Abstract:
A surgical tool handle and separate disposable orthopedic tool head assembly is disclosed. The surgical tool handle has a reinforcing member extending from it. The reinforcing member is receivable in an internal bore of the disposable orthopedic tool head and provides structural reinforcement for the tool head. This reinforcement allows the use of disposable materials in the construction of the tool head that otherwise could not be use (e.g., plastic and resin materials) because of an increased risk of breakage or failure relative to metallic tool heads.

Description:
[0001]     The present application claims the benefit of prior filed U.S. Provisional Application Ser. No. 60/806,360 filed 30 Jun. 2006, to which the present application is a regular US national application, and which is fully incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is in the field of orthopedic surgical instrumentation for particular use in a surgical procedure on bone structure, and relates to cutting devices particularly adapted to cut into bone or associated softer bone like tissues of the body, wherein a portion of a bone or associated cartilage is removed by a sharpened blade, chisel or a device having tooth-like projections which wear the bone or cartilage dawn by friction. More specifically, the present invention relates to disposable cutters and abraders on a handle, which are moved in a push-pull fashion, and have cutting formed prominences used to modify the shape of a bone or cartilage surface.  
       BACKGROUND OF THE INVENTION  
       [0003]     Abraders, broaches, rasps and similar orthopedic surgical instruments are used in surgical procedures to modify bone structure. These instruments are adapted to cut into bone or associated softer bone-like tissues of the body to remove a portion of a bone or cartilage. Such instruments accomplish their purpose by means of tooth-like projections which wear or grind away the bone or cartilage. Typically, the tool head of these instruments is attached to a handle and perform its cutting function in a push-pull fashion.  
         [0004]     The tool head of these instruments have cutting means formed on the cutting surface of the tool head in the form of prominences projecting from the tool head surface. The prominences or teeth act to modify the shape of a bone or cartilage when drawn across the surface to be modified.  
         [0005]     Usually, these instruments are made of surgical steel or other metal alloys, and are designed for reuse. Reuse requires that the instrument be thoroughly cleaned and sterilized subsequent to its use, before it can be used again. It is the nature of the cutting surface on the tool head of these instruments to be covered with prominences that readily trap tissue debris during use. This tissue residue can be very difficult to remove from a tool head, especially from one with a particularly tortuous cutting surface. Even an intensive cleaning effort may not result in complete removal of all tissue residue.  
         [0006]     Additionally, the subsequent sterilization of these tool heads does not tend to result in the removal of such debris from the cutting surface. The presence of tissue debris residue (even though sterilized) is a potential source of infectious material such as prions. A prion is a type of infectious agent made only of protein. Devices that are not properly cleaned and sterilized increase the risk of disease transfer from patient to patient. This is especially true following the emergence of certain prions that are not killed by normal hospital sterilization. Therefore, it would be beneficial to the field to have these tool heads available as disposable, one-time use items.  
         [0007]     The field has been motivated to seek such a solution. For example, Geisser et al. (U.S. Pat. No. 5,454,815) disclose a one-time use bone rasp made of plastic. The working part of the Geisser rasp is made of a plastic material, and preferably, is provided with a hollow through bore from its proximal to its distal end. The through bore can be connected to a flush and suction line, to facilitate removal of cutting debris from the work site. However, because the tool head is made completely of plastic, and has an interior hollow through bore, there is the possibility of the tool head breaking during use. As another example, Grünig et al. (U.S. Pat. No. 6,120,508) disclose a one-time use surgical rasp having a two-piece tool head made of thin sheet metal sleeve, in the surface of which rasp teeth are formed. A plastic support is received in the sleeve, and the combination of the sleeve and plastic support are attached to a handle. Although the Grünig device may be useful for its intended purpose, it is still relatively complex, in that the tool head is a two-piece construction requiring the two mating steps: the support to the sleeve, and the combination to a handle.  
