Patent Publication Number: US-6340351-B1

Title: Connector for a replaceable biopsy needle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. national phase of international application No. PCT/US98/19360 filed Sept. 16, 1998, which is a continuation-in-part of U.S. application Ser. No. 08/932,109 filed Sept. 17, 1997 now U.S. Pat. No. 5,843,001. The entire disclosures of the prior applications are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an assembly for the proximal end of a medical device, and, more particularly, a needle assembly that is operable when connected to a handle. 
     BACKGROUND OF THE INVENTION 
     It is known in the art of medical devices that at least a portion of the device must be sterilized prior to being inserted into a patient. To facilitate the sterilization process, sterilization is sometimes performed prior to assembly of the medical device. 
     U.S. Pat. No. 5,429,138 to Jamshidi discloses a biopsy needle that is attachable to a handle by a threaded connector. The common practice prior to using the Jamshidi device is to sterilize both the needle and the handle, either as a complete unit or separately for later assembly by the operator or her assistant. U.S. Pat. Nos. 5,522,798 and 5,634,473 of Goldenberg et al. also discloses a biopsy needle that threadedly connects to a handle mechanism. In all of these designs, the handle mechanism remains external to the patient and does not require sterilization. 
     A common problem of each of the foregoing biopsy needle designs is that the connection of the needle to the handle requires that a threaded element be passed over the distal tip of the needle to secure the needle to the handle. This threaded connector must also be sterilized or else the sterility of the needle and the safety of the patient will be compromised. Further, the ordinary course of using a biopsy needle requires the operator to twist the needle within the patient and such manipulation could result in a loosening of the threaded connection between the needle and the handle. 
     The present invention resolves these and other problems by providing a snap- lock connection between the operative handle and the medical device. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a connector assembly for snap-connecting the proximal end of a medical device to a handle is disclosed. The assembly comprises a body that is rigidly attached to the proximal end of the medical device. A lever is attached to body and is resiliently biased towards a first position which engages the handle. A lock-tab projects from the lever in a direction generally away from the body and is shaped to be received in a lock-slot within the handle. Preferably, the lock-tab and handle are shaped to permit a snap-lock engagement of the handle and the body upon insertion of the body into the handle. This assembly can be used on a variety of medical devices and with a variety of handles. 
     In accordance with another aspect of the present invention, a needle assembly is disclosed which includes a hollow needle having a proximal end attached to the above described connector assembly for snap-lock engagement of the needle to the handle. A particular advantage of this construction is that the body at the proximal end of the needle can be securely engaged to a handle without the need for a threaded connector as in the above-described prior art designs. Further, the needle assembly can be provided in a sterile package and assembled to a handle without compromising the sterility of the working end of the needle prior to use. 
     According to a further aspect of the present invention, a biopsy needle kit is disclosed which includes a hollow needle having the above described connector assembly attached at a proximal end thereof and a handle having an aperture sized to receive the body at the proximal end of the needle. Further, the handle has lock-slots positioned within the aperture to receive the lock-tabs of the connector assembly. Upon insertion of the needle into the handle, the lever of the body is cammed toward the body until the lock-tab of the body aligns with the lock-slot of the handle at which moment the lever resiliently moves towards its rest position to lock the needle assembly to the handle. The operator can then use the needle to, for example, extract a biopsy sample, without concern for the sterility of the needle assembly as a result of the steps taken to connect the needle assembly to the handle. 
     In general terms, the invention provides a connector arrangement which securely engages two elements to one another without the need for manipulating the elements relative to one another (e.g., threading), yet with minimal risk of element separation. More particularly, through the use of camming surfaces, a secure engagement of the elements is automatically achieved by the inventive connector upon insertion of the connector, attached to a first element, into a second element. 
     The invention is described in connection with a preferred arrangement in which a medical device is provided with a connector assembly having a lever and a lock-tab projecting therefrom for engagement with a lock-slot within a handle. However, other arrangements are within the scope of the invention, including arrangements in which (1) the lock-slot is provided on the body (at the proximal end of the medical device) for engaging a cammable lock-tab on the handle; (2) a lever or cammable element provided on the body has a lock-slot which engages a corresponding lock-tab provided on the handle; or (3) a lever or cammable element provided on the handle has a lock-slot which engages a corresponding lock-tab provided on the body. In each arrangement, the handle and medical device positively engage one another in a reversible snap-lock interconnection, that is, in a snap-lock connection between the two which can be undone upon manually releasing the engagement therebetween. 
