Maxillofacial anchoring system for alveolar and small bone skeletal distraction

Abstract

A maxillofacial anchoring and distraction system having an internally threaded anchoring or distraction fixture ( 12 ) and a selected length jack screw ( 14 ) for placement in an osteotomy. To minimize required bone height, a cut-away bone screw ( 16 ) or a solid mesh tip ( 17 ) is provided for insertion in bone in a direction generally perpendicular to the longitudinal axes of the anchoring and jack screws. A flat surface portion ( 16 c, 17 a ) serves as a reaction surface for the distal end of the jack screw. In a second embodiment a sealing screw ( 24 ) is used with distraction fixture ( 20 ) modified to include a sealing surface. After completion of distraction the sealing screw is used to seal off the distraction fixture for conversion into an implant suitable for receiving conventional prosthetic components.

1 . (canceled)  
   
   
       2 . A maxillofacial anchoring and distraction system comprising 
 an anchoring screw body having upper and lower sides and having a longitudinal axis and having a longitudinally extending threaded bore extending through the anchoring screw body from the upper side to the lower side, the anchoring screw body having an external bone screw thread,    an elongated generally cylindrical member having head and distal ends and a longitudinal axis, an externally threaded portion for threaded engagement in the threaded bore of the anchoring screw body, the generally cylindrical member being capable of being inserted in the bore of the anchoring screw body with the distal end inserted from the upper side and so that the distal end can extend out of the threaded bore beyond the lower side of the anchoring screw body with the generally cylindrical member being removable through the upper side upon completion of distraction, the head end including a driving surface, and the distal end having a distraction force transferring surface a selected diameter, and    a reaction element having a flat surface portion for engagement with the distraction force transferring surface of the distal end of the generally cylindrical member when the cylindrical member is in threaded engagement with the anchoring screw body, the flat surface portion extending along a selected axis a distance at least as great as the diameter of the distal end of the elongated generally cylindrical member to serve serving as an engagement surface to distract against when the reaction element is placed in a horizontally extending osteotomy in a bone with the flat surface portion of the reaction element generally perpendicular relative to the longitudinal axis of the anchoring screw body and the elongated generally cylindrical member, according to  claim 1  in which the reaction element comprises comprising a bone screw having a generally cylindrical body portion with a longitudinal axis and having an external screw thread, the generally cylindrical body being formed with the flat surface portion recessed below the threads and with the selected axis extending parallel with the horizontal longitudinal axis.    
   
   
       3 - 8 . (canceled)  
   
   
       9 . A maxillofacial anchoring and distraction system according to  claim 2  in which the bone screw has a head formed with an indexing surface portion to reflect the angular position of the recessed flat surface portion.  
   
   
       10 . A maxillofacial anchoring and distraction system according to  claim 9  in which the head has a generally circular outer periphery formed with a flat surface portion in the outer periphery at an angular position matching that of the angular position of the flat surface portion in the body.  
   
   
       11 . A maxillofacial anchoring and distraction system according to  claim 2  in which the head is formed with a recessed polygonal driving feature.  
   
   
       12 . A maxillofacial anchoring and distraction system comprising 
 a generally cylindrical base plug having a longitudinal axis, a crestal end and having a closed ended, threaded bore formed through the crestal end and extending along the longitudinal axis,    an anchoring screw body having a longitudinal axis and having a head end and a distal end and having a longitudinally extending bore extending through the anchoring screw body, the bore being threaded along at least a portion of its length and having a circumferentially extending sealing surface, the anchoring screw body having external threads,    an elongated generally cylindrical member having first and second ends, an externally threaded portion for threaded engagement in the threaded bore of the anchoring screw body, the second end having a diameter selected to be received within the bore of the base plug bypassing the threaded portion of the bore and the sealing surface of the screw body, and    a sealing screw having a distal free end and an external thread for threaded engagement in the threaded bore of the anchoring screw body after the generally cylindrical member has been removed upon completion of distraction, the sealing screw having a circumferentially extending sealing surface for engagement with the sealing surface of the anchoring screw body.    
   
   
       13 . A maxillofacial anchoring and distraction system according to  claim 12  in which the sealing surface of the sealing screw is formed of a generally cylindrical surface and the sealing surface of the sealing anchoring screw body is formed of a generally cylindrical surface having a slight taper with the diameter increasing decreasing in a direction going toward the distal end.  
   
   
       14 . A maxillofacial anchoring and distraction system according to  claim 12  in which the head end is formed with a polygonal driving surface.