Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to a medical device having one or more replaceable cutting tips. More specifically, the present invention relates to a rongeur that has at least one replaceable cutting tip. In another embodiment, the tip or tips may be disposable.  
         SUMMARY OF THE INVENTION  
         [0002]    The rongeur is a surgical tool commonly used in performing spinal surgery. A key to the safe and efficient use of a rongeur is the sharpness of the opposing biting or cutting ends. Because they are used to remove bone, cartilage and other fibrous tissue, the cutting surfaces may dull prematurely, diminishing the utility of the device, and increasing the surgical risks.  
           [0003]    To address this problem it is necessary periodically, actually quite frequently, to sharpen the cutting surfaces of the rongeur. The sharpening is typically performed by an outside service which requires that the entire device be delivered to this outside service and then returned. This procedure is not only costly, it may also require a few days to even weeks before the resharpened rongeur is returned. Moreover, the resharpened tool may not be as sharp as a new rongeur which may result in further delay in its availability. As a consequence, the neuro-surgical team at a particular medical facility or hospital may require several sets of these relatively expensive tools. Indeed, repeated sharpening may result in slightly displaced or non-symmetrically cutting surfaces so that approximation and/or alignment of the cutting surfaces is adversely affected. Ultimately then, the entire rongeur is rendered unuseable.  
           [0004]    The present invention overcomes the drawbacks mentioned above by providing a rongeur that has one or more replaceable cutting surfaces. To facilitate the removal, as well as to securely retain the tips, the tips may be attached through the use of threaded fasteners as well as other interlocking mechanisms. In this way, the turnaround time required for a rongeur with dulled cutting surfaces can be reduced dramatically, while maintaining excellent sharpness of the tool&#39;s cutting surfaces at all times. In addition, the number of sets of rongeurs required at a given facility may be reduced. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0005]    These and other features, objects and advantages of the present invention will become apparent from the following description and drawings wherein like reference numerals represent like elements in several views, and in which:  
         [0006]    [0006]FIG. 1 shows a standard prior art rongeur without replaceable tips.  
         [0007]    [0007]FIG. 2 shows a partial exploded view of the rongeur shown in FIG. 1.  
         [0008]    [0008]FIG. 3 shows a partial exploded view of one embodiment of the present invention.  
         [0009]    [0009]FIG. 4 shows a partial exploded view illustrating how cutting tips may be replaced.  
         [0010]    [0010]FIG. 5 is a top view of one embodiment the present invention.  
         [0011]    [0011]FIG. 6 is a cross-sectional view taken along line  6 - 6  in FIG. 5.  
         [0012]    [0012]FIG. 7 is a top view of another embodiment of the present invention.  
         [0013]    [0013]FIG. 8 is a cross-sectional view of the embodiment shown in FIG. 7 taken along line  8 - 8 .  
         [0014]    [0014]FIG. 9 is a partial perspective view of an alternate embodiment of the present invention.  
         [0015]    [0015]FIG. 10 is a partial perspective view of yet another embodiment of the present invention.  
         [0016]    [0016]FIG. 11 is a partial perspective view of still another embodiment of the present invention.  
         [0017]    [0017]FIG. 12 is a partial, exploded view of another embodiment of the present invention.  
         [0018]    [0018]FIG. 13 is a top view of the embodiment shown in FIG. 12.  
         [0019]    [0019]FIG. 14 is a partial perspective view of the embodiment shown in FIG. 12.  
         [0020]    [0020]FIG. 15 is a partial, exploded view of another embodiment of the present invention.  
         [0021]    [0021]FIG. 16 is a cross-sectional view of the embodiment shown in FIG. 15 taken along line  16 - 16 .  
         [0022]    [0022]FIG. 17 illustrates how the sections of the embodiment shown in FIG. 15 inter-connect.  
         [0023]    [0023]FIG. 18 illustrates another embodiment of the present invention.  
         [0024]    [0024]FIG. 19 is a sectional view of the embodiment shown in FIG. 18 taken a long line  19 - 19 .  
         [0025]    [0025]FIG. 20 is a sectional view of the embodiment shown in FIG. 18 taken along line  20 - 20 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    Set forth below is a description of what are currently believed to be the preferred embodiments or best examples of the invention claimed. Future and present alternatives and modifications to the preferred embodiments are contemplated. Any alternates or modifications in which insubstantial changes in function, in purpose, in structure or in result are intended to be covered by the claims of this patent.  
