Patent Publication Number: US-2009222018-A1

Title: Instrument for Introducing Solid Fillers into the Interior of a Bone

Description:
The present invention relates to an instrument for the delivery of solid fillers into a inner space of a bone in accordance with the preamble of claim  1 . 
     Document WO2005/094735, whose disclosure is herewith included herein by reference, describes a filler, a delivery device as well as a method for the formation of a support structure in an inner space of a bone. In this respect, a plurality of support bodies are introduced into an inner space of a bone, in particular into a vertebral body. 
     Reference US 2005/0228397 discloses an instrument for the delivery of bone cement, in particular liquid bone cement, into the inner space of a vertebra. This instrument has the disadvantage that it is not suitable for the delivery of solid fillers. The instrument is moreover difficult to operate so that it is difficult for a surgeon to fill an inner space of a bone reliably and reproducibly. 
     It is the object of the present invention to propose an instrument for the delivery of solid fillers into an inner space of a bone, said instrument permitting a particularly simple, secure and reliable delivery. 
     This object is satisfied by an instrument having the features of claim  1 . Dependent claims  2  to  15  relate to further, advantageously designed instruments. 
     The object is in particular satisfied using an instrument including a cannula as well as a handle connected thereto, with a reservoir being mounted displaceably in the handle and with the reservoir having a plurality of chambers for the reception of solid fillers, with the chambers being arranged in the reservoir such that the chambers can be sequentially positioned in a dispensing position with respect to the cannula by displacement of the reservoir so that the fillers can be delivered to the chamber of the cannula respectively located in the dispensing position. 
     The instrument in accordance with the invention has the advantages that it is very simple to operate, that the instrument can be connected very easily to the inner space of the bone and that the fillers can be delivered very simply and reliably to the inner space of the bone. In addition, a surgeon can himself determine in a simple manner how many fillers are delivered to the inner space of the bone since the instrument includes a reservoir loaded with fillers and the fillers are arranged in groups of, for example, 2, 3, 5 or 10 pieces in a chamber of the reservoir so that in each case such a group of fillers arranged sequentially can be supplied to the inner space of the bone. After the delivery of such a group of fillers, a decision can be made whether a further group should be delivered, with the procedure of the delivery of groups of fillers being able to be repeated until the vertebral body has been sufficiently filled with fillers. 
     The instrument in accordance with the invention in particular allows a particularly simple access to the spinal column in that a short, and above all slim and rigid cannula is used which is set at the vertebral body. The handle of the instrument is usually fixedly connected to the cannula so that the cannula can be aligned and placed at the vertebral body to be treated by a corresponding holding of the handle. This permits a simple and secure operation of the instrument. This cannula, which is usually provided with a trocar during the first introduction, has the great advantage that, on the introduction through the sensitive back musculature, it is precisely these muscles which are spared to a maximum. The patient thereby becomes mobile faster again after the operation. He is also spared pronounced scar formation in the region of the back muscles. 
     The instrument has a rigid cannula which is preferably fixedly connected to the handle. In a preferred embodiment, the handle is made such that it can be held by the left hand. In a preferred embodiment, the instrument has a push button with which the reservoir can be moved to position fillers in a dispensing position. In a preferred embodiment, this push button can be acquitted using the thumb of the left hand. A plunger is preferably held in the right hand. This plunger is introduced into the handle, with the fillers present in the dispensing position simultaneously being expelled from the reservoir or from the reservoir chamber by the plunger tip and the fillers thereafter being expelled into the inner space of the bone via the cannula. The manual operation of the plunger has the advantage that the expulsion force to be applied on the introduction of the fillers into the inner space of the bone is felt by surgeons so that, for example, too large an expulsion force which could damage the bone can be avoided. The manual operation of the plunger additionally has the advantage that the fillers present in the inner space of the bone can be positioned, for example when an image producing process, for example an X-ray machine, is used during the introduction of the fillers. 
