Steerable laser probe

1. An instrument comprising:

an actuation structure of a handle having an actuation structure distal end and an actuation structure proximal end wherein the handle has a handle distal end and a handle proximal end;

a nosecone having a housing tube housing;

a first link wherein the first link is fixed to the actuation structure by a first link pin and wherein the first link is fixed to the nosecone by a second link pin;

a first spacer disposed over the first link pin, the first spacer configured to prevent movement of the first link relative to the first link pin;

a second spacer disposed over the second link pin, the second spacer configured to prevent movement of the first link relative to the second link pin;

a second link wherein the second link is fixed to the actuation structure by a third link pin and wherein the second link is fixed to the nosecone by a fourth link pin and wherein a rotation of the first link about the first link pin and the second link pin and a rotation of the second link about the third link pin and the fourth link pin is configured to extend the nosecone relative to the handle proximal end;

a single housing tube having a housing tube distal end and a housing tube proximal end wherein the housing tube proximal end is disposed within the housing tube housing and wherein the housing tube proximal end is fixed within the housing tube housing;

a first housing tube portion of the housing tube having a first inner diameter, the first housing tube portion having a first stiffness;

a second housing tube portion of the housing tube having a second inner diameter, the second housing tube portion having a second stiffness wherein the second stiffness is greater than the first stiffness and wherein the first inner diameter is larger than the second inner diameter;

a cable having a cable distal end and a cable proximal end, the cable disposed in a cable housing and the housing tube wherein the cable is fixed in the cable housing and wherein the cable is fixed to a portion of the housing tube; and

an optic fiber having an optic fiber distal end and an optic fiber proximal end, the optic fiber disposed in the actuation structure and the housing tube wherein the optic fiber distal end is adjacent to the housing tube distal end and wherein a portion of the optic fiber is fixed to the housing tube.

2. The instrument of claim 1 wherein a compression of the actuation structure is configured to curve the optic fiber.

3. The instrument of claim 2 wherein the compression of the actuation structure is configured to curve the optic fiber at least 45 degrees relative to the housing tube proximal end.

4. The instrument of claim 3 wherein the compression of the actuation structure is configured to curve the optic fiber at least 90 degrees relative to the housing tube proximal end.

5. The instrument of claim 1 wherein a compression of the actuation structure is configured to curve the housing tube.

6. The instrument of claim 5 wherein the compression of the actuation structure is configured to curve the housing tube at least 45 degrees.

7. The instrument of claim 6 wherein the compression of the actuation structure is configured to curve the housing tube at least 90 degrees.

8. The instrument of claim 1 further comprising:

a piston having a piston distal end and a piston proximal end.

9. The instrument of claim 1 further comprising:

an inner hypodermic tube having an inner hypodermic tube distal end and an inner hypodermic tube proximal end.

10. The instrument of claim 1 further comprising:

an actuation guide having an actuation guide distal end and an actuation guide proximal end.

11. The instrument of claim 1 further comprising:

an outer sleeve having an outer sleeve distal end and an outer sleeve proximal end.

12. The instrument of claim 1 further comprising:

a redundant cable having a redundant cable distal end and a redundant cable proximal end, the redundant cable configured to maintain a particular curved position of the housing tube if the cable fails to maintain the particular curved position of the housing tube.

13. An instrument comprising:

an actuation structure of a handle having an actuation structure distal end and an actuation structure proximal end wherein the handle has a handle distal end and a handle proximal end;

a nosecone having a housing tube housing;

a first link wherein the first link is fixed to the actuation structure by a first link pin and wherein the first link is fixed to the nosecone by a second link pin;

a first spacer disposed over the first link pin, the first spacer configured to prevent movement of the first link relative to the first link pin;

a second spacer disposed over the second link pin, the second spacer configured to prevent movement of the first link relative to the second link pin;

a second link wherein the second link is fixed to the actuation structure by a third link pin and wherein the second link is fixed to the nosecone by a fourth link pin and wherein a rotation of the first link about the first link pin and the second link pin and a rotation of the second link about the third link pin and the fourth link pin is configured to extend the nosecone relative to the handle proximal end;

a single housing tube having a housing tube distal end and a housing tube proximal end wherein the housing tube proximal end is disposed within the housing tube housing and wherein the housing tube proximal end is fixed within the housing tube housing;

a first housing tube portion of the housing tube having a first inner diameter, the first housing tube portion having a first stiffness;

a second housing tube portion of the housing tube having a second inner diameter, the second housing tube portion having a second stiffness wherein the second stiffness is greater than the first stiffness and wherein the first inner diameter is larger than the second inner diameter;

a cable having a cable distal end and a cable proximal end, the cable disposed in a cable housing and the housing tube wherein the cable is fixed in the cable housing and wherein the cable is fixed to a portion of the housing tube;

a redundant cable having a redundant cable distal end and a redundant cable proximal end; and

an optic fiber having an optic fiber distal end and an optic fiber proximal end, the optic fiber disposed in the actuation structure and the housing tube wherein the optic fiber distal end is adjacent to the housing tube distal end and wherein a portion of the optic fiber is fixed to the housing tube.

14. The instrument of claim 13 wherein a compression of the actuation structure is configured to curve the optic fiber.

15. The instrument of claim 13 wherein a compression of the actuation structure is configured to curve the housing tube.

16. The instrument of claim 13 wherein a decompression of the actuation structure is configured to straighten the optic fiber.

17. The instrument of claim 13 wherein a decompression of the actuation structure is configured to straighten the housing tube.

18. The instrument of claim 13 further comprising:

a piston having a piston distal end and a piston proximal end; and

an inner hypodermic tube having an inner hypodermic tube distal end and an inner hypodermic tube proximal end wherein the inner hypodermic tube proximal end is disposed in the piston.

19. The instrument of claim 13 further comprising:

an outer sleeve having an outer sleeve distal end and an outer sleeve proximal end.

20. The instrument of claim 19 further comprising:

an actuation guide having an actuation guide distal end and an actuation guide proximal end wherein the actuation guide is disposed in the outer sleeve.