Tissue core biopsy cannula

摘要

A tissue core biopsy cannula of the present invention includes a distal end which is ground in two planes which intersect each other at a first angle along a line which intersects the longitudinal axis of the cannula at a second angle. This produces a cardioid shaped opening in the distal end of the cannula. The entire edge of the sidewall is thereby inclined inward toward the distal opening and two distal cutting edges are provided. According to the presently preferred embodiment, the first angle at which the two planes intersect is approximately 60 DEG and the second angle at which the intersection of the two planes intersects the longitudinal axis of the cannula is approximately 20 DEG . In order to aid in removal of the biopsy sample from the target tissue site, the cannula according to the invention is provided with side fenestration holes and/or a split end which aids in grasping the tissue so that it can be pulled away from the target tissue site. The cannula according to the invention may be used with a solid stylet or a notched stylet and may be provided as part of a manual or automatic biopsy tool. A preferred stylet for use with the cannula has a distal end which is also ground in two planes like the distal end of the cannula.