Bone marrow biopsy needle

Abstract

The present invention is directed to a biopsy needle for extracting bone marrow from a living bone. The biopsy needle comprises an outer cannula, an inner cannula slidable therein, an obturator and an ejector rod. The outer cannula has a proximal end, affixed to a handle, and a distal end which has a tapered inner diameter. The inner cannula likewise has a proximal end, affixed to an interlocking handle, and a distal end. The inner cannula distal ends consists of a tissue receiving region and a tissue grasping mechanism. The tissue grasping mechanism comprises a resilient deformable wall with an asymmetric configuration, preferably, two opposing slits, and a structure-maintaining spanning member. The tissue grasping member is which are deformed and at least partially closed upon insertion into the tapered region of the outer cannula. In operation, this deformation severs a tissue sample into the receiving region of the inner cannula, which may then be withdrawn from a patient. A spring biased ejector rod displaces the sample from the inner cannula, while also reforming the tissue grasping portion of the inner cannula to its original pre-biopsy shape. The obturator may be used in combination with the outer cannula for initial insertion of the needle into the patient.