Systems and methods for delivering bone cement to a bone anchor

Abstract

A method of stabilizing a first vertebra and a second vertebra includes implanting a first bone anchor into the first vertebra, implanting a second bone anchor into the second vertebra, connecting a first anchor connection instrument to the first anchor, connecting a second anchor connection instrument the second anchor, positioning a cement delivery tube into a passage provided through the first anchor, delivering bone cement from a bone cement delivery system coupled to the bone cement delivery tube through the passage in the first anchor to the first vertebra, removing the cement delivery tube from the first anchor connection instrument and the first anchor, connecting the cement delivery tube to second anchor connecting instrument connected to the second anchor, delivering bone cement through a passage in the second anchor to the second vertebra, connecting a spinal connection element to the first anchor and the second anchor.

Description

REFERENCE TO RELATED APPLICATIONS

202A and 202B 204A and 204B are positioned diametrically opposed to one another. Thus, the connection member 200 has a threaded section 206 interposed between each unthreaded section 202A and 202B 204A and 204B. The connection member 200 may be spaced a distance F from the tip of the distal end 54 of the tube 14 selected to allow the distal end 54 of the tube 14 to be advanced into the passage 34 provided in the bone anchor 16, as illustrated in FIG. 8A.

In use, the cement delivery tube 14 may be connected to the bone anchor 16 by advancing the distal end 54 of the tube 14 into the passage 34 of the bone anchor 16, as illustrated in FIG. 8B. During insertion of the tube 14, the connection member 200 is oriented such that the unthreaded sections 204A and 204B face the internally threaded portions of the proximal portion 30 of the bone anchor 16 and the threaded sections 206 are aligned with the rod slot 31 of the proximal portion 30 of the one anchor 16, as illustrated in FIGS. 8C-D. Once the distal end 54 of the tube 14 reaches the desired depth within the passage 34 of the bone anchor 16, the tube 14 may be rotated approximately 90° to engage the thread 202 on the threaded portions 206 with the internal thread 33 on the threaded portions of the bone anchor 16, as illustrated in FIG. 8E. The tube 14 may be quickly removed from the bone anchor 16 by rotating the tube 14 approximately 90° in the opposite direction to disengage the thread 202 on the threaded portions 206 from thread 33. The tube 14 may be connected to a cement delivery system such as the cement delivery system 18 described above and cement may be injected through one or more bone anchors in a manner analogous to the methods described above.

FIGS. 11A-11B illustrate another exemplary embodiment of a system for delivering bone cement or other materials to a bone anchor. In the exemplary system, the cement delivery tube 14 may be connected to bone anchor 16 with an anchor connection instrument 300 configured to engage the interior of the proximal portion 30 of the bone anchor 16. The exemplary anchor connection instrument 300 is generally tubular in shape and has a proximal end 302, a distal end 304, and an internal lumen or passage 306 extending from the proximal end 302 and the distal end 304 for receiving the cement delivery tube 14 therein. The distal end 304 of the anchor connection instrument 300 includes two spaced-apart prongs or fingers 308A and 308B configured to selectively engage the thread 33 on the proximal portion 30 of the bone anchor 16. The prongs 308A and 308B are diametrically opposed to each other and are connected at a proximal end 310A, 310B to the anchor connection instrument 300. The prongs 308A and 308B have a free distal end 312A, 312B opposite the proximal ends 310A, 310B. Each prong 308A, 308B may pivot or flex about its proximal end 310A,B between a first, spaced-apart position, illustrated in FIG. 11A and a second, compressed position in which the prongs 308A, 308B pivot towards one another to facilitate insertion of the distal end 304 of the instrument 300 into the bone anchor. The prongs 308A, 308B are biased to the first position. The distal ends 312A, 312B of each prong 308A, 308B includes a projection 314A, 314B for engaging the internal thread 33 of the bone anchor 16.

