Apparatus And Methods For Aspirating Tissue

Abstract

A bone marrow aspiration device and associated method includes an introducer needle and an aspiration needle. The introducer needle includes an introducer cannula and a removable introducer stylet that includes a sharp tip to penetrate bone. The aspiration needle includes an optionally flexible aspiration cannula and a blunt stylet. The aspiration needle is receivable in the introducer cannula when the introducer stylet is removed from the introducer needle. The aspiration cannula forms a channel for aspirating bone marrow when the stylet is removed. The aspiration device also includes a locking mechanism to lock the aspiration cannula to the introducer cannula when the aspiration cannula is received in the introducer cannula, whereby the aspiration cannula can be advanced distally relative to the introducer cannula in a controlled manner, and whereby pulling the aspiration cannula proximally causes the introducer cannula to move proximally with the aspiration cannula.

What is claimed is: 
     
         1 . A bone marrow aspiration device comprising:
 an introducer needle including   an introducer cannula having a proximal end and a distal end, each end including an opening,   an introducer handle connected to the proximal end of the introducer cannula, and   a removable introducer stylet having a proximal end and a distal end, the stylet extending through the introducer cannula from the cannula handle, the distal end of the stylet extending beyond the distal end of the introducer cannula and including a sharp tip to penetrate bone;   an aspiration needle receivable in the introducer cannula when the introducer stylet is removed from the introducer needle, the aspiration needle including   an aspiration cannula having a proximal end and a distal end, the proximal end including an opening,   an aspiration handle connected to the proximal end of the aspiration cannula, and   a removable blunt stylet having a proximal end and a distal end, the stylet extending through at least a portion of the aspiration cannula from the aspiration handle,   the aspiration cannula forming a channel for aspirating bone marrow when the blunt stylet is removed; and   a locking mechanism to lock the aspiration cannula to the introducer cannula when the aspiration cannula is received in the introducer cannula, the aspiration cannula being able to advance distally relative to the introducer cannula in a controlled manner, the locking mechanism causing the introducer cannula to move proximally with the aspiration cannula when the aspiration cannula is pulled proximally.   
     
     
         2 . The aspiration device of  claim 1 , wherein the locking mechanism includes a ratchet mechanism. 
     
     
         3 . The aspiration device of  claim 2 , wherein the ratchet mechanism includes one or more teeth at the introducer needle configured to engage the aspiration cannula. 
     
     
         4 . The aspiration device of  claim 2 , wherein the ratchet mechanism includes a tube positioned over a proximal portion of the aspiration cannula, the tube including at least one of ratchet teeth to engage the introducer handle and holes to engage with a pin of introducer handle. 
     
     
         5 . The aspiration device of  claim 2 , wherein the ratchet mechanism includes a release button to unlock the aspiration cannula from the introducer cannula. 
     
     
         6 . The aspiration device of  claim 2 , wherein the ratchet mechanism includes an extension extending distally from the aspiration handle and configured to mate with the introducer handle, the extension and the introducer handle having respective mating ratchet teeth. 
     
     
         7 . The aspiration device of  claim 1 , wherein the locking mechanism includes a screw mechanism. 
     
     
         8 . The aspiration device of  claim 7 , wherein the screw mechanism includes a threaded guide in a threaded tube, the guide being attached to the aspiration cannula and the tube configured to couple to the introducer cannula. 
     
     
         9 . The aspiration device of  claim 8 , wherein the tube is configured to couple to the introducer via a luer connection, the luer connection and screw mechanism providing an air-tight fit. 
     
     
         10 . The aspiration device of  claim 8 , wherein the guide is hollow and the aspiration cannula passes through the hollow guide and the tube. 
     
     
         11 . The aspiration device of  claim 8 , wherein the screw mechanism is configured to advance the aspiration cannula distally when the aspiration handle is turned in one direction and to withdrawn the aspiration cannula proximally when the aspiration handle is turned in an opposite direction. 
     
     
         12 . The aspiration device of  claim 11 , wherein a length of the aspiration cannula that extends beyond the distal end of the introducer cannula is adjustable by advancing the threaded guide into the threaded tube or reversing the threaded guide out of the threaded tube. 
     
     
         13 . The aspiration device of  claim 7 , further including a depth guide coupled to the introducer handle, the depth guide configured to control depth of entry of the introducer cannula into bone. 
     
     
         14 . The aspiration device of  claim 13 , wherein the depth guide is adjustable and includes a lead screw and a threaded tube, whereby a length of the introducer cannula that extends beyond a distal end of the depth guide is adjustable by advancing the lead screw into the threaded tube or reversing the lead screw out of the threaded tube. 
     
     
         15 . The aspiration device of  claim 14 , wherein the lead screw is attached to the introducer handle. 
     
     
         16 . The aspiration device of  claim 14 , wherein the lead screw is hollow and the introducer cannula extends through the hollow lead screw. 
     
     
         17 . The aspiration device of  claim 14 , wherein the length of the introducer cannula that extends beyond the distal end of the depth guide is adjustable between about 1 and about 8 inches. 
     
     
         18 . The aspiration device of  claim 1 , wherein the distal end of the aspiration cannula is open and the distal end of the blunt stylet is configured to extend beyond the distal end of the aspiration cannula. 
     