     The reservoir can be made in very varied manners, for example also in the form of a bar-shaped reservoir extending in the longitudinal direction or of a circular reservoir made as a drum. 
     The instrument is preferably supplied together with a trocar which in particular serves for the opening of the inner space of the bone. The instrument is preferably supplied with a trocar extending through the cannula and fastened to the handle, with the reservoir additionally already being filled with fillers so that the essential components are supplied as a single unit. 
     The instrument in accordance with the invention makes it possible for a surgeon to carry out all the major process steps using two hands without any additional help so that the instrument can be operated very easily, securely and reliably. 
     The instrument in accordance with the invention is in particular suitable for the filling of vertebral bodies. The instrument in accordance with the invention, however, allows any inner spaces of bones to be provided with fillers, for example also bones damaged or weakened in the most varied manner, for example due to trauma, infection, wear, tumor growth or degenerative diseases such as osteoporosis. In older people, in particular osteoporosis, that is the degradation of the spongiosa, represents a problem because the load capability of the bone is thereby weakened, which has the result that bone fractures occur more frequently, above all at the spinal column, at the femoral neck and at the wrist. The instrument in accordance with the invention makes it possible to introduce fillers into such bones, with the introduction, if necessary, moreover enabling a disimpacting of a bone, for example of a collapsed vertebral body. 
    
    
     
       The invention will be described in detail in the following with reference to Figures, with the same reference numbers designating the same objects. There are shown: 
         FIG. 1  a perspective view of the instrument for the delivery of solid fillers into an inner space of a bone; 
         FIG. 2  a perspective view of the instrument from below; 
         FIG. 3  a side view of the instrument; 
         FIG. 4  a view of the end face of the instrument; 
         FIG. 5  an inner view of the lower half of the handle part of the instrument in accordance with  FIG. 1 ; 
         FIG. 6  a detailed view of the left hand end section of the upper half of the handle part; 
         FIG. 7  a plan view of a reservoir; 
         FIG. 8  a side view of the reservoir in accordance with  FIG. 7 ; 
         FIG. 9   a  a plan view of a filler; 
         FIG. 9   a  a side view of a plurality of stacked fillers; 
         FIGS. 10 ,  11  views of a trocar; 
         FIG. 12  a plunger; 
         FIG. 13  an instrument during the connection to a bone; 
         FIG. 14  a section through a vertebra during the introduction of the fillers; 
         FIGS. 15   a - 15   e  a plurality of differently made plunger tips; 
         FIG. 16  the instrument in combination with an actively driven plunger; 
         FIG. 17  a perspective view of a further embodiment of an instrument with a rotatable reservoir; 
         FIG. 18  a perspective view of a rotatable reservoir; 
         FIG. 19  a perspective view of a further embodiment of an instrument with a rotatable reservoir. 
     
    
    
       FIGS. 1 to 4  show the same instrument  1  for the delivery of solid fillers into an inner space of a bone from different directions of view. The instrument  1  includes a handle  4  as well as a rigid cannula  3  which are fixedly connected to one another. The handle  4  includes an upper housing half  4   a  as well as a lower housing half  4   b  which are likewise fixedly connected to one another. The handle  4  moreover includes a holder  4   d  for the cannula  3  as well as an access opening  4   c  which is surrounded by a projecting sleeve  41 . As can be seen from the side view in accordance with  FIG. 3 , the access opening  4   c  is arranged in a straight-line extension with respect to the cannula  3  so that the shaft  8   a ,  7   a  of a trocar  8  or of a plunger  7  can be introduced into the access opening  4   c  and can be introduced via the cannula  3  up to the cannula tip  3   a  and, if necessary, also beyond it. The cannula  3  is made rigid or stiff and is preferably made of a metal or of a firm plastic. 
