Patent ID: 7497833

Claim:
A biopsy apparatus comprising: a housing having a distal end; an outer cannula defining first inner lumen and a tissue-receiving opening adjacent a distal end of said outer cannula, said first inner lumen having a longitudinal axis extending therethrough, said tissue receiving opening communicating with said first inner lumen, said first inner lumen having an open proximal end that terminates at said distal end of said housing; an inner cannula slidably disposed within said first inner lumen of said outer cannula and defining second inner lumen from an open distal end to an open proximal end, said second inner lumen being coaxial with said longitudinal axis of said first inner lumen, said inner cannula defining a cutting edge at said open distal end operable to sever tissue projecting through said tissue-receiving opening of said outer cannula; at least one motor that is capable of performing at least one of the following operations: rotating said inner cannula within said outer cannula; and translating said inner cannula within said outer cannula; a vacuum source in fluid communication with said second inner lumen of said inner cannula to aspirate tissue through said second inner lumen; and a leak path positioned substantially transverse to said longitudinal axis of said first and second inner lumens at said distal end of said housing and adjacent said proximal end of said first inner lumen such that the leak path is positioned outside of tissue when the biopsy device is in operation and the tissue receiving opening is positioned within tissue, wherein said leak path provides communication between said outer cannula and the atmosphere at said proximal end of said first inner lumen; and wherein said first inner lumen is selectively in communication with said second inner lumen such that said leak path operates to selectively relieve vacuum distally of tissue that has been cut, while vacuum is continuously applied to said second inner lumen and delivered to tissue through said second inner lumen to aspirate tissue through said second inner lumen when said tissue receiving opening is positioned within tissue.