Surgical instrument and method

Abstract

A surgical system includes a bone fastener having a head and a shaft, The head has a drive interface surface including elliptical edges. A surgical instrument includes an inner drive and an outer sleeve that is engageable with an outer surface of the head to dispose the inner drive and the outer sleeve with the head in a co-axial, capture orientation, The inner drive has a drive interface surface including a plurality of spaced apart lobes. Each lobe has an elliptical edge engageable with one of the elliptical edges of the drive interface surface of the head. Spinal constructs, implants and methods are disclosed.

1 - 14 . (canceled) 
     
     
         15 . A bone fastener comprising:
 a head including a female drive interface surface having a plurality of elliptical edges being spaced apart about the interface surface; and   a shaft extending from the head in co-axial alignment with the head and configured for penetrating tissue.   
     
     
         16 . A bone fastener as recited in  claim 15 , wherein the interface surface comprises a hexalobe socket having six spaced apart protrusions including the edges, the edges being defined by an ellipse having a major axis of between about 2.0 mm and 2.3 mm and a minor axis of between about 1.00 mm and 1.3 mm. 
     
     
         17 . A bone fastener as recited in  claim 15 , wherein the head includes an outer surface having a threaded portion attachable with a surgical instrument in a co-axial, capture orientation. 
     
     
         18 . A bone fastener as recited in  claim 17 , wherein the threaded portion is attachable with an alternative surgical instrument. 
     
     
         19 - 20 . (canceled) 
     
     
         21 . A bone fastener as recited in  claim 15 , wherein the interface surface comprises a hexalobe socket having six spaced apart protrusions including the edges, the socket having a major diameter and a minor diameter, the minor diameter being greater than 75% of the major diameter. 
     
     
         22 . A bone fastener as recited in  claim 15 , wherein the interface surface comprises a hexalobe socket having six spaced apart protrusions including the edges, the socket having a major diameter of about 4.6 mm and a minor diameter of between about 3.8 mm. 
     
     
         23 . A bone fastener as recited in  claim 15 , wherein the socket is compatible with a T25 drive. 
     
     
         24 . A bone fastener as recited in  claim 15 , wherein the elliptical edges define elliptically shaped lobes. 
     
     
         25 . A bone fastener as recited in  claim 15 , wherein the interface surface comprises a hexalobe socket having six spaced apart protrusions including the edges, the head including a countersunk configuration disposed about an opening of the socket. 
     
     
         26 . A bone fastener as recited in  claim 15 , wherein the interface surface is deformable. 
     
     
         27 . A bone fastener as recited in  claim 15 , wherein the shaft is cannulated. 
     
     
         28 . A bone fastener comprising:
 a head including an inner surface defining a socket, the head having six spaced apart recesses extending into the inner surface to provide the socket with a hexalobe configuration, the inner surface defining a first radius of curvature between adjacent recesses and the recesses each defining a second radius of curvature, the second radius of curvature being less than the first radius of curvature; and   a shaft extending from the head in co-axial alignment with the head and configured for penetrating tissue.   
     
     
         29 . A bone fastener as recited in  claim 28 , wherein the recesses each having a dimension defined by a distance from the inner surface to a bottommost portion of a respective one of the recesses, a distance between adjacent recesses being greater than the dimension. 
     
     
         30 . A bone fastener as recited in  claim 28 , wherein the inner surface is concavely curved between adjacent recesses. 
     
     
         31 . A bone fastener as recited in  claim 28 , wherein the socket has a major diameter and a minor diameter, the minor diameter being greater than 75% of the major diameter. 
     
     
         32 . A bone fastener as recited in  claim 28 , wherein the socket has a major diameter of about 4.6 mm and a minor diameter of between about 3.8 mm. 
     
     
         33 . A bone fastener as recited in  claim 28 , wherein the head includes a countersunk configuration disposed about an opening of the socket. 
     
     
         34 . A bone fastener as recited in  claim 28 , wherein the inner surface is deformable. 
     
     
         35 . A bone fastener as recited in  claim 28 , wherein the shaft is cannulated and includes proximal and distal threads extending outwardly from an outer surface of the shaft, the proximal thread having a first pitch and the distal thread having a second pitch, the second pitch being different than the first pitch. 
     
     
         36 . A bone fastener comprising:
 a head including an inner surface defining a socket, the head having six spaced apart recesses extending into the inner surface to provide the socket with a hexalobe configuration, the inner surface defining a first radius of curvature between adjacent recesses and the recesses each defining a second radius of curvature, the second radius of curvature being less than the first radius of curvature; and   a shaft extending from the head in co-axial alignment with the head and configured for penetrating tissue,   wherein the recesses each have a dimension defined by a distance from the inner surface to a bottommost portion of a respective one of the recesses, a distance between adjacent recesses being greater than the dimension,   wherein the inner surface is concavely curved between adjacent recesses,   wherein the socket has a major diameter and a minor diameter, the minor diameter being greater than 75% of the major diameter,   wherein the head includes a countersunk configuration disposed about an opening of the socket,   wherein the inner surface is deformable, and   wherein the shaft is cannulated and includes proximal and distal threads extending outwardly from an outer surface of the shaft, the proximal thread having a first pitch and the distal thread having a second pitch, the second pitch being different than the first pitch.