Abstract:
A single-use biopsy instrument for mounting at a multiple-use biopsy apparatus, comprises a cartridge enclosing proximal end portions of a canula, a finger tube slidingly disposed on the canula, and a stylet slidingly disposed in the canula. The canula and the finger tube have proximal holding portions and are displaceable in regard of the cartridge by displacement means disposed in the biopsy apparatus engaging with the holding portions through one or several engagement openings in one wall of the cartridge. Also disclosed is a corresponding biopsy apparatus.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a multiple-use biopsy apparatus. The present invention also relates to a single-use biopsy instrument for use with the biopsy apparatus of the invention.  
         BACKGROUND OF THE INVENTION  
         [0002]    The invention departs from an apparatus for collecting tissue samples by excising a segment from tissue, and a corresponding method for harvesting of tissue samples described in WO 99/44505 which is incorporated by reference into this specification. The biopsy apparatus of WO 99/44505 comprises a biopsy instrument and a holder.  
           [0003]    In this specification, the terms “proximal” and “distal” refer to the person extracting a biopsy sample; the terms “front” and “rear” have a corresponding meaning. Thus, the proximal end of a biopsy apparatus is its rear end, pointing away from the patient.  
           [0004]    The biopsy instrument of WO 99/44505 comprises a canula with a distal open cutting end and a through opening in its wall near the distal end, a finger tube slidingly disposed on the canula and provided with a finger at its distal end, and a stylet slidingly disposed in the canula, the finger being insertable into the opening in the canula wall and axially displaceable in a forward direction so as to be deflected towards the axis of the canula.  
           [0005]    The holder of WO 99/44505 comprises a housing, means for releasably coupling the biopsy instrument to the housing; and compressed coil means for consecutive axial displacement of the canula and the tube in combination in a distal direction, and of the tube in respect of the canula in the same direction. To expulse a harvested biopsy sample from the canula, the further comprises means for consecutive displacement of the tube, and of the tube and the canula in combination, in a proximal direction. At their respective distal ends the canula, the tube and the stylet are provided with end sections for mounting in the holder.  
           [0006]    WO 99/44504 also discloses a loading assembly for the holder. The loading assembly comprises a loading arm swivellingly attached at its one end to the housing, a intermediate arm swivellingly attached at its one end to the loading arm and at its other end to a catch holding the canula end section during tensioning and in a tensioned position in respect of a tension spring or during compression or in a compressed position in respect of a compression spring (the latter being preferred), the catch being displaceable in a proximal direction against the resistance of the spring and being adapted to be held there for intentional release.  
           [0007]    A biopsy apparatus comprising the holder and the loading assembly of WO 99/44504 can be manufactured for single use in which case it is supplied to the customer preferably with the biopsy instrument of WO 99/44505 already mounted. It can, however, also be designed for repeated use with disposable sets of the biopsy instrument.  
           [0008]    The aforementioned biopsy apparatus intended for single use, that is, provided to the user with the biopsy instrument already mounted, does not require other manual skills than performing its proper medical operation, that is, taking a biopsy sample from a patient and expelling the sample from the canula thereafter.  
           [0009]    This is not so with the multiple-use biopsy apparatus in which a new biopsy instrument has to be mounted for each biopsy. Since the biopsy apparatus comprises three parts which are slidingly displaceable in regard of each other, their mounting, in a given spatial relationship, requires skilful handling. To this adds the sharp tip of the stylet and the front edge of the canula which may cause wounds if not properly handled in mounting or may be accidentally damaged, as may be the tiny tissue excision means, that is the finger of the finger tube. Thus there is ample room for improvement in respect of making the loading process a routine measure, including modification of the biopsy apparatus and the loading assembly.  
         OBJECTS OF THE INVENTION  
         [0010]    It is an object of the invention to provide a biopsy apparatus comprising a loading assembly for multiple use in which a disposable biopsy instrument can be easily and safely mounted and dismounted.  
           [0011]    It is an object of the invention to provide a corresponding biopsy instrument.  
           [0012]    Additional objects of the invention will become obvious from the following short description of the invention, the accompanying drawings illustrating a preferred embodiment of the invention described in greater detail, and the appended claims.  
