Systems and methods for treating bone using expandable bodies

1 . A method comprising:

establishing a percutaneous path into a tissue in a patient's spine;

introducing an cavity-forming device into the tissue through the percutaneous path, wherein the cavity-forming device comprises a expandable structure having a first volume,

expanding the expandable structure to a second volume larger than the first volume resulting in a cavity being created in the tissue,

contracting the expandable structure to a third volume between the first and second volumes such that a space is created within the cavity that is unoccupied by the expandable structure, and

conveying a filler material to fill the space in the cavity unoccupied by the expandable structure.

2 . A method according to claim 1 further comprising contracting the expandable structure towards the first volume while conveying a filler material to fill the cavity.

3 . A method according to claim 1 , wherein the tissue comprises a vertebral body.

4 . A method according to claim 1 , wherein the filler material comprises a bone cement.

5 . A method according to claim 1 , wherein the expandable structure expands by inflation.

6 . A method according to claim 1 , wherein the expandable structure comprises a balloon.

7 . A method comprising:

establishing a percutaneous path into a tissue in a patient's spine;

introducing an expandable structure into the tissue through the percutaneous path;

expanding the expandable structure to create a cavity; and

contracting the expandable structure while concurrently filing the cavity with a filler material.

8 . A method according to claim 7 , wherein the tissue comprises a vertebral body.

9 . A method according to claim 7 , wherein the filler material comprises a bone cement.

10 . A method according to claim 7 , wherein the expandable structure expands by inflation.

11 . A method according to claim 1 , wherein the expandable structure comprises a balloon.

12 . A method comprising:

establishing a percutaneous path into a tissue in a patient's body;

introducing a balloon on a balloon catheter into the vertebral body through the percutaneous path;

inflating the balloon to create a cavity in the tissue; and

injecting a filler material through the balloon catheter into the cavity while the balloon is at least partially inflated inside the cavity.

13 . A method according to claim 12 , wherein the tissue comprises a vertebral body.

14 . The method according to claim 12 , wherein the filler material comprises a bone cement.

15 . A system comprising

a source of a bone filling material,

a tool for conveying the bone filling material into a cancellous bone volume, and

an expandable structure carried on the tool sized and configured for expansion within the cancellous bone volume to create a cavity for receiving the bone filling material.

16 . A system according to claim 15

wherein the bone filling material comprises bone cement.

17 . An apparatus according to claim 15

wherein the expandable structure expands by inflation.

18 . An apparatus according to claim 15

wherein the expandable structure comprises a balloon.

19 . A system comprising

a source of a bone filling material,

a tool for conveying the bone filling material into a cancellous bone volume, and

an expandable structure carried on the tool sized and configured for expansion within the cancellous bone volume to move fractured cortical bone.

20 . A system according to claim 19

wherein the bone filling material comprises bone cement.

21 . An apparatus according to claim 19

wherein the expandable structure expands by inflation.

22 . An apparatus according to claim 19

wherein the expandable structure comprises a balloon.