     In the embodiment shown, a reservoir  5  is mounted in the interior of the handle  4 , displaceable in the direction of movement B and extending in its longitudinal direction. The handle  4  additionally includes a feed part  6  with a push button  6   a  by whose actuation the reservoir  5  is displaceable by a defined path in the direction of movement B. 
     The instrument  1  shown is optimized for the left hand in that the handle  4  can be surrounded by the left hand such that the push button  6   a  can be actuated in the direction of displacement B. Thus, both the handle  4  can be held and the position of the reservoir  5  can be changed. Since the cannula  3  is fixedly connected to the handle  4 , the tip of the cannula  3  can contact the vertebral body by a corresponding holding of the handle  4 . 
       FIG. 5  shows an inner view of the lower half  4   b  of the handle  4 . The lower handle half  4   b  has lateral guides  4   f  which extend in the direction of extent B and between which a reservoir  5  is displaceably mounted in the direction B. The reservoir  5  includes a plurality of chambers  5   a ,  5   b  arranged spaced apart in the direction B. One of the chambers, designated by  5   b , is located directly above the cannula  3 . This position of a chamber is designated as the dispensing position A since the chamber  5   b  is located directly above the cannula  3 . The instrument  1  moreover includes a feed part  6  which, in the embodiment shown, includes a push button  6   a , a spring  6   b  and an engagement nose  6   c  as well as a restoration spring  6   d.    
       FIG. 8  shows a side view of the reservoir  5  with a plurality of grooves  5   d  spaced apart in the longitudinal direction B. These grooves  5   d  are aligned toward the engagement nose  6   c  in the arrangement shown in  FIG. 5  so that, when the push button  6   a  is actuated, its engagement nose  6   c  engages into the groove  5   b , with the push button  6   a  simultaneously being moved in the direction B so that the reservoir  5  is displaced in the direction B by a path defined such that the chamber  5   a  most closely following the chamber  5   b  moves into the dispensing position A. 
       FIG. 7  shows a plan view of the reservoir  5  with a plurality of chambers  5   a  arranged spaced apart in the direction of extent as well as with a projecting protrusion  5   c.    
       FIG. 6  shows a detailed view of the upper half  4   a  of the handle  4 . The lateral guide  4   f  shown at the bottom has grooves  4   h  which are spaced apart at regular intervals and into which the protrusion  5   c  of the reservoir  5  engages so that the reservoir  5  has latch positions defined with respect to the handle  4  in the direction of displacement B. These latch positions are selected such that a chamber  5   a  always comes to lie in the dispensing position A in which the fillers  2  present in the chamber  5   a  can be delivered to the cannula  3 . 
       FIG. 9   a  shows a filler  2  in a plan view. In the embodiment shown, the filler is made as a hexagonal body with a cylindrical inner space. The filler could also have different outer contours.  FIG. 9   b  shows four fillers  2  stacked over one another. In the representation in accordance with  FIG. 5 , as a rule at least some of the chambers  5   a , and preferably all of the chambers  5   a , are filled with the fillers  2  shown in  FIGS. 7   a  and  7   b  so that the fillers  2  are arranged in each case sequentially in the direction of extent of each chamber  5   a  or next to one another. The fillers  2  are preferably arranged identically at opposite sides. 
     The fillers  2  located in the dispensing position in the chamber  5   a  can be expelled downwardly in the direction of extent of the chamber  5   b  into the cannula  3  located below it, for example via a plunger  7  acting perpendicular to the plane of observation. All the fillers  2  present in this chamber are thereby supplied group-wise to the cannula  3  and are pushed into the vertebral body  9 . 