         [0008]     Therefore, it would be beneficial to the field also to have a relatively simple, one-time use orthopedic cutting tool head made of plastic, but that has a reduced possibility of breaking during use.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention is a reinforcing surgical tool handle combinable with disposable plastic surgical cutting tool head to provide a surgical tool handle and reinforced plastic surgical cutting tool assembly. The surgical tool holder/handle is specialized in that it is adapted to removably receive and securely hold a disposable surgical tool head, and to reinforce it during use. The plastic surgical broach used as an example in the embodiments illustrated below is merely an example of a type of disposable tool head. Other types of tool heads are anticipated and intended in the present invention, such as abraders, chisels, rasps and the like. In the embodiments illustrated, the tool head is made of a plastic material. Such materials can soft and/or brittle relative to their metal counterparts in the field, and at risk of bending or breaking during use. Therefore, it is an object of the present holder/handle to include a means for internally reinforcing the disposable surgical tool head to reduce or prevent the risk of the tool head bending or braking during use. Referring now to the drawings, the details of preferred embodiments of the present invention are graphically and schematically illustrated.  
         [0010]     The present surgical tool holder and disposable tool head combination assembly comprises, in main, a handle with a reinforcement member, a tool head, and a releasable locking mechanism to hold the head and the handle together for use. The reinforcing member extends from the tool interface on the surgical tool handle along an axis in the direction of the distal end of the tool head. The surgical tool head has an internal bore disposed to closely receive the reinforcing member. The handle interface on the tool head engages the tool interface on the handle when the reinforcing member is fully received in the internal bore. The handle interface on the tool head has a handle end catch means. The handle end catch means is disposed to selectably engage a pawl of a locking mechanism disposed in the handle proximate the tool interface of the handle.  
         [0011]     The locking mechanism has a locking pawl, which is operable by the locking mechanism to releasably engage the catch means of the tool head when the reinforcing member is fully received in the internal bore. Engagement of the locking pawl with the catch means secures the position of the surgical tool head relative to the handle while the pawl is engaged with the catch means. In this configuration, the present invention combination surgical tool handle and disposable plastic tool head assembly is ready for use.  
         [0012]     The combination of the reinforcement member in the present invention allows the use of disposable materials in the construction of the tool head that otherwise could not be use (e.g., plastic and resin materials) because of an increased risk of breakage or failure relative to metallic tool heads.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1A  is a side plan view of a combination surgical tool handle and disposable broach assembly of the present invention showing a portion of the handle with a reinforcing member extending from it.  
         [0014]      FIG. 1B  is a side plan view of a disposable surgical tool head configured as a broach with an internal bore for closely receiving a reinforcing member.  
         [0015]      FIG. 2A  is a side plan view of the assembly of the present invention showing a portion of the handle with a partially threaded reinforcing member extending from it.  
         [0016]      FIG. 2B  is a side plan view of a disposable surgical tool head configured to be threaded onto the reinforcing member.  
         [0017]      FIG. 2C  is a view of the insert of  FIG. 2A  showing an alternative configuration of the handle and tool head interfaces.  
         [0018]      FIGS. 3A-3C  are side plan views of an alternative embodiment of the assembly of the present invention illustrating an alternative configuration of the reinforcing member and the tool head bore, and an alternative configuration of the handle and tool head interfaces.  
         [0019]      FIGS. 4A and 4B  are (A) a side plan view of an assembly of the present invention showing a portion of the handle with a locking tongue extending from the tool interface, and (B) a rear plan view of the corresponding locking groove on the handle interface of the tool head.  
         [0020]      FIG. 5  is a schematic side view of a reinforcing member received within the bore of a tool head, the reinforcing member incorporating a hollow tube connecting with a fluid chamber and outlets on the working surface of the tool head, to provide a lavage capability when using the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Referring now to the drawings, the details of preferred embodiments of the present invention are graphically and schematically illustrated. Like elements in the drawings are represented by like numbers, and any similar elements are represented by like numbers with a different lower case letter suffix.  
