Abstract:
A medical instrument includes a channel, a first interacting structure, a slider, and a control member. The first interacting structure can extend along at least a portion of the channel. At least a portion of the slider can also be disposed in the channel, so as to move in the channel. The slider can additionally have a first attraction portion. The control member can be rotatably coupled to the slider, and have a second interacting structure and a second attraction portion. The second interacting structure can engage the first interacting structure so as to move the slider in the channel when the control member is rotated. The second attraction portion can be disposed such that a distance between the second attraction portion and the first attraction portion changes as the control member is rotated relative to the slider.

Description:
PRIORITY INFORMATION 
       [0001]    This application claims the priority benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/122,686 (filed Dec. 15, 2008), the entirety of which is hereby expressly incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to medical instruments that provide tactile feedback to an operator. More particularly, magnets are used to provide the tactile feedback. 
         [0004]    2. Description of the Related Art 
         [0005]    Preferably, human-operated medical instruments provide some form of visible, audible, and or tactile feedback during use. This feedback can indicate a state of the instrument and/or a state of what the instrument is operating upon such as the patient. Prior art instruments typically use mechanisms such as springs, mechanical stops, or ratchets to provide feedback. 
       SUMMARY OF THE INVENTION 
       [0006]    The prior art instruments are unsatisfactory in a number of ways. For example, the mechanical feedback devices such as springs, mechanical stops, or ratchets can wear out over time, and thus are not always reliable. As another example, these mechanisms may be difficult to modify to provide a specific desired resistance. 
         [0007]    In one embodiment of the invention, a medical instrument includes a channel, a first interacting structure, a slider, and a control member. The first interacting structure can extend along at least a portion of the channel. At least a portion of the slider can also be disposed in the channel, so as to move in the channel. The slider can additionally have a first attraction portion. The control member can be rotatably coupled to the slider, and have a second interacting structure and a second attraction portion. The second interacting structure can engage the first interacting structure so as to move the slider in the channel when the control member is rotated. The second attraction portion can be disposed such that a distance between the second attraction portion and the first attraction portion changes as the control member is rotated relative to the slider. 
         [0008]    In another embodiment of the invention, a medical instrument for receiving an attachment having a fixed portion and a moveable portion is provided. The medical instrument can include a handle, a slider, and a controller. The handle can be configured to receive the fixed portion of the attachment and have a channel. At least a portion can be disposed so as to move within the channel. Further, the slider can be configured to receive the movable portion of the attachment and have at least one magnetic portion. The controller can have at least one magnetic portion disposed so as to create a magnetic force with the at least one magnetic portion of the slider. Further, the controller can be configured such that movement of the controller causes movement of the slider, up to a threshold force at which the magnetic force is overwhelmed and the slider and the controller separate. 
         [0009]    In a further embodiment of the invention, a medical instrument for operating a tool can include a track and a slider. The track can have a plurality of magnetic portions disposed thereto at a plurality of different locations along the track. The slider can be disposed on the track and have at least one magnetic portion disposed generally adjacent the track. The slider can move along the track such that when the slider slides through a full range of motion along the track the magnetic portions of the track and the magnetic portion of the slider are brought into a plurality of generally adjacent positions. This can affect a magnetic force between the magnetic portions of the track and the magnetic portion of the slider. 
         [0010]    In an additional embodiment a kit can include a medical instrument and a plurality of magnetic portions. The medical instrument can have a moveable portion operatively connected to an operating portion of the medical instrument to control the operating portion. The medical instrument can also have a plurality of magnetic portions that provide at least one of an audible or tactile feedback to a user. Further, at least one of the magnetic portions can be removable and replaceable by one of the plurality of magnetic portions. 
         [0011]    In yet another embodiment, a medical instrument can include an instrument and a first member. The instrument can include an operating portion and a non-operating portion, the non-operating portion comprising at least one first magnetic portion. The first member can include a moveable rod, a slot, and a release member. The moveable rod can include a second magnetic portion in magnetic connection with the first magnetic portion. The moveable rod can be housed with in the slot, allowing movement through the slot away from the first magnetic portion. The release member can be in operative communication with the moveable rod, such that actuation of the release member causes movement of the rod away from the first magnetic portion. This movement away from the first magnetic portion can release the magnetic connection with the first magnetic portion. 
