Catheter for aspirating, fragmenting and removing extractable material from blood vessels
The invention relates to a catheter for aspirating, fragmenting and removing extractable material from hollow bodies, in particular thrombi and emboli from blood vessels, with a working head, which is arranged at the distal end of the catheter, is axially displaceable along a guide wire, independently thereof, and comprises at least one lateral opening. The catheter comprises a flexible feed screw which has a distal end and a proximal end and which can be rotated at a speed of rotation by means of a rotary drive of a drive unit remote from the working head. A flexible tube which surrounds the feed screw and is connected to the working head removes the material or the detached thrombi and emboli fragments. The feed screw is designed as a shearing cutting tool which cooperates with the opening in the working head in order to size-reduce and remove the materials or aspirated and/or detached thrombi and emboli which penetrate between the peripheral edges of the feed screw and edges of the openings. A thrust bearing is arranged between the distal end of the feed screw and the working head so as to axially support the feed screw, and is designed as a disc which can be rotated by the feed screw during operation.
1. A catheter for aspirating, fragmenting and removing extractable material from hollow bodies, in particular thrombi and emboli from blood vessels, comprising:
a working head, which has an inner diameter of an inner surface, arranged at a distal end of the catheter and axially displaceable along a guide wire, independently thereof, which working head comprises at least one lateral opening;
a flexible tube connected to the working head to remove the material or the detached thrombi and emboli fragments; and
a flexible feed screw disposed within the flexible tube and the working head, the flexible feed screw having an outer diameter, a distal end and a proximal end, and rotating at a speed of rotation by means of a rotary drive of a drive unit remote from the working head, the feed screw being designed as a shearing cutting tool which cooperates with the opening in the working head in order to size-reduce the materials or aspirated and/or detached thrombi and emboli which penetrate between the peripheral edges of the feed screw and edges of the at least one lateral opening; and
a thrust bearing arranged between the distal end of the feed screw and the working head, the thrust bearing being designed as a disc which is rotated by the feed screw during operation.
2. The catheter according to claim 1 , wherein the disc includes a material with a low coefficient of friction, preferably of plastics material.
3. The catheter according to claim 1 , wherein the feed screw is biased under axial pressure by the thrust bearing.
4. The catheter according to claim 3 , wherein the biasing pressure of the feed screw is adjustable, the biasing pressure of the feed screw preferably being set in such a way that the thrust bearing co-rotates at approximately half the speed of rotation of the feed screw.
5. The catheter according to claim 1 , wherein the at least one lateral opening in the working head is formed as circular holes, each having a circumference.
6. The catheter according to claim 5 , wherein the at least one lateral opening in the working head is formed in each case as at least two holes arranged axially in succession.
7. The catheter according to claim 6 , wherein the circumferences of the holes overlap.
8. The catheter according to claim 6 , wherein the holes are interconnected by a slit which extends in the axial direction and is arranged substantially centrally to the holes.
9. The catheter according to claim 8 , wherein the slit extends beyond the holes toward the proximal end of the catheter.
10. The catheter according to claim 1 , wherein two approximately diametrically opposed openings are arranged in the working head.
11. The catheter according to claim 1 , wherein the outer diameter of the distal part of the feed screw in the region of the working head is designed so as to fit precisely against the inner diameter of the preferably cylindrical working head, in such a way that the outer diameter of the feed screw has only minimal diametrical play relative to the inner diameter of the inner surface of the working head.
12. The catheter according to claim 1 , wherein edges are provided on the outer face of the feed screw and are sharp-edged, at least in the region of the opening in the working head.
13. The catheter according to claim 1 , wherein the working head is tapered toward its distal end.
14. The catheter according to claim 1 , wherein the lateral opening comprises cutting edges in the region of the inner surface of the working head, which cutting edges are sharp-edged, at least over portions.
15. The catheter according to claim 1 , wherein edges of the lateral opening are rounded, at least over portions, in the region of the outer surface of the working head.