Device for retrieving a body from a tubular structure

1. A device for retrieving a body from within a tubular structure, the device having a proximal end and a distal end and comprising:

a device body at the proximal end, the device body defining a guide channel;

a conduit extending away from the device body to the distal end and sized to be receivable in the tubular structure;

at least one actuator operably associated with the device body, the at least one actuator comprising a first actuator and a second actuator, wherein the first and second actuators are separately operable;

a first strand extending at least in part through the conduit;

a second strand extending at least in part through the conduit;

wherein the first and second strands are affixed at the distal end of the device, and wherein the second strand is wound around the first strand along at least a distal length of the first strand;

wherein moving the first actuator proximally away from the second actuator causes the second strand to adopt an expanded state in which the second strand defines a trawl volume to catch the body for retrieval of the body from the tubular structure;

wherein at least one of the first actuator and the second actuator is moveable relative to the device body within the guide channel, and has at least one engagement portion to engage with at least one complementary structure of the channel, such that when the at least one engagement portion is engaged with the at least one complementary structure, the at least one of the first actuator and the second actuator are caused to be retained in place relative to the device body by the engagement portion; and

wherein the first strand is coupled to the first actuator and the second strand is coupled to the second actuator, whereby relative movement between the first and second actuators causes relative movement between the first and second strands, and wherein the first actuator is movable in an axial direction to cause axial movement of at least a proximal end of the first strand and the second actuator is movable in a proximal direction to cause proximal movement of at least a proximal end of the second strand.

2. The device of claim 1 , wherein the trawl volume is defined by a spiral shape of the second strand in the expanded state.

3. The device of claim 1 , wherein the trawl volume tapers inwardly toward the first strand in a direction toward the distal end.

4. The device of claim 1 , wherein the second strand is formed of a shape-memory alloy along at least a distal length of the second strand.

5. The device of claim 4 , wherein the distal length of the second strand is formed to have a shape memory that defines the trawl volume.

6. The device of claim 1 , wherein in the expanded state, the second strand extends radially beyond an outside diameter of the conduit.

7. The device of claim 1 , wherein relative movement between the first actuator and the second actuator causes the second strand to adopt a contracted state in which the second strand extends radially adjacent the first strand.

8. The device of claim 1 , wherein the first strand has a larger diameter and stiffness than a diameter and stiffness of the second strand.

9. The device of claim 1 , further comprising a distal tip sleeve located at a distal extremity of the device, the distal tip sleeve receiving distal ends of the first and second strands, wherein the distal tip sleeve has a diameter greater than or equal to a diameter of the conduit.

10. The device of claim 9 , wherein the distal tip sleeve retains the distal ends of the first and second strands in fixed relation to each other by clamping or crimping them together.

11. The device of claim 9 , wherein the distal tip sleeve has a rounded external profile.

12. The device of claim 1 , wherein relative movement between the first actuator and the second actuator causes the first and second strands to adopt a retracted state in which distal lengths of the first and second strands are substantially enclosed within the conduit, wherein in the retracted state, the conduit obstructs the second strand from adopting the expanded state.

13. The device of claim 1 , wherein relative movement between the first actuator and the second actuator causes the first and second strands to adopt an extended state in which distal lengths of the first and second strands are substantially uncovered by the conduit, wherein in the extended state, the conduit does not obstruct the second strand from adopting the expanded state.

14. The device of claim 1 , wherein the second strand is caused to adopt the expanded state in response to relative movement between the first and second actuators.

15. The device of claim 1 , wherein the at least one engagement portion and the at least one complementary structure comprises a resiliently deflectable portion and a mating socket, wherein manual force can be applied to remove the resiliently deflectable portion from the mating socket.

16. The device of claim 1 , wherein at least one of the first actuator and the second actuator is slidably moveable relative to the device body.

17. The device of claim 1 , wherein the conduit defines a lumen within which the first and second strands extend, the lumen and the first and second strands being sized to allow flow of fluid through the lumen toward the distal end.

18. The device of claim 17 , further comprising a fluid inlet arranged on the device body, the fluid inlet in fluid communication with the lumen to allow contrast fluid to be passed from the fluid inlet to the distal end via the lumen.

19. The device of claim 1 , wherein the conduit is sized to be receivable within an instrument channel of an endoscope.

20. The device of claim 1 , wherein the first and second strands are metallic strands formed of bio-compatible materials.

21. Use of the device of claim 1 to retrieve a body from a tubular structure.