Abstract:
A driver for medical wires has a hollow drive shaft, rotatable about a rotation axis. The hollow drive shaft has a distal end and a proximal end. Furthermore, a plurality of clamping jaws penetrates under an angle into the hollow drive shaft close to its distal end. The clamping jaws are moved into or out of the hollow drive shaft by means of a jaw guide mounted slidable parallel to the rotation axis and movably connected to the clamping jaws. An actuator is provided to shift the jaw guide parallel to the rotation axis and therefore modify the penetration depth of the clamping jaws.

Description:
BACKGROUND 
       [0001]    The invention relates to a surgical wire driver adapted to insert a circular prosthetic device into or through bones to provide support and fixation to bone structures and fractured bones, and particularly to a rotary wire-inserting device utilizing a surgical wire. 
         [0002]    In the prior art, prosthetic wire drivers are known, driving the wire and letting the wire bore its own hole into the bone. Such an instrument is disclosed in U.S. Pat. No. 4,091,880. It has a split spring collet, holding a specifically adapted wire of a substantially circular cross-section, having one or more flats to provide anti-rotational keying with the collet. The disadvantage of the prior art is the requirement for special wires and the complex adjustment and setting of the collet, which requires an Allen wrench. 
         [0003]    A surgical chuck which allows comparatively quick fastening and releasing is disclosed in DE 199 45 322 B4. Here, clamping jaws, which are preloaded by a spring, are used. The drawback is the complex configuration, missing a control on locking/release actions. Furthermore, a significant access length of the wire is required to penetrate into the chuck and interact with the clamping jaws. 
         [0004]    A surgical hand piece is disclosed in EP 2 238 920 A1, which is included herein by reference. 
       SUMMARY 
       [0005]    The embodiments of the present invention are directed to improve surgical wire drivers by providing a simplified mechanical design, which can handle wires having a minimal excess length for holding the wire, and which can be operated easily. 
         [0006]    In an embodiment, the wire driver has an at least partially hollow drive shaft, which may be driven by a motor or coupled to a hand piece by a shaft connector and may rotate around a rotation axis. It has a proximal and a distal end. The distal end of the drive shaft is hollow and has a diameter sufficiently large to hold a surgical wire. The proximal end of the drive shaft preferably is open to allow penetration of long surgical wires, but it may also be closed. Close to the distal end of the drive shaft, there is a plurality of clamping jaws. Preferably, there are three clamping jaws, which can be moved to penetrate into the inner volume of the hollow drive shaft. It is preferred, if all clamping jaws are moved with the same distance at the same time. The clamping jaws define an opening sufficiently large to guide and hold the wire. Preferably, the jaws are preloaded by a spring, pressing the jaws towards the distal end, resulting in pressing the jaws together or to the wire and therefore holding the wire. The clamping jaws are operated by a jaw guide which is mounted slidable parallel to the rotation axis. The jaw guide is movably connected to the clamping jaws to move the clamping jaws in or out of the hollow drive shaft. For moving the jaw guide, an actuator may be provided. This actuator preferably generates a linear motion of the jaw guide parallel to the rotation axis. It is further preferred, if the actuator is a lever, which preferably is tiltable about a lever axis. 
         [0007]    According to a further aspect, an actuator spring is provided to preload the actuator and therefore to preload the clamping jaws via the jaw guide. Furthermore, a slider may be operated by the actuator. The slider may be mounted slidable parallel to the rotation axis, holding a drive shaft bearing which is in contact with the jaw guide. It is further preferred, if a jaw guide spring is provided to hold the jaw guide against the drive shaft bearing. 
         [0008]    It is further preferred, if the clamping jaws have at least one pin contact surface which contacts the surgical wire preferably causes friction to the wire. For moving the clamping jaws, it is preferred, if the clamping jaws have a guiding cutout, which may interact with at least one cam provided at the jaw guide. 
         [0009]    To improve connection to a medical handpiece, it is preferred, if a flange is provided at the proximal end of the driver. Furthermore an input shaft may be provided, which is rotatably coupled with the drive shaft, to be driven by a medical handpiece. 
         [0010]    Examples of medical wires or pins are Kirschner wires or K-wires, which may be sharpened, smooth stainless steel pins. 
