is shaped to include a downwardly extending central portion  191 , central portion  191  being dimensioned to extend downwardly a short distance through slot  142  of body  117 . A slot  193  is provided in central portion  191 , slot  193  extending upwardly a short distance from the bottom surface of portion  191 . Slot  193  is shaped to include a pair of substantially orthogonal arms  193 - 1  and  193 - 2 , which, as will be described further below, are adapted to matingly receive the proximal end of wire  105 .  
         [0068]     Distal end  187  is shaped to include a generally rectangular central portion  195 , central portion  195  being dimensioned to extend downwardly a short distance through slot  142 . A bore  197  is provided in central portion  195 , bore  197  being aligned with arm  193 - 1  of slot  193  to receive an intermediate length of wire  105 .  
         [0069]     Inner tab portion  183  is generally trapezoidal in shape and includes a proximal end  201 , a distal end  203  and a pair of sides  205 - 1  and  205 - 2 . Proximal end  201  is hingedly connected to proximal end  185  of frame  181 , with distal end  203  being free and upwardly biased. A pair of pawls  207 - 1  and  207 - 2  extend upwardly from sides  205 - 1  and  205 - 2 , respectively, of tab portion  183 . Pawls  207 - 1  and  207 - 2  are adapted to be received either within proximal notches  169 - 1  and  169 - 2 , respectively, or distal notches  171 - 1  and  171 - 2 , respectively, of cover  119 .  
         [0070]     A button  209  is provided on the top surface of tab portion  183  proximate to distal end  203 , button  209  being adapted to extend upwardly through slot  167  of cover  119 . With button  209  thus accessible through slot  167 , an operator may use button  209  to exert downward pressure on tab portion  183  to disengage pawls  207 - 1  and  207 - 2  from either notches  169 - 1  and  169 - 2  or notches  171 - 1  and  171 - 2 , as well as to slide button slide  121  proximally or distally along rails  141 - 1  and  141 - 2 . Gripping elements  211  extend outwardly from the top of button  209  to facilitate manipulation of button  209 .  
         [0071]     Referring now to FIGS.  10 ( a ) through  10 ( e ), syringe connector  123  is a generally teardrop-shaped unitary member, preferably made of a durable molded plastic or another similarly suitable material, comprising a proximal end  221 , a distal end  223  and a side  225 . A port  227  extends proximally a short distance from proximal end  221 , port  227  defining a tapered cavity  229  adapted to receive the medical luer of a syringe. The proximal end of port  227  is shaped to include a pair of radially outwardly extending tabs  229 - 1  and  229 - 2 , tabs  229 - 1  and  229 - 2  being adapted for threaded engagement with the internally threaded sleeve of a syringe. Port  227  is oriented so that, with a syringe connected thereto and with connector  123  mounted on body  117 , said syringe extends longitudinally through cavity  139  and on top of bottom portion  155  of body  117 .  
         [0072]     An oval-shaped ridge  231  extends distally a short distance from distal end  223 , ridge  231  being receivable within a correspondingly shaped groove  235  provided in distal end portion  133  of body  117  (see  FIG. 7 ( d )). An adhesive (not shown) may be used, if desired, to more securely retain ridge  231  within groove  235 . Ridge  231  defines an oval-shaped cavity  237  that is adapted to bounded proximally by distal end  223  of syringe connector  123  and distally by distal end portion  133  of body  117 . Cavity  237  is adapted to be aligned with distal portion  151 - 1  of bore  151  of body  117  for reasons to become apparent below.  
         [0073]     A first transverse bore  241  extending between proximal end  221  and distal end  223  is provided in syringe connector  123 , bore  241  being in fluid communication with each of cavity  229  and cavity  237 . Accordingly, by connecting a syringe to connector  121 , one can apply negative or positive suction force through cavity  229 , bore  241 , and cavity  237  and into bore  151 .  
         [0074]     A second transverse bore  245  extending between proximal end  221  and distal end  223  is provided in syringe connector  123 , bore  245  being alignable with bore  151  for an intermediate portion of wire  105  to pass therethrough.  