         [0022]     As illustrated in  FIGS. 1A and 1B , the present surgical tool holder  10  includes a handle  16  having a reinforcing member  40  for internally reinforcing a disposable surgical tool head  60  attached to the holder  10 . The handle  16  in the preferred embodiments illustrated is know in the art as a surgical broach holder. Similar handles are described in detail in patent applications: U.S. Ser. No. 60/710,845 filed 24 Aug. 2004; U.S. Ser. No. 60/634,467, filed 9 Sep. 2004; and WO S/N PCT/IB2005/003720, filed 7 Dec. 2005, the contents of which are incorporated herein by reference. Other examples of handles similar to that of the present invention are described in U.S. Pat. No. 5,324,293 to Rehmann, and also in U.S. Pat. Nos. 5,665,091 and 5,993,455 to Noble. Other examples of handles suitable for practice in the present invention are known to and selectable by one of ordinary skill in the art in view of the figures and disclosure herein. The handle includes a locking mechanism  20  which engages a tool head  60  to securely attach the tool head  60  to the tool interface  24  of the handle  16 .  
         [0023]     A reinforcing member  40  extends from the tool interface  24  on the handle  16 , along a force axis  26  in the direction of the work. The reinforcing member  40  is made of a material that is compatible with the typical use and treatment of surgical tool handles in this field, and can take various configurations. Preferably, the reinforcing member is metal or a metallic alloy. Attachment of the reinforcing member  40  to the handle  20  in a variety of ways known to and selectable by one of ordinary skill in the art for practice in the present invention as exemplified below. In  FIG. 1A , the reinforcing member  40  is a rod  42 . In this preferred embodiment the rod  42  is tapered at least slightly for its interface end  44  toward its distal end  45 . The reinforcing rod  42  can be fixed into the handle  16  in any of a number of manners known to and selectable by the ordinary skilled artisan for practice in the present invention. For example, as illustrated in  FIG. 1A , the rod  42  is accepted into a receiver  80  set into the tool interface  24  of the handle  16 . In the figure, the rod  42  is retained in the receiver  80  by a retention pin  82  which passes through the rod  42  as shown. Alternatively, the interface end  44  of the rod  42  may be threaded and screwed in to a complimentary threaded receiver  80  (not shown), or rather than a pin through the rod  42  a set screw in place of the retention pin  82  could be screwed against the rod  42  to secure it to the handle  16 . A further alternative fixing mechanism is illustrated in  FIG. 3A , as described below.  
         [0024]      FIG. 1B  shows a tool head  60  for practice in the present assembly  10 . In this preferred embodiment the tool head  60  is configured as a surgical broach. The tool head  60  has a tool bore  65  partially extending from the handle interface  66  of the tool  60  toward the distal/work end  68  of the tool head  60 . The tool bore  65  is configured to very closely receive the rod  42  and to engage the rod  42  with a friction force when the rod  42  is pressed into the rod bore  65 .  
         [0025]     The tool head  60  also has a catch means  70  disposed to be engaged by the locking mechanism  20  of the handle  16 . In the example illustrated, the catch means  70  is a notch engageable by the pawl  28  of the locking mechanism  20 . Engagement of the locking mechanism  20  with the tool catch  70  acts to prevent the tool head  60  from sliding on the reinforcing rod  42 , and to prevent (in combination with the angle of the interfaces  24  &amp;  66  between the handle  16  and the tool head  60 ) rotation of the tool head  60  about the rod  42 .  
