| 摘要 |
A cutting member for a medical material removal instrument comprises a cutting head having an axis and an elongate drive rod eccentrically attached at a distal end to the cutting head at a location spaced from the axis. The drive rod extends substantially parallel to the axis. The cutting member is used with an introducer sheath or catheter which has a distal end portion inserted into a patient. The cutting head is provided with a cut-out on the proximal side in part for enabling a drawing of material in a proximal direction internally from a patient into a distal end of the sheath upon a partial ejection of the cutting head from the distal end of the sheath during a material removal operation. The material drawn into the sheath is severed in a scissors-type action of the cutting head against the distal end of the sheath upon a drawing of the cutting head via the drive rod into the distal end of the sheath. The cutting head has a maximal transverse cross-section conforming in a close fit to an inner surface of the sheath and is tapered from the maximal transverse cross-section in a proximal direction to facilitate a smooth and unobstructed drawing of the cutting head into the distal end of the sheath and also without damaging the sheath. The cutting head has an at least approximately semicylindrical outer surface located between the maximal transverse cross-section and a most proximal end of the cutting head. The semicylindrical outer surface serves to ensure a locating of the drive rod eccentrically relative to the sheath upon the drawing of the cutting head into the distal end of the sheath. Irrigation is optionally provided to aid in clot removal.
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