Abstract:
A needle guide system for a medical imaging instrument comprises a needle guide assembly ( 1, 2 ) and a mounting assembly ( 3, 4 , optionally  5 ) for attaching the needle guide assembly to a transducer, the mounting assembly comprising self-destroying means effective on dismounting. The mounting assembly comprises an attaching clip (4) mountable on a transducer directly or via an adapter ( 5 ), and a locking clip ( 3 ) mountable on the attaching clip from which it can be dismounted easily only by breaking indications of fracture comprised by the attaching clip. The needle guide assembly ( 1, 2 ) comprises a revolver ( 1 ) capable of receiving needles of varying diameter and a journal clip ( 2 ) by which it is mounted on the locking clip ( 3 ).

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a disposable needle guide system for a medical imaging instrument, in particular an ultrasonic transducer, for guiding a needle into a selected location of a patient relative to the imaging instrument, for use in percutaneous interventional procedures, such as fine needle aspiration, core biopsy, amniocentesis, and drainage.  
         BACKGROUND OF THE INVENTION  
         [0002]    A great number of needle guide systems for use with ultrasonic transducers and the like are known in the art. Most of them are confined to be used with a transducer of particular geometry which is a considerable drawback in consideration of the considerable number of ultrasonic transducers of differing geometry on the market.  
           [0003]    Another problem with most known needle guide systems is that they accept only one diameter size of needle, and that, therefore, their use with needles of different size necessitates the change of one or several parts. Present systems also suffer from the drawback that the user has to assemble the system from a number of parts. In addition most known needle guide systems require some sort of adapter which may constitute a substantial investment on its own. Also, such adapters may be lost or mislaid between individual percutaneous interventions.  
           [0004]    A further problem with many known needle guide systems is that they are not truly disposable, that is, they are not easy and cheap to manufacture and, therefore, tend to be re-used, even if not suited or designed to be repeatedly used. They thus may constitute a risk to patients when being re-used improperly.  
           [0005]    The present invention seeks to avoid the aforementioned problems.  
         OBJECTS OF THE INVENTION  
         [0006]    It is an object of the present invention to provide a needle guide system of the aforementioned kind which can be adapted to transducers of varying shape, in particular ultrasound transducers.  
           [0007]    It is another object of the present invention to provide a needle guide system of the aforementioned kind which has improved flexibility and functionality in comparison with needle guide systems presently in use.  
           [0008]    It is an additional object of the invention to provide a needle guide system accepting needles of varying diameter without the need for exchanging parts.  
           [0009]    It is a further object of the invention to provide a needle guide system which enables the user to choose between an adapter-based solution and a solution where a disposable device is directly fit to the transducer.  
           [0010]    It is a particularly important object of the invention to provide a truly disposable needle guide system, that is, a system which cannot be re-used at all or with considerably difficulty only.  
           [0011]    Further objects of the invention are evident from the following short description of the invention, the attached drawings illustrating a preferred embodiment, the detailed description thereof, and the appended claims.  
         SUMMARY OF THE INVENTION  
         [0012]    According to the present invention is provided a needle guide system of the aforementioned kind, comprising a needle guide assembly and a mounting assembly for attaching the needle guide assembly to a transducer, the mounting assembly comprising self-destroying means effective on dismounting.  
           [0013]    It is preferred for the needle guide assembly to comprise needle guide means accepting needles of different diameters, in particular needles from three to six different diameters.  
           [0014]    It is also preferred for the needle guide means to comprise a revolver mounted in a stepwise lockable revolving manner on a journal clip.  
           [0015]    The journal clip is mountable on the mounting assembly. According to the invention it is possible to provide a journal clip which can be mounted in two or more angular or height positions in respect of the mounting assembly.  
           [0016]    According to a preferred aspect of the invention, the mounting assembly comprises an adapter mountable on a transducer, an attaching clip mountable on the adapter and a locking clip mountable on the attaching clip. It should be understood that the attaching clip is interposed between the adapter and the locking element on which the needle guide assembly is mountable.  
