Cannulated internally threaded bone screw

Abstract

A combination bone screw and driver assembly for driving a cannulated internally threaded bonescrew, comprising: a bone screw with shank having a head integrally formed at the proximal end and defining a cannula extending through the head and shank. An external thread is formed on the shank outer surface and an internal thread formed on a surface defining the inner cannula. An engagement structure is formed in the head to receive and rotatably engage a driver having a shape complimentary to the shape of the engagement structure. The driver comprises a cylindrical shaft member defining an internal throughgoing cannula and an engagement structure formed at the distal end of the shaft member to engage the shaft member to a complimentary engagement structure formed on the cannulated internally threaded screw, a handle member mounted to the proximal end of the shaft member and a rod member movably disposed within the cannula of the shaft member defining a thread portion formed at one end which can be threaded along the internal thread of said bone screw. A cap member removably mounted on the other end of the rod member retains the rod member within the shaft member when a the bone screw is threadedly engaged on the one end of the rod member and applies torque to the rod member. In operation a plurality of bores are drilled in different sections of fractured bone site and at least two bone screws are driven into respective bores of said different sections of a fractured bone with a driver. The drivers are secured respectively, to the bone screws to form a first and a second bone fixation and reduction assembly; and the first and second bone fixation and reduction assemblies are transported toward each other to reduce the fracture. The first and second bone fixation and reduction assemblies are then clamped together to effect fixation of the fractured bone.

I claim:  
     
         1 . A cannulated torque receiving bone screw comprising: 
 an elongated cylindrical shank defining a throughgoing cylindrical bore and having a proximal end, a head integrally formed at the proximal end, a distal end, and an outer surface, an engagement structure defined by said head is shaped to receive and rotatably engage a driver having a shape complimentary to the shape of the engagement structure; an external thread is formed on said shank outer surface and an internal thread is formed on a surface defining said inner cylindrical bore.    
     
     
         2 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein said head defines a geometrically shaped recess which is axially aligned with said throughgoing bore.  
     
     
         3 . A cannulated torque receiving bone screw as claimed in  claim 2  wherein said head has a planar surface.  
     
     
         4 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein said distal end defines a plurality of flutes.  
     
     
         5 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein an outer periphery of said head defines an engagement structure.  
     
     
         6 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein said external thread formed on the outer surface of said shank extends the length of said shank.  
     
     
         7 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein said external thread formed on the outer surface of said shank extends along a section of said shank and the rest of the outer surface is unthreaded.  
     
     
         8 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein said internal thread formed on a surface defining the bore of said shank extends the length of said bore.  
     
     
         9 . A cannulated torque receiving bone screw as claimed in  claim 1  wherein a plurality of flutes extend distally from said tip portion at least partially into said outer surface of said body portion and said external thread structure.  
     
     
         10 . A combination bone screw and driver assembly for driving a cannulated internally threaded bonescrew, comprising: 
 a bonescrew with an elongated cylindrical shank having a proximal end, a distal end, an outer surface; a head integrally formed at the proximal end and a tip portion formed at the distal end; a cannula extending through said head and shank defining an inner throughgoing cylindrical bore; an engagement structure formed in said head shaped to receive and rotatably engage a driver having a shape complimentary to the shape of the engagement structure; an external thread formed on said shank outer surface and an internal thread formed on a surface defining said inner cylindrical bore;    said driver comprising a shaft member defining an internal throughgoing cannula and an engagement structure formed at the distal end of said shaft member to engage the shaft member to a complimentary engagement structure formed in said head of the cannulated internally threaded screw;    a handle member mounted to the proximal end of said shaft member;    a rod removably mounted within said shaft member cannula, said rod having a length which is greater than the length of the shaft member, and an outer diameter which is less than the inner diameter of said shaft member cannula, said rod defining a thread portion formed at one end which can be threaded along the internal thread of said bone screw; and    a cap member removably mounted on the other end of said rod to apply torque to said rod and retain said rod within said shaft member when a said bone screw is threadedly engaged on the one end of said rod.    
     
     
         11 . A combination bone screw and driver assembly as claimed in  claim 10  wherein said handle member has two sections, each of which defines a longitudinal groove which when aligned form a bore to receive the proximal end of said shaft member.  
     
     
         12 . A combination bone screw and driver assembly as claimed in  claim 10  wherein said handle member has a unitary body which defines a longitudinal bore allowing the the proximal end of said shaft member to be mounted therein.  
     
     
         13 . A combination bone screw and driver assembly as claimed in  claim 10  wherein said rod thread portion has a greater diameter than the shaft member cannula.  
     
     
         14 . A combination bone screw and driver assembly as claimed in  claim 10  wherein said shaft member defines at least one annular groove along its length.  
     
     
         15 . A combination bone screw and driver assembly as claimed in  claim 10  further comprising a release member mounted in said cap member, said release member being movable between a released position and a locked position so that the cap member is selectively rigidly secured to said rod member when the release member is in the locked position and removable from said rod member when the release member is in the released position.  
     
     
         16 . A combination bone screw and driver assembly as claimed in  claim 10  wherein said release member is a set screw with a Allen head.  
     
     
         17 . A combination bone screw and driver assembly as claimed in  claim 10  wherein said cap member is cylindrical and knurled on the outside surface.  
     
     
         18 . A combination bone screw and driver assembly as claimed in  claim 15  wherein said rod includes a well formed at the proximal end thereof which well cooperates with said release member to releaseably lock the cap member to the rod.  
     
