Abstract:
A cannulated injection system having or more hollow bodies to receive material to be injected, a piston in each said hollow body to force material from said body through a nozzle having a passageway sized and selected to accommodate flow of the material therethrough and with the passageway arranged to accommodate a guide wire passed therethrough, the guide wire further being passed through support structure including a piston and hollow body in which said piston reciprocates or a support structure for a plurality of hollow bodies in which pistons reciprocates during use in simultaneously injecting material from said hollow bodies through said injection tip and around a guide wire passing through the tip.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable.  
       REFERENCE TO MICROFICHE APPENDIX  
       [0003]     Not Applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     This invention relates to injection systems and more particularly, to a cannulated injection system for orthopedic applications which may be guided to its desired location by a previously placed guide wire.  
         [0006]     2. Description of the Prior Art  
         [0007]     Recently a number of healing enhancing products have come to market. These include calcium triphosphates, high hyaluronic acid products, platelet healing factors and others. These materials are used to enhance bone tunnel fixation of soft tissue ligament grafts as well as arthroscopically treating non-unions of long bones, bone cysts of the hip, knee and other related skeletal abnormalities. The sites at which the healing enhancing products must be placed are frequently difficult to access making the required accurate placement of the materials difficult. This is particularly true for endoscopic techniques. The injection system must be well suited to the site and material placement requirements of the procedure. Sites more remote from the access point require a device with an elongated delivery nozzle. Additionally, some applications require a large diameter nozzle for uniform material distribution while others require a smaller diameter nozzle for precise material placement.  
         [0008]     The use of guide wires in orthopedic surgery, particularly arthroscopy, is common. A guide wire (a long, rigid, small diameter, stainless steel member), or a small diameter flexible stainless steel cable is precisely positioned at the desired site and its position verified by direct visualization. The guide wire or cable is then inserted into the cannulation of a cannulated instrument and the instrument is precisely guided to the desired site by the wire or cable. Guide wires and cables are produced in a range of diameters and lengths to suit a variety of procedures.  
         [0009]     The viscosity of the materials to be injected also affects the choice of an injection device and the manner of use of such device. The materials may include liquified products, emulsified products or even slurries and, as such, may have quite high viscosities. Liquids are commonly drawn into a syringe through the needle. The distal end of the syringe is then directed upward and the piston advanced to expel air from the syringe. To load higher viscosity materials into a syringe the piston must be removed and the materials loaded into the body of the syringe through its proximal end. The material settles into the distal end of the syringe body. When the piston is inserted into the proximal end of the syringe body, air is trapped between the piston distal end and the material. Advancing the piston will cause material to be expelled from the device. With currently available devices, removing trapped air is problematic when materials are loaded through the proximal end of the syringe body.  
         [0010]     U.S. Pat. No. 6,395,007 discloses apparatus and method for the fixation of osteoporotic bone. The patent discloses an injection device including a delivery cannular, a liner acting as an injection material conduit, a plunger capable of passing through the liner to force injectable material through the liner while permitting air to escape past the plunger and a removable handle attachable to the delivery cannulae.  
         [0011]     Further, the patent discloses use of a guide wire passed through an aligning cannulae and having a tapered end that will breach cortical bone sufficient to form a channel through the cortical bone. An aligning cannulae passes over the guide wire and with the delivery cannulae passing over the aligning cannulae. The injectable materials disclosed include polymethylmetaery, bone cement, antibiotics, whole cellular implants, natural products of cells, recombinant nucleic products and protein products of recombinant cells.  
       SUMMARY OF THE INVENTION  
     Objects of the Invention  
       [0012]     It is an object of this invention to produce an injection system which may be guided to its desired position by a guide wire or cable.  
         [0013]     It is also an object of this invention to produce an injection system which may be guided to its desired position by a guide wire and which may accommodate guide wires or cables having a range of diameters.  
         [0014]     It is also an object of this invention to produce an injection system which may be guided to its desired position by a guide wire and which has a range of nozzle diameters and lengths suitable for a variety of applications.  
         [0015]     It is further an object of this invention to produce an injection system which may be guided to its desired position by a guide wire and which can be used with materials, including liquefied products, emulsified products and slurries.  