           [0017]    It is however also possible for the attaching clip to be directly mountable the transducer; the portion of the transducer at which the attaching clip is mountable should be designed in a manner functionally corresponding to the mounting portion of the adapter. In such case no separate adapter will be needed. The variant of the needle guide assembly in which mounting portion of the adapter is comprised by the transducer is fully encompassed within the present invention.  
           [0018]    It is preferred for the adapter to be of a generally abutable shape in respect of the transducer to which it is intended to be mounted in a transducer encircling position. The adapter preferably has two free ends provided with a cooperating snap connection which is closed on mounting and which is preferably not easily dismountable by hand.  
           [0019]    According to a preferred second aspect of the invention the attaching clip comprises a base and first and second pairs of prehensile organs extending from the short or lateral ends of the base (or from positions close to the short ends) in opposite directions. A rough approximation of the general shape of a preferred attaching clip of the invention are two letters C joined back-to-back but not necessarily of the same size. The first pair of prehensile organs, such as claws, is designed in a manner to enable it to grip a U-formed portion of the adapter mounted on a transducer (or to directly grip a portion of the transducer of corresponding design) and to snap into position by its terminal portions interlocking with recesses provided in corresponding external faces of the adapter. Preferably further means for firmly attaching the adapter to the attaching clip are provided at facing faces of the attaching clip and the adapter, such as a transverse ridge disposed on an external face of the adapter insertable into a facing transverse recess disposed in the attaching clip.  
           [0020]    According to a preferred aspect of the invention the claws of the second prehensile organ are adapted to grip opposite sides of the locking clip in a way so as to hold it against the attaching clip and locking it in this position. Once snapped into position the locking element is not easily removed by hand from the attaching clip.  
           [0021]    The locking element preferably comprises a front and back support areas, such as support faces, grids or similar, tilting in respect to each other, the back face facing the attaching clip whereas the front face faces the needle is preferably selectable to fit a particular type of transducer or needle insertion depth.  
           [0022]    The needle assembly is mountable on the mounting assembly by attaching the journal clip to the locking element. Preferably the journal clip is mounted in a manner making it difficult or impossible to remove it from the locking element in a mounted position, for instance by snap tongues inserted into through openings in the locking element into which they lock and/or by snap tongues which can grip edges of the locking element.  
           [0023]    It is preferred for the needle guide system of the invention to be easily detachable from a position mounted on a transducer only by damaging (breaking) a weak point, such as a fracture zone or line, of the mounting assembly. Particularly preferred is for such a weak point, kerf or facture zone to be comprised by the second prehensile means, in particular by one claw thereof.  
           [0024]    It is preferred for the attaching clip to comprise breaking means for such destructive dismounting, the breaking means comprising a twisting element and a fracture zone or line. It is preferred for the fracture zone or line to be easily broken by displacement of sections adjacent to the zone or line in the direction of the transducer axis. Particularly preferred is the removal of a support for one or both second prehensile means providing for release of the locking element. By making the dismounting of the attaching clip conditional on its destruction the unsafe re-use of the needle assembly is prevented.  
           [0025]    It is preferred for the revolver to comprise a multitude of needle receiving slots, for instance, three to six slots, each slot being dimensioned to receive a needle of different diameter. The revolver has about cylindrical shape with the slots disposed in its mantle in parallel with the cylinder axis and in an about equidistant manner along its circumference corresponding to an exactly equidistant manner in regard of the axes of their respective needles. Whereas the width of each slot corresponds closely to the diameter of the needle which it is intended to receive, its depth is slightly less than said diameter. Thereby the needle protrudes somewhat in a radial direction from the slot.  
           [0026]    It is furthermore preferred for the revolver to comprise a multitude of locking elements. The locking elements, for instance, radially extending locking ribs, are arranged for locking the revolver in a position in which the a needle disposed in the slot of corresponding diameter is made abut a recess in a wall of the angular clip facing away from the transducer. Thereby the displacement of the needle is restricted to be strictly axial.  