         [0012]    In an additional embodiment, a medical instrument can include an operating portion, a handle, and a magnet. The handle can be operatively connected to the operating portion and include at least one control piece that is moveable relative to the handle. The magnet can be disposed on at least one of the handle and the control piece so as to provide audible and/or tactile feedback to an operator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    These and other features, aspects, and advantages of the medical devices disclosed herein are described below with reference to the drawings of preferred embodiments, which are intended to illustrate and not to limit the invention. Additionally, from figure to figure, the same reference numerals have been used to designate the same components of an illustrated embodiment. Like components between the illustrated embodiments are similarly noted as the same reference numbers with a letter suffix to indicate another embodiment. The following is a brief description of each of the drawings. 
           [0014]      FIG. 1A  is a perspective view of an embodiment of a medical instrument configured in accordance with the present invention and includes a handle and rotary dial or control portion. 
           [0015]      FIG. 1B  is a partially exploded perspective view of a distal portion of the medical instrument of  FIG. 1A  with the control portion removed from the handle to show complementary magnets. 
           [0016]      FIG. 1C  is a partially exploded perspective view like that of  FIG. 1B  except that the control portion includes a plurality of magnets. 
           [0017]      FIG. 1D  is a partially exploded perspective view like that of  FIG. 1B  except that the complementary magnets are disposed on components of the control portion. 
           [0018]      FIG. 1E  is a portion of a cross-sectional view through the control portion and handle from  FIG. 1A  showing the complementary magnets illustrated in  FIG. 1B  in an aligned state. 
           [0019]      FIG. 2A  is a perspective view of another embodiment of a medical instrument configured in accordance with the present invention. 
           [0020]      FIG. 2B  is a partially exploded perspective view of a portion of the medical instrument of  FIG. 2A  with a control portion removed from a handle. 
           [0021]      FIG. 2C  is a perspective view of a handle of another embodiment of a medical instrument configured in accordance with the present invention that can be used with the control portion depicted in  FIGS. 2A and 2B . 
           [0022]      FIG. 2D  is a side cross-sectional view of the medical instrument of  FIG. 2C , taken at  2 D- 2 D. 
           [0023]      FIG. 3A  is a partial perspective view of a portion of another embodiment of a medical instrument configured in accordance with the present invention. 
           [0024]      FIG. 3B  is a perspective view of the medical instrument of  FIG. 3A  with a control portion moved towards a proximal end of the handle. 
           [0025]      FIG. 3C  is a perspective view of the medical instrument of  FIG. 3A  with the control portion removed from the handle. 
           [0026]      FIG. 4A  is a side cross-sectional view of another embodiment of a medical instrument that includes a push drive apparatus configured in accordance with the present invention. 
           [0027]      FIG. 4B  is a side view of the medical instrument of  FIG. 4A  with a sliding block and fixed block of the push drive apparatus in a separated state. 
           [0028]      FIG. 5  is a perspective view of an exemplary embodiment of a stone basket that can be attached to the medical instruments disclosed herein. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    The present disclosure provides magnetic detent mechanisms for medical instruments. The figures depict the magnetic detent mechanisms in the context of a handle for a stone basket. More specific descriptions of various stone baskets and basket handles can be found in, e.g., U.S. Pat. Nos. 6,676,668 and 6,652,537, which are both incorporated by reference herein in their entirety. However, it will be clear from the disclosure that the magnetic detent mechanisms can include other medical and non-medical instruments. For example, the magnetic detent mechanisms can be employed with steering catheters, stents, and a variety of other medical articles. In a more general set of embodiments, the magnetic detent mechanisms are employed with any instrument for which it is desirable to provide tactile or audible feedback in addition to or in place of visible feedback, such as where an operator may be looking elsewhere or require feedback more precise than available by sight alone. In another general set of embodiments, the magnetic detent mechanisms are employed with instruments used for delicate procedures, where excessive force may cause complications, potentially causing damage to the instrument or something the instrument is acting on (such as a medical patient). In another general set of embodiments, the magnetic detent mechanisms are employed with instruments which are held in a prescribed position until released. It will be clear from the disclosure herein that the magnetic detent mechanisms can include a much greater variety of instruments than those explicitly described, medical or otherwise. 