         [0011]    It is further preferred, if there is a housing having openings and/or gaps to provide for a quick gas and/or liquid exchange to simplify sterilization. 
         [0012]    Another embodiment is a method for driving of a medical wire includes the steps of:
       inserting the medical wire into a hollow drive shaft ( 22 ), rotatable about a rotation axis ( 13 ), the hollow drive shaft has a distal end and a proximal end,   clamping the medical wire by a plurality of clamping jaws ( 30 ,  31 ,  32 ) which are moved to penetrate under an angle into the hollow drive shaft close to its distal end,   moving the clamping jaws ( 30 ,  31 ,  32 ) into or out of the hollow drive shaft by a jaw guide ( 33 ) mounted slidable parallel to the rotation ax-is ( 13 ) and movably connected to the clamping jaws to increase friction between the medical wire and the clamping jaws.       
 
         [0016]    The method may be combined with any other embodiment disclosed herein. 
         [0017]    Another embodiment relates to a method for fixing of bones or parts thereof by driving a medical wire or pin by using a driver for medical wires as disclosed herein or by using a method for driving of a medical wire as disclosed herein. 
         [0018]    A further embodiment relates to a medical handpiece having a driver for medical wires according to any one of the previous claims. 
         [0019]    As the clamping jaws are arranged close to the distal end of the drive shaft and therefore close to the distal end of the pin driver, there is only a minimal excess length of the medical wire necessary for holding the wire. Due to the simple operation by shifting or moving the actuator or lever, a medical wire may quickly be held or released. There may also be a quick sequence of holding and releasing operations by simply pushing and pulling the actuator or lever. The driver must not be adapted to specific wire diameters. Instead, a simple locking action is sufficient. When looking or clamping the wire, the clamping jaws penetrate into the hollow channel of the drive shaft until the pin contact surfaces of the clamping jaws contact the wire and lock it. Then no further movement of the clamping jaws is possible. 
         [0020]    Due to the simple design with a low number of simple mechanical components together with gaps and openings for liquid and/or gas exchange, the driver for medical wires can be easily sterilized. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    In the following, embodiments of the invention are described in reference to examples, drawings, and without limitation of the general inventive concept. 
           [0022]      FIG. 1  shows a pin driver according to an embodiment in an open state. 
           [0023]      FIG. 2  shows a pin driver in a closed state. 
           [0024]      FIG. 3  shows a wire driver with inserted wire. 
           [0025]      FIG. 4  shows a sectional side view of the whole pin driver including the lever. 
           [0026]      FIG. 5  shows a sectional front view of the whole pin driver including the lever. 
       
    
    
       [0027]    While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
       DETAILED DESCRIPTION 
       [0028]    In  FIG. 1 , a preferred embodiment of a pin driver is shown. This pin driver is an attachment, which for example may be attached to a hand piece as disclosed in EP 2 238 920 A1. It is understood that the pin driver may also be part of a hand piece, and may therefore be integrated or enclosed into such a hand piece. The pin driver has a housing  10 , having a distal side (shown at the left side of the figure) and a proximal side (shown at the right side of the figure). This housing contains the mechanical components. This specific embodiment of a pin driver has a flange  11  for attachment to a hand piece. The flange  11  may have a conical shape and it may have at least one attachment ball  12 . There is an input shaft  20  which is rotatable around a rotation axis  13 , and which is driven by a hand piece or a motor. The input shaft  20  may be connected to a hand piece by shaft connector  21  for transmitting torque. For holding a wire, a drive shaft  22  is provided. This drive shaft  22  may be at least rotatably fixed to the input shaft, or it may be a part thereof. The drive shaft  22  has a hollow channel  25  for accommodating a wire. The drive shaft  22  has an open end at the distal side and may be either open or closed towards the proximal side. There may be a drive shaft bearing  24  for supporting the drive shaft  22 . Furthermore, there may be an input shaft bearing  23  for supporting the input shaft  20 . For holding a wire, clamping jaws  30 ,  31 ,  32  are provided. Preferably, there are three clamping jaws having an angular displacement of 120° to each neighbored jaw. Alternate embodiments may include a different number of clamping jaws, like a single jaw, two jaws, or a higher number of jaws. The clamping jaws are at an angle of less then 90°, preferably less than 40°, most preferably between 20° and 30° with respect to the rotation axis. A jaw guide  33  is provided for pulling the jaws back into proximal direction or pushing the jaws forward into distal direction, therefore enlarging or decreasing the opening between the jaws. The jaw guide preferably has a ring-shaped structure, and at least one cam to interact with a jaw. The jaw guide is moved into proximal or distal direction parallel to the rotating axis. Preferably, it rotates together with the jaws, which are rotatably fixed in channels of the drive shaft. For actuating the rotating jaw guide  33 , preferably a non-rotating slider  35  is provided. This slider is coupled to the jaw guide  33  by means of the drive shaft bearing  24 . For preloading this bearing and holding the jaw guide  33  to this bearing, a jaw guide spring  34  may be provided. The slider  35 , which is non-rotatable, but slidable into proximal and distal direction, preferably is operated by a Ilever  40 , which preferably is tilted around a lever axis  41  into two directions  42 . There may be an actuator spring  36  to preload the slider  35  and/or the lever  40 . 