           [0027]    According to the present invention is also provided a disposable needle guide system comprising a needle guide assembly and a mounting assembly mountable on a transducer, the mounting assembly comprising an attaching clip mountable on a mounting portion of the transducer or on an adapter mountable on the transducer, and a locking clip mountable on the attaching clip so as to be releaseably held at its opposite ends by holding portions of the attaching clip, the release means including a kerf or other indication of fracture comprised by a support portion of the attaching clip supporting one of said holding portions and being easily breakable by hand. It is preferred for the release function to comprise a handle which can be turned to break the kerf or other indication of fracture and thereby irreversibly release the locking clip.  
           [0028]    If not indicated otherwise, in this specification the orientation of the various elements of the needle guide system of the invention is in relation to the transducer. Ultrasound and other transducers are normally of a cylindrical, rectangular, parallelepipedeal or similar configuration for which a longitudinal axis can be defined. Directions perpendicular to that axis are termed “transverse” or “lateral”. Faces facing the transducer are termed “interior” or “inwardly facing” or similar. Faces facing away from the transducer are termed “exterior” or “outwardly facing” or similar. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    In the following the invention will be explained in greater detail by reference to preferred embodiments illustrated in a raw drawing showing in  
         [0030]    [0030]FIG. 1 a first embodiment of the needle guide system according to the invention mounted on an ultrasonic transducer, in a perspective view and with the transducer not shown;  
         [0031]    [0031]FIG. 2 the embodiment of FIG. 1, in an exploded view;  
         [0032]    [0032]FIGS. 3 a - e the individual elements of the embodiment of FIG. 1, in substantially the same view as in FIG. 1;  
         [0033]    [0033]FIG. 4 the adapter of the embodiment of FIG. 1 in an unmounted state, in a bottom view;  
         [0034]    [0034]FIG. 5 the embodiment of FIG. 1 with the transducer shown and a hypodermic needle mounted, in a bottom view;  
         [0035]    [0035]FIG. 6 a second embodiment of the needle guide system according to the invention, in the same view as in FIG. 5.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0036]    The first embodiment of the needle guide system of the invention shown in FIGS.  1 - 5  comprises five elements: a revolver  1 , an journal clip  2 , a locking clip  3 , an attaching clip  4 , and an adapter  5 . The elements  1 - 5  are preferably made of suitable polymer material(s).  
         [0037]    The revolver  1  is mounted rotatably between lower  14  and upper  15  arms of the journal clip  2  extending from a base plate  13  and carrying bearing necks  17  and  18 , respectively, which extend into a central bore  6  of the revolver at its respective ends. Juts  7  are disposed in the bore  6  close to its lower and upper end for snapping interaction with catches  19  on the bearing necks  17 ,  18 . Five such catches  19  are symmetrically arranged on each bearing neck  17 ;  18  allowing the revolver  1  to be displaced between five fixed positions by hand. These fixed positions correspond to five axial slots  8 - 12  on the revolver  1 , each slot being dimensioned to receive a hypodermic needle  70  of certain width. Thereby the needle guide of the invention can be used with needles of various (standard) dimensions. For mounting the needle  70  is placed in the slot  10  of corresponding width, and the revolver  1  with the needle  70  in the slot  10  is rotated until the needle  70  is locked in the slot  10  by the abutting the base plate  13  at a shallow indentation (not shown). The locking mechanism uses the resilient nature of the polymer materials of the revolver  1  and the journal clip  2 ; it does not prevent the needle from being moved in the direction of the slot  10 . The journal clip  2  comprises a stiffening rib  16 . It is useful to provide the journal clip  2  and the elements  3  and  4  with further stabilizing structures like the stiffening rib  16  but is not shown in the drawing for the sake of clarity. How the journal clip  2  with the revolver  1  is mounted on the remainder of the needle guide system by of upper  20 ,  21  and lower  24  claws extending from the rear side of the base plate  13  (the side facing away from the revolver  1 ) will be explained later.  
