BACKGROUND OF THE INVENTION

Bone is made up of a hard outer core, known as cortical bone or cortical plate, and a soft spongy interior known as cancellous bone or trabecular bone, which includes a marrow filling in the porous space within the spongy bone (commonly referred to as bone marrow). The cortical plate is very hard and provides the rigid structure to the skeleton, which allows the skeleton to bear weight. Bone marrow is rich in capillary beds.

Marrow aspiration is usually obtained from the hip bone. Currently, to draw larger volumes of marrow, clinicians usually go into the hip bone through the iliac crest. The goal is to penetrate deep into the spongy bone and then to withdraw small aliquots of marrow as the needle is withdrawn. Traditionally, marrow aspiration is performed with an aspiration needle100(FIG. 1). This needle has two basic components: a component comprising a handle104with a luer connector110for attaching a syringe106on one end, and a hollow metal tube or cannula102(also referred to as a cannulated trocar) on the other end; and a component (not shown inFIG. 1) comprising a second handle attached to a solid metal rod or stylet with a sharp pointed tip. The stylet of the marrow aspiration needle is removable. When assembled, the second handle fits over the first handle and the stylet fits through the cannula102, including the luer connector110and handle104, such that the pointed tip of the stylet extends past the distal end of the cannula102. This entire needle assembly is often referred to as a JAMSHIDI® aspiration needle.

To perform a marrow aspiration, a clinical practitioner uses the fully assembled needle to penetrate cortical bone112using the point of the stylet. The clinician uses hand pressure or a mallet to tap the assembled aspiration needle through the bone. The cannula and stylet are usually made of stainless steel or titanium. The assembled aspiration needle is very hard and stiff so that the needle will not bend or buckle when longitudinal force is applied against the proximal handle to allow it to penetrate the cortical bone. Once the hard cortical bone112is penetrated, the assembled needle easily advances through the trabecular bone, including spongy marrow,114. During insertion, the stylet is left in place to prevent the hollow cannula from becoming clogged with debris as the needle is pushed through the spongy marrow. Once the needle assembly is advanced sufficiently into the trabecular bone114, the stylet, including the stylet handle, is removed to expose the luer connector110. Luer connector108of syringe106is attached to the luer connector110of the needle and a vacuum created by pulling the syringe plunger will remove the marrow (FIG. 1). Marrow aspirate is pulled through the distal end of the cannula102and into the syringe106as the needle100is slowly removed from the marrow space114.

A traditional bone marrow aspiration needle is typically used to access marrow from the hip or iliac bone. Because the traditional aspiration needle is stiff, the needle can only advance linearly within the marrow space. Once the needle is through the cortical plate, the cannula only has access to whatever marrow is directly ahead of the cannula tip, but cannot bend or access marrow to the sides of the cannula. Thus, clinicians often need to perform multiple punctures in order to gain larger volumes of aspirate from a more diverse cross section of the marrow space. Since the hip bone is long and thin, once the traditional aspiration needle has penetrated cortical bone, the sharp and stiff instrument has the potential to penetrate through the other side of the cortical bone, resulting in significant trauma. Consequently, it is important for the surgeon to have a proper angle and skilled technique to ensure a safe aspiration. Since the iliac crest curves from the front to the back of the patient, the best angle of entry is from the back. Since the stylet is made of a stiff material, once inside the spongy bone, the needle assembly can only go straight, thus requiring multiple punctures to obtain the required volume of aspirate.

A traditional marrow aspiration needle is meant to access bone marrow from larger cavities and is not ideally suited to drawing marrow from the smaller confines such as the vertebral body of the spine. Because of the sharpness and stiffness of a traditional aspiration needle, using such an instrument in the small curved marrow space of a vertebral body would greatly increase the likelihood of introducing trauma. Less invasive and safer methods to access the marrow tissue of the vertebral body are needed in an effort to support the emerging field of orthobiologics. One fast growing area of this field combines marrow aspirate with synthetic matrix material in order to facilitate instrumented assisted spinal fusion.

Therefore, a need exists for a bone marrow aspiration device that can reduce or minimize the aforementioned problems.

SUMMARY OF THE INVENTION

A bone marrow aspiration device includes an introducer needle, an aspiration needle and a locking mechanism to lock the aspiration cannula to the introducer cannula. The introducer needle includes 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. The introducer stylet has a proximal end and a distal end and extends through the introducer cannula from the cannula handle. The distal end of the introducer stylet extends beyond the distal end of the introducer cannula and includes a sharp tip to penetrate bone. The aspiration needle includes an, optionally flexible, aspiration cannula having a proximal end and a distal end, the distal end including an opening, an aspiration handle connected to the distal end of the aspiration cannula, and a removable blunt stylet. The blunt stylet has a proximal end and a distal end and extends through at least a portion of the aspiration cannula from the aspiration handle. The distal end of the blunt stylet can extend beyond the distal end of the aspiration cannula. 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 blunt stylet is removed. The locking mechanism is configured 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.

The locking mechanism can include a ratchet mechanism, a screw mechanism, or combination thereof.

The ratchet mechanism can include one or more teeth at the introducer needle configured to engage the aspiration cannula. In an embodiment, 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. The ratchet mechanism may include a release button to unlock the aspiration cannula from the introducer cannula. In an embodiment, 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 can have respective mating ratchet teeth.