     The reservoir  5  shown in the  FIGS. 7 and 8  preferably has between 4 and 20 chambers  5   a  spaced apart in the longitudinal direction. Depending on the height of the fillers  2  used, between 1 and 20 individual fillers  2 , as shown in  FIG. 9   a , can be arranged in each chamber  5   a . In a preferred embodiment, the inner cross-section of the chamber  5   a  is made in accordance with the outer contour of the fillers  2 . In the embodiment shown, the outer contour of the filler  2  is hexagonal and the inner contour of the chamber  5   a  is likewise correspondingly hexagonal. All the chambers  5   a  are preferably filled with fillers  2  of the same size. It is, however, also possible to fill the chambers  5   a  with fillers  2  of different size, that is with a different diameter, a different outer contour and/or also a different height. It can prove to be advantageous for this purpose also to match the inner cross-section of the chamber  5   a  in accordance with the respective outer contour of the filler  2 . The fillers  2  can be made in a plurality of possible outer contours, for example, also circular, elliptical, square, rectangular, etc. 
       FIG. 10  shows a front view and  FIG. 11  shows a side view of a trocar  8  which includes a shaft  8   a  having a sharp, triangular tip and an actuation handle  8   b . The trocar  8  moreover includes a fastening means  8   c  with the help of which the trocar  8  can be fastened via the cut-out  4   e  to the handle  4 . 
       FIG. 12  shows a plunger  7  comprising a handle  7   b  as well as a shaft  7   a  having a plunger end  7   c.    
     The total instrument  1  is preferably supplied in the arrangement shown in  FIG. 13  in that the trocar  8  is fastened to the handle  4  with the help of the fastening means  8   c  and in that the shaft  8   a  extends through the access opening  4   c , through the cylindrical chamber  5   a  and through the cannula  3  so that the tip of the shaft  8   a  projects out of the cannula tip  3   a  at the front. This arrangement has the additional advantage that the reservoir  5  cannot move in the direction of movement B due to the shaft  8   a  extending through the chamber  5   b  and is thus blocked and held in a defined position. Only after the complete removal of the trocar  8  from the instrument  1  can the reservoir  5  be displaced with respect to the handle  4 . 
     As shown in  FIG. 13 , the instrument  1  can now, for example, be introduced into the human body such that the tip of the trocar  8  is introduced first. In the example shown, the trocar  8  is introduced into a vertebral body  9  only shown schematically. The cannula tip  3   a  is then placed onto the vertebral body  9  and the cannula  3  is screwed into the vertebral body  9  by turning in the direction of rotation C at the handle  4 . The handle  4  is preferably made such that the handle  4  can also be actuated with the right hand or with both hands during this screw movement. As soon as the cannula  3  is arranged sufficiently deeply in the vertebral body  9 , the trocar  8  is released from the handle  4  and is completely removed from the instrument  1 . The reservoir  5  is thus unblocked and thereby displaceable in the handle  4 . The handle  4  can now advantageously be held by the left hand. The first chamber  5   a  arranged subsequent to the chamber  5   b  is pushed into the dispensing position A by an actuation of the push button  6   a . Thereupon, the plunger  7  is introduced by the right hand via the access opening  4   c  into the handle  4  and the fillers  2  present in the chamber  5   a  are pushed into the cannula  3  by the plunger  7 .  FIG. 3  schematically shows the chamber  5   a  present in the dispensing position A with fillers  2  which are pushed in the direction of the cannula  3  by the plunger  7 . 
       FIG. 14  schematically shows a section through a vertebral body  9  in whose inner space  9   a  the fillers  2  are pushed in that the plunger  7  exerts a force F onto the fillers  2  present in the cannula  3  via the plunger end  7   c . The number of the fillers  2  delivered simultaneously sequentially can be determined in that either in each case all the fillers  2  present in a chamber  5   a  are pushed into the vertebral body  9  or, after the first emptying of a chamber  5   a , the plunger  7  is retracted, the push button  6   a  is actuated and the content of the subsequent chamber  5   a  is likewise pushed into the cannula  3  by the plunger  7 . This procedure can, if desired, be repeated a plurality of times, in order, for example, to displace  2 ,  3 ,  5  or  10  contents of the chambers  5   a  into the cannula  3  first before all the fillers  2  sequentially arranged in the cannula  3  in this manner are pressed into the vertebral body  9  with the help of the plunger  7 . 