         SUMMARY OF THE INVENTION  
         [0013]    These and other objects of the invention are achieved by a single-use biopsy instrument of the aforementioned kind designed for mounting in a multiple-use biopsy apparatus, the biopsy instrument including a cartridge enclosing proximal end portions of the canula, the finger tube, and the stylet, the cartridge being provided with a displaceable lock on one of its sides, the displacement being substantially in the lock plane and in a proximal direction. It is preferred for the cartridge to comprise a safety latch which must be removed before the lock can be displaced. By removing the safety latch and displacing the lock in a proximal direction the biopsy instrument is prepared for mounting at the biopsy apparatus of the invention.  
           [0014]    In particular the single-use biopsy instrument for mounting at a multiple-use biopsy apparatus includes a cartridge enclosing proximal end portions of a canula, a finger tube slidingly disposed on the canula, and a stylet slidingly disposed in the canula, the canula and the finger tube having proximal holding portions and being displaceable in regard of the cartridge by displacement means disposed in the biopsy apparatus engaging with said holding portions through one or several engagement openings in one wall of the cartridge.  
           [0015]    It is preferred for the cartridge to comprise a cartridge body having an opening on one of its sides covered by a lock in which said one or several engagement openings are disposed. The displacement opening is advantageously a slit extending in parallel with the canula.  
           [0016]    According to a first preferred aspect of the invention, the cartridge lock extends outside the cartridge body opening and is displaceable in the lock plane in the direction of the cartridge body so as to cover the opening of the cartridge body opening more fully. It is advantageous for the cartridge lock to be securable in a displaced position at the cartridge body or at an element secured thereat.  
           [0017]    According to a second preferred aspect of the invention, the biopsy instrument comprises a removable safety latch partly covering the cartridge body opening. It is particularly preferred for the cartridge lock to be displaceable only upon removal of a safety latch covering a portion of the cartridge body opening.  
           [0018]    According to a third preferred aspect of the invention, the holding portion of the stylet is fixed to the cartridge body.  
           [0019]    According to a fourth preferred aspect of the invention, the cartridge body comprises laterally disposed projections for mounting in hooks of the biopsy apparatus.  
           [0020]    According to the present invention is also disclosed a biopsy apparatus comprising a casing, means for releasably coupling the biopsy instrument of the invention to the casing, compressed coil means disposed in the casing for consecutive axial displacement of the canula and the finger tube in combination in a distal direction, and of the tube in respect of the canula in the same direction, the displacement being effected via a first displacement member slidingly disposed in the casing cooperating with a proximal end portion of the canula of and a second displacement member slidingly disposed in the casing distally of the first displacement member cooperating with a proximal end portion of the finger tube.  
           [0021]    According to a fifth preferred aspect of the invention, the first and second displacement members comprise pins extending through a longitudinal slit in the cartridge lock which are engageable with corresponding bores in the end portions of the canula and the finger tube.  
           [0022]    According to a sixth preferred aspect of the invention, the biopsy apparatus comprises a mechanism for step-less control of the canula stroke.  
           [0023]    According to a seventh preferred aspect of the invention, the biopsy apparatus is designed to receive the entire biopsy instrument cartridge in an opening disposed on one of its sides so as to make the visible side of the cartridge (the cartridge bottom) flush with portions of the same side of the biopsy instrument. It is important for the biopsy instrument cartridge to be relaseably securable in said opening. Preferably the biopsy instrument is securable by means of an axially displaceable frame comprising hooks disposed in the opening, the hooks being releaseably engageable with laterally disposed projections of the cartridge body.  
           [0024]    According to an eight preferred aspect of the invention, the biopsy apparatus is provided with a loading mechanism for compression of a spring coil affecting said first and second displacement members, the mechanism comprising a loading arm, a loading catch and an intermediate arm swivellingly fixed at the loading arm and the loading catch. It is preferred for the apparatus to comprise means for releasing the first and second displacement members in combination to displace them in a distal direction by the action of the spring coil. Also preferred is for the apparatus to comprise a stroke limiter for limiting the displacement of the second and/or the first displacement member in a distal direction. Preferably the displacement of the second displacement member is so limited as to make it displaceable further in a distal direction than the first displacement member.  
           [0025]    According to still another preferred aspect of the invention, the biopsy apparatus comprises means for expulsion of a harvested biopsy sample from the canula.  