         [0075]     Referring now to FIGS.  11  ( a ) through  11  ( d ), strain relief member  125  is a unitary member, preferably made of a durable molded plastic or another similarly suitable material, comprising a generally cylindrical proximal portion  251  and a frustoconical distal portion  253 . A longitudinal bore  255  extends the length of member  125 , the proximal portion  256  of bore  255  being shaped to receive, among other things, post  149  of body  117 , the distal portion  257  of bore  255  being shaped to receive, and thereby provide strain relief to, a length of catheter  107  proximate to the proximal end of catheter  107 .  
         [0076]     Referring now to FIGS.  12 ( a ) and  12 ( b ), hub  111  is a unitary tubular member, preferably made of stainless steel or another similarly suitable material, comprising a proximal portion  261  and a distal portion  263 . Proximal portion  261  is straight and has a uniform diameter over its entire length. Distal portion  263  flares outwardly from proximal portion  261  to a distal end  265  for reasons to become apparent below. (It should be understood that the proximal end could also be outwardly flared, if desired.) Referring back to  FIGS. 3, 4 ,  5 ,  6 ( a ) and  6 ( b ), catheter  107  is a unitary flexible tubular member, preferably made of nylon or another similarly suitable material, having a length of about 160 cm and comprising a proximal end  271  and a distal end  273 . Proximal end  271  of catheter  107  is coaxially received and fixedly secured within distal portion  151 - 1  of bore  151 . As seen best in FIGS.  6 ( a ) and  6 ( b ), catheter  107  is dimensioned relative to hub  111  so that hub  111  may be press-fit into catheter  107  through distal end  273 , with distal end  273  of catheter  107  being inverted over distal end  265  of hub  111  and shaped to define an opening  275 . Although not shown herein, the shaping of distal end  273  of catheter  107  around distal end  265  of hub  111  to define opening  275  may be performed by inserting a mandrel through hub  111  and catheter  107  and then using heat to shape distal end  273  to said mandrel. Preferably, opening  275  of catheter  107  is dimensioned to conform closely to the outer diameter of a shaft  277  of needle  109  to promote an air-tight seal between shaft  277  and catheter  107  when needle  109  is extended through opening  275  (as in  FIG. 6 ( b )). Alternatively, one could position an annular seal (not shown) coaxially within catheter  107  between distal end  273  of catheter  107  and distal end  265  of hub  111 , said annular seal being appropriately dimensioned and made of a suitable material to promote an air-tight interface with the outer surface of needle  109  inserted therethrough.  
         [0077]     Referring now to  FIG. 13 , wire  105  is a solid flexible unitary member, preferably made of stainless steel or another similarly suitable material, comprising a proximal portion  281  and a distal portion  283 . Proximal portion  281 , which has a length of about 52 inches and a thickness of about 0.022 inch, includes a proximal end  285 . Proximal end  285  is bent into an L-shape and is adapted to be securely received within slot  193  of button slide  121 . The remainder of proximal portion  281  is adapted to be inserted through bore  197  of button slide  121 , through an annular seal  291  (see  FIGS. 4 and 5 ) positioned between button slide  121  and syringe connector  123 , through bore  245  of syringe connector  123 , through bore  151  of body  103  and into catheter  107 , terminating a few inches proximally of hub  111 .  
         [0078]     Distal portion  283 , which has a length of about 2 inches, is shaped to include a proximal segment  287 - 1  and a distal segment  287 - 2 . Proximal segment  287 - 1  has a length of about 0.2 inch and decreases uniformly in thickness from about 0.022 inch at its proximal end to about 0.01 inch at its distal end. Distal segment  287 - 2 , which extends distally from segment  287 - 1 , has a length of about 1.8 inch and a uniform thickness of about 0.01 inch over its entire length.  
         [0079]     As will be described further below, the reason for providing a reduced thickness over much of the length of distal portion  283  of wire  105  is to endow distal portion  283  with additional flexibility, which may be advantageous in enabling distal portion  283  to be delivered to certain remote sampling sites accessible only through contorted paths. Endowing distal portion  283  of wire  105  with additional flexibility may also be advantageous in allowing passage through aggressive scope channels. Notwithstanding the above, distal portion  283  may be varied in size and/or shape depending upon the characteristics desired therefor.  
