Triple lead bone screw

Abstract

Pedicle screw assemblies and related bone screws. In some embodiments, the bone screw may comprise a head portion and an axial shaft. The axial shaft may comprise a threaded portion comprising a triple lead thread disposed about the axial shaft. The axial shaft may further comprise a tapering portion and a non-tapering portion. The tapering portion may comprise multiple tapering portions tapering at differing rates, and may be positioned adjacent to a tip of the axial shaft. Each of the three leads may extend coextensively along at least a majority of the length of the axial shaft, the threaded portion, the tapering portion, and/or the non-tapering portion.

1 . A pedicle screw assembly, comprising:
 a bone screw comprising a head portion and a threaded portion, wherein the threaded portion comprises an axial shaft and a triple lead thread disposed about the axial shaft, wherein the axial shaft comprises a tapering portion and a non-tapering portion, wherein the tapering portion is positioned adjacent to a tip of the axial shaft, wherein the triple lead thread comprises three distinct thread leads, wherein each of the three leads terminates at a different point along a tapering portion of the axial shaft, and wherein each of the three leads extends coextensively along at least a majority of the length of the threaded portion; and   a rod retention member selectively coupled to the head portion of the bone screw.   
     
     
         2 . The pedicle screw assembly of  claim 1 , wherein the rod retention member comprises a U-shaped member comprising a hole for receiving the head portion of the bone screw. 
     
     
         3 . The pedicle screw assembly of  claim 2 , wherein the head portion is configured to be pivotably seated in the U-shaped member. 
     
     
         4 . The pedicle screw assembly of  claim 1 , wherein each of the three leads extends coextensively along at least substantially the entire length of the threaded portion. 
     
     
         5 . The pedicle screw assembly of  claim 1 , wherein the axial shaft further comprises a second tapering portion. 
     
     
         6 . The pedicle screw assembly of  claim 5 , wherein the second tapering portion is positioned between the tapering portion and the non-tapering portion. 
     
     
         7 . The pedicle screw assembly of  claim 6 , wherein the tapering portion tapers more steeply than the second tapering portion. 
     
     
         8 . The pedicle screw assembly of  claim 5 , wherein at least one of the three leads terminates at a point along the second tapering section. 
     
     
         9 . A bone screw, comprising:
 a head portion; and   a threaded portion, wherein the threaded portion comprises an axial shaft and a triple lead thread disposed about the axial shaft, wherein the axial shaft comprises a tapering portion and a non-tapering portion, wherein the tapering portion is positioned adjacent to a tip of the axial shaft, wherein the triple lead thread comprises three distinct thread leads, wherein at least two of the three leads terminate at a different points along the tapering portion of the axial shaft, and wherein each of the three leads extends coextensively along at least a majority of the length of the axial shaft.   
     
     
         10 . The bone screw of  claim 9 , wherein at least one of the three thread leads comprises a biting surface. 
     
     
         11 . The bone screw of  claim 10 , wherein each of the three thread leads comprises a biting surface. 
     
     
         12 . The bone screw of  claim 10 , wherein the biting surface comprises a notch formed within the at least one of the three thread leads. 
     
     
         13 . The bone screw of  claim 9 , wherein the three thread leads start with about 120 degrees of separation. 
     
     
         14 . The bone screw of  claim 9 , wherein at least one of the three thread leads originates at a different point along the threaded portion than the other two thread leads. 
     
     
         15 . The bone screw of  claim 9 , wherein the axial shaft further comprises a reduced diameter portion, and wherein the reduced diameter portion is positioned adjacent to the head portion. 
     
     
         16 . The bone screw of  claim 9 , wherein the axial shaft further comprises a second tapering portion. 
     
     
         17 . The bone screw of  claim 16 , wherein the second tapering portion is positioned between the tapering portion and the non-tapering portion. 
     
     
         18 . The bone screw of  claim 16 , wherein the tapering portion tapers more steeply than the second tapering portion. 
     
     
         19 . The bone screw of  claim 9 , wherein each of the three leads terminates at a different point along the tapering portion of the axial shaft. 
     
     
         20 . A bone screw, comprising:
 a head portion;   an axial shaft; and   a tip, wherein the axial shaft comprises a tapering portion and a non-tapering portion, wherein the axial shaft further comprises a triple lead thread disposed about the axial shaft, wherein the triple lead thread comprises three distinct thread leads, wherein the tapering portion is positioned adjacent to the tip, and wherein each of the three leads extends coextensively along at least a majority of the length of the non-tapering portion.