Percutaneous spinal implants and methods

1. An apparatus, comprising:

a support member having an outer surface extending between proximal and distal ends of the support member, a lumen extending through an interior of the support member, and a slot extending from the outer surface into the lumen;

a retention member rotatably coupled to the support member; the retention member having a first configuration in which a portion of the retention member is disposed within the lumen and a second configuration in which the portion of the retention member extends through the slot and is disposed outside of the lumen;

in the second configuration, a first end portion of the retention member is spaced apart from the outer surface of the support member the by a first distance along an axis substantially normal to a longitudinal axis of the support member;

in the second configuration, a second end portion of the retention member is spaced apart from the outer surface of the support member by a second distance along the axis substantially normal to the longitudinal axis of the support member;

the first end portion of the retention member and the second end portion of the retention member configured to cooperatively limit movement of the support member along the longitudinal axis of the support member;

wherein a length of the support member extends along the outer surface from the proximal end to the distal end and remains constant in the first and second configurations.

2. The apparatus of claim 1 , wherein:

the axis substantially normal to the longitudinal axis of the support member is a first axis; and

the retention member is rotatably coupled to the support member about a second axis substantially normal to the longitudinal axis of the support member and substantially normal to the first axis.

3. The apparatus of claim 1 , wherein the first distance is substantially equal to the second distance.

4. The apparatus of claim 1 wherein:

the first end portion of the retention member is configured to engage a first spinous process when the outer surface of the support member is disposed between the first spinous process and an adjacent second spinous process;

the second end portion of the retention member is configured to engage the second spinous process when the outer surface of the support member is disposed between the first spinous process and the adjacent second spinous process.

5. The apparatus of claim 1 , wherein the retention member includes a central portion disposed between the first end portion and the second end portion, the central portion disposed within the support member.

6. The apparatus of claim 1 wherein in the first configuration, the support member and the retention member are configured to be inserted between a first spinous process and an adjacent second spinous process percutaneously.

7. The apparatus of claim 1 wherein the retention member is configured to rotate relative to the support member when the outer surface of the support member is disposed between a first spinous process and an adjacent second spinous process.

8. The apparatus of claim 1 wherein a portion of outer surface of the support member and at least one of the first end portion of the retention member or the second end portion of the retention member collectively form at least a portion of a saddle configured to receive a portion of a first spinous process when the outer surface of the support member is disposed between the first spinous process and an adjacent second spinous process.

9. The apparatus of claim 1 wherein the retention member is a first retention member, the apparatus further comprising:

a second retention member rotatably coupled to the support member,

a first end portion of the second retention member spaced apart from the outer surface of the support member the by a third distance along the axis substantially normal to the longitudinal axis of the support member when the outer surface of the support member is disposed between a first spinous process and an adjacent second spinous process

a second end portion of the second retention member spaced apart from the outer surface of the support member by a fourth distance along the axis substantially normal to the longitudinal axis of the support member when the outer surface of the support member is disposed between the first spinous process and the second spinous process,

the first end portion of the second retention member and the second end portion of the second retention member configured to cooperatively limit movement of the support member along the longitudinal axis and relative to the first spinous process and the second spinous process.

10. The apparatus of claim 1 further comprising a locking member configured to releasably maintain the first end portion of the retention member in engagement with a first spinous process when the outer surface of the support member is disposed between the first spinous process and an adjacent second spinous process.

11. The apparatus of claim 1 further comprising a biasing member operatively coupled to the retention member and the support member, the biasing member configured to maintain the first end portion of the retention member in engagement with a first spinous process when the outer surface of the support member is disposed between the first spinous process and an adjacent second spinous process.