Interspinous process implant with slide-in distraction piece and method of implantation

1 . An interspinous implant adapted to be arranged between spinous processes, the implant comprising:

an initiating piece; and

a distraction piece that can be slidably associated with the initiating piece so that the distraction piece is disposed adjacent the initiating piece;

wherein the initiating piece is adapted to be arranged between the spinous processes before the distraction piece is disposed over the initiating piece.

2 . The implant of claim 1 , further comprising:

a cavity disposed within at least a portion of the initiating piece;

a protrusion extending from at least a portion of the distraction piece; and

wherein when the distraction piece is slidably associated with the initiating piece, the protrusion is received within the cavity.

3 . The implant of claim 2 , wherein:

the cavity is a slot having a flange extending from a periphery of the slot; and

the protrusion is a rail having a flange extending from a periphery of the rail.

4 . The implant of claim 1 , wherein:

the initiating piece includes a sliding surface against which the distraction piece can slide and a contact surface adapted to contact one of the spinous processes; and

the sliding surface is arranged at a non-zero angle relative to the contact surface.

5 . The implant of claim 4 , wherein:

the sliding surface of the initiating piece is a first sliding surface;

the distraction piece includes a second sliding surface against which the first sliding surface is adapted to slide; and

the second sliding surface is adapted to be arranged substantially parallel to the first sliding surface when disposed between the spinous processes.

6 . The implant of claim 5 wherein:

the contact surface of the initiating piece is a first contact surface; and

the distraction piece includes a second contact surface adapted to contact the other of the spinous processes; and

when the distraction piece is disposed over the initiating piece, a spacer is defined between the first contact surface and the second contact surface.

7 . The implant of claim 1 , wherein:

the initiating piece includes a lower distraction element, a lower portion of a first wing, a lower portion of a spacer, and a lower portion of a second wing; and

the distraction piece includes an upper distraction element, an upper portion of the first wing, an upper portion of the spacer, and an upper portion of the second wing; and

when the distraction piece is disposed over the initiating piece, the spacer is disposed between the first wing and the second wing.

8 . The implant of claim 7 , wherein one or both of the first wing and the second wing are adapted to limit movement of the implant relative to the spinous processes.

9 . The implant of claim 3 , wherein the rail includes a catch and the slot includes a recess so that when the catch is received within the recess, relative movement of the initiating piece and the distraction piece is limited.

10 . An interspinous implant adapted to be arranged between spinous processes, the interspinous implant having a first wing at a distal end of the interspinous implant, a second wing, a spacer disposed between the first wing and the second wing, and a distraction guide at the proximal end of the interspinous implant, wherein the improvement comprises:

the implant includes an initiating piece and a distraction piece adapted to be slidably associated with one another;

wherein the initiating piece includes an initiating sliding surface and an initiating contact surface, the initiating contact surface having a first portion of the first wing, a first portion of the spacer, a first portion of the second wing and a first portion of the distraction guide; and

wherein the distraction piece includes a distraction sliding surface and a distraction contact surface, the distraction contact surface having a second portion of the first wing, a second portion of the spacer, a second portion of the second wing and a second portion of the distraction guide.

11 . The implant of claim 10 , wherein:

the initiating sliding surface is arranged at a non-zero angle relative to the first portion of the spacer; and

the distraction sliding surface is adapted to be arranged substantially parallel to the initiating sliding surface when the implant is disposed between the spinous processes.

12 . The implant of claim 10 , further comprising:

a cavity disposed within at least a portion of the initiating sliding surface;

a protrusion extending from at least a portion of the distraction sliding surface; and

wherein when the distraction piece is slidably associated with the initiating piece, the protrusion is received within the cavity.

13 . The implant of claim 12 , wherein:

the cavity is a slot having a flange extending from a periphery of the slot; and

the protrusion is a rail having a flange extending from a periphery of the rail.

14 . The implant of claim 13 , wherein the rail includes a catch and the slot includes a recess so that when the catch is received within the recess, relative movement of the initiating piece and the distraction piece is limited.

15 . The implant of claim 1 , wherein:

the initiating piece including a first sliding surface and a first contact surface; and

the distraction piece including a second sliding surface and a second contact surface, the second sliding surface being adapted to slide along the first sliding surface so that the distraction piece is disposed over the initiating piece.

16 . The implant of claim 15 , further comprising:

a cavity disposed within at least a portion of the first sliding surface;

a protrusion extending from at least a portion of the second sliding surface; and

wherein when the distraction piece slides along the initiating piece, the protrusion is received within the cavity.

17 . The implant of claim 16 , wherein:

the cavity is a slot having a flange extending from a periphery of the slot; and

the protrusion is a rail having a flange extending from a periphery of the rail.

18 . The implant of claim 15 , wherein:

the first sliding surface is arranged at a non-zero angle relative to the first contact surface; and

the second sliding surface is adapted to be arranged substantially parallel to the first sliding surface when disposed between the spinous processes.

19 . A method of arranging an interspinous implant between spinous processes, the implant having a first wing, a second wing, and a spacer disposed between the first wing and the second wing, the method comprising:

using the implant, the implant including an initiating piece and a distraction piece adapted to be slidably associated with the initiating piece, the initiating piece and the distraction piece each having a portion of a first wing, a portion of a second wing, and a portion of a spacer disposed between the first wing and the second wing;

urging the initiating piece between the spinous processes so that the portion of the spacer is disposed between the spinous processes;

slidably associating the distraction piece with the initiating piece so that the distraction piece is disposed over the initiating piece such that the spacer is disposed between the spinous processes.

20 . The method of claim 20 ,

wherein:

the initiating piece includes a cavity disposed therein; and

the distraction piece includes a protrusion extending therefrom; and

further comprising:

arranging the protrusion within the cavity.