         [0038]    The needle guide assembly of the invention can be mounted on transducers of different geometry by an adapter  5  designed to fit the individual transducer. It is also possible to incorporate the portion of the adapter at which the remainder of the needle guide assembly is to be mounted in the transducer; in such case a separate adapter becomes superfluous. Only one external wall (a wall facing away from the transducer) of the adapter  5  (or the transducer, if no separate adapter is being used) need to be designed in a standard manner so as receive the remaining needle guide system elements  1 - 4 .  
         [0039]    This wall is the facing wall of the base plate  51  in FIG. 3 e . The base plate  51  forms part of a belt structure comprising left  52  and right  53  arms provided with angular end portions  64 ,  63  and joined to the base plate  51  by right  56  and left  57  thin flexible hinge sections. On mounting the base plate  51  on a transducer  71  its internal wall is pressed against the corresponding transducer wall, the arms  52 ,  53  are folded towards each other so as to enclose the transducer  71 , and the adapter  5  is secured at the transducer  71  by a snap connection  65 ,  66 ,  67  disposed at the external walls of it angular end portions  63 ,  64  comprising a tongue  65  with a head  66  integral with the right end portion  63  insertable into a catch  67  integral with the left end portion  64 . The snap connection  65 ,  66 ,  67  is of a self-locking sort that is not easily disassembled by hand.  
         [0040]    The journal clip  2  with the revolver  1  is attached to and locked on the adapter  5  by means of an attaching clip and a locking clip.  
         [0041]    The attaching clip  4  comprises a base plate separated into right  36  and left  38  sections by a thin-walled flexible bridge  40  which has a hinge function. To the right section  36  is joined a claw  37  at a right angle provided with an inwardly extending claw head  49 . To the left section  38  is joined a left claw  39  at a right angle provided with an inwardly extending claw head  48 .  
         [0042]    The attaching clip  4  is placed with its left right base plate section  38  against the external face of the adapter base plate  51  so as to make a retainer key  72  disposed at the interior face of left section  36  fit into a recess  55  disposed on the exterior face of the adapter base plate and the right claw head  49  fit into a recess  54  disposed at the external face of the right arm  53  of the adapter  5 . Then the left section  38  is swiveled around the flexible bridge  40  which forms a sort of hinge until it abuts the adapter base plate  51 ; thereby the right claw head  48  is inserted in recess (not shown) disposed on the external face of the adapter left arm  52  corresponding to recess  54 . In FIGS.  2 - 4  the attaching clip  4  is shown in a state prior to it being clamped on adapter  5 .  
         [0043]    The attaching clip  4  is locked on the adapter  5  by means of the locking clip  3  which comprises two faces, an outwardly facing first face identical with the exterior face of a base plate  25  and an inwardly facing second face defined by the internal face of a right locking flange  30  provided with a locking cylinder  31  and the internal face of a transverse stiffening rib  34  as well as the internal faces of vertical stiffening ribs (not shown) extending downwards from rib  34 . The first face is tilted in respect of the second face by an angle of about 15°. The internal face of the locking clip comprises a recess (not shown) which is engageable with a retainer key  47  disposed at the external face of the right base element section  36 .  