         [0016]     It is also an object of this invention to produce an injection system which may be guided to its desired position by a guide wire and from the body of which air can be expelled with the syringe distal end pointed downward.  
         [0017]     Additional objects and features of the invention will become apparent to persons skilled in the art to which the invention pertains from the following detailed description and claims.  
       Features of the Invention  
       [0018]     Principal features of the invention herein disclosed include a cannulated injection system comprising a cannulated syringe and demountable nozzle, which may be configured for a variety of applications. A cannulated syringe has a clear hollow cylindrical body, including a cannulated distal end with a mounting means to which a nozzle can be mounted and an open proximal end into which a piston assembly is inserted. The piston assembly has a proximal end and a distal end and comprises an outer member and an inner member, with the inner member concentrically and rotatably positioned within the outer member. The inner member may be rotated by a proximal end means so that passages in the inner member and outer member distal ends align to provide an aspiration path through the piston assembly. The piston inner member comprises a cannulation of sufficient size to allow passage of common guide wires of various sizes. A seal made from silicone, or a similar material, within the inner member cannulation, prevents leakage of material through the inner member cannulation during use. A seal prevents leakage through the clearance between the piston assembly and the hollow cylindrical body.  
         [0019]     During use a guide wire is placed to aid in positioning the syringe. The piston assembly is removed from the syringe and the desired material loaded into the hollow cylindrical body through its proximal opening. The piston inner member is rotated to an “aspirate” position. While blocking the distal end of the body to prevent loss of material, the piston assembly is inserted into the body and advanced until the piston assembly distal end contacts the upper surface of the material and all trapped air is aspirated. The piston inner member is rotated to a “ready” position. An appropriate nozzle is selected and mounted to the syringe. The syringe, with the nozzle thereon, is positioned and advanced such that the guide wire passes through the cannulation of the nozzle; through the cannulation of the inner member; through the seal, which elastically deforms to accept the guide wire diameter; and exits the piston proximal end. The syringe is advanced along the guide wire until properly positioned at a desired site. The piston is advanced in the syringe so as to deposit the desired amount of material at the site.  
         [0020]     In an alternate embodiment for use with low-viscosity materials only, the piston assembly does not contain a means for aspirating trapped air therethrough since trapped air can be expelled by pointing the nozzle upward and advancing the piston into the body. The cannulated piston assembly does, however, contain a sealing means for preventing material loss around the guide wire and through the cannulation during use.  
         [0021]     Some injectable, healing enhancing products are supplied as two components which are mixed immediately prior to use, the ratio of the mix being specified by the manufacturer. In another embodiment for use with these low-viscosity, two-component systems, the body of the syringe has to cylindrical barrels, the ratio of their cross-sectional areas being equal to the required mixing ratio of the components. The body of the syringe has a cannulation to allow passage of a guide wire therethrough and a sealing means to prevent material loss through the cannulation during use. The piston assembly has two pistons corresponding in size to the cylindrical barrels, the pistons being connected to a common flange at their proximal ends so that their axial movements are simultaneous.  