         [0080]     Referring now to FIGS.  14 ( a ) and  14 ( b ), jacket  113  is a unitary tubular member, preferably made of arnitel, polypropylene or another similarly suitable material. Jacket  113  is shaped to include a proximal end  301 , a distal end  303 , a central bore  305 , and a plurality of external ribs  307 - 1  through  307 - 4 . Bore  305  is appropriately dimensioned to securely receive wire  105  by a friction-fit, with proximal end  301  of jacket  113  being aligned with that portion of wire  105  that is disposed within distal portion  151 - 1  of bore  151  when button slide  121  is in its retracted position and with distal end  303  of jacket  113  being aligned with that portion of wire  105  that is positioned just proximally of distal portion  283 . An alternative to the aforementioned friction-fit between wire  105  and jacket  113  is a sliding-fit between wire  105  and jacket  113 . Such a sliding-fit allows wire  105  to move with respect to jacket  113  in situations where jacket  113  encounters resistance when sliding within catheter  107 . This allows for movement of wire  105  to occur in the manner of least resistance.  
         [0081]     Ribs  307 - 1  through  307 - 4 , which extend longitudinally along the entire length of jacket  113 , are evenly spaced about the circumference of jacket  113 . Each of ribs  307 - 1  through  307 - 4  extends in a direction radially outwardly from bore  305  and is generally triangular in shape, as viewed from an end of jacket  113 . Ribs  307 - 1  through  307 - 4  are appropriately sized so that at least one of their respective vertices  309 - 1  through  309 - 4  is adapted to be in contact with the inside surface of catheter  107 . In this manner, ribs  307 - 1  through  307 - 4  serve to keep wire  105  substantially centered within catheter  107  throughout its length (even when a load force is applied to needle  109 ) while, at the same time, providing ample space (i.e., between adjacent ribs  307 ) for fluid flow within catheter  107 .  
         [0082]     As can readily be appreciated, there are a myriad number of ways in which ribs  307 - 1  through  307 - 4  may be changed in size, shape and number while still satisfying the foregoing objectives of keeping wire  105  centered within catheter  107  and providing an ample volume within catheter  107  for fluid flow. (For examples of these and other modifications, see commonly-assigned U.S. Pat. No. 6,454,702 and commonly-assigned U.S. patent application Ser. No. 09/716,710, both of which are incorporated herein by reference.)  
         [0083]     In another embodiment (not shown), one could replace jacket  113  with a plurality of beads or similarly suitable elements over-molded around wire  105  at spaced intervals thereof, said beads being sized to engage the inside surface of catheter  107  and, thus, to keep wire  105  centered within catheter  107 . If desired, said beads could have longitudinal grooves or channels oriented along the longitudinal axis of catheter  107  to allow maximum fluid flow from the proximal to the distal portions of catheter  107  and vice versa. The dimensions of said beads may also be chosen so as to regulate fluid flow by controlling the gap between the bead surface and catheter  107 .  
         [0084]     In still another embodiment (not shown), one could replace both jacket  113  and wire  105  with a wire that is shaped (e.g., by machining, stamping, etc.) to include one or more elements adapted to keep said wire centered within catheter  107 .  
         [0085]     Referring now to FIGS.  15 ( a ) and  15 ( b ), spring  115  is a unitary member, preferably made of stainless steel or another similarly suitable material, comprising a plurality of closely spaced or compressed coils  311  terminating at a proximal end  313  and a distal end  315 . (Although coils  311  are shown in the present embodiment having a rectangular transverse cross-sectional shape, it is to be understood that coils  311  are not limited to a rectangular transverse cross-sectional shape and could have, for example, a circular transverse cross-sectional shape or the like.) As seen best in FIGS.  16 ( a ) through  16 ( c ), spring  115  coaxially surrounds distal portion  283  of wire  105 , with proximal end  313  of spring  115  being secured, preferably by a weld  314 - 1  (see  FIG. 16 ( c )) or like means, to wire  105  just proximally of segment  287 - 1  and with distal end  315  of spring  115  being secured, preferably by a weld  314 - 2  (see  FIG. 16 ( d )) or like means, to the distal end of segment  287 - 2 . Spring  115  has a uniform inner diameter of about 0.026 inch, which is slightly greater than the thickness of wire  105 , and a uniform outer diameter of about 0.034 inch.  