     It can be found to be advantageous to provide a plurality of plungers  7  with, as shown in  FIGS. 15   a  to  15   e , differently made tips  7   c . After the fillers  2  have been introduced in the vertebral body  9 , their position can still partly be influenced in that a plunger  7  with a correspondingly shaped tip  7   c  is used in order, for example, to laterally displace the fillers  2  with the tip  7   c  shown in  FIG. 15   b . The position of the fillers  2  in the vertebral body  9  is preferably made visible with the help of an X-ray machine. 
       FIG. 16  schematically shows a further embodiment of a plunger  7  with whose help fillers  2  are supplied via an instrument  1  with a cannula  3  to a vertebral body  9 . The plunger  7  shown includes a handle  7   b , an active drive  7   d , a sensor  7   e , a regulation device  7   f  and a shaft  7   a . The drive is, for example, made as an electrical motor drive or as a compressed air drive and preferably also enables a vibration movement in order, for example, to embed fillers  2  present in the vertebral body  9  in a compacted form. The regulation device  7   f  allows force or distance to be measured, for example with the sensor  7   e , and the maximum thrust force or the maximum stroke of the vibration movement to be limited. 
     The cannula  3  can also have a curved extent, in particular if no screw movement is required for the fastening to the bone. The cannula  3  is preferably made of metal, but can also be made of a plastic. The plunger  7  can be made of metal or also of a plastic, in particular also of a resilient plastic. 
     The reservoir  5  can be made in different manners, for example also as a drum with chambers  5   a  arranged spaced apart in circular form in the peripheral direction respect to an axis of rotation, with the reservoir being mounted rotatably in the handle  4 . 
     The fillers  2  can have a plurality of possible shapes such that the fillers  2  can be stored in the reservoir  5 . The fillers  2  could, for example, also be spherical. 
       FIG. 17  shows an instrument  1  having a cannula  3 , a handle  4  and a drum-shaped reservoir  5  which is rotatably mounted on the handle  4  in the indicated direction of rotation and has a chamber located in the dispensing position  5   b  and a plurality of further chambers  5   a  arranged spaced apart in the peripheral direction for the reception of fillers  2 . The reservoir  5  has grooves at the cylindrical outer peripheral surface via which grooves the position of the reservoir  5  can be rotated manually. The instrument  1  preferably has a latch device so that the chambers  5   a  are respectively located in the dispensing position  5   b  after a rotation. 
       FIG. 18  shows a plan view of the reservoir  5  shown in  FIG. 17 . The reservoir is rotatably mounted around an axis of rotation  5   e.    
       FIG. 19  shows a further embodiment of an instrument  1 . Unlike the embodiment shown in  FIG. 18 , this instrument  1  has a push button  6   a , with the push button  6   a  and the reservoir  5  being made such that, when the push button  6   a  is actuated, the reservoir  5  is rotated in each case around a position in the direction drawn so that sequential chambers  5   a  are conveyed into the dispensing position  5   b  so that the fillers  2  present in the chamber  5   a  can be delivered to the cannula  3  using the plunger  7 . 
     The instrument  1  is preferably made as a disposable instrument. It can, however, also prove to be advantageous to use the instrument  1  a plurality of times and only to replace the reservoir  5  with a new reservoir  5  filled with fillers  2  after the use of the instrument  1 . 
     It can prove to be advantageous to heat the fillers  2  before the introduction into the vertebral body, for example to a temperature between 50 and 70 degrees C., or up to 100 degrees C. This can be achieved, for example, in that the reservoir  5  filled with fillers  2  is heated before the reservoir  5  is introduced into the instrument  1 . It can also prove to be advantageous to provide the instrument  1  with a heating, for example with an electrical heating, to heat the fillers  2  present in the instrument  1 . It can moreover prove to be advantageous to heat the cannula  3 .