         [0022]     The more important features of the invention have been outlined rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]     In the Drawings  
         [0024]      FIG. 1  is a front elevation view of a cannulated injection system of the invention;  
         [0025]      FIG. 2 , a side elevational view of the system of  FIG. 1 ;  
         [0026]      FIG. 3 , a proximal end view of the system of  FIG. 1 ;  
         [0027]      FIG. 4 , a perspective view of the system of  FIG. 1 ;  
         [0028]      FIG. 5 , is a front elevational view of the syringe body of the invention;  
         [0029]      FIG. 6 , a side elevational view of the syringe body of  FIG. 5 ;  
         [0030]      FIG. 7 , a proximal end view of the syringe of  FIG. 5 ;  
         [0031]      FIG. 8 , a distal end view of the syringe body of  FIG. 5 ;  
         [0032]      FIG. 9 , a perspective view of the syringe body of  FIG. 5 ;  
         [0033]      FIG. 10 , is a front elevational view of the syringe piston outer member;  
         [0034]      FIG. 11 , a side elevational view of the outer member of  FIG. 10 ;  
         [0035]      FIG. 12 , a proximal end view of the outer member of  FIG. 10 ;  
         [0036]      FIG. 13 , a distal end view of the outer member of  FIG. 10 ;  
         [0037]      FIG. 14 , a perspective view of the outer member of  FIG. 10 ;  
         [0038]      FIG. 15 , is a front elevational view of the piston inner member of the invention;  
         [0039]      FIG. 16 , a side elevational view of the inner member of  FIG. 15 ;  
         [0040]      FIG. 17 , a proximal end view of the inner member of  FIG. 15 ;  
         [0041]      FIG. 18 , a distal end view of the inner member of  FIG. 15 ;  
         [0042]      FIG. 19 , a perspective view of the inner member of  FIG. 15 ;  
         [0043]      FIG. 20 , is a plan view of the piston assembly rotatable cap;  
         [0044]      FIG. 21 , a front elevational view of the rotatable cap of  FIG. 20 ;  
         [0045]      FIG. 22 , a side elevational view of the rotatable cap of  FIG. 20 ;  
         [0046]      FIG. 23 , a bottom view of the rotatable cap of  FIG. 20 ;  
         [0047]      FIG. 24 , a perspective view of the rotatable cap of  FIG. 20 ;  
         [0048]      FIG. 25 , is a plan view of the inner member retainer of the invention;  
         [0049]      FIG. 26 , a side elevational view of the retainer of  FIG. 25 ;  
         [0050]      FIG. 27 , a perspective view of the retainer of  FIG. 25 ;  
         [0051]      FIG. 28 , is a distal end view of the inner member seal retainer of the invention;  
         [0052]      FIG. 29 , a side elevational view of the seal retainer of  FIG. 28 ;  
         [0053]      FIG. 30 , a perspective view of the seal retainer of  FIG. 28 ;  
         [0054]      FIG. 31 , is a plan view of the inner member seal of the invention;  
         [0055]      FIG. 32 , a side elevational view of the seal of  FIG. 31 ;  
         [0056]      FIG. 33 , a perspective view of the seal of  FIG. 31 ;  
         [0057]      FIG. 34 , is a front elevational view of the piston assembly with the inner assembly rotated to its “aspirate” position;  
         [0058]      FIG. 35 , a side elevational view of the piston assembly of  FIG. 34 ;  
         [0059]      FIG. 36 , a proximal end view of the piston assembly of  FIG. 34 ;  
         [0060]      FIG. 37 , a distal end view of the piston assembly of  FIG. 34 ;  
         [0061]      FIG. 38 , a perspective view of the piston assembly of  FIG. 34 ;  
         [0062]      FIG. 39 , an expanded view of the distal portion of  FIG. 34 ;  
         [0063]      FIG. 40 , an expanded perspective view of the distal portion of  FIG. 34 ;  
         [0064]      FIG. 41 , is a front elevational view of the piston assembly with the inner assembly rotated to its “use” position;  
         [0065]      FIG. 42 , a side elevation view of the distal portion of  FIG. 40 ;  
         [0066]      FIG. 43 , a proximal end view of the distal portion of  FIG. 40 ;  
         [0067]      FIG. 44 , a distal end view of the distal portion of  FIG. 40 ;  
         [0068]      FIG. 45 , a perspective view of the distal portion of  FIG. 40 ;  
         [0069]      FIG. 46 , an expanded view of the distal portion of  FIG. 40 ;  
         [0070]      FIG. 47  is a front elevational view of the nozzle;  
         [0071]      FIG. 48 , a side elevational view of the nozzle of  FIG. 47 ;  
         [0072]      FIG. 49 , a proximal end view of the nozzle of  FIG. 47 ;  
         [0073]      FIG. 50 , a distal end view of the nozzle of  FIG. 47 ;  
         [0074]      FIG. 51 , a perspective view of the nozzle of  FIG. 47 ;  
         [0075]      FIG. 52 , is a plan view of an alternate embodiment of a cannulated injection system of the invention;  
         [0076]      FIG. 53 , a front elevational view of the system of  FIG. 52 ;  
         [0077]      FIG. 54 , a perspective view of the system of  FIG. 52 ;  
         [0078]      FIG. 55 , an expanded front elevational view of the piston assembly of the system of  FIG. 52 , showing internal features;  
         [0079]      FIG. 56 , an expanded front elevational view of the body and nozzle of the object of  FIG. 52 , showing internal features;  
         [0080]      FIG. 57 , is a plan view of another alternate embodiment of cannulated injection system of the invention;  
         [0081]      FIG. 58 , a front elevational view of the system of  FIG. 56 ;  
         [0082]      FIG. 59 , a front perspective view of the system of  FIG. 56 ;  
         [0083]      FIG. 60 , a front elevational view of the body and nozzle of the system of  FIG. 57 , showing internal features;  
         [0084]      FIG. 61 , a plan view of the system of  FIG. 61 ; and  
         [0085]      FIG. 62 , an expanded perspective view of the piston assembly of the system of  FIG. 57 . 