         [0086]     The purpose of spring  115  is to provide greater column strength to distal portion  283  of wire  105 , i.e., to make distal portion  283  less likely to buckle when a compressive force is applied thereto. Such increased column strength is desirable since, as noted above, distal portion  283  has a decreased thickness as compared to the remainder of wire  105 . One advantageous feature of spring  115  is that, whereas spring  115  cannot be compressed and, therefore, provides the aforementioned column strength to distal portion  283 , spring  115  can be bent and, therefore, does not substantially diminish the flexibility of distal portion  283 .  
         [0087]     Referring now to FIGS.  17 ( a ) through  17 ( d ), needle  109  is a unitary member, preferably made of stainless steel or another similarly suitable material, comprising a proximal base portion  321  and a distal stem portion  323 . Base portion  321 , which is generally cylindrical in shape, is about 0.2 inch in length and includes a proximal end  325 , a rounded distal end  327 , a longitudinal bore  329  and an upwardly-facing slot  331 , slot  331  extending distally from proximal end  325  to a point just prior to distal end  327 . Slot  331  is bounded by a flat edge  332  onto which wire  105  may be secured, preferably by welding or like means.  
         [0088]     Stem portion  323 , which is generally cylindrical in shape and coaxial with base portion  321 , is about 0.8 inch in length and includes a proximal end  333 , a distal end  335  and a longitudinal bore  337 . Distal end  335  is shaped to define an upwardly-facing, open-ended tip, said tip being appropriately shaped and dimensioned to acquire a tissue sample for biopsy. As in the embodiment shown, slot  331  and the tip of needle  109  both face in the same direction; in this manner, wire  105  may be (but is not necessarily) welded to needle  109  on the same side as the tip. This permits force applied to the tip to be transmitted along the axis of wire  105 . When joining wire  105  to needle  109 , a small space is left between the distal end of wire  105  and the distal end of slot  331 , said space being appropriately sized to permit fluid flow between catheter  107  and longitudinal bores  337  and  329  of needle  109  while, at the same time, preventing passage of the sample from needle  109  into catheter  107 . This gap may be varied in size and/or length to regulate fluid flow for a given purpose.  
         [0089]     Rounded distal end  327  of base portion  321  and proximal end  333  of stem portion  323  together define a shoulder that is shaped to abut directly the proximal end of hub  111  in such a way as to form an air-tight seal therewith when needle  109  is placed in its advanced position.  
         [0090]     As discussed above, the outer diameter of stem portion  323  is appropriately dimensioned to form a tight seal with distal end  273  of catheter  107  when needle  109  is moved to its extended position (see  FIG. 6 ( b )). In addition, as noted above, the shoulder formed by rounded distal end  327  of base portion  321  and proximal end  333  of stem portion  323  is appropriately dimensioned to engage proximal end  261  of hub  111  so as to form a seal therewith, as well as to delimit distal movement of needle  109  (and, in so doing, prevent needle  109  from being lost distally from the remainder of device  101  and, perhaps, becoming lost in a patient). Although not shown, one could, if desired, enhance the seal formed between the shoulder of needle  109  and proximal end  261  of hub  111  by heat-shrinking an elastomeric sleeve over the shoulder of needle  109 , said sleeve conforming to the shape of the shoulder and forming a sealing interface with the proximal end  261  of hub  111 . (It should be noted that the use of such an elastomeric sleeve in device  101  would make considerably more difficult any reprocessing of device  101 .)  
         [0091]     Referring now to FIGS.  18 ( a ) through  18 ( c ), there are shown various views of a first alternate needle usable instead of needle  109  in device  101 , said first alternate needle being constructed according to the teachings of the present invention and being represented generally by reference numeral  359 .  
         [0092]     Needle  359  is a unitary structure shaped to include a stem portion  361  and abase portion  363 . Stem portion  361 , which is substantially identical to stem portion  323  of needle  109 , is a generally tubular element shaped to include a proximal end  365  and a distal end  367 , distal end  367  being an upwardly-facing, open-ended tip.  
