Shape-transferring cannula system and method of use

1. A medical device comprising:

an inner element;

a pressure source operably coupled to the inner element; and

an outer element positioned at least in part around the inner element and translatable with respect to the inner element;

wherein:

the inner element comprises compression-stiffening particles, the compression-stiffening particles being transitionable from a first state to a second state in response to application of pressure, and the compression-stiffening particles having a higher rigidity in the second state than in the first state; and

the pressure source is configured to apply pressure to the inner element sufficient to transition the compression-stiffening particles from the first state to the second state.

2. The medical device of claim 1 , wherein the inner element and the outer element are elongated in a longitudinal direction.

3. The medical device of claim 1 , wherein the medical device is part of a cannula system.

4. The medical device of claim 3 , wherein:

the inner element is a core structure, and the outer element is a sheath positioned concentrically around the core structure.

5. The medical device of claim 1 , wherein, in the second state, the compression-stiffening particles are interlocked.

6. The medical device of claim 5 , wherein the compression-stiffening particles comprise expanded polystyrene.

7. The medical device of claim 1 , wherein the pressure source is a vacuum source.

8. The medical device of claim 1 , wherein:

the compression-stiffening particles are first compression-stiffening particles;

the outer element comprises a tube having a lateral wall surrounding a passage, the lateral wall being a double-walled structure comprising an outer wall and an inner wall; and

the outer element comprises second compression-stiffening particles located in a space between the outer wall and the inner wall.

9. The medical device of claim 8 , wherein the pressure source is operably coupled to the passage.

10. The medical device of claim 8 , wherein the pressure source is a vacuum source operably coupled to draw a vacuum in the space between the outer wall and the inner wall.

11. The medical device of claim 10 , wherein:

the inner wall is compliant, the inner wall being suctioned against the second compression-stiffening particles of the outer element in response to the vacuum being drawn in the space.

12. The medical device of claim 1 , wherein:

the inner element further comprises a tube comprising a lateral wall surrounding a passage, and

the compression-stiffening particles are in the passage of the tube.

13. The medical device of claim 1 , wherein:

the compression-stiffening particles are first compression-stiffening particles;

the outer element comprises second compression-stiffening particles, the second compression-stiffening particles being transitionable from a first state to a second state in response to application of pressure, and the second compression-stiffening particles having a higher rigidity in the second state than in the first state; and

the pressure source is operably coupled to the outer element and configured to apply pressure to the outer element sufficient to transition the second compression-stiffening particles from the first state to the second state.

14. The medical device of claim 13 , wherein the outer element comprises a tube having a lateral wall surrounding a passage, the lateral wall being a double-walled structure comprising an outer wall and an inner wall, the second compression-stiffening particles located in a space between the outer wall and the inner wall.

15. A medical device comprising:

an inner tube surrounding an interior space;

a pressure source operably coupled to the inner tube to pressurize the interior space;

an outer tube positioned at least partially around the inner tube, a space located between the outer tube and the inner tube; and

compression-stiffening particles in the space between the outer tube and the inner tube, the compression-stiffening particles being transitionable from a first state to a second state in response to application of pressure from the pressure source to the interior space, the pressure causing expansion of the inner tube against the compression-stiffening particles, the compression-stiffening particles having a higher rigidity in the second state than in the first state.

16. The medical device of claim 15 , wherein the medical device is part of a cannula system.

17. The medical device of claim 16 , wherein the medical device is a core structure of the cannula system.

18. The medical device of claim 16 , wherein the medical device is a sheath of the cannula system that is positioned concentrically around a core structure of the cannula system.

19. A medical device comprising:

a tube comprising a lateral wall surrounding a central passage; and

compression-stiffening particles in the central passage of the tube, the compression-stiffening particles being transitionable from a first state to a second state in response to application of pressure to the compression-stiffening particles, the compression-stiffening particles having a higher rigidity in the second state than in the first state.

20. The medical device of claim 19 , further comprising a pressure source operably coupled to the central passage.

21. The medical device of claim 20 , wherein the pressure source comprises a vacuum source configured to draw a vacuum in the central passage.

22. The medical device of claim 19 , wherein the medical device is part of a cannula system.

23. The medical device of claim 22 , wherein the medical device is configured to be a core structure of the cannula system.