     
    
     DETAILED DESCRIPTION  
       [0086]     Referring Now to the Drawings  
         [0087]     In the portion of the invention shown in  FIGS. 1 through 4 , cannulated injection system  1  has a proximal end  2  and a distal end  3  to which is mounted nozzle  4 . System  1  has a hollow body  5  and a piston assembly  6  in the body.  
         [0088]     Referring to  FIGS. 5-9 , body  5  of inner diameter  10 , outer diameter  11  and length  12  has a proximal end  13  and a distal end  14 . Proximal end  13  has a flange  15  of thickness  16  and, as viewed in  FIG. 7 , an approximately rectangular shape of width  17  and length  18 . Distal end  14  has a cannulation  19  of diameter  20 , grooves  21  of width  22  and shoulders  23 .  
         [0089]     Referring to  FIGS. 10-14 , piston outer member  30  has a proximal end  31  having a flange  32  of thickness  33  and approximate rectangular shape of width  34  and length  35 . Protruding from the most proximal surface  36  of flange  32  is cylindrical projection  37  of diameter  38  and height  52 , displaced a distance  39  from axis  40  of outer member  30  and at angle  41 . Distal end  42  has a cylindrical portion  54  of diameter  43  and length  44 . Positioned distance  45  from the most distal surface  46  is an O-ring groove  47  of width  48  and depth  49 . Centered with surface  46  is circular pocket  50  of diameter  51  and depth  53 . A cannulation  59  of diameter  55  extending coaxial with axis  40  and from the most proximal surface  36  to pocket  50 . Four equally spaced grooves  60  of width  56  and depth  57  extend distance  58  from a planar surface  59  of pocket  50 . Distal to and adjacent to flange  32 , cylindrical segment  62  of diameter  63  extends a distance  64 . Coaxial with cannulation  59  and extending from most distal surface  65  of cylindrical segment  62  to most proximate surface  66  of distal cylindrical portion  54 . Outer member mid-portion  67  has a circular cross-section radius  68 . Four ribs  69  each have a thickness  70  and length  71  that are twice the sum of radius  68 . Length  71  and diameter  43  are each slightly less than inner diameter  10  of body  5 .  
         [0090]     Referring to  FIGS. 15-19 , piston inner member  80  having a central cannulation  81  of diameter  82 , has a length  83 , a proximal end  84  and a distal end  85 . Distal end  85  has a distal flange  86  of thickness  87  and diameter  88  that is coaxial with cannulation  81 . Thickness  87  is equal to depth  53  of pocket  50  of piston outer member  30  ( FIGS. 10-13 ) and diameter  88  is slightly less than diameter  51  of pocket  50  of piston outer member  30  ( FIGS. 10-13 ). Four axial holes  89  of diameter  90  are equally spaced angularly in flange  86  a distance  91  from axis  92  of cannulation  81 . Coaxial with flange  86  and extending distance  93  therefrom is cylindrical segment  94  of diameter  95 . Diameter  95  is slightly less than the diameter  58  of grooves  60  of outer member  30  ( FIGS. 10-13 ). Coaxial with cannulation  81  and extending proximally from cylindrical segment  94  distance  96  cylindrical segment  97  of diameter  98  has four axially oriented pockets  191 , each having orthogonal planar faces  99  and radial surfaces  100  coaxial with cannulation  81  extending the length of segment  97  so as to form ribs  102  of thickness  101 . Diameter  98  is slightly less than diameter  55  of cannulation  59  of outer member  30 . Cylindrical pocket  110  of diameter  111  equal to twice the radius of radial faces  100  extends length  112  from distal end  84  so as to form four protruding ribs  116  of axial length  112 . Coaxial with pocket  110  is cylindrical pocket  113  of diameter  114  and length  115 , diameter  114  being less than diameter  111 . Distance  117  from proximal end  84  is circumferential groove  118  of width  119  and depth  120 . Cannulation  81  is flared at angle  109  at its distal end.  