           [0026]    By definition, the top side of the biopsy instrument of the invention is the side covered by a lock. The top side of the biopsy apparatus of the invention is the side provided with the loading mechanism. The biopsy instrument is mounted at the bottom side of biopsy apparatus with its top side facing the apparatus.  
           [0027]    The invention will now be described by reference to preferred embodiments of the biopsy instrument of the invention and the biopsy apparatus of the invention, by the study of which further advantages of the present invention will become obvious. The preferred embodiments are illustrated in drawings showing rough perspective views thereof. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0028]    The drawings illustrate the following:  
         [0029]    [0029]FIG. 1 a preferred embodiment of the biopsy apparatus of the invention, with a biopsy instrument mounted, in a proximal side/bottom view, with the loading arm abutting the casing;  
         [0030]    [0030]FIG. 2 the biopsy apparatus of FIG. 1 in a distal side/top view, with the loading arm raised;  
         [0031]    [0031]FIG. 3 the biopsy apparatus of FIG. 1, in a distal side/bottom view, with the biopsy instrument removed;  
         [0032]    [0032]FIG. 4 the biopsy apparatus of FIG. 2 and in the same view, with the casing and part of the loading mechanism removed, in a secured loaded condition;  
         [0033]    [0033]FIG. 5 the biopsy apparatus of FIG. 4 and in the same view and condition, with a shorter stroke length set;  
         [0034]    [0034]FIG. 6 the biopsy apparatus of FIG. 5, in the same view, in an unsecured loaded condition;  
         [0035]    [0035]FIG. 7 the biopsy apparatus of FIG. 5, in the same view, in a released condition at the end of the canula movement;  
         [0036]    [0036]FIG. 8 the biopsy apparatus of FIG. 5, in the same view, in a released condition at the end of the finger tube movement;  
         [0037]    [0037]FIG. 9 the biopsy apparatus of FIG. 5, in the same view, after withdrawal of the finger from the canula but before sample expulsion and loading;  
         [0038]    [0038]FIG. 10 the biopsy apparatus of FIG. 5, in a frontal top view, after sample expulsion;  
         [0039]    [0039]FIG. 11 the biopsy apparatus of FIG. 5 but with the loading arm shown, in the same view, at the start of a loading operation;  
         [0040]    [0040]FIG. 12 the biopsy apparatus of FIGS.  11 , at the end of a loading operation;  
         [0041]    [0041]FIG. 13 the biopsy instrument of FIG. 1, in a top/proximal view, complete with the safety latch;  
         [0042]    [0042]FIG. 14 the biopsy instrument of FIG. 1, in another top/proximal view, with the safety latch removed and the cartridge lock inserted;  
         [0043]    [0043]FIG. 15 the biopsy instrument of FIG. 1, in still another top/proximal view, with the cartridge lock removed;  
         [0044]    [0044]FIG. 16 the biopsy instrument of FIG. 1, in an exploded top/proximal view, without the safety latch;  
         [0045]    [0045]FIG. 17 the cartridge lock and safety latch of the biopsy instrument in FIG. 1, in a bottom/proximal perspective view, aligned but slightly separated;  
         [0046]    [0046]FIG. 18 the cartridge body of the biopsy instrument in FIG. 1, in a front/proximal view;  
         [0047]    [0047]FIG. 19 the cartridge mounting frame, in a top/proximal view. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0048]    Indications of lateral direction such as ‘from above’, ‘underside’, ‘top side’ are defined by the views of the Figures. The steel coil compression springs are only shown schematically as cylinders.  
         [0049]    The biopsy instrument illustrated in FIGS. 1 and 13- 19  comprises a canula, a finger tube  201  and a stylet  301  of the same kind as illustrated in FIG. 4 of WO 99/44505; see also U.S. Pat. No. 5,644,542, where the design and function of these elements is explained in detail and which is incorporated herein by reference. In FIG. 29 rear (proximal) end portions of the finger tube  201  enclosing the canula and the stylet  301  are shown to illustrate their relationship with their respective holders  200 ,  300 , each made in one piece of a polymer material, preferably an ABS polymer (acrylonitrile-butadiene-styrene copolymer) or another polymer of high impact and tensile strength. Also shown in FIG. 29 is the canula holder  100 .  