     These and other objects of the present invention will be appreciated from the following detailed description in conjunction with the detailed accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view showing the connector assembly of the present invention attached to a biopsy needle and a handle in accordance with a preferred embodiment; 
     FIG. 2 is a plan view, partially in section, showing the connector assembly of the preferred embodiment in spaced relation to the handle having an aperture sized to receive the assembly; 
     FIG. 3 is an exploded, perspective view of the biopsy needle of the preferred embodiment; 
     FIG. 4 is a detailed view, partially in section, of a distal tip of the biopsy needle of FIG. 3; 
     FIG. 5 is a top perspective view of the handle that may be used with the preferred embodiment of the present invention; 
     FIG. 6 is a plan view, partially in section, showing the connector assembly fully inserted within the handle of the preferred embodiment; 
     FIG. 7 is a detailed cross-sectional view of a preferred engagement of the connector assembly to a medical device; 
     FIG. 8 is a plan view, partially in section, showing a modified arrangement of the connector assembly; and 
     FIG. 9 is a plan view of a modified arrangement for a lock-tab as may be used with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     By way of overview in introduction, a preferred embodiment of the invention is illustrated in FIG.  1 . The preferred industrial application of the invention is a biopsy needle  14  and operative handle  16  assembly, where the needle  14  and handle  16  are securely engaged to one another by way of a snap-lock connector  10  constructed in accordance with the present invention. The snap-lock connector  10  is fixed to the proximal end of the needle  14  and is shaped to be received in an aperture  18  of the handle  16  (see FIG.  2 ). 
     With reference now to FIG. 2, the connector assembly  10  is shown in spaced relation to the handle  16  for insertion into the aperture  18  by moving the connector assembly  10  in the direction of arrow A. The connector assembly  10  has use with many different types of medical devices including catheters and scopes which may be introduced cutaneously or percutaneously into a vessel or other body passageway. The presently preferred embodiment is in the context of biopsy needle design, and the present invention will be described in detail with regard to this presently preferred embodiment and the problems solved in the art of biopsy needle designs, with the understanding that the structure of the connector assembly  10  can be used without limitation with other medical devices. 
     The biopsy needle  14  has a distally tapering region  20  that is introduced into the body of the patient. The distal tip  22  of the biopsy needle is sharp and preferably is stored within a base  24  or other device until the needle is ready for use. 
     FIG. 3 illustrates further aspects of the biopsy needle  14 . A tube  26  is housed within the needle  14  and advanced in the direction of arrow B into the needle  14  until a tab  28  on the end of the distal end of the tube  26  is received within an aperture  21  in the tapering region  20  of the needle  14  (see FIG.  4 ). The proximal end of tube  26  includes a knurled surface  30  which is engaged by a toothed aperture  32  of a lever  34  within the handle  16 . As described more fully in the aforesaid Goldenberg et al. 5,522,398 patent, the lever  34  causes rotational movement of the inner tube  26  relative to the outer needle  14  which, in the illustrated embodiment, causes a snare  36  to grab a biopsy sample with a force sufficient to remove the sample from the patient. (Alternatively and equivalently, the tab can be provided on a cylinder (see element  80  in FIG. 8 of the aforementioned Goldenberg et al. 5,634,473 patent) attached to the distal end of the snare  36 .) The biopsy needle  14  further has a stylet  38  slidingly received within the inner tube  26  and outer tube  14  until the distal end  40  of the stylet  38  projects from the outer needle  14  (see FIG.  4 ). As understood by those of skill in the art, the stylet  40  assists in penetrating the patient&#39;s skin and accessing the site from which the sample is extracted. In accordance with an aspect of the present invention, the stylet  38  includes a keyed proximal end  42  which is received within the correspondingly shaped aperture  44  of the handle  16  when the needle is assembled to the handle (see FIG.  5 ). A particular advantage of this arrangement as compared to known designs is that a sterilized stylet can be inserted within a sterilized needle assembly  14 , and the needle  14  and stylet  38  together can be connected to the handle  16  without the distal end  40  of the stylet  38  having to pass through the non-sterile handle  16 . 
