Posterior process dynamic spacer

1. An interspinous implant for insertion into an interspinous space between adjacent spinous processes, comprising:

a) a central body having an upper surface for bearing against an upper spinous process, a lower surface for bearing against a lower spinous process, and first and second side portions,

b) a first upper extension extending upward from the first side portions,

c) a second upper extension extending upward from the second side portion, the upper extensions collectively defining an upper bracket, and

d) a first lower extension extending downward from the first side portion,

e) a second lower extension extending downward from the second side portion, the lower extensions collectively defining a lower bracket,

wherein each of the first upper and first lower extensions comprises a shape memory metal,

wherein the implant is a unitary body,

wherein the first upper and first lower extensions are adapted to superelastically extend sideways in a martensitic phase, and

wherein the first upper and first lower extensions are adapted to extend upwards and downwards in an austenitic phase.

2. The implant of claim 1 wherein the first upper and first lower extensions are adapted to superelastically extend in a substantially parallel manner in a martensitic phase.

3. The implant of claim 2 wherein at least one of the first upper and first lower extensions has a chamfered end.

4. The implant of claim 2 wherein the upper and lower surfaces of the central body define a body height H CB , wherein each of the first and second lower extensions have an end defining an extension height therebetween H E , and wherein the extension height H E is less than the central body height H CB .

5. The implant of claim 2 wherein the first upper and first lower extensions are adapted to extend in a substantially parallel manner in an austenitic phase.

6. The implant of claim 2 wherein the upper and lower surfaces of the central body have an anterior-posterior groove adapted to cradle the spinous processes.

7. The implant of claim 2 wherein the upper and lower surfaces of the central body are parallel.

8. The implant of claim 2 wherein the upper and lower surfaces of the central body are angled.