         [0030]    For example, an embodiment of a stone basket  1 , which can be attached to a basket handle  10  that includes a magnetic detent mechanism as is illustrated in  FIG. 1A , is depicted in  FIG. 5 . As shown, the basket  1  comprises basket wires  2 , a control wire  3 , and a sheath  4 . The basket and control wires  2 ,  3  can connect and pass through the sheath  4 . When the control wire  3  is pushed into the sheath  4  the basket  1  can expand as the basket wires  2  flex outward. When the control wire  3  is withdrawn, the basket  1  can close as the basket wires  2  fold. Depending for example on what is carried by the basket  1 , it may be desirable to reliably control the force with which the basket opens or closes, how far the basket opens or closes, how fast the basket opens or closes, etc. Although the magnetic detent mechanism is primarily described herein in the context of using the basket handle  10  and stone basket  1 , other embodiments are possible. It should generally be understood that the control wire  3  can act as a non-operating portion of the basket  1 , while the basket wires  2  act as an operating portion. In further embodiments, operating and non-operating portions can take different forms. 
         [0031]      FIGS. 1A and 1B  depict one embodiment of a basket handle  10 . The basket handle  10  can include a hand grip  11  and a wire entry portion  12 . A slider  14  residing in a slot or channel  13  of the handle  10 , depicted as a track, can hold a control wire  3  of the basket  1 . As the slider  14  moves back in the slot  13  in a proximal direction toward the hand grip  11  (as indicated in  FIG. 1A ), the slider pulls the control wire  3  causing the basket wires  2  to close at a point distal from the basket handle  10 . Similarly, movement of the slider  14  in the other or distal direction causes the basket  1  to open. In non-basket embodiments, movement of the slider  14  may cause a stent to open, a sheath to pass over a needle, or many other desired actions. 
         [0032]    As depicted, in this embodiment movement of the slider  14  can be caused in two distinct ways. First, the slider  14  can be moved directly by a finger of an operator. The slider  14  may further include one or more ridges  15  on its upper surface to increase traction with the finger. However, the slider  14  can also move via the control portion  20 . As most clearly shown in  FIG. 1B , the handle  10  also include a gear track  16 . The control portion  20  can include a gear  21  annularly disposed on an axle  22 . The axle  22  passes through a slider hole  18  into the slot  13 , allowing the gear  21  to engage with the gear track  16 . As the control portion  20  rotates, it can move forward or backward at a controlled rate via the gear  21  and gear track  16 . As shown, the axle  22  and hole  18  can have varying widths configured to ensure both a secure fit and adequate clearance for the gear  21 . While it is preferable that the slider  14  be movable in more than one way, in some embodiments the slider  14  may only move in a single way such as with the control portion  20 . 
         [0033]    As depicted, at least one of the control portion  20  and the slider  14  comprises a magnet  17 ,  24 . A magnet is defined as a material that produces a magnetic field. The other one of the control portion  20  and the slider  14  can comprises either a magnet  17 ,  24 , a non-magnetized ferromagnetic material, or a paramagnetic material. For ease of explanation, the term magnet is used throughout the disclosure to include materials that produce a magnetic field, non-magnetized ferromagnetic materials, and paramagnetic materials. 
         [0034]    The magnet  24  on the slider  14  can be positioned directly above the center of the slider hole  18  at a distance approximately the same as the distance the magnet  17  on the control portion  20  is from the center of the axle  22 . However, it will be clear that the magnets  17 ,  24  need not be at these exact locations such as being directly above the slider hole  18 . For example, the magnets  17 ,  24  can be an equal radial distance from the hole  18  or axle  22 . As the control portion  20  rotates, so does the magnet  24 , bringing it eventually into alignment with the magnet  17 . Similarly, the magnets  17 ,  24  can be at different radially distances, since they need not be in perfect alignment to have a mutual magnetic force. 
