Interbody implant with concave profiled nose

Abstract

An interbody implant and inserter tool for spinal fusion. The interbody implant includes a cage portion and a nose portion. In some embodiments, an outer surface of the nose portion defines at least a first concave profile in a first direction, and may define a second concave profile in a second direction, the second direction being perpendicular to the first direction. The outer surface may also define an oblong cross-section normal to a nose axis. The oblong cross-section may be axisymmetric or continuously curved (or both) about the nose axis. The concave profile(s) enable easier initial insertion of for more precisely locating the interbody implant, so that the greater insertion forces required during implantation do not occur until the interbody implant is securely and accurately placed.

1 . An interbody implant, comprising:
 a cage portion defining a cage axis that passes through a proximal portion and a distal portion thereof; and   a nose portion extending in a distal direction from the distal portion of the cage portion, the nose portion defining a nose axis that is concentric with the cage axis, the nose axis extending in the distal direction from the cage portion through a distal extremity of the nose portion, the nose portion defining an outer surface about the nose axis that tapers toward the nose axis in the distal direction, the outer surface defining a first concave profile in a first direction from the nose axis, the first direction being perpendicular to the nose axis, the nose portion defining a through-passage concentric about the nose axis.   
     
     
         2 .- 7 . (canceled) 
     
     
         8 . The interbody implant of  claim 1 , wherein the outer surface of the nose portion defines a second concave profile in a second direction from the nose axis, the second direction being perpendicular to the first direction at any point along the nose axis. 
     
     
         9 . The interbody implant of  claim 8 , wherein the outer surface of the nose portion defines an oblong cross-section at a cross-section plane that intersects and is orthogonal to the nose axis, the oblong cross section defining a major dimension and a minor dimension, the minor dimension being perpendicular to the major dimension. 
     
     
         10 . The interbody implant of  claim 9 , wherein the oblong cross-section is continuously curved. 
     
     
         11 . The interbody implant of  claim 10 , wherein the oblong cross-section is elliptical. 
     
     
         12 . The interbody implant of  claim 9 , wherein a ratio of the major dimension to the minor dimension is in a range of 1.05 to 1.20 inclusive. 
     
     
         13 .- 14 . (canceled) 
     
     
         15 . The interbody implant of  claim 9 , wherein the cross-section plane intersects the nose axis at a midpoint that is equidistant between the base plane and the distal extremity. 
     
     
         16 .- 19 . (canceled) 
     
     
         20 . The interbody implant of  claim 1 , wherein the nose axis is linear. 
     
     
         21 . The interbody implant of  claim 1 , wherein:
 the proximal portion of the cage portion includes a proximal wall and the distal portion of the cage portion includes a distal wall;   the proximal wall and the distal wall are separated by opposing side walls;   the proximal wall, distal wall, and opposing side walls define a superior edge surface and an inferior edge surface;   the cage axis passes through a center of the proximal wall and a center of the distal wall and   the distal wall defines an inlet to the through-passage of the nose portion that is concentric with the nose axis.   
     
     
         22 . The interbody implant of  claim 21 , wherein at least one of the superior edge surface and the inferior edge surface defines a plurality of gripping facets. 
     
     
         23 . The interbody implant of  claim 22 , wherein each of the plurality of gripping facets defines a ridge that extends along a ridge line, the ridge line extending proximally at a swept angle relative to the cage axis, the swept angle defining an acute angle. 
     
     
         24 . The interbody implant of  claim 21 , wherein each of the opposing side walls defines a side graft window that passes therethrough. 
     
     
         25 . The interbody implant of  claim 24 , wherein the side graft window defines an elongate slot. 
     
     
         26 . The interbody implant of  claim 25 , wherein the elongate slot extends substantially parallel to the cage axis. 
     
     
         27 . The interbody implant of  claim 21 , wherein the proximal wall defines an exterior recess and a through-hole, the through-hole being defined at a distal face of the exterior recess and concentric about the cage axis. 
     
     
         28 . The interbody implant of  claim 27 , wherein the exterior recess is polygonal. 
     
     
         29 . (canceled) 
     
     
         30 . The interbody implant of  claim 21 , wherein at least one of the superior edge surface and the inferior edge surface defines a convex profile that is arcuate about a lateral axis, the lateral axis being perpendicular to the cage axis and passing through the opposing side walls. 
     
     
         31 . The interbody implant of  claim 1 , wherein the nose portion extends from a base plane proximate the distal portion of the cage portion, the base plane being orthogonal to the nose axis. 
     
     
         32 . The interbody implant of  claim 1 , wherein the outer surface of the nose portion is axisymmetric about the nose axis. 
     
     
         33 . The interbody implant of  claim 1 , wherein the interbody implant is titanium. 
     
     
         34 .- 37 . (canceled)