Other ratchet mechanisms are contemplated. For example, a ratchet mechanism can include at least one ribbon ratchet extending between the aspiration handle and the introducer handle. For example, the ribbon ratchet may be fixedly coupled to the aspiration handle and may extend from the aspiration handle through a slot in the introducer handle. In another example, the ribbon ratchet is attached to a locking ring configured to couple the ribbon ratchet to the introducer handle, the ribbon ratchet extending from the locking ring through a slot in the aspiration handle.

The screw mechanism can include 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. The tube can be configured to couple to the introducer via a luer connection, the luer connection and screw mechanism providing an air-tight fit. The guide can be hollow and the aspiration cannula can pass through the hollow guide and the tube. The screw mechanism can be configured to advance the aspiration cannula distally when the aspiration handle is turned in one direction and to withdraw the aspiration cannula proximally when the aspiration handle is turned in an opposite direction. In an embodiment, 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.

In another embodiment, the screw mechanism includes a lead screw in a threaded receptor at the aspiration handle, the lead screw having a proximal end and a distal end, the proximal end including a handle, the distal end receivable in a dead-end receptor at the introducer handle.

The aspiration device can further include a depth guide coupled to the introducer handle, the depth guide configured to control depth of entry of the introducer cannula into bone. In one example, 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. The lead screw can be attached to the introducer handle. In an embodiment, the lead screw is hollow and the introducer cannula extends through the hollow lead screw. For example, the length of the introducer cannula that extends beyond the distal end of the depth guide can be adjustable between about 1 and about 8 inches.

In some embodiments, the distal end of the aspiration cannula is open, which can be opening near the distal end, for example, in a side of the aspiration cannula. The distal end of the blunt stylet can be configured to extend beyond the distal end of the aspiration cannula. In some embodiments, the distal end of the aspiration cannula is closed and the aspiration cannula includes one or more ports in fluid communication with the channel for aspirating bone marrow. The port(s) can be near the distal end of aspiration cannula. In some embodiments, the aspiration cannula includes plural ports along a length of the aspiration cannula. The ports may vary in size along a length of the aspiration cannula. For example, ports near the proximal end of aspiration cannula can be larger than ports near the distal end of aspiration cannula.

In an embodiment, the aspiration cannula includes a wire wound tube. The entire length of the cannula may be formed of wire wound tube or only a portion thereof. For example, a portion of the aspiration cannula, e.g., a proximal portion, may be a solid wall cannula to which a wire wound portion is welded or attached by other suitable means. The wire wound tube can have a winding in one direction and the locking mechanism can be 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.

The aspiration cannula can be flexible and the length of the aspiration cannula may be substantially greater than the length of the introducer cannula. In one embodiment, 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. The stiffness of the assembled aspiration cannula and stylet can be sufficiently high to allow the aspiration cannula and stylet to penetrate bone marrow when a longitudinal force is applied to the aspiration cannula and stylet in a distal direction. Further, the stiffness of the assembled aspiration cannula and stylet can be sufficiently low to not allow the aspiration cannula and stylet to penetrate cortical bone but to flex or bend when a longitudinal force is applied to the aspiration cannula and stylet in a distal direction. The introducer cannula may be substantially straight when the introducer stylet extends through the introducer cannula, but may revert to a preset bend when the stylet is removed.

In some embodiments, the introducer cannula includes plural holes. The holes can be near the distal end of the introducer cannula, for example along a side of the introducer cannula. The aspiration cannula can include a cutout alignable with at least one of the plural holes of the introducer cannula. In one example, the distal end of the aspiration cannula is configured to close the opening of the distal end of the introducer cannula. The aspiration needle can include a connector, e.g., a luer connector, to couple to the introducer needle in an air-tight manner.

In an embodiment, a bone marrow aspiration device includes an aspiration needle including a flexible 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 extends through at least a portion of the aspiration cannula from the aspiration handle. The aspiration cannula forms a channel for aspirating bone marrow when the blunt stylet is removed. The aspiration device further includes a depth guide coupled to the aspiration handle, the depth guide configured to control depth of entry of the aspiration cannula into bone.

A method for aspirating bone marrow includes inserting an aspiration needle into bone marrow through an introducer cannula placed in a bone, the aspiration needle including an aspiration cannula and a stylet, removing the stylet from the aspiration needle, the aspiration cannula forming a channel for aspirating bone marrow when the stylet is removed, and aspirating bone marrow through the channel. The method further includes locking the aspiration cannula to the introducer cannula with a locking mechanism, 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. The aspiration cannula has a proximal end and a distal end, the proximal end including an opening. The aspiration cannula can be flexible and the length of the aspiration cannula can be substantially greater than the length of the introducer cannula. The aspiration needle further includes an aspiration handle connected to the proximal end of the aspiration cannula. The blunt stylet has a proximal end and a distal end, the stylet extending through at least a portion of the aspiration cannula from the aspiration handle. The distal end of the stylet can extend beyond the distal end of the aspiration cannula.

In an embodiment, inserting the aspiration needle includes flexing or bending the aspiration cannula and stylet against cortical bone. Furthermore, aspirating bone marrow can include retracting the aspiration needle assembly from the bone. The locking mechanism may include a screw mechanism and inserting the aspiration needle can include employing the screw mechanism to advance the aspiration needle distally in a controlled manner. Further, aspirating bone marrow can include retracting the aspiration cannula from the bone, for example, by employing the locking mechanism to move the aspiration cannula proximally with the aspiration cannula. Before the aspiration needle is inserted, the cortical bone may be penetrated with an introducer needle that includes an introducer cannula and a stylet, such as the introducer needle described above, and the introducer stylet may be removed. The method may also include advancing the introducer needle into the bone to a selected depth before removing the introducer stylet.