         [0027]    [0027]FIG. 1 illustrates a standard prior art rongeur  100  that does not include replaceable or removable tips. The device includes an elongated upper cutting arm  112  that moves between an open and closed position. A second, stationary arm  114  is also provided. At the distal ends of the arms are sharpened sections  116  and  118  that are cupped or concave in construction. Sections  116  and  118  provide the ability to cut bone, cartilage or other fibrous tissue.  
         [0028]    A moveable handlebar  120  is attached to stationary handlebar  122  at pivot point  124  by a fastener  123 . Handlebar  120  is coupled to arm  112  so as to urge the arm into a closed position to effectuate cutting. A spring  130  urges arm  112  into an open position by biasing handlebar  120  away from handlebar  122 .  
         [0029]    As shown in FIG. 2, arm  112  further includes a flat section  132  that engages or abuts flat section  134  of arm  114  to facilitate smooth operation of arm  112  with respect to arm  114 . To link the arms in a sliding relationship, keys or guides  136  and  137  are configured to seat within keyways or passageways  138  and  139 . Of course, the guides may be located on arm  114  and the passageways on arm  112 .  
         [0030]    To service or sharpen the cutting sections, the entire device is disassembled by the removal of screw  123  which allows the device to be broken down into its component parts. Of course, prior to operation the entire device needs to be re-assembled as well.  
         [0031]    The present invention improves upon this design by providing replaceable tips  240  and  270  as shown in FIGS.  3 - 6 . Tips  240  and  270  each include a cutting section that together effect the tissue cutting function. Arms or base sections  212  and  214  receive and support the replaceable tips. The present invention contemplates that either one of the arms or bases may be configured with a replaceable tip or that both may be so configured. In addition, one or more of the tips may be disposable and removable as well.  
         [0032]    As shown in FIGS.  3 - 6 , cutting tips or sections  240  and  270  are attached to arms  212  and  214  through the use of threaded fasteners  242  and  272  which seat within bores  244  and  274  and coact with internal threads  246  and  276 . The length of the fasteners and bores may be configured to result in fastener head  243  seating within the bore at a location which allows head  243  to be recessed from the cutting surface  216 . Alternately, as shown in FIG. 8, head  243  may also be further configured to conform to the concavity of section  216 . This preserves cutting efficiency and prevents tissue and other matter from collecting within the bore. Fastener head  273  may be similarly configured to mimic surface  275  so as to avoid creating a sharp edge on the device and to prevent tissue and other matter from collecting within the bore.  
         [0033]    [0033]FIGS. 3 and 4 show that cutting sections or tips  240  and  270  may also be configured to incorporate sections of guide  236  and passageway  238 . More specifically, tip  240  uses guide portion  236 A which aligns with guide portion  236 B to form a complete guide. Similarly, tip  270  includes passageway portion  238 A which aligns with passageway portion  238 B to form a complete passageway.  
         [0034]    As illustrated in FIG. 4, section or tip  240  may also include an attachment member  250  that is configured to seat within receiving section  256  on arm  212 . Member  250  may be frusto-conical in shape so as to promote a solid attachment but may also be a wide variety of shapes known to those of skill in the art including, but not limited to, cylindrical, circular, and triangular. Likewise, receiving section  256  may be an opening or aperture that is shaped to mate with the attachment member or of such a shape to form a solid and stable fit. With this embodiment, fasteners may be used but are not required since the member and receiving section are interlocking in design.  
         [0035]    Tip or section  240  also includes a shoulder  252  that abuts receiving shoulder  258  on arm  212 . Shoulders  252  and  258  further assist in the secure and stable attachment of the tip. The shoulders may also be angled relative to the longitudinal axis of arm  212 , as illustrated by line  259  in FIG. 6, so as to resist upward forces created when cutting is performed. FIG. 4 also illustrates that section or tip  270  may be attached in a similar fashion. As shown, tip  270  includes an attachment member  150  that is configured to seat within receiving section  156  on arm  214 . Member  150  may be frusto-conical in shape so as to promote a solid attachment but may be a wide variety of shapes known to those of skill in the art including, but not limited to, cylindrical, circular, and triangular. Likewise, receiving section  156  may be an opening or aperture that is shaped to mate with the attachment member or to at least form a solid and stable fit. With this embodiment, fasteners may be used but are not required since the member and receiving section are interlocking in design.  
