Endo-distractor

Abstract

The invention relates to a device for the distraction of bones or bone segments. The device comprises an anchoring screw having a longitudinal axis, a screw tip, a screw end for rotatably driving the anchoring screw, a threaded shank which adjoins the screw tip and has a screw thread, and a screw shank adjoining the screw end; and a distraction sleeve axially displaceable on the screw shank including a rear end, a front end, a through-bore extending coaxially therebetween, an external thread adjoining the front end, and a coupler portion formed in the rear end for receiving a driving tool. The anchoring screw comprises a collar positioned between the threaded shank and the screw shank that radially projects at least from the screw shank and which serves as an axial stop for the front end of the distraction sleeve when the distraction sleeve is positioned over the screw shank. The through-bore has a boring section with an enlarged cross-section which adjoins the rear end provided with a lateral surface and a seal ring coaxially arranged between the lateral surface and the screw shank.

What is claimed is:  
     
         1 . A device for the distraction of bones or bone segments comprising: 
 an anchoring screw having a threaded shank, a screw shank and a longitudinal axis;    a distraction sleeve extending coaxially along the longitudinal axis; the distraction sleeve having a first end, a second end and a through-bore extending from the first end to the second end sized and dimensioned to receive the screw shank; at least a portion of the first end of the distraction sleeve comprises an external screw thread;    a seal ring sized and dimensioned to fit between the screw shank and the distraction sleeve;    a collar positioned between the threaded shank and screw shank; and    means for rotatably driving the anchoring screw.    
     
     
         2 . The device in  claim 1  wherein the through-bore includes a boring section with an enlarged cross-section which adjoins the second end of the distraction sleeve, the boring section being provided with a lateral surface, the seal ring being arranged between the lateral surface and the screw shank.  
     
     
         3 . The device in  claim 1  wherein the second end of the distraction sleeve includes coupling means for receiving a driving tool.  
     
     
         4 . The device in  claim 3  wherein the coupling means includes a plurality of slots.  
     
     
         5 . The device in  claim 1  wherein the distraction sleeve is axially displaceable on the screw shank.  
     
     
         6 . The device in  claim 4  wherein the collar radially projects from the screw shank such that the collar acts as an axial stop for the first end of the distraction sleeve when the distraction sleeve is positioned over the screw shank.  
     
     
         7 . The device in  claim 1  wherein the threaded shank has a first diameter; the screw shank has a second diameter and the collar has a third diameter, the third diameter being larger than the first and second diameter.  
     
     
         8 . The device in  claim 7  wherein the first diameter is larger than the second diameter.  
     
     
         9 . The device in  claim 7  wherein the diameter of the threaded shank is approximately 2.2 mm to approximately 3.5 mm and the diameter of the screw shank is approximately 1.8 mm to approximately 2.5 mm.  
     
     
         10 . The device in  claim 7  wherein the diameter of the threaded shank is approximately 2.7 mm and the diameter of the screw shank is approximately 2.2 mm.  
     
     
         11 . The device in  claim 1  wherein the threaded shank further includes a screw tip.  
     
     
         12 . The device in  claim 1 , wherein the threaded shank has a self-tapping screw thread.  
     
     
         13 . The device in  claim 1 , wherein the threaded shank has a screw thread with an asymmetrical thread profile.  
     
     
         14 . The device of  claim 13 , wherein the screw thread includes flanks directed towards a screw tip that form an angle of between 80 and 90 degrees with respect to the longitudinal axis.  
     
     
         15 . The device of  claim 1 , wherein the external screw thread of the distraction sleeve has an asymmetrical thread profile.  
     
     
         16 . The device of  claim 15 , wherein the external thread includes flanks directed towards the second end that form an angle of between 80 and 90 degrees with respect to the longitudinal axis.  
     
     
         17 . The device in  claim 1 , wherein the external screw thread formed on the distraction sleeve is a left-hand thread.  
     
