Bone anchor

Abstract

An anchor assembly can be couplable to a bone and can include an anchor and a housing. The anchor can include a shank securable to bone and a head coupled to a proximal portion of the shank.

1 - 20 . (canceled) 
     
     
         21 . An anchor assembly couplable to bone, the assembly comprising:
 an anchor comprising:
 a shank including distal threading that is securable to bone; and 
 a head at a proximal end; 
   a housing including an anchor bore extending distally into the housing along a longitudinal axis of the housing, wherein the anchor bore is at least a diameter of the head of the anchor at a proximal end of the housing, wherein the anchor bore is configured to retain at least a portion of the head of the anchor therein, and wherein the head of the anchor is insertable into the anchor bore at a distal end of the housing; and   a saddle receivable within the housing and configured to receive a connecting member thereon, wherein a distal end of the saddle is configured to engage a proximal end of the head of the anchor.   
     
     
         22 . The assembly of  claim 21 , wherein the head comprises:
 a proximal first threaded portion of the shank, wherein the proximal first threaded portion of the shank is insertable into the anchor bore at the distal end of the housing; and   a donut including a corresponding second threaded portion, wherein the donut is threadably securable to the shank via threaded engagement of the first threaded portion and the second threaded portion,   wherein the anchor bore is configured to retain the donut therein, and wherein the distal end of the saddle is configured to engage a proximal end of the donut.   
     
     
         23 . The assembly of  claim 22 , wherein the anchor includes a necked portion between the proximal first threaded portion of the shank and the distal threading of the shank, wherein the necked portion has a smaller diameter than the proximal first threaded portion of the shank, and wherein the anchor further includes a distally tapered transition surface between the proximal first threaded portion of the shank and the necked portion. 
     
     
         24 . The assembly of  claim 23 , wherein the housing includes a tapered outer diameter at the distal end of the housing, wherein the necked portion of the anchor corresponds to the tapered outer diameter at the distal end of the housing, and wherein the corresponding tapered outer diameter of the housing and the necked portion of the anchor provides a high degree of angulation for the position of the anchor relative to the longitudinal axis of the housing. 
     
     
         25 . The assembly of  claim 22 , wherein the proximal end of the anchor includes a tool notch configured to receive a tool for applying a torque on the proximal end of the anchor to secure the first threaded portion to the second threaded portion. 
     
     
         26 . The assembly of  claim 22 , wherein the proximal end of the donut includes one or more notches configured to receive a tool for applying a torque on the proximal end of the donut to secure the first threaded portion to the second threaded portion. 
     
     
         27 . The assembly of  claim 22 , wherein the saddle includes one or more ridges that extend at least one of radially inward and distally from the saddle and toward the proximal end of the donut, and wherein the one or more ridges are configured to engage the proximal end of the donut to limit movement between the donut and the saddle. 
     
     
         28 . The assembly of  claim 21 , wherein the saddle includes a plurality of engagement teeth configured to engage the connecting member when received by the saddle to limit movement of the connecting member within the housing. 
     
     
         29 . The assembly of  claim 21 , wherein the saddle includes one or more ledges that extend radially outward from a radially outer surface of the saddle and that are configured to engage an interior surface of the housing to limit movement of the saddle within the housing. 
     
     
         30 . The assembly of  claim 29 , wherein the one or more ledges are tapered distally to create a proximal-facing flat face for retaining the saddle within the housing via engagement of the one or more ledges and the housing. 
     
     
         31 . The assembly of  claim 21 , further comprising:
 a set screw configured to be inserted into the housing following the insertion of the head at the proximal end of the anchor and following the insertion of the saddle into the housing, wherein the set screw threadably engages an interior surface of the housing to secure the set screw within the housing.   
     
     
         32 . The assembly of  claim 31 , wherein a proximal end of the set screw includes a tool notch configured to receive a tool for applying a first torque on the proximal end of the set screw to threadably engage the set screw to the housing. 
     
     
         33 . The assembly of  claim 32 , wherein when a connecting member is inserted between the saddle and the set screw, threadably engaging the set screw to the housing compresses the connecting member between the saddle and the set screw following the application of a second torque on the proximal end of the set screw by the tool. 
     
     
         34 . The assembly of  claim 21 , wherein a diameter of the proximal first threaded portion is less than a diameter of the anchor bore of the housing, and wherein a diameter of the shank is greater than the diameter of the anchor bore of the housing. 
     
     
         35 . An anchor assembly couplable to bone, the assembly comprising:
 an anchor comprising:
 a shank including distal threading that is securable to bone; 
 a head at a proximal end; and 
 a necked portion between the head and the distal threading, wherein the necked portion has a smaller diameter than the head; 
   a housing including an anchor bore extending distally into the housing along a longitudinal axis of the housing, wherein the anchor bore is configured to retain at least a portion of the head of the anchor therein, wherein the head of the anchor is insertable into the anchor bore at a distal end of the housing, wherein the housing includes a tapered outer diameter at the distal end of the housing that corresponds to the necked portion of the anchor, and wherein the corresponding tapered outer diameter of the housing and the necked portion of the anchor provides a high degree of angulation for the position of the anchor relative to the longitudinal axis of the housing; and   a saddle receivable within the housing and configured to receive a connecting member thereon, wherein a distal end of the saddle is configured to engage a proximal end of the head of the anchor.   
     
     
         36 . The assembly of  claim 35 , wherein the anchor further includes a distally tapered transition surface between the head and the necked portion. 
     
     
         37 . The assembly of  claim 35 , wherein the anchor bore is at least a diameter of the head of the anchor at a proximal end of the housing. 
     
     
         38 . An anchor assembly couplable to bone, the assembly comprising:
 an anchor comprising:
 a shank including distal threading that is securable to bone; and 
 a head at a proximal end; 
   a housing including an anchor bore extending distally into the housing along a longitudinal axis of the housing, wherein the anchor bore is configured to retain at least a portion of the head of the anchor therein, and wherein the head of the anchor is insertable into the anchor bore at the distal end of the housing; and   a turret couplable to the distal end of the housing, wherein the turret includes a tapered outer diameter at a distal end of the turret that corresponds to the necked portion of the anchor, and wherein the corresponding tapered outer diameter of the turret and the necked portion of the anchor provides a high degree of angulation for the position of the anchor relative to the longitudinal axis of the housing.   
     
     
         39 . The assembly of  claim 38 , wherein the turret is rotatable with respect to the housing to allow the anchor to be positioned at the high degree of angulation relative to the longitudinal axis of the housing. 
     
     
         40 . The assembly of  claim 38 , further comprising:
 a saddle receivable within the housing and configured to receive a connecting member thereon, wherein a distal end of the saddle is configured to engage a proximal end of the head of the anchor.