         [0093]     Base portion  361  includes a distal portion  369  and a proximal portion. Distal portion  369 , which is generally tubular in shape, forms a shoulder with proximal end  365  of stem portion  361 . The proximal portion of base portion  361  is bifurcated into a left side member  373  and a right side member  375 , left side member  373  and right side member  375  being centered relative to the top and bottom surfaces of distal portion  369  of base portion  361 . Wire  105  may be mounted along the top or bottom surfaces of left and right side members  373  and  375 , respectively.  
         [0094]     Referring now to FIGS.  19 ( a ) through  19 ( c ), there are shown various views of a second alternate needle usable instead of needle  109  in device  101 , said second alternate needle being constructed according to the teachings of the present invention and being represented generally by reference numeral  379 .  
         [0095]     Needle  379  is a unitary structure shaped to include a stem portion  381  and a base portion  383 . Stem portion  381 , which is substantially identical to stem portion  323  of needle  109 , is a generally tubular element shaped to include a proximal end  385  and a distal end  387 , distal end  387  being an upwardly-facing, open-ended tip.  
         [0096]     Base portion  383  is a generally tubular element shaped to include a transverse slot  389  extending distally a short distance from the proximal end of base portion  383 . Slot  389 , which is appropriately sized for wire  105  to be mounted therewithin, extends from the left side of base portion  383  to the right side of base portion  383  and is centered relative to the top and bottom surfaces of base portion  383 .  
         [0097]     One desirable attribute of needle  379  is that slot  389  permits wire  105  to be coupled to needle  379  in such a way that wire  105  and needle  379  share a common axis.  
         [0098]     In use, prior to inserting device  101  into a bronchoscope, an operator typically tests device  101  by using button slide  121  to alternately position needle  109  in its advanced position and its retracted position. Once the operability of said needle positioning mechanism has been confirmed, needle  109  is then locked in its retracted position by positioning slide  121  so that pawls  207 - 1  and  207 - 2  are positioned within notches  169 - 1  and  169 - 2 , respectively. The distal end of device  101  is then loaded into a bronchoscope (which has previously been inserted into the patient to a neutral location), and a syringe is attached to port  227  of connector  123 . Once confirmation is received that distal end  273  of device  101  has passed entirely through the bronchoscope (such confirmation typically being provided using a video channel of the same bronchoscope), the bronchoscope and device  101  are advanced together to the target site, and needle  109  is advanced to its extended position by positioning slide  121  so that pawls  207 - 1  and  207 - 2  are positioned within notches  171 - 1  and  171 - 2 , respectively. Distal end  335  of needle  109  is then inserted through the bronchial wall of the patient and into a nearby lymph node. At this time, the syringe is used to apply suction. In the unfortunate event that needle  109  has errantly penetrated a blood vessel, instead of a lymph node, the application of suction causes blood to be aspirated through bore  337  of needle  109  and into catheter  107  and the syringe, where such blood is detected. In such a case, the application of suction is discontinued and the soiled device  101  is removed from the bronchoscope and the patient. A fresh TBNA device  101  is then loaded into the bronchoscope and the patient in the manner described above, and another attempt is made to penetrate the lymph node.  
         [0099]     If, while suction is applied, it appears that needle  109  has penetrated a lymph node, as is desired, catheter  107  is agitated to help shear tissue from the penetrated lymph node into bore  337  of needle  109 . With a tissue sample thus disposed within bore  337  of needle  109 , needle  109  is moved back to its retracted position within catheter  107  by positioning slide  121  so that pawls  207 - 1  and  207 - 2  are positioned within notches  169 - 1  and  169 - 2 , respectively. Device  101  is then removed from the bronchoscope and the patient. Needle  109  is then placed in its advanced position by positioning slide  121  so that pawls  207 - 1  and  207 - 2  are positioned within notches  171 - 1  and  171 - 2 , respectively, and negative suction is then used to expel the tissue from needle  109  onto a slide or the like for histological examination.  
         [0100]     Device  101  is intended to be a single-use device. However, it is envisioned that, if device  101  is constructed from materials capable of withstanding reprocessing conditions, e.g., flushing with suction, followed by (or preceded by) washing in an ultrasonic bath, flushing again with suction, and then autoclaving, device  101  may be reprocessed for additional use.  
         [0101]     The embodiments of the present invention described above are intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.