     
         18 . The device of  claim 1 , wherein the external screw thread formed on the distraction sleeve displays flattened, threaded tips.  
     
     
         19 . The device of  claim 1 , wherein the external screw thread formed on the distraction sleeve extends approximately one-half the length of the distraction sleeve.  
     
     
         20 . The device of  claim 1 , wherein the collar comprises a cone.  
     
     
         21 . The device of  claim 1 , wherein the collar comprises a spherically convex, tapered portion.  
     
     
         22 . The device of  claim 1 , wherein the means for driving the anchoring screw is arranged on a screw end of the screw shank.  
     
     
         23 . The device of  claim 1 , wherein the means for rotatably driving the anchoring screw do not radially protrude from the screw shank.  
     
     
         24 . The device of  claim 1 , wherein the means for driving the anchoring screw includes a hexagon having external surfaces arranged about the periphery of the screw shank.  
     
     
         25 . The device of  claim 1 , wherein the screw shank further includes a bore having an internal screw thread for threadedly receiving a cover screw.  
     
     
         26 . A device for the distraction of bones or bone segments comprising: 
 an anchoring screw having a longitudinal axis; the screw including a threaded shank, a screw shank and a collar disposed between the threaded shank and the screw shank;    a distraction sleeve having a first end, a second end and a through-bore extending from the first end to the second end sized and dimensioned to receive the screw shank such that the distraction sleeve is axially displaceable on the screw shank; at least a portion of the first end of the distraction sleeve comprises an external screw thread; and    a seal ring sized and dimensioned to fit between the screw shank and the distraction sleeve;    wherein the screw shank includes a screw end having a multi-sided configuration with external surfaces arranged about the periphery of the screw shank for rotatably driving the anchoring screw;    wherein the collar radially projects from the screw shank such that the collar acts as an axial stop for the first end of the distraction sleeve when the distraction sleeve is positioned over the screw shank.    
     
     
         27 . The device in  claim 26  wherein the through-bore includes a boring section with an enlarged cross-section which adjoins the second end of the distraction sleeve, the boring section being provided with a lateral surface, the seal ring being arranged between the lateral surface and the screw shank.  
     
     
         28 . The device in  claim 26  wherein the second end of the distraction sleeve includes coupling means for receiving a driving tool.  
     
     
         29 . The device in  claim 28  wherein the coupling means includes a plurality of slots.  
     
     
         30 . The device in  claim 26  wherein the threaded shank has a first diameter; the screw shank has a second diameter and the collar has a third diameter, the third diameter being larger than the first and second diameter.  
     
     
         31 . The device in  claim 30  wherein the first diameter is larger than the second diameter.  
     
     
         32 . The device in  claim 30  wherein the diameter of the threaded shank is approximately 2.2 mm to approximately 3.5 mm and the diameter of the screw shank is approximately 1.8 mm to approximately 2.5 mm.  
     
     
         33 . The device in  claim 30  wherein the diameter of the threaded shank is approximately 2.7 mm and the diameter of the screw shank is approximately 2.2 mm.  
     
     
         34 . The device in  claim 26  wherein the threaded shank further includes a screw tip.  
     
     
         35 . The device in  claim 26 , wherein the threaded shank has a self-tapping screw thread.  
     
     
         36 . The device in  claim 26 , wherein the threaded shank has a screw thread with an asymmetrical thread profile.  
     
     
         37 . The device of  claim 36 , wherein the screw thread includes flanks directed towards a screw tip that form an angle of between 80 and 90 degrees with respect to the longitudinal axis.  
     
     
         38 . The device of  claim 26 , wherein the external screw thread of the distraction sleeve has an asymmetrical thread profile.  
     
     
         39 . The device of  claim 38 , wherein the external thread includes flanks directed towards the second end that form an angle of between 80 and 90 degrees with respect to the longitudinal axis.  
     