         [0036]    Tip  270  also includes an attachment surface or shoulder  152  that abuts or mates with receiving shoulder  158  on arm  214 . Shoulders  152  and  158  further assist in the stable attachment of the tip to arm  214 . The edges or surfaces may also be angled relative to the longitudinal axis of arm  214 , as illustrated by line  159  in FIG. 6, so as to resist downward forces created when cutting is performed. In addition, while cutting sections  216  and  218  are shown in a standard concave, cupped configuration, other shapes may be used as well. Providing a rongeur with the ability to change its cutting characteristics greatly increases the flexibility of the tool over current designs. As mentioned above, the cutting sections may also be disposable.  
         [0037]    Alternately, the attachment member and receiving sections may be eliminated or used on just one of the tips. In addition, the edges or shoulders may or may not be angled.  
         [0038]    In addition, the present invention contemplates that the stationary arm may include the guides and that the movable arm may include the passageways so as to link the arms in a sliding relationship. Likewise, the cutting tips may include the receiving sections while the arms may include the attachment members.  
         [0039]    In use, when the cutting edges wear down, or when a different cutter is desired, the desired tip is replaced by simply unthreading the fastener securing the tip to the base or by disengaging the interlocking member and receiving section. The attachment member is slid out of the receiving section and the procedure is reversed for the installation of a new, sharpened or different tip. Moreover, guide portion  236 A will need to be positioned in passageway section  238 B prior to removal of the tip.  
         [0040]    [0040]FIGS. 9 and 10 show two alternate embodiments of the present invention. As shown in FIG. 9, the cutting tip or section  300  is secured to base or arm  302  by a threaded rod  304  which extends from tip  300 . Threaded rod  304  coacts with internally threaded bore  306  in arm  302  to secure the two sections together.  
         [0041]    The embodiment shown in FIG. 10 is of a similar construction with the locations of the threaded rod and threaded bore reversed. Tip  310  contains the internally threaded bore  312  and arm  314  has threaded rod  316 . Again the coaction between the threaded elements secures the two components together.  
         [0042]    [0042]FIG. 11 shows yet another embodiment of the present invention which is similar in design to the embodiments shown in FIGS.  3 - 5 . Tip  320  includes an attachment member  324  that seats within a receiving section  326  in a section of arm  322 . A threaded fastener in inserted into a thread bore and transects the receiving section and attachment member to lock the components together. Alternately, a pin may be used instead of fastener  328 . Of course, as with the earlier described embodiments, the attachment member may be located on the arm and the receiving section may be located on the tip.  
         [0043]    FIGS.  12 - 14  illustrate an alternate embodiment of the present invention. Tip  350  includes an attachment member  351  having threads  353 . As with the earlier described embodiments, arm  352  includes a receiving section  355  that receives the attachment member  351 . As illustrated, the receiving section includes internal threads  357 . The components are joined together by inserting member  351  into receiving section  355  and rotating the tip so that threads  353  and  357  coact. This coaction joins the sections together. Of course, as with the earlier described embodiments, the attachment member may be located on the arm and the receiving section may be located on the tip.  
         [0044]    FIGS.  15 - 17  illustrate yet another embodiment of the present invention. Tip  370  includes an extended section  372  having an enlarged portion  374 , which may take the form of a rod and crossbar to form a T-shaped section. A deformable pad  376  is also provided. Arm  380  includes internal bore  382  with enlarged section  384 .  
         [0045]    The arm and tip are joined together by inserting the T-shaped section into bore  382  and then rotating the tip 90 degrees. This permits cross-bar  374  to engage inner wall  390  and prevents the disengagement of the components. Pad  376  is configured to be slightly compressed when the arm and tip are joined together. This results in a force which biases the cross-bar against the inner wall.  
         [0046]    FIGS.  18 - 20  illustrate an alternate embodiment of the present invention. In this design, tip  500  is secured to base  502  by fastener  504 . To accomplish this, tip  500  is configured so that section  510  overlaps section  512  of base  502 .  
         [0047]    Tip  500  also has internal threads  508 , which coact with fastener  504 . Of course, the internal threads may be located in arm  502  as well.  
         [0048]    Tip  520  is attached to arm or base  522  in a similar fashion through the use of fastener  524  and internal threads  526 . Again, the internal threads may also be located in base  522 .  
         [0049]    While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those of ordinary skill in the art that changes and other modifications can be made without departing from the invention in its broader aspects. Various features of the present invention are set forth in the following claims. For example, although only the stationary arm is illustrated, the moveable arm may also be configured in the same manner for the embodiments shown in FIGS.  7 - 20 .

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