         [0091]     Referring to  FIGS. 20-24 , rotational cap  120  of thickness  121  has a serrated upper surface  122  of width  123  and length  124  equal to width  34  and length  35  of flange  32  of outer member  30 . A circular recess  125  of diameter  126  and depth  127  is centered in upper surface  122 . Coaxial with recess  125 , passage  128  has a cross-section identical to the cross-section of segment  97  of inner member  80  except slightly larger. Radial passage  130  of width  131 , depth  132  and angular length  133  is centered distance  134  from the center of cap  120 , width  131  being slightly greater than diameter  38  of protrusion  37  and depth  132  being greater than length  52  of protrusion  37 , and distance  134  being equal to distance  39  of outer member  30 . Four holes  135  of diameter  136  are equally spaced on a circle of diameter  137  coaxial with recess  125 .  
         [0092]     Referring to  FIGS. 25-27 , retainer  140  is formed from resilient stainless steel sheet material of thickness  141 . Retainer  140  of diameter  142  has a perimetral planar region  143  and a central domed region  144  formed to a spherical radius  145 . Central in retainer  140 , opening  146  has a cross-section identical to that of opening  128  in rotational cap  120  except that distance  147  is less than diameter  98  of segment  97  of inner member  80 . Four holes  148  of diameter  149  are equally spaced on a circle of diameter  201 .  
         [0093]     Referring to  FIGS. 28-30 , seal retainer  150  has outer diameter  151 , length  152  and cannulation  153  of diameter  154  and is made of a rigid polymeric material.  
         [0094]     Referring to  FIGS. 31-33 , seal  160  of diameter  161  and thickness  162  is made from a compliant silicone material or similar. Centered in seal  160  is hole  163  of diameter  164 .  
         [0095]     Referring to  FIGS. 34-38 , piston assembly  6  has inner member  80  rotatably assembled within cannulation  59  of outer member  30  such that the distal surface of distal flange  86  is flush with distal-most surface  46  of outer member  30 . Proximal end  84  of inner member  80  protrudes through opening  128  of rotational cap  120 . Inner member  80  is retained within outer member  30  by retainer  140  which engages groove  118  of inner member  80 . Retainer  140  produces a tensile force in member  80  such that distal flange  86  is held tightly against proximal planar surface  59  of pocket  50  of outer member  80 . Seal  160  is retained between the shoulder formed by the intersection of cylindrical pocket  113  with the distal end of cylindrical pocket  110 , and seal retainer  150  which is inserted into cylindrical pocket  110 . O-ring  180  is installed in groove  47  of outer member  30 . Protrusion  37  of outer member  30  engages radial slot  130  of rotational cap  120  so as to limit rotation to no more than angle  133 .  
         [0096]     Referring to  FIG. 39 , with inner member rotated as shown in  FIGS. 34-38  (“aspirate” position), holes  89  in distal flange  86  of inner member  80  are aligned with grooves  60  in cannulatiion  59  of outer member  30 . Grooves  60  allow aspiration flow past cylindrical segment  94  of inner member  80  into axial pockets  190  of inner member  80  to produce aspiration path  200 . The aspiration path continues from pockets  190  through holes  135  in rotational cap  120  and through holes  148  in retainer  140 .  
         [0097]     Referring to  FIGS. 41-45 , with inner member rotated to the “ready” position, rotation is limited by protrusion  37  of outer member  30  acting with radial slot  130  of rotational cap  120 . Referring to  FIG. 46 , with the inner member in the “ready” position, distal flange  86  of inner member  80  prevents flow from entering grooves  60  in cannulation  59  of outer member  30 .  