     With further reference to FIG. 3, the connector assembly  10  of the invention includes an axially asymmetric body  50  having an axial aperture  52  therethrough. The biopsy needle  14  is received within the aperture  52  and preferably forms a tight interference fit therewith. The connector assembly  10  and the outer needle  14  also can be fixed together using an epoxy or a heat welding process. In a preferred configuration, the body  50  includes first and second lever arms  54  which are hingedly attached in the vicinity of a proximal face  56  of the asymmetric body  50 . The hinge may be formed by a weakened piece of the same material that forms the body  50 . Each of the lever arms  54  includes a lock-tab  58  projecting in a direction away from the body  50  for securely, snap-lock engaging the connector assembly  10  within the aperture  18  of the handle  16 . Specifically, the aperture  18  has lock-slots  60  which receive the lock-tabs  58  when the connector assembly  10  is inserted into the handle (see FIG.  2 ). 
     The levers  54  are resiliently biased into a first position as shown in FIGS. 2 and 3 and are cammed toward the body to the position shown in phantom in FIG. 2 as the connector assembly  10  is inserted into the aperture  18 . However, when the lock-tabs  58  are aligned with the lock-slots  60 , the levers  54  resiliently move toward their first position and snap-lock engage the needle  14  into engagement with the handle  16 . A distally facing surface  59  of the lock-tabs  58  abuts an edge of the lock-slots  60  and prevents the needle  14  from being withdrawn from the handle  16  unless the levers  54  are manually squeezed in the direction of arrows C (see FIG.  6 ). A camming surface  57  on the leading edge of the lock-tabs  58  (and/or a camming surface within the aperture  18 , aligned with the lock-slots  60 ) enables an automatic and secure engagement of the body  50  to the handle  60  once the surfaces  59  snap into the lock-slots  60 , with minimal risk of the needle  14  (or connector assembly  10 ) separating from the handle  60 . 
     While the preferred embodiment is described in connection with levers  54 , other elements which do not pivot like a lever yet which are resiliently biased toward a first position can be used such as a spring-biased button or slide, a resiliently deflectable protrusion (e.g. a hard, hollow rubber cup), or other mechanically equivalent structure. 
     Use of such elements can permit a snap-lock engagement and subsequent disengagement by moving or forcing the element clear of the lock-slot. If the separation is by force, the force required should exceed that reasonably expected during normal use of the medical device to preclude inadvertent separation of the medical device from the handle. 
     At the same time that the levers  54  are cammed toward the body during insertion of the connector assembly  10  within the aperture  18 , the keyed proximal end  42  of the stylet  38  and the knurled proximal end  30  of the inner tube  26  are received into the handle  16 . The knurled proximal end  30  is seated within the toothed aperture  32  of the lever  34 , and the keyed proximal end  42  of the stylet projects beyond a correspondingly shaped keyed aperture  44  into a well  62  at the proximal end of the handle  16  (see FIGS.  5  and  6 ). A cap  64  having threadings  66  is received within the well  62  and secured in place. An abutment surface  68  of the cap  64  prevents the proximal most end  70  of the stylet from retracting in the direction of arrow A relative to the handle  16 . This enables the operator to cutaneously insert the needle  14  and stylet  38  into the patient without stylet retraction. Once the skin has been punctured, the cap  64  can be unscrewed and the stylet  38  withdrawn from the needle  14  by grasping the keyed proximal end  42  and withdrawing the stylet  38 . 
     It can be appreciated from the foregoing that the needle  14 , inner tube  26 , and stylet  38  can be provided in a sterile condition and snap-lock engaged to the handle  16  via the connector assembly  10  without any further element contacting these sterilized components. The handle  16  need not be sterile because that element remains outside of the patient. Therefore, operator can manipulate the handle  16  with the one hand and the operator&#39;s other hand remains sterile for contacting the patient or perhaps other devices. Of course, the handle  16  can also be sterilized. 