     
         19 . A combination bone screw and driver assembly for driving a cannulated internally threaded bonescrew, comprising: 
 a bonescrew with an elongated cylindrical shank having a proximal end, a distal end, an outer surface; a head integrally formed at the proximal end and a tip portion formed at the distal end; a cannula extending through said head and shank defining an inner throughgoing cylindrical bore; an engagement structure formed in said head shaped to receive and rotatably engage a driver having an engagement structure with a shape complimentary to the shape of the engagement structure; an external thread formed on said shank outer surface and an internal thread formed on a surface defining said inner cylindrical bore running the length of said cylindrical bore;    said driver comprising a shaft member defining an internal throughgoing cannula and an engagement structure formed at the distal end of said shaft member to engage the shaft member to a complimentary engagement structure formed on the cannulated internally threaded screw; said shaft member additionally defining at least one annular groove along its outer surface;    a removable handle member mounted to the proximal end of said shaft member;    a rod movably disposed within said shaft member cannula, said rod having a length which is greater than the length of the shaft member, and a section with an outer diameter which is less than the diameter of said shaft member cannula, said rod defining a thread portion formed at one end having a thread outer diameter which is greater than the diameter of said shaft member cannula and which can be threaded along the internal thread of said bone screw; and    a cap member removably mounted on the other end of said rod to retain said rod member within said shaft member when a bone screw is threadedly engaged with the thread portion of said rod.    
     
     
         20 . A method for the reduction and fixation of a fractured bone, comprising the steps of: 
 a) drilling a plurality of bores in different bone sections of a fractured bone site;    b) driving bone screws into respective bores of said different sections of a fractured bone with a driver device; 
 each of said driving devices comprising; 
 a shaft member having a throughgoing cannula and an first engagement structure formed at a distal end;  
 a handle member mounted at the proximal end of said shaft member,  
 a rod member having a length greater than the length of the shaft member slidably disposed within and removable from the cannula of the shaft member; and  
 a cap member secured to said proximal end of said rod member;  
 
 each of said bone screws comprising; 
 a shank with a throughgoing cannular, a head portion integrally formed at the proximal end of said shank defining an engagement structure for said shaft member engagement structure;  
 an exterior thread formed on the exterior surface of said shank;  
 an interior thread formed on an interior surface of said shank defining said cannula;  
 
   c) securing the driving devices to respective bone screws to form a first and a second bone fixation and reduction assembly;    d) moving the first and second bone fixation and reduction assemblies toward each other transporting the sections of fractured bone to reduce the fracture; and    e) clamping the first and second bone fixation and reduction assemblies together to effect fixation of the fractured bone.    
     
     
         21 . A method for the reduction and fixation of a fractured bone as claimed in  claim 20  including the steps of: 
 guiding a bone screw and an associated driving device with the rod member removed into a first guide hole in a bone portion of the fractured bone with a guide wire;  
 removing the guide wire from the first bone screw and from the first driving device; and  
 placing a rod of the first driving device into the cannula thereof and rotating the cap member to secure the first driving device to the bone screw.  
 
     
     
         22 . A method for the reduction and fixation of a fractured bone as claimed in  claim 20  wherein 
 the distal threaded end of each rod member threadably engages the interior thread of the associated bone screw; and  
 the cap member is rotated to tighten the shaft member to the bone screw.  
 
     
     
         23 . A method for the reduction and fixation of a fractured bone as claimed in  claim 20  including a step after step a) of: placing a planar bone plate with a plurality of elongated slots over the fracture site so that the slots overlie the bores in adjacent bone sections; and replacement of step (e) with the step of securing the first and second bone fixation assemblies in the bone plate.  
     
     
         24 . A method for the reduction and fixation of a fractured bone with a bone plate comprising the steps of: 
 assembling a plurality of driving devices, a bone plate, a plurality of bone screws, a plurality of secondary screw members and a guide wire, 
 each driving device comprising; 
 a shaft member defining a cannula from the proximal end to the distal end and an engagement structure at the distal end;  
 a handle member removably mounted at the proximal end of said shaft member;  
 a rod member mounted within the cannula of said shaft member, said rod being provided with a threaded portion at the distal end; and  
 a rotatable cap member releaseably secured to said proximal end;  
 
 each bone screw comprising; 
 a shaft body with an integral head and a cannula formed in said body leading from the head to the distal end;  
 an external thread formed-on an exterior surface of said body and an interior thread formed on an interior surface defining said cannula; and  
 an engagement structure formed on said head;  
 
 said bone plate comprising; 
 an essentially planar base member with a plurality of elongated slots formed therein;  
 placing the bone plate adjacent the fracture site with the slots positioned over bores  
 drilled in bone sections of said fracture site;  
 guiding a bone screw through a first slot on the bone plate into a bore and driving the first bone screw into a first section of a fractured bone;  
 guiding a second bone screw through a second slot on the bone plate into another bore and driving the second bone screw into a second section of a fractured bone;  
 securing a first and a second bone screw-driving device assembly to the first and second bone screws, respectively;  
 applying force to the first and second bone screw-driving device assemblies to reduce the fracture; and  
 tightening the first and second bone screws to effect the fixation of the fracture site.  
 
   
     
     
         25 . The method of  claim 24  for the repair of a fractured bone further comprising the step of clamping said first bone screw driving assembly to said second bone screw driving assembly to effect fixation of the fracture site.  
     
     
         26 . The method of  claim 24  for the repair of a fractured bone wherein each bone reduction and fixation assembly is provided with a removable handle and wherein the method further comprises the step of: 
 connecting a plurality of rods to said first bone screw driving assembly and said second bone screw driving assembly to effect fixation of the fracture site.