1. Description of the Prior Art
It is often necessary to obtain samples of bone and to penetrate to the bone marrow cavity, to withdraw bone marrow or other bone marrow cavity fluids for such purposes as diagnostic study or for obtaining sufficient quantity of bone marrow to be used in transplant procedures.
In penetrating the hard, outer layer of marrow containing bones a sharpened surgical instrument such as a stylet, often fittingly mated within a cannula, is generally used. The instrument must be designed to allow the physician to exercise both the necessary pressure to penetrate the hard outer layer of the bone as well as extreme care to avoid unnecessary damage to bone and surrounding tissue. During the penetration procedure, the instrument must be able to be properly handled to avoid slipping in the outer surface of the bone and to allow proper positioning and orientation of the instrument, particularly when the bone marrow cavity must be reached.
Previous biopsy needles have presented disadvantages when used in this procedure. Often the handle does not allow maintaining a secure grip on the instrument, while also controlling the orientation of the stylet and cannula during the twisting and penetrating forces exercised in the bone penetration procedure. Representative of previously available biopsy needles are those described in U.S. Pat. Nos. 4,141,365, 4,256,119, 4,262,676, 4,326,519 4,487,209 and 4,513,754.
In the commonly assigned U.S. Pat. Nos. 4,403,617 and 4,630,616 there is disclosed a bone biopsy needle having a cannula and a stylet which is slideably received within the lumen of the cannula. The stylet has a handle rigidly attached to its proximal end, the handle having a broad, palm-contacting surface extending at right angles on either side of the axis of the stylet. The cannula has a handle-receiving recess designed to prevent rotation of the handle about the stylet axis when the handle and the handle-receiving means are mated together.
2. Field of the Invention
This invention relates to instruments for withdrawing samples of bone, bone marrow and other bone marrow cavity fluids from bones as in biopsy and transplant procedures.