     In FIG. 6, the connector assembly  10  is showing fully inserted within the aperture  18 . The lock-tabs  58  of the connector assembly  10  are aligned with and disposed within the lock-slots  60  within the walls  72  of the aperture  18 . The lever arm  54  has moved toward its first position but not to its first position, due to an interference between the lever arm  54  and the wall  72 . Because the lever arm  54  is not able to fully return to its naturally biased position, the body  50  sits tight within the aperture  18 . Also, the axially asymmetric shape of the body  50  minimizes movement of the connector assembly  10  relative to the handle  16  and simplifies insertion (it only fits one way). 
     FIG. 6 also illustrates slots  82  in the body  50  which facilitate movement of the lever arms  54  toward the body  50  to disengage the lock-tabs  58  from the lock-slots  60 , and enable the body  50  to have a relatively low profile shape. 
     The detail view of FIG. 7 is provided to illustrate a series of protuberances  80  within the aperture  52  of the body  50  to fictionally engage the proximal end of the needle  14  or other medical device in accordance with a preferred mode of engaging the connector to the proximal end of the medical device. As noted above, the connector assembly  10  and the needle  14  are affixable using an epoxy or a heat welding process instead of, or in addition to, the aforementioned protuberances  80 . 
     Other designs for the body  50  can be provided within the spirit of the present invention. For example, the lever arms  54  may be arranged in an opposite direction to that shown in the Figures, namely, so as to extend proximal of the proximal face  56  of the asymmetric body  50  with each lever arm  54  hingedly mounted to the body  50  at an acute angle relative to the axis of the body  50 . This alternative arrangement still permits the levers  54  to be compressed by the operator so that the lock-tabs  58  can be initially received within the lock-slot  60  and later disengaged. The present design is preferred, however because the body may be provided with an asymmetric shape that fits within a correspondingly shaped aperture  18  of the handle  16 . Such an arrangement ensures that the medical device (that is, the needle  14 ) is snap-locked to the handle with only one orientation. Further, the keyed aperture  44  within the handle  16  ensures that the distal tip  40  of the stylet  38  has a predetermined rotational orientation relative to the distal tip  22  of the needle  14  because the keyed proximal end  42  of the stylet  38  can only be received within the slot  44  with one orientation. 
     With further reference to FIGS. 5 and 6, the operation of the biopsy needle according to this preferred embodiment is described. With the needle  14  and connector assembly  10  assembled to the handle  16 , the knurled end  30  of the inner tube  26  is received within the toothed aperture  32  of the lever  34 . Rotation of the lever  34  in the direction of arrow D (FIG. 5) causes rotation of the inner tube  26  relative to the needle  14 . In other words, because the needle  14  is rigidly attached to the connector assembly  10  which, in turn, is irrotatably engaged to the handle  16 , rotation of the lever  34  causes relative rotation of the inner tube  26 . As a result, the snare  36  is wound down to grab a biopsy sample in the manner described in the aforementioned Goldenberg et al. patents. 
     Of course, the lever can engage the inner tube  26  in other manners to cause a biopsy sample to be grabbed. For example, a lever  34 ′, upon engaging the proximal end  30 ′ of inner tube  26 ′, may cause axial movement of the inner tube  26 ′ relative to the outer needle  14 . In such an arrangement, as shown for example in U.S. Pat. No. 4,785,826 to Ward, the inner tube  26 ′ advances towards the distal tip  22  of the needle  14 , and a biopsy grasping element  36 ′ at the distal end of the inner tube  26 ′ is cammed inwardly to simultaneously sever or contain a sample and occlude the lumen of the inner tube  26 ′ to prevent the captured sample from escaping. The present invention is not directed to nor limited by a particular arrangement of the distal end  22  of the biopsy needle  14 . Rather, the present invention has utility in fields other than biopsy needle design for example in the design of connectors for catheters and other medical devices. 