         [0035]    When the magnets  17 ,  24  approach each other, their attractive or repulsive force can increase, providing a tactile response to an operator. This force can further cause the slider  14  to naturally tend to stay (or stay away from) a given position. In some embodiments this position can be configured to coincide with, a preferred state, such as a preferred size opening of the stone basket  1 . Further, the magnets  17 ,  24  can be chosen to have an attractive force strong enough to hold the slider  14  at the chosen position without application of some dislodging force greater than a force expected in normal operation that preferably would not cause the slider  14  to move. 
         [0036]    To indicate this position to the operator, the control portion  20  can further include a tactile indicator  25  (depicted as a larger ridge in  FIG. 1B ) among ridges  23  indicating when the control portion  20  is the desired position. The magnets  17 ,  24  can also align at multiple positions along the slot  13 , potentially defining multiple intervals that can correspond to a given distance of significance to the operator. For example, in some embodiments the control portion  20  can be configured to provide a tactile feedback at every inch of travel of the slider  14 . 
         [0037]      FIG. 1C  depicts another embodiment of a control portion  20   a.  In this embodiment, the control portion  20   a  comprises multiple magnets (or magnetic materials)  24 . Accordingly, the control portion  20   a  provides multiple tactile feedback forces in a single rotation, allowing potentially higher fidelity feedback. Further, in some embodiments the magnetic force can vary with each magnet  24 , indicating an angular position of the control portion  20   a.    
         [0038]      FIG. 1D  depicts another embodiment of a control portion  20   b.  In this embodiment, the control portion  20   b  includes a handle  30  and a clutch  31 , each including attractive clutch magnets  32 . When combined, the handle  30  and the clutch  31  can be identical to the previous control portions  20 ,  20   a  (although the outward facing magnet  24  may or may not be distinct from the clutch magnets  32 ). 
         [0039]    As depicted the handle  30  and clutch  31 , when combined are still free to spin independently via the smooth axle  33  of the handle  30 . However, the clutch magnets  32 , when aligned, can provide an attractive force inhibiting the relative rotation of the handle  30  and the clutch  31 . When the handle  30  is rotated by an operator, the entire control portion  20   b  can rotate, causing the slider  14  to move. However, if this rotation requires too much force, the force resisting rotation of the clutch  31  can overwhelm the attractive force between the clutch magnets  32  and cause the handle  30  and the clutch  31  to rotate independently. The attractive force between the clutch magnets  32  can thus be chosen to prevent an excessive force in opening and closing the basket  1 . Further, an operator can feel the sudden change in resistance as the clutch magnets  32  come out of alignment, indicating that the magnets  32  have released and that a threshold force has been reached. As discussed further below, in some embodiments the strength of the magnetic force can be adjusted to fit individual needs. 
         [0040]    If the outer control portion magnet  24  is also present on the control portion  20   b,  e.g. on the clutch  31 , the operator can feel the additional tactile feedback previously discussed. In some embodiments the outer magnet  24  can be the same magnet as the clutch magnet  32  on the clutch  31 . In such embodiments, the tactile feedback magnetic force can be less than the clutch magnetic force. 
         [0041]      FIG. 1E  depicts an enlarged cross-sectional view of an embodiment of a control portion  20  like that in  FIG. 1A , taken at  1 E- 1 E. As depicted, the control portion  20  forms a recess  26  holding the magnet  24 . Further, the magnet  24  and the recess  26  can optionally interengage to prevent the magnet from exiting the recess. The recess  26  can also have a depth greater than at least a portion of the magnet  24 , allowing the magnet  24  to move inward or outward within the recess. A corresponding magnet  17  on the slider  14  can be fixed within the slider at a recessed, beveled position. 