         [0098]     Referring to  FIGS. 47-51 , nozzle  4  has a proximal end  210  and a distal end  211 . Proximal end  210  has a cylindrical portion  212 , cylindrical protrusions  213  orthogonal to axis  214  of nozzle  4 , and hub  215  which in combination form a J-lock  222 . Cylindrical distal region  216  has diameter  217  and length  218 . Multiple nozzles having a range of diameters  217  and lengths  218  will be supplied with each instrument. Diameters  217  and length  218  of a nozzle selected for use are determined by the application to which cannulated syringe  1  will be aplied. For instance, some procedures may require a nozzle having a large diameter and short length, while others require a small diameter and long length, or some other combination of diameter  217  and length  218 . A cannulation  219  of diameter  220  extends the length of nozzle  4  coaxial with axis  214 .  
         [0099]     Referring again to  FIGS. 1-4 , nozzle  4  is mounted to body  5  by J-lock  222 .  
         [0100]     During use a guide wire is placed to aid in positioning the syringe. Piston assembly  6  is removed from the syringe and desired material to be injected is loaded into body  5 . Rotatable cap  120  of piston assembly  6  is rotated to the “aspirate” position. While blocking cannulation  19  of body  5  to prevent loss of material, piston assembly  6  is inserted into body  5  and is advanced until the piston assembly distal end contacts the upper surface of the material and all air is aspirated. Rotatable cap  120  is rotated to the “ready” position. An appropriate nozzle  4  is selected and mounted to syringe  1 . Syringe  1  with nozzle  4  is positioned and advanced such that the guide wire passes through cannulation  219  of nozzle  4 , through cannulation  81  of inner member  80 , through seal  160  which deforms to accept the guide wire diameter, and through seal retainer  150  to exit the syringe proximal end. The syringe is advanced along the guide wire until properly positioned at the desired site. The piston is advanced in the syringe so as to deposit the desired amount of material at the site.  
         [0101]     When low viscosity materials which can be sucked into the syringe through the needle are used, or when the material is pre-loaded into the syringe by the manufacturer, it is not necessary for a user surgeon to vent air trapped between the face of the plunger and the material. In the case of low-viscosity materials, the syringe can be positioned with the needle pointed upward and the plunger advanced to expel the air. When the material is supplied pre-loaded in the syringe the air will have bee4n vented prior to shipping to the surgeon. An alternate embodiment of the invention, shown in  FIGS. 52-55 , has a simplified plunger which does not have a means for venting, but does have a passage to allow the guide wire to pass through the plunger and a sealing means to prevent leakage around the guide wire.  
         [0102]     Cannulated injection system  301  has a body  302  and a piston assembly  303 , body  302  having a proximal end  304  and a distal end  305  to which is removably mounted nozzle  306 , the nozzle being mounted in the same manner as in the previous embodiment. Piston assembly  303  has an elongated portion  320  having seal  307  and retainer  308  mounted in its distal end  321 , the seal and the manner of mounting being the same as in the previous embodiment. Cannulation  309  extends axially from seal  307  to proximal end  310  of component  320 , cannulation  309  being of a diameter sufficient to allow passage of a guide wire therethrough. Sealing means  311  is mounted to component  320  at its distal end  321 .  
         [0103]     Referring to nozzle  306 , cylindrical distal region  316  has diameter  317  and length  318 . Multiple nozzles having a range of diameters  317  and lengths  318  will be supplied with each instrument. Diameter  317  and length  318  of a nozzle selected for use are determined by the application to which cannulated syringe  301  will be applied. For instance, some procedures may require a nozzle having a large diameter and a short length, while other require a small diameter and long length, or some other combination of diameter  317  and length  318 . A cannulation  319  of diameter  328  extends the length of nozzle  306  coaxial with axis  329 .  
