| 摘要 |
An instrument (10) for removing tissue samples from a tissue mass which automatically penetrates, severs, and removes a tissue portion for examination. The instrument is motor (18) powered, preferably by self-contained rechargeable batteries, and employs electrically actuated stops to control the action of penetration into and retraction from the tissue mass. The tissue penetrating means and severing means includes an inner stylet (14) which penetrates the tissue mass and a hollow outer tube or cannula (13) which surrounds the stylet and serves to sever a sample of tissue. In a preferred form the tissue penetrating end of the stylet is notched so that when the stylet penetrates the tissue mass, a portion of the tissue relaxes in the notched area. After tissue penetration by the stylet, the cannula, having a cutting surface at its distal end, penetrates the tissue and cuts off the tissue portion residing in the notched area of the stylet. The tissue penetrating and severing means are operably connected to a motor powered rotary cam assembly (55) by means of cam followers (60) and the rotary motion of the cam is converted to sequential, linear motion in the tissue penetrating means and severing means. The angular position of a cam is monitored with a pair of optoelectronic sensors, thereby providing position feedback without mechanical wear on the position sensor assembly. Improved action is provided by a cam having an S-curve profile (56). <IMAGE> |