         [0026]     As illustrated in  FIGS. 2A and 2B , in another preferred embodiment the reinforcing member  40  is a partially threaded rod  48  having a thread  50  disposed at the distal end  45   a  of the threaded rod  48 . The threaded portion can be practiced at another portion along the length L of the reinforcing member  40  as selectable by the ordinary skilled artisan. In this embodiment, the handle  16  has a flat tool interface  24   a  and the tool head  60  has a flat handle interface  66   a , i.e., the interfaces  24   a  and  66   a  are perpendicular to the force axis  26  of the reinforcing member  40   a . The thread  50  can be a self-tapping, but preferably screws into a complementary pre-tapped bottom-portion  69  of the bore  65 . Alternatively, the tool head  60   a  can have a threaded fastener (not shown) set into the bottom portion  69  of the bore  65 , into which the thread  50  of the threaded reinforcing rod  48  can be screwed. Referring now to  FIGS. 4A and 4B , unwanted rotation of the tool head  60   d  may further be prevented by a locking tongue  17  extending from the tool interface  24  of the handle  16 . The locking tongue  17  which enters a corresponding groove  61  at the handle interface  66  of the tool head  60   d , and when engaged therewith rotation of the tool head  60   d  is further prevented.  
         [0027]     In this embodiment, as further illustrated in  FIG. 2B , the interface end  64   a  of the tool head  60   a  is configured with an arcuate portions  72  to rotate without obstruction relative to the handle  16 .  FIG. 2C  illustrates an example of an alternative configuration of the relationship of the handle and tool interfaces  24   b  and  66   b  relative to each other to allow their rotation without obstruction relative to the each other. As in the examples above, this embodiment utilizes a lock catch notch  70  to be engaged by the pawl  28  of the locking mechanism  20 . Engagement of the locking mechanism  20  with the tool catch  70  acts to prevent the tool head  60  from rotating about the rod  42 .  
         [0028]      FIGS. 3A-3C  illustrate an alternative preferred embodiment of the assembly  10  of the present invention having an alternative configuration of the reinforcing member  60   c , the tool head bore  65   b , and the handle and tool head interfaces  24   b  &amp;  66   b . Additionally shown in the figures is a further alternative mechanism for fixing the reinforcing rod  54  to the tool interface  24   b  of the handle  16 . In this embodiment, the reinforcing member  40   b  is a blade  54  having a somewhat flat configuration, and has an interface end  44   c  terminating in a T-fitting  90 . A blind-ended channel  86  is disposed proximate the tool interface  24   b  and communicates at its open end with the surface of the handle  16 . As illustrated, the T-fitting  90  at the interface end  44   c  of the reinforcing member  40   b  is slid into the channel  86 . The bore  65   b  of the tool head  60   c  is slid over the reinforcing blade  54 . A shoulder  94  on the handle interface  66   b  the tool head  60   c  is received against a seat  96  on the tool interface  24   b  of the handle  16 . Once the shoulder  94  and the seat  96  are engaged, the locking mechanism  20  is set and the tool head  60   c  is prevented from sliding or twisting relative to the handle  16 . Additionally, the disposition of the shoulder  94  against the seat  96  prevents the T-fitting  90  of reinforcing blade  54  from sliding out of the channel  86 .  
         [0029]     In an alternative preferred embodiment illustrated in  FIG. 5 , the reinforcing member  90  of the surgical tool handle has an inner flow passage  92  along at least a portion of the length L of the reinforcing member. In the embodiment illustrated, the flow passage is through the entire length of the reinforcing member  90 . At the handle  16 , the flow passage  92  communicates with a proximal in/out port (not shown), which is connectable to a suction or liquid source. One or more delivery ports  98  are disposed along the length L of the hollow reinforcing member  90 . The delivery ports communicate with a flow chamber system  94  disposed within the tool head  60 . The flow chamber system  94  further communicates with one or more outer surface ports  96  in the outer surface of the tool head  60 . In this embodiment, a lavage liquid can be delivered to or removed from the work site.  
         [0030]     While the above description contains many specifics, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of one or another preferred embodiment thereof. Many other variations are possible, which would be obvious to one skilled in the art. Accordingly, the scope of the invention should be determined by the scope of the appended claims and their equivalents, and not just by the embodiments.