         [0042]    As depicted in  FIG. 1E , when the magnets  17 ,  24  align, the magnet  24  on the control portion  20  can be attracted in an outward direction toward the magnet  17 . Their contact can create a clicking sound, providing audible feedback to the operator. The beveled edges on the slider  14  and magnet  24  can then allow the magnets  17 ,  24  to slide out of alignment after clicking. Other embodiments providing similar functionality are possible. For example, the recess  26  can be open such that the magnet  24  can escape, but also include a weaker magnet in its interior pulling the magnet back into the recess when not overpowered by the slider magnet  17 . As another example, a similar opposing force can be provided with springs. 
         [0043]      FIGS. 2A ,  2 B depict another embodiment of a basket handle  10   c.  In this embodiment, a slider  40  rides in a slot  13   c  and holds a control wire  3 . The slider  40  can include ridges  15  and a magnet  41 . The slot  13   c  can include one or more magnets  42 . Thus, as the slider  40  moves along the slot  13   c  an operator can receive tactile feedback as the slider  40  moves past the slot magnets  42 . As depicted here, these slot magnets  42  can indicate a starting and stopping position for the control wire  3 . As discussed previously, one of either the slider magnet  41  and the slot magnets  42  may comprise a non-permanent magnet. 
         [0044]    Further, as depicted, the slot magnets  42  can be in the form of pins or screws. An operator can easily adjust the depth of the pins or screws to modify the attractive force between the magnets  41 ,  42 . Similarly, the slider magnet  41  can have a threaded portion with a screw head allowing its depth to be varied, or for it to be removed and replaced with a magnet of a different strength. These variations can affect both the tactile feedback and the tendency for the slider  40  to stay near or away from the slot magnets  42 , as discussed above. 
         [0045]      FIG. 2C  depicts another embodiment of a basket handle  10   d.  The handle  10   d  can be used with the slider  40  depicted in  FIGS. 2A ,  2 B. In this embodiment, the slider  40  interacts with a metal sheet  44  along the slot  13   d.  The metal sheet  44  can include one or more raised portions  45 , at which the force from the magnet  41  on the slider  40  will be strongest due to the decreased distance between the magnet  41  and the metal sheet  44 . Accordingly, the metal sheet  44  can provide similar functionality as the magnets  17 ,  24 ,  42  discussed above. 
         [0046]    Advantageously, the metal sheet  44  can be easily replaced and reconfigured. For example, the slot  13   d  can have small slits at its ends, into which ends of the metal sheet  44  can be inserted, thus holding the sheet in place and allowing easy removal, as depicted in  FIG. 2D . Thus a variety of magnetic strength profiles can be applied by using different metal sheets  44 . 
         [0047]    As depicted in the embodiment in  FIG. 2C , the handle  10   d  can have a wavy hand grip  11   d,  with horizontal waves. The wavy hand grip  11   d  can provide additional tactile indications of position for the operator. As depicted, the wavy hand grip  11   d  includes three maxima and three minima, but other combinations or patterns are possible. In some embodiments the profile can include a short wavelength (high frequency) wave superimposed on a long wavelength (low frequency) wave, providing varying precisions on a unitary surface. In additional exemplary embodiments, the profile can be different on each side of the handle  10   d.    
         [0048]      FIGS. 3A ,  3 B,  3 C depict another embodiment of a basket handle  10   e . Although slot magnets  42  and a metal sheet  44  are not depicted, it will be clear that these elements could be included. It will also be clear that the wavy features on the hand grip  10   e  can be similar to those on handle  10   d.  As depicted, the basket handle  10   e  includes a multi-piece slider  40   e.  For example, the slider  40   e  can include a wire holder  50  and a control piece  51 . The wire holder  50  can attach to the control wire  3  and the control piece  51  can magnetically attach to the wire holder  50 . The control piece  51  may further include finger ridges  23 . Both the wire holder  50  and the control piece  51  can ride in the slot  13   e.  The slot  13   e  can further include a removable pin stop  53 , adjustably limiting the travel of the slider  40   e.  As shown, each piece of the slider  40   e  can include a magnet  52 , but as discussed above both need not be magnets. 