         [0044]    For locking the locking  3  on the attaching clip  4  the former is provided with laterally extending left  28  and right  30  locking arms, the right locking arm comprising a cylindrical end portion  31  from which upper  32  and lower  46  projections extend and the left locking arm comprising a handle  29 . The left and right locking arms  28 ,  30  are insertable into the gaps  68 ,  69  of left  41  and right  45  locking clip holders arranged on the external faces of the left  38  and right  36  attaching clip base plate sections. The left locking clip holder comprises clamping flanges  42 ,  43  and a rear support portion  44 . In combination with the cylindrical end portion  31  of the right locking arm  30  the right locking clip holder  45  provides a slight hinge function used on mounting: the cylinder portion  31  of locking clip  3  is first inserted into gap  69  of the right locking clip holder  45 ; then the left side of locking clip  3  is flipped towards clamp flange  42  of the left locking clip holder  41  to make it snap into its gap  68  from which position it is not easily dismounted by hand. The locking clip  3  furthermore is locked in this position by a retainer key  47  disposed on the external face of the right section  36  of the attaching clip base plate engaging with a grove and rib indentations (not shown) disposed on the internal face of the locking clip  3 .  
         [0045]    The journal clip  2  with the revolver  1  is mounted on the locking clip by inserting a pair of lower claws  24  (only one shown) disposed on the interior face of base plate  13  of the journal clip  2  into claw ducts  26 ,  27  penetrating the locking clip base plate  25 , the claws being retained in the ducts  26 ,  27  by keyways (not shown) engaging with the base plate. Simultaneously a pair of upper claws  20 ,  21  disposed on the interior face of base plate  13  of the journal clip  2  above said lower claws  24  are pushed over the top face  73  of the locking clip base plate  25  with which they engage by keyways  22 ,  23  in two selectable positions providing for different angles of hypodermic needle orientation. Thereby the journal clip  2  is locked on the locking clip  3  in a irreversible manner since the snap connection provided by claws  20 ,  21 ,  24  is not easily dismounted by hand.  
         [0046]    The various snap connections make use of the resiliency of selected polymer materials.  
         [0047]    As already pointed out the various snap connections in combination with the design of the needle guide system according to the invention provide for the mounted system not being easily dismountable in its integrity, thus preventing unautorized multiple use which might put the patient at risk.  
         [0048]    The needle guide system according to the invention can be easily dismounted only by damaging an important component, the attaching clip. To this effect, the attaching clip is provided with an arrangement supporting the left locking clip holder  41  which is attached to the left base plate section  38  by a rather thin bridge  58  of material which is sufficiently stable to provide support (in a mounted position) in direction perpendicular to the base plate and parallel with grove (gap)  68  but not in a transverse direction indicated by arrow A in FIG. 4. In that transverse direction the clip holder  41  is supported by a release grip  50  via supports  59  and, to a lesser degree,  60 . The clip holder  50  is attached to the external face of the left claw  39  by a hinge pin  62  and a further support  61 . The supports  59 ,  60 ,  61  are designed to be easily broken by relative displacement of the elements which they connect in a perpendicular direction. This capability is used when releasing the left locking clip holder  41  by turning the release grip around the hinge pin  62 . The hinge pin  62  is not and need not be a pin freely rotatable in a bearing or hinge, it is sufficient that the material constituting it allows the clip holder  50  to be rotated by hand while being sufficiently rigid to hold the clip holder  50  in position against the pressure exerted by the mounted locking clip  3  in normal use. The breaking of supports  59 ,  60  on rotating clip holder  50  out of its plane allows the left locking clip holder  41  to flip away from the locking clip  3  in the direction of arrow A, thus allowing the locking clip  3  with the journal clip  2  and the revolver  1  to be removed. Thereby the attaching clip  4  can be folded away from the adapter  5  (in the direction of arrow B) and removed. The pressure exerted on the adapter  5  by claws  37 ,  39  thus comes to an end which facilitates its dismounting.  
         [0049]    The second embodiment of the needle guide system of the invention shown in FIG. 6 comprises four elements: a revolver  1 , an journal clip  2 , a locking clip  3 , and an attaching clip  4 . The four elements  1 ,  2 ,  3 ,  4  of the second embodiment fully correspond to elements  1 ,  2 ,  3 ,  4  of the first embodiment and are therefore identified by same reference numbers. In the second embodiment the mounting portion of the adapter  5  of the first embodiment is incorporated in the transducer  80  on which the attaching clip  4  is directly mounted.