         [0104]     During use, a guide wire is placed to aid in positioning syringe  301 . A suitable nozzle  306  is selected and mounted to body  302 . If the material to be injected is not pre-loaded into syringe  301 , material is drawn into syringe  301  through nozzle  306  by partially withdrawing piston assembly  303 . Nozzle  306  is then pointed upward and entrapped air expelled by advancing piston assembly  303 . Syringe  301  with nozzle  306  is positioned and advanced such that the guide wire passes through cannulation  319  of nozzle  306 , through seal retainer  308 , through seal  307  whoch deforms to accept the guide wire diameter and through cannulation  309  to exit piston assembly  320  at its proximal end  310 . The syringe is advanced along the guide wire until properly positioned at the desired site. The piston is advanced in the syringe so as to deposit the desired amount of injectable material at the site.  
         [0105]     Some materials to be injected are mixed from two components immediately prior to use in a ratio specified by the material manufacturer. Such materials are most efficiently supplied pre-loaded into a syringe which has two barrels, the cross-sectional area of the barrels being of the same ratio as the required mixing ratio of the material. The pistons for the two barrels are mechanically linked so that advancing the pistons causes material to be expelled from each barrel of the syringe simultaneously. An embodiment of the cannulated injection system herein disclosed which is suitable for the injection of two-component materials is shown in  FIGS. 57-61 . Because the component materials are of low viscosity, venting of trapped air through the piston assembly is not required.  
         [0106]     Referring to  FIGS. 57-62 , cannulated injection system  501  has a body  502  and a piston assembly  503 , body  502  having a proximal end  504  and a distal end  505  to which is removably mounted nozzle  506 , the nozzle being mounted in the same manner as in the previous embodiments. Body  502  has a first longitudinal cylindrical bore  508  of diameter  509  having a passage  510  at its distal end. Passage  510  allows fluid flow between bore  508  and the proximal end of nozzle  506 . A second longitudinal cylindrical bore  511  of diameter  512  has a passage  513  at its distal end. Passage  513  allows fluid flow between bore  511  and the proximal end of nozzle  506 . Diameters  509  and  512  are selected such that the ratio of the cross-sectional area of bore  508  to bore  511  is the same as the required mixing ration of the material components. Coaxial with nozzle  506 , seal  514  and seal retainer  515  are mounted within body  502  in the same manner as in the previous embodiments. Coaxial with nozzle  506 , cannulation  516  having a diameter sufficient for passage of a guide wire therethrough extends from seal  514  to proximal end  504  of body  502 .  
         [0107]     Referring to nozzle  506 , cylindrical distal region  516  has diameter  517  and length  518 . Multiple nozzles having a range of diameters  517  and lengths  518  will be supplied with each instrument. Diameter  517  and length  518  of a nozzle selected for use are determined by the application to which cannulated syringe  501  will be applied. For instance, some procedures may require a nozzle having a large diameter and a short length, while other require a small diameter and long length, or some other combination of diameter  517  and length  518 . A cannulation  519  of diameter  528  extends the length nozzle  506 , coaxial with axis  529 .  
         [0108]     As best seen in  FIG. 62 , piston assembly  503  has a first elongated portion  540  with a proximal end  541  and a distal end  542  on which is mounted a sealing means  543 . Assembly  503  also has a second elongated portion  545  with a proximal end  546  and a distal end  547  on which is mounted sealing means  548 . Proximal ends  541  and  546  are joined by a proximal flange  550  having a cylindrical opening  551  positioned so that when piston assembly  503  is assembled to body  502 , opening  551  is coaxial with axis  529 .  
         [0109]     During use, a guide wire is placed to aid in positioning syringe  501 . A suitable nozzle  506  is selected and mounted to body  502 . Nozzle  506  is then pointed upward and entrapped air is expelled by advancing piston assembly  503 . Syringe  501  with nozzle  506  is positioned and advanced such that the guide wire passes through cannulation  519  of nozzle  506 ; through seal retainer  515 ; through seal  514 , which deforms to accept the guide wire diameter; and through cannulation  516  to exit body  502  at its proximal end  504 . The syringe is advanced along the guide wire until properly positioned at the desired site. The piston is advanced in the syringe so as to deposit the desired amount of material at the site.  
         [0110]     Although preferred forms of my invention have been herein disclosed, it is to be understood that the present disclosure is by way of example and that variations are possible without departing from the subject matter coming within the scope of the following claims, which subject matter I regard as my invention.