Agent delivery catheter

1. An agent delivery catheter, comprising a first hollow tube and a second hollow tube which protrudes from a distal opening of the first hollow tube and defines an agent delivery lumen extending along the entire length of the catheter, wherein: a distal end of the first tube is coupled to the second tube to form an annular cavity between the first tube and the second tube, the annular cavity being configured to accommodate a retractable stylet shaft, wherein a ceramic member which is disposed at the distal end of the first tube encompasses the second tube and couples the first tube to the second tube, wherein a protective shrink-fit tube is disposed radially on the outside of the ceramic member and extends over at least a length of the ceramic member, and wherein the agent deliver catheter further comprises an adapting member which is disposed on and coupled to a proximal end of the ceramic member and configured to receive a distal end of the retractable stylet shaft.

2. The agent delivery catheter according to claim 1 , wherein the second tube protrudes from a distal opening of the ceramic member, wherein a stiffening tube protrudes from the distal opening of the ceramic member and extends over at least a part of a protruding portion of the second tube.

3. The agent delivery catheter according to claim 2 , wherein the stiffening tube is disposed radially between the second tube and the ceramic member.

4. The agent delivery catheter according to claim 1 , wherein the adapting member comprises a circumferential inner surface which is configured to establish a frictional fit or positive fit between the distal end of the stylet shaft and the adapting member.

5. The agent delivery catheter according to claim 1 , wherein the adapting member comprises a protrusion which extends centrally in a distal direction from a distal end of the adapting member into a proximal opening of the ceramic member.

6. The agent delivery catheter according to claim 1 , wherein an outer diameter of a distal section of the ceramic member decreases in a distal direction, or an outer diameter of a proximal section of the ceramic member is constant.

7. The agent delivery catheter according to claim 1 , wherein the shrink-fit tube extends beyond a distal opening of the ceramic member, and wherein a curable agent is provided between the shrink-fit tube and the ceramic member.

8. The agent delivery catheter according to claim 7 , wherein the shrink-fit tube extends up to a distal opening of a stiffening tube.

9. The agent delivery catheter according to claim 1 , wherein a diameter of the portion of the catheter situated proximally with respect to the ceramic member is substantially constant or is smaller than a diameter of the ceramic member.

10. The agent delivery catheter according to claim 1 , wherein the shrink-fit tube is shrunk directly onto the outer surface of the ceramic member.

11. The agent delivery catheter according to claim 10 , wherein the shrink-fit tube is shrunk directly onto an outer surface of the first tube or onto an outer surface of a stiffening tube.

12. The agent delivery catheter according to claim 1 , wherein a distal opening of a stiffening tube or the ceramic member is disposed at a predetermined position relative to a distal opening of the second tube.

13. The agent delivery catheter according to claim 1 , further comprising at least one additional ceramic member at a predetermined position relative to the catheter.

14. The agent delivery catheter according to claim 1 , wherein the catheter is configured to allow tunnelling.

15. The agent delivery catheter according to claim 1 , further comprising a hollow head fixation member which defines a volume for accommodating the first tube for attaching the catheter directly to a bony anatomical structure, wherein the head fixation member comprises a hollow bone fixation member which has an outer bone fixation thread at its distal end, a threaded proximal end, and a receptacle for receiving a correspondingly formed portion of a tightening and loosening tool, wherein the head fixation member also comprises: a soft hollow silicone tube which is accommodated in the bone fixation member; a hollow adapting member which is configured to allow the second tube, which leaves the fixation member, to be tunnelled without kinking, wherein the hollow adapting member has a distal thread which corresponds to the threaded proximal end of the bone fixation member; and a covering member which is adapted to be attached to an open proximal end of the hollow adapting member for providing a cover or a seal for an opening of the head fixation member.

16. An agent delivery system, comprising a catheter according to claim 1 , and a stylet which comprises a handle portion and a ceramic shaft which is configured to be accommodated within the annular cavity of said catheter, wherein a shrink-fit tube is disposed radially on the outside of the ceramic shaft and extends over at least the length of the ceramic shaft.

17. The agent delivery system according to claim 16 , further comprising tracking members at the handle portion of the stylet or the distal section of the catheter, which allow the catheter or stylet to be tracked, wherein the tracking members comprise one or more tracking markers selected from the group consisting of:

optical, IR tracking markers;

EM tracking markers;

MRI-compatible tracking markers.

18. The agent delivery catheter according to claim 1 , wherein the adapting member is configured to be releasably secured to the distal end of the stylet shaft via a positive fit or a frictional fit.

19. The agent delivery catheter according to claim 1 , wherein the ceramic member is disposed distally with respect to the distal opening of the first tube or couples the first tube to the second tube via a third hollow tube which encompasses the first tube and the ceramic member.

20. An agent delivery catheter, comprising a first hollow tube and a second hollow tube which protrudes from a distal opening of the first hollow tube and defines an agent delivery lumen extending along the entire length of the catheter, wherein: a distal end of the first tube is coupled to the second tube to form an annular cavity between the first tube and the second tube, the annular cavity being configured to accommodate a retractable stylet shaft, wherein a ceramic member which is disposed at the distal end of the first tube encompasses the second tube and couples the first tube to the second tube, and wherein a protective shrink-fit tube is disposed radially on the outside of the ceramic member and extends over at least a length of the ceramic member, further comprising a hollow head fixation member which defines a volume for accommodating the first tube for attaching the catheter directly to a bony anatomical structure, wherein the head fixation member comprises a hollow bone fixation member which has an outer bone fixation thread at its distal end, a threaded proximal end, and a receptacle for receiving a correspondingly formed portion of a tightening and loosening tool, wherein the head fixation member also comprises: a soft hollow silicone tube which is accommodated in the bone fixation member; a hollow adapting member which is configured to allow the second tube, which leaves the fixation member, to be tunnelled without kinking, wherein the adapting member has a distal thread which corresponds to the threaded proximal end of the bone fixation member; and a covering member which is adapted to be attached to an open proximal end of the adapting member for providing a cover or a seal for an opening of the head fixation member.