     
         19 . The aspiration device of  claim 1 , wherein the distal end of the aspiration cannula is closed and the aspiration cannula includes a port in fluid communication with the channel for aspirating bone marrow 
     
     
         20 . The aspiration device of  claim 19 , wherein the port is near the distal end of aspiration cannula. 
     
     
         21 . The aspiration device of  claim 19 , wherein the port includes plural ports along a length of the aspiration cannula. 
     
     
         22 . The aspiration device of  claim 21 , wherein the ports vary in size along a length of the aspiration cannula. 
     
     
         23 . The aspiration device of  claim 22 , wherein ports near the proximal end of aspiration cannula are larger than ports near the distal end of aspiration cannula. 
     
     
         24 . The aspiration device of  claim 1 , wherein the aspiration cannula is flexible and includes a wire wound tube. 
     
     
         25 . The aspiration device of  claim 24 , wherein the wire wound tube has a winding in one direction, and wherein the locking mechanism is configured to allow the aspiration cannula to be withdrawn from the bone marrow by turning the aspiration handle in a direction opposite to direction of the winding, whereby the wire wound tube is tightened as the aspiration cannula is withdrawn. 
     
     
         26 . The aspiration device of  claim 1 , wherein the length of the aspiration cannula is substantially greater than the length of the introducer cannula. 
     
     
         27 . The aspiration device of  claim 1 , wherein the stiffness of the assembled introducer cannula and stylet is sufficiently high to allow the introducer cannula and stylet to penetrate cortical bone when a longitudinal force is applied to the introducer cannula and stylet in a distal direction. 
     
     
         28 . The aspiration device of  claim 27 , wherein the aspiration cannula is flexible, and wherein the stiffness of the assembled aspiration cannula and blunt stylet is sufficiently high to allow the aspiration cannula and blunt stylet to penetrate bone marrow when a longitudinal force is applied to the aspiration cannula and blunt stylet in a distal direction. 
     
     
         29 . The aspiration device of  claim 28 , wherein the stiffness of the assembled aspiration cannula and blunt stylet is sufficiently low to not allow the aspiration cannula and blunt stylet to penetrate cortical bone but to flex or bend when a longitudinal force is applied to the aspiration cannula and blunt stylet in a distal direction. 
     
     
         30 . The aspiration device of  claim 1 , wherein the distal end of the blunt stylet includes an atraumatic tip. 
     
     
         31 . The aspiration device of  claim 1 , wherein the aspiration handle includes a port in fluid communication with the aspiration cannula for aspirating or injecting fluid or fluid containing cells, including bone marrow. 
     
     
         32 . The aspiration device of  claim 1 , wherein the aspiration cannula and blunt stylet, upon insertion through the introducer cannula into a bone cavity, will advance through spongy bone marrow inside the bone cavity but will deflect off cortical bone, thereby conforming to the shape of the bone cavity. 
     
     
         33 . The aspiration device of  claim 1 , wherein the persistence in length of the aspiration cannula is such that the maximum angle of deflection for the first 0.5 inch segment of the aspiration cannula that extends beyond the distal end of the introducer cannula is between 0 and 30 degrees. 
     
     
         34 . A method of aspirating bone marrow, the method comprising:
 placing a needle assembly into bone of a patient, the needle assembly comprising a cannula attached to a handle and a stylet assembled into the cannula through a luer connector at the handle, the cannula having at least one side aperture, the cannula passing through a mechanism that is attached to and distal to the handle, the mechanism including a threaded tube and a lead screw receivable in the threaded tube;   removing the stylet after the needle assembly is placed into the bone;   aspirating bone marrow through the at least one side aperture; and   retrieving the cannula from the bone by rotating the lead screw relative to the threaded tube.   
     
     
         35 . The method of  claim 34 , wherein the stylet extends through the cannula and past the at least one side aperture. 
     
     
         36 . The method of  claim 34 , wherein the lead screw is attached to the handle, and wherein rotating the threaded lead screw relative to the threaded tube includes turning the handle. 
     
     
         37 . The method of  claim 34 , wherein rotating the lead screw relative to the threaded tube includes turning the threaded tube. 
     
     
         38 . The method of  claim 34 , further comprising adjusting a length of the cannula that extends beyond a distal end of the threaded tube by advancing the lead screw into the threaded tube or reversing the lead screw out of the threaded tube. 
     
     
         39 . The method of  claim 38 , wherein the length of the cannula that extends beyond the distal end of the threaded tube is adjustable between about 1 inch and about 8 inches. 
     
     
         40 . The method of  claim 34 , wherein the lead screw is hollow and the cannula extends through the hollow lead screw. 
     
     
         41 . The method of  claim 34 , wherein the at least one side aperture includes plural side apertures arranged along a length of the cannula near a distal end of the cannula. 
     
     
         42 . The method of  claim 34 , wherein the bone marrow is aspirated during retrieval of the cannula from the bone. 
     
     
         43 . The method of  claim 34 , wherein the at least one side aperture is near a distal end of the cannula, the distal end of the cannula being closed. 
     
     
         44 . The method of  claim 43 , wherein the cannula is a first cannula and the distal end of the first cannula is closed by inserting a second cannula coaxially through the first cannula after the stylet is removed, a distal end of the second cannula closing the distal end of the first cannula but leaving open the at least one side aperture of the first cannula.