         [0029]    The operation of the pin driver is as follows: in an idle state, the lever  40  is released, as shown in  FIG. 2 . It is held in this state by the actuator spring  36 , which furthermore presses slider  35 , drive shaft bearing  24 , and jaw guide  33  into distal direction, causing the jaws also to move into distal direction and to close the opening. When a wire is inserted into the pin driver from the distal side, it will first be pushed against the clamping jaws&#39; distal side. Due to the low angle of the clamping jaws with respect to the rotating axis, the clamping jaws can be pushed backwards into proximal direction against the force of the actuator spring  36 . By this movement, the clamping jaws increase their opening until the wire may slide through the opening into the hollow channel  25  of drive shaft  22 . Now, the pin contact surfaces  39  of the clamping jaws  30 ,  31 ,  32  are in close contact with the surface of the wire and press on the wire, therefore allowing to transfer torque from the drive shaft, and therefore to rotate the pin. For releasing the pin, the lever  40  may be pushed into a distal direction, therefore releasing force asserted by actuator spring  36  to the clamping jaws and moving the clamping jaws into proximal direction, causing the opening between the clamping jaws to increase and release the wire. It is preferred to manually open the opening before inserting a wire by actuating the lever. Opening the jaws is also necessary, if a wire will be inserted from the proximal side of the pin driver. 
         [0030]    Generally, the lever is held in proximal direction by the actuator spring  36 , closing the clamping jaws. The lever may be moved into distal direction for opening the clamping jaws. It may further be held in proximal direction to increase the clamping force of the clamping jaws. 
         [0031]    In  FIG. 2 , a pin driver in a closed state of the clamping jaws is shown. Here, the lever  40  is pressed in proximal direction by the actuator spring  36 , while it has manually been held in distal direction by the operator, as shown in  FIG. 1 . Compared to  FIG. 1 , here, the slider  35  together with the drive shaft bearing  24  and the jaw guide  33  are displaced in distal direction, pushing the clamping jaws in distal direction, and therefore closing the opening between the clamping jaws. A further detail of the clamping jaws is shown in this figure. To push the clamping jaws into distal direction and to pull them into proximal direction, a guiding cutout  37  is provided. This cutout interfaces with at least one cam for each clamping jaw. The cams are part of the jaw guide  33 . 
         [0032]    In  FIG. 3 , a pin driver with an inserted wire  50  is shown. The wire is centered at the rotation axis  13 . For holding the wire, the clamping jaws and the other movable parts are in an intermediate position adapted to the diameter of the wire. 
         [0033]    In  FIG. 4 , a sectional side view of the pin driver including the lever  40  is shown. 
         [0034]    In  FIG. 5 , a sectional front view of the pin driver including the lever  40  is shown. 
         [0035]    It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide a driver for medical wires. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           10  housing 
           11  flange 
           12  attachment bolt 
           13  rotation axis 
           20  input shaft 
           21  shaft connector 
           22  drive shaft 
           23  input shaft bearing 
           24  drive shaft bearing 
           25  hollow channel 
           30 ,  31 ,  32  clamping jaws 
           33  jaw guide 
           34  jaw guide spring 
           35  slider 
           36  actuator spring 
           37  guiding cutout 
           38  jaw proximal end 
           39  pin contact surface 
           40  lever 
           41  lever axis 
           42  lever tilt 
           50  wire