Biopsy device and method

A method of securing a biopsy sample from animal tissue, consisting essentially of the steps of:

• providing a device having a first cutting means and a second cutting means, said first cutting means being partially contained within the second cutting means, said second cutting means being advanceable, said first cutting means having first and second chambers each having a substantially constant but different diameter, and a plug means in sealed relation within the second chamber and slidably mounted therein, said plug means dividing said second chamber into an adjustable volume vacuum region located between said first chamber and said plug means that is in fluid communication with said first chamber and a non-vacuum region that is not in fluid communication with said first chamber;
• extending the first cutting means outwardly beyond the first cutting means;
• inserting the device into the tissue to be sampled;
• holding the first cutting means stationary and advancing the second cutting means further into the tissue so that a distal end of the first cutting means is spaced from the distal end of the second cutting means and contained within the second cutting means and such that said distal end of said second cutting means is spaced further away from said plug means that it was in said inserting step;
• creating a partial vacuum within only the first chamber and said vacuum region of the second chamber during said holding and advancing step thereby simultaneously coring the biopsy sample and retaining the sample within the first cutting means;
• and
• removing the device from the tissue with the biopsy sample within the second cutting means.

A device for obtaining a biopsy sample consisting essentially of:

• a stylet having proximal and distal ends and an intermediate area between said proximal and distal ends;
• plug means having an aperture therethrough, first and second sides and inner and outer surfaces, said stylet extending through said aperture of said plug means, and said inner surface of said plug means being rigidly attached to said intermediate area of said stylet;
• a hollow cannula having proximal and distal ends, a first chamber having an inner surface with a smaller diameter than said plug means, and a second chamber having an inner surface integral with and larger in diameter than said first chamber, said first and second chambers partially enclosing said stylet, said outer surface of said plug means being in sealed relation with said inner surface of said second chamber and being slidable relative thereto, said first chamber being in fluid communication with a portion of said second chamber and the diameters of each said chambers being substantially constant along their entire lengths;
• means for coring a sample at said distal end of said cannula;
• said cannula being movable from a first position where the distal end thereof is spaced from the distal end of said stylet and where the distal end of said stylet protrudes beyond the distal end of said cannula to a second position where the distal end thereof is extended in a direction away from said plug means and the distal end of said stylet is contained within said cannula, said stylet being substantially stationary during the movement of said cannula from said first to said second position such that the biopsy sample is cored by said coring means and simultaneously urged into and contained within said first chamber and a partial vacuum is created in said first chamber and a portion of said second chamber due to the movement of said cannula from said first to said second position;
• means for moving said cannula from said first position to said second position;
• said moving means including means for supporting and holding said stylet in a fixed position;
• and
• means for supporting and guiding said stylet and cannula.