         [0049]    Via the magnetic attachment, a force moving the control piece  51  in a rearward or proximal direction can similarly move the wire holder  50  in the same direction, moving the control wire  3  as well. If the force required is too great, the wire holder  50  and the control piece  51  can separate, as the magnetic attractive force is overcome. Further as discussed above, the magnets  52  can be chosen to require a specific desired force of separation, such as a force that would cause a controlled medical article to break or that would potentially cause damage to an object on which the medical article is acting. 
         [0050]    It should also be noted that in the embodiment of  FIGS. 3A ,  3 B,  3 C, the magnetic separation occurs when moving in the proximal or rearward direction. It will be clear that in those embodiments where the control piece  51  is placed on the other side of the wire holder  50  that the separation will occur when moving in the opposite direction. Further, in some embodiments control pieces  51  can be placed on both sides, allowing the operator to have force-limited control in both directions. Similarly, if the magnets  52  are located on a non-axial side of the wire holder  50  (i.e. a side non-perpendicular to the slot  13   e ) and the control piece  51  does not abut a perpendicular side, then the control piece  51  can release in both directions. 
         [0051]      FIGS. 4A ,  4 B depict another embodiment of a medical instrument. The medical instrument in this embodiment is depicted as a push drive apparatus  60 . As depicted, the push drive apparatus includes two blocks: a sliding block  61  and a fixed block  65 . The sliding block  61  and the fixed block  65  can be held together by the interaction of a magnet  62  on the sliding block and a magnetic yet unmagnetized attachment portion  66  (depicted as a pin) residing in a hole  68  on the fixed block  65 . As discussed above in relation to other embodiments, the pin  66  can also be permanently-magnetized in other embodiments. The attractive force between the magnet  62  and the pin  66  can be sufficient to resiliently hold the blocks  60 ,  65  together in normal operation absent actuation of a release member  67 . 
         [0052]    The fixed block  65  can release the sliding block  61  by actuation of a release member  67 , depicted as a lever. It will be clear from the disclosure herein that other release members  67  can be used, including cross pins, cams, and the like. The lever  67  can attach to or abut the pin  66 , and upon actuation can move the pin away from the magnet  62  through the hole  68 . As the remaining material of the blocks  61 ,  65  prevent the magnet  62  from coming any closer to the withdrawn pin  66 , the magnetic attraction can weaken sufficiently to allow separation of the blocks. The sliding block  61  can thus move away from the fixed block  65 , allowing an extension  63  to perform a desired function. 
         [0053]    Referring back to the embodiments previously discussed, the embodiment in  FIGS. 4A ,  4 B can be integrated with a variety of medical instruments. Using the basket handles  10  as an example, the push drive apparatus  60  can prevent the movement of a slider  14  prior to actuation of a release member  67 . Of course, the push drive apparatus  60  and similar embodiments can be used with other medical instruments, as discussed above. 
         [0054]    In conjunction with the invention and the embodiments described above, a variety of materials can be used. For permanent magnets, materials such as iron, neodymium boron iron, samarium cobalt, magnetite, and cobalt can be used. For unmagnetized, magnetic materials, the invention can use steel, iron, other paramagnetic and ferromagnetic materials, by way of example. The magnetic properties can further be modified by adjusting alloys, sizes, distances between magnets, and other properties. In some embodiments, the materials can be chrome or nickel plated to improve resistance to corrosion. 
         [0055]    In further embodiments, a medical instrument can come in the form of a kit. The magnets can reversibly insert into the medical instrument, for example by a screw-thread mechanism. Accordingly, a variety of magnets can be interchanged to modify the attractive forces. Further, via the screw-thread arrangement the magnetic force can be more finely calibrated by rotating through the thread, modifying the precise position of the magnets. 
         [0056]    In some embodiments, a practitioner can test a medical instrument, directly or indirectly observing the magnetic force. If the magnetic force is too strong or weak by at least a given amount, the practitioner can interchange the magnets. If the magnetic force is not too strong or weak by at least the given amount, the practitioner can adjust the position of any of the magnets to more finely tune the magnetic force. 
         [0057]    Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.