     With further reference to FIG. 6, the well  62  under the cap  64  enables the operator to grasp the proximal end  42  of the stylet  38  when the threaded cap  64  is removed. The connector assembly  10  of the present invention enables a medical device to be snap-locked to another element, for example, a handle or other operating instrument. An advantage of the inventive connector assembly  10  is that it enables the medical device to be maintained in a sterile condition while being assembled to a handle. A further advantage is that it enables a secure connection between the medical device and the handle. A further advantage is that it may be manufactured at a relatively low cost, for example, by injection molding the connector assembly  10  as a unitary element. A particularly preferred material for the connector assembly  10  is plastic and may be made out of any conventional material including LEXAN, PEBAX, nylon, PET or other material. 
     With reference now to FIGS. 8 and 9, a variation on the connector assembly of FIGS. 1-7 is illustrated wherein like elements have been accorded corresponding reference numerals. 
     In FIG. 8, a lever arm  54 ′ is associated with the handle instead of the medical device. In particular, the lever arm  54 ′ is provided within or adjacent to the aperture  18 ′, and has a lock-tab  58 ′ and an abutment surface  59 ′, as described above. In the arrangement of FIG. 8, the lever arm  54 ′ is hinged to the handle for resilient pivotal movement, as shown by the double-headed arrow. The lever arm  54 ′ may be integral with the handle or may extend from a collar  55 ′, for example, a plastic material of one of the materials noted above, secured within the aperture  18 ′. 
     As in the arrangement of FIGS. 1-7, the lever arm  54 ′ engages a lock-slot  60 ′. In the arrangement of FIG. 8, the lock slot  60 ′ is associated with the body  50 ′. The lever arm  54 ′ is resiliently biased into a first position as shown in FIG.  8  and is temporarily cammed outward, while the body  50 ′ is being inserted into the aperture  18 ′, to the position shown in phantom in FIG.  8 . However, when the lock-tab  58 ′ is aligned with the lock-slot  60 ′, the lever  54 ′ resiliently moves inward toward its first position and snap-lock engages the medical device (e.g., the needle  14 ) into engagement with the handle  16 ′. A proximally facing surface  59 ′ of the lock-tab  58 ′ abuts an edge of the lock-slot  60 ′ and prevents the medical device from being withdrawn from the handle  16 ′ unless the lever  54 ′ is manually moved to the position shown in phantom in FIG. 8. A camming surface  57 ′ on the leading edge of the lock-tab  58  (and/or on the lever arm  54 ′) enables an automatic and secure engagement of the body  50 ′ to the handle  16 ′. The assembly of the body  50 ′ to the handle  16 ′ in accordance with this arrangement includes receiving and seating the knurled proximal end  30  of the stylet, as described above. 
     In FIG. 9, the lever arm  54 ′′ is provided with a lock slot  60 ′′ instead of a lock-tab  58  as another possible rearrangement of elements that is within the scope of the invention. In accordance with this variation, the handle includes a lock-tab for engaging the lock-slot  60 ′′, substantially as described above. 
     Preferably, pre-sterilized needles  14  having the connector assembly  10 ,  10 ′ attached thereto can be sold for use with suitable handle mechanisms  16 ,  16 ′. Alternatively or in addition, a kit comprising the handle mechanism and one or more needles  14  having a connector assembly  10 ,  10 ′ attached thereto may be sold together. 
     The needles  14  may be disposable or reusable after subsequent sterilization. Because the needle is separable from the handle, the conventional sterilization procedure may be simplified by sterilizing the needles only instead of sterilizing both the needle the handle. Such a protocol enables the use of pre-packaged, disposable, sterile needles with a non-sterile handle. Of course, the handle could also be sterilized between uses or on a periodic basis. The benefit that this protocol provides, if the hand used to manipulate the handle does not contact the needle or the patient&#39;s skin, is reduced expense in treating patients and elimination of a sterilization step. 
     The aforementioned Jamshidi, Goldenberg et al. and Ward patents are hereby incorporated by reference as if set forth in their entireties herein. Each of the devices disclosed in the said aforementioned patents, as well as a panoply of other medical devices to numerous to mention, can be modified to include the connector of the present invention to interconnect two elements, including the interconnection of a sterile element to a non-sterile element without compromising the sterility of the working end of the sterile element. 
     From the foregoing description, it will be clear that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and not limited to the foregoing description.