Interspinous devices and methods of use
The present application is directed to devices and methods for spacing apart spinous processes. In one embodiment, the device includes a body having a central portion that separates first and second sections. The body is constructed of a combination of an elastic material and a bio-absorbable material. When initially implanted within a patient, the bio-absorbable material affects the stiffness of the device. The device stiffness changes to that of the elastic material as the bio-absorbable material is absorbed by the body.
1 . A device to space first and second spinous processes comprising:
an elastic material positioned within a central portion that is positioned between the first and second spinous processes; and
a bio-absorbable material surrounding the elastic material;
the elastic material and bio-absorbable material acting in combination during an initial time period and comprising a first stiffness to space the first and second spinous processes, and comprising a second stiffness property after the initial time period to space the first and second spinous processes.
2 . The device of claim 1 , wherein the second stiffness is provided exclusively by the elastic material.
3 . The device of claim 1 , wherein the elastic material comprises first and second sections each at least partially positioned within the central portion.
4 . The device of claim 1 , wherein the bio-absorbable material comprises first and second sections positioned on lateral sides of the elastic material, the first and second sections comprising a greater height than the central portion.
5 . The device of claim 4 , further comprising a first set of arms extending upwardly from the first and second sections and a second set of arms extending downwardly from the first and second sections, the first and second sets of arms forming gaps to receive the spinous processes.
6 . The device of claim 1 , wherein the bio-absorbable material comprises a holding section to contain the elastic material.
7 . The device of claim 1 , further comprising a band positioned around the elastic material to control deformation of the elastic material during the initial time period.
8 . A device to space first and second spinous processes within a body, the device comprising:
an elastic material positioned within a central portion between the first and second spinous processes; and
a bio-absorbable material surrounding the elastic material, the bio-absorbable material being absorbed into the body after an initial time period of being implanted within the body;
the elastic material and bio-absorbable material together providing a stiffness during the initial time period, and the elastic material alone providing the stiffness after the initial time period.
9 . The device of claim 8 , wherein the stiffness decreases during the initial time period.
10 . The device of claim 9 , wherein the stiffness is substantially constant after the initial time period.
11 . The device of claim 8 , wherein the bio-absorbable material provides a majority of the stiffness during a first part of the initial time period and the elastic material provides the majority of the stiffness during a second part of the initial time period.
12 . The device of claim 8 , wherein the bio-absorbable material is non-compliant.
13 . The device of claim 8 , wherein the bio-absorbable material is rigid during a first part of the initial time period.
14 . The device of claim 8 , wherein the bio-absorbable material and the elastic material are both deformable during the initial time period.
15 . The device of claim 8 , wherein the bio-absorbable material is constructed of a woven fabric.
16 . The device of claim 8 , wherein the bio-absorbable material completely surrounds the elastic material.
17 . The device of claim 8 , further comprising a band that extends around the elastic material, the band configured to restrict deformation of the elastic material.
18 . A device to space first and second spinous processes within a body, the device comprising:
a bio-absorbable material comprising a holding section positioned within a central portion between the first and second spinous processes, the holding section varying between a first shape when the first and second spinous processes are in a first position and a second shape when the first and second spinous processes are in a second position; and
an elastic material confined within the holding section and having a shape determined by the holding section, the elastic material having a first stiffness when the holding section has a first shape, and a second stiffness when the holding section has a second shape;
a stiffness of the device being defined by the bio-absorbable material and the elastic material during an initial time period, and defined by the elastic material after the initial time period.
19 . The device of claim 18 , wherein the holding section is contained completely within the bio-absorbable material.
20 . The device of claim 18 , wherein the stiffness decreases during the initial time period.
21 . The device of claim 18 , wherein the stiffness is substantially constant after the initial time period.
22 . The device of claim 18 , wherein the bio-absorbable material provides a majority of the stiffness during a first part of the initial time period and the elastic material provides the majority of the stiffness during a second part of the initial time period.
23 . A device to space first and second spinous processes comprising:
an elastic material;
a bio-absorbable material surrounding at least a portion of the elastic material, the elastic material and the bio-absorbable material comprising a shape to position the elastic material between the first and second spinous processes;
the elastic material and bio-absorbable material acting in combination during an initial time period and comprising a first stiffness to space the first and second spinous processes, and comprising a second stiffness property after the initial time period to space the first and second spinous processes.