     
         40 . The device in  claim 26 , wherein the external screw thread formed on the distraction sleeve is a left-hand thread.  
     
     
         41 . The device of  claim 26 , wherein the external screw thread formed on the distraction sleeve displays flattened, threaded tips.  
     
     
         42 . The device of  claim 26 , wherein the external screw thread formed on the distraction sleeve extends approximately one-half the length of the distraction sleeve.  
     
     
         43 . The device of  claim 26 , wherein the collar comprises a cone.  
     
     
         44 . The device of  claim 26 , wherein the collar comprises a spherically convex, tapered portion.  
     
     
         45 . The device of  claim 26 , wherein the screw shank further includes a bore having an internal screw thread for threadedly receiving a cover screw.  
     
     
         46 . A device for the distraction of bones or bone segments comprising: 
 a threaded shank having a screw tip on one end thereof and a collar on the other end;    a screw shank having an internally threaded bore for receiving a cover screw on an end thereof, the screw shank being coupled to the collar;    a distraction sleeve having a first end, a second end and a through-bore extending from the first end to the second end sized and dimensioned to receive the screw shank such that the distraction sleeve is axially displaceable on the screw shank, at least a portion of the first end of the distraction sleeve comprises an external screw thread, at least a portion of the second end of the distraction sleeve has an enlarged cross-section forming a boring section,    a seal ring sized and dimensioned to fit between the screw shank and the boring section of the distraction sleeve;    wherein the end of the screw shank having the internally threaded bore has a multi-sided outer configuration with external surfaces about the periphery of the screw shank for receiving a driving tool;    wherein the collar radially projects from the screw shank such that the collar acts as an axial stop for the first end of the distraction sleeve when the distraction sleeve is positioned over the screw shank.    
     
     
         47 . The device in  claim 46  wherein the second end of the distraction sleeve includes coupling means for receiving a driving tool.  
     
     
         48 . The device in  claim 47  wherein the coupling means includes a plurality of slots.  
     
     
         49 . The device in  claim 46  wherein the threaded shank has a first diameter; the screw shank has a second diameter and the collar has a third diameter, the third diameter being larger than the first and second diameter.  
     
     
         50 . The device in  claim 49  wherein the first diameter is larger than the second diameter.  
     
     
         51 . The device in  claim 49  wherein the diameter of the threaded shank is approximately 2.2 mm to approximately 3.5 mm and the diameter of the screw shank is approximately 1.8 mm to approximately 2.5 mm.  
     
     
         52 . The device in  claim 49  wherein the diameter of the threaded shank is approximately 2.7 mm and the diameter of the screw shank is approximately 2.2 mm.  
     
     
         53 . The device in  claim 46 , wherein the threaded shank has a self-tapping screw thread.  
     
     
         54 . The device in  claim 46 , wherein the threaded shank has a screw thread with an asymmetrical thread profile.  
     
     
         55 . The device of  claim 54 , wherein the screw thread includes flanks directed towards a screw tip that form an angle of between 80 and 90 degrees with respect to the longitudinal axis.  
     
     
         56 . The device of  claim 46 , wherein the external screw thread of the distraction sleeve has an asymmetrical thread profile.  
     
     
         57 . The device of  claim 56 , wherein the external thread includes flanks directed towards the second end that form an angle of between 80 and 90 degrees with respect to the longitudinal axis.  
     
     
         58 . The device in  claim 46 , wherein the external screw thread formed on the distraction sleeve is a left-hand thread.  
     
     
         59 . The device of  claim 46 , wherein the external screw thread formed on the distraction sleeve displays flattened, threaded tips.  
     
     
         60 . The device of  claim 46 , wherein the external screw thread formed on the distraction sleeve extends approximately one-half the length of the distraction sleeve.  
     
     
         61 . The device of  claim 46 , wherein the collar comprises a cone.  
     
     
         62 . The device of  claim 46 , wherein the collar comprises a spherically convex, tapered portion.