         [0050]    The canula, the finger tube  201  and the stylet  301  are mounted in a cartridge body  700 , a distal portion of which is covered a lock  701  and an portion adjoining thereto proximally by a safety latch  702 . The cartridge lock  701  extends over the distal end of the cartridge body  700  and is held by projectures  706 , 707  in lateral slits  704 ,  705  of the latter so that it can be displaced in a distal direction upon removal of the safety latch  702  to cover most of the cartridge body  700 . Initially, the safety latch  702  is positionally stabilized in respect of the cartridge lock by pegs  708  extending from its distal end wall inserted in corresponding bores in the proximal end wall of the cartridge lock  701  and a transversal flange  709  at its bottom side abutting the rear wall  710  of the cartridge body  700 . It is in this configuration the biopsy instrument of the invention is supplied to the user for mounting at the biopsy apparatus of the invention by a procedure explained further down. The canula, the stylet  301  and the finger tube  201  are mounted in the cartridge body  700  in an assembled state, that is with the canula inserted in the finger tube  301  and the stylet  201  in the canula. The canula, the stylet and the finger tube extend through a slit  703  in the front wall of the cartridge body  700  in a distal direction. The neck  302  of the stylet holder  300  which has an I-profile is snapped between two snap tonges  713  extending from the bottom  714  of the cartridge body  700 . The stylet  301  thus is rigidly secured at the cartridge body  700 . In contrast, the canula and finger tube  201  are not definitely fixed but only constrained in their movement inside the cartridge. The distal wall of a lateral notch  715  inside of the cartridge lock  701  cooperates with the tip  214  of a tongue  213  of the finger tube holder  200  projecting above its top face. Thereby the finger tube holder  200  and canula holder  100  proximally abutting thereto can be displaced in a proximal direction by pushing the cartridge lock  701  fully over the cartridge body  700 , once the safety latch  702  has been removed by pulling it rearwards while lifting it slightly so as to disengage its transversal flange  709  from the rear wall  710  of the cartridge body. The cartridge lock  701  is pushed back until a snap tongue  716  extending from its proximal end wall engages with an elevated transverse portion  304  of the stylet holder  300 . This makes the biopsy instrument ready for mounting at the biopsy apparatus.  
         [0051]    The biopsy apparatus of the invention comprises a casing  500  consisting of two substantially symmetrical halves sectioned perpendicular to the larger faces of the holders  100 ,  200 . The casing  500  which has about the form of a rectangular bar can be of a suitable polymer, for instance polycarbonate, but preferably of metal, such as aluminum or stainless steel, since the biopsy apparatus has to withstand rough cleaning and sterilizing conditions. The casing halves fit by appropriate design of rims and other elements, such as snaps (not shown) but may also be connected by bolts or similar means. The casing includes a loading assembly according to WO 99/44505 to which reference is made and by which holders  100 ,  200  are brought to a ‘loaded’ position from which they can be released for tissue sampling. Instead of the single spring coil of the apparatus of WO 99/44505 three spring coils  601  disposed in parallel are provided; for simplicity reasons they are only shown as cylinders in the drawings.  
         [0052]    In contrast to the arrangement in WO 99/44505 in which the holders  100 ,  200  of the biopsy instrument are directly displaced against the force of a spring coil in the loading procedure, the present invention employs intermediate structures pertaining to the biopsy apparatus termed finger tube and canula control members  543 , 544  which provide for control of the biopsy instrument by the biopsy apparatus. The finger tube and canula control members have coupling pins disposed at their lower faces for engagement with the finger tube holder and the canula holder, respectively,. The finger tube control member  543  has one pair of coupling pins  546 , the canula control member  544  also has one pair  547 . In addition the finger tube control member has a pair of guide pins  548  disposed distally of the finger tube coupling pins  546  which guide pins  548  are shorter than the coupling pins. Thus two longitudinally extending parallel rows of coupling and guide pins result. The coupling pins of each pin row are arranged to engage with corresponding bores disposed in the finger tube holder bores  210 , and the canula holder, bores  110 . The control members  543 , 544  with their guide and coupling pins are accessible from outside through an opening in the bottom wall of the casing  500 . The opening is of a size allowing the cartridge to be fully inserted and secured in the inserted position by an axially displaceable mounting frame  570  comprising pairs of hooks  571 , 572  which engage with rectangular front and rear shoulders  720 , 721  extending laterally from the cartridge body  700 . The mounting frame  570  can be operated from outside by knobs  573  extending through openings in the lateral walls of the casing  500 . The engagement of the pairs of coupling pins  546 ,  547  of the control members  543 , 544  with the pairs of bores  210 , 110  in the finger tube holder  200  and the canula holder  100 , respectively, is provided for by two longitudinally extending slits  730 , 731  in the cartridge lock  701 . To provide for easy loading the loading assembly employs three elements, a loading arm  520 , a intermediate arm  530 , and a loading catch  540  comprising a catch arm  541  holding the finger tube control member  543  during compression of the spring coils  601  and in their compressed (loaded) state. With its hook-like front end of the catch arm  541  the catch  540  grips a loading grip  542  of the finger tube control member  543 . The canula control member  544  is in turn held in position by the finger tube control member  543 . The canula holder/finger tube holder assembly  100 ,  200  can be released from the loaded state by an oblong trigger  600  disposed distally/laterally of the catch  540 . The rear end of trigger  600  forming a release button  602  passes through an opening in the rear wall of the casing  500 . By pressing the release button  602  the trigger  600  is pushed forwards whereby a slanting portion  603  of it affects a slanting rear face  549  of the catch arm  541  which is journalled at  545 , so to make it swivel by a few degrees, thereby releasing the grip  542  and, hence, the finger tube control member  543  and the finger tube holder  200 . The biopsy apparatus can be secured in the loaded position by a transversely displaceable locker pin  604  disposed near the rear end of the housing in through bores  605  of the casing. In a secured position the locker pin  604  cooperates with an arc-formed cutout of the trigger  600 .  
         [0053]    A biopsy sampling cycle will now be explained by reference to FIGS.  4 - 10 . In FIG. 4 the biopsy instrument is in a loaded and secured position. In FIG. 5 the stroke length has been reduced from the maximally possible by displacing the stroke limiter  580  in a distal direction by means of a screw mechanism of which the screw  581  and the knob  582  disposed at the front face of the biopsy apparatus for continuous setting the stroke length is shown, whereas an additional release mechanism by which any stroke setting can be released to provide for maximum stroke length setting is not shown. Next (FIG. 6), the locker pin  604  is unsecured (the stylet  301  will have been injected into the tissue at this stage but this is not shown) and the trigger  600  is pushed forwards by pressing the release button  602 ; The figure shows the situation just after the front end of the catch arm has released the loading grip  542  of the finger tube control member  543 . In FIG. 7 the situation at the end of the first phase of biopsy sampling is shown, that is when the combined distal movement of the canula and the finger tube  201  along the stylet  301  has come to an end whereby the distal movement of the canula is stopped by the front face of the canula control member  544  hitting the side bar end faces of the U-formed stroke limiter  580 . FIG. 8 illustrates the situation at the end of the second phase of biopsy sampling, that is when the distal movement of the finger tube  201  is stopped by the base of the U-formed stroke limiter  580 . In FIG. 9 the person taking a biopsy sample has ceased the thumb pressure on the release button  602 . This allows the catch arm  541  to swivel back to its original position, thereby permitting a spring-loaded (at  550 ) L-formed lever  554  to swing by a few degrees around a pinion  551  by which it is fixed at upper face of the finger tube control member  543 . At its frontal transversal section the L-formed lever  554  has an L-shaped through opening  555  with the same orientation as the lever  554 . A pin  556  extending from the upper face of the canula control member  544  extends into the opening  555  in which it had been disposed up to now along the vertical L-bar of the opening  555 . By the slight rotation of the lever the pin  556  is now located at the free end of the transversal L-bar of the opening  555  while the finger tube control member  543  has been slightly withdrawn from the canula control member which is sufficient for withdrawing the finger tip of the finger tube  201  from the opening in the canula wall. This, in combination with the release (not shown) of the stroke limiter  580  to allow it to moved back to the, maximum stroke position, provides for the ejection of the biopsy sample from the canula in the next step, the situation at the end of which is illustrated in FIG. 10. Thereafter the biopsy apparatus is again loaded and the used biopsy instrument released from the apparatus by displacing the mounting frame  570  in a distal direction by means of knobs  571 .