In use, the anchor connection instrument 300 and the tube 14 may be advanced toward the bone anchor 16 to position the distal end 54 of the tube 14 within the passage 34 of the bone anchor 16, as illustrated in FIG. 11A. As the distal end 304 of the instrument 300 engages the proximal portion 30 of the bone anchor 16, the prongs 308A and 308B are compressed to the first, compressed position. The projections 314A and 314B may include a ramped surface to compress the prongs 308A, 308B toward the second position. In the second position, the projections 314A, 314B may pass the leading edge of the thread 33 of the bone anchor 16 and then snap into place beneath a crest of the thread 33 as the prongs 308A, 308B move to the first position thereby connecting the anchor connection instrument 300 and the tube 14 to the bone anchor. The anchor connection instrument 300 may be removed from the bone anchor 16 by compressing the prongs 308A, 308B to the second position and retracting the distal end 304 from the proximal portion 30 of the bone anchor 16. The tube 14 may be connected to a cement delivery system such as the cement delivery system 18 described above and cement may be injected through one or more bone anchors in a manner analogous to the methods described above.

FIGS. 12A-12C illustrate another exemplary embodiment of a system for delivering bone cement or other materials to a bone anchor. In the exemplary system, the cement delivery tube 14 may be connected to bone anchor 16 with an anchor connection instrument 400 configured to engage the interior of the proximal portion 30 of the bone anchor 16. The exemplary anchor connection instrument 400 is analogous in construction and use to the anchor connection instrument 300 described above except the anchor connection instrument 400 has a single prong 408 rather two prongs 308A, 308B. In addition, the distal end 404 of the anchor connection instrument 400 is shaped to fit within the rod slot 31 of the bone anchor 16. For example, the distal end 404 of the instrument 400 is generally T-shaped having a pair of opposed extensions 420A, 420B that extend from the instrument and that each have an arcuate lower surface for engaging the arcuate surface on the proximal portion 30 of the bone anchor 16 that bounds the rod slot 31. The extensions 420A, 420B, when positioned in the rod slot 31 of the bone anchor 16, provide stability and limit rotation of the anchor connection instrument 400 relative to the bone anchor 16. The anchor connection instrument 300 described above in connection with FIGS. 11A and 11B may also be provided with extensions analogous to extensions 420A, 420B.

FIGS. 13A-15 illustrate an another exemplary embodiment of a system for delivering bone cement or other materials to a bone anchor. In the exemplary system, a cement delivery tube 514 may be connected to bone anchor 16 with an anchor connection instrument 500 configured to engage the interior of the proximal portion 30 of the bone anchor 16 through a screw extension connected 516 to the bone anchor 16. The exemplary screw extension 516 is used to percutaneously place a bone anchor, such as bone anchor 16, and to delivery a spinal rod to the bone anchor and other bone anchors in a minimally invasive procedure. Exemplary screw extensions are available in the VIPER and VIPER II Spinal Fixation Systems available from DePuy Spine of Raynham, Mass., and are described in U.S. Patent Application Publication Nos. US 2005/0131408 and US 2005/0131421, each of which is incorporated herein by reference. The exemplary anchor connection instrument 500 is sized to fit within the exemplary screw extension 516, e.g., having an external diameter less than the inner diameter of the screw extension.

The anchor connection instrument 500 includes an inner longitudinally adjustable member 502 that receives the cement delivery tube 514 and an outer sleeve 504 positioned about the inner member 502. A handle 506 is connected to the inner member 504. The inner member 502 may be adjusted between a proximal position and a distal position relative to the outer sleeve 504. The outer sleeve 504 has a distal end 508 having two laterally adjustable prongs 510A, 510B. Advancement of the inner member 502 relative to the outer sleeve 504 from the proximal position to the distal position causes the prongs 510A, 510B to move laterally, in a direction transverse to the longitudinal axis, which facilitates engagement with bone anchor. For example, the prongs 510A, 510B may enter the rod slot 31 in the proximal portion 33 of the bone anchor thereby connecting the outer sleeve 508, and the cement delivery tube 514 to the bone anchor 30. Handle 506 may be rotated to effect movement of the inner member between the proximal position to the distal position.

FIGS. 16A and B illustrate another exemplary embodiment of a cement delivery tube 614 that includes an integral valve at the distal end of the cement delivery tube. The exemplary cement delivery tube 614 includes a compressible section 670 in which a portion of the wall of the tube 614 may be compressed to selectively interrupt flow of cement through the cement delivery tube 14. In one embodiment, for example, the cement delivery tube 14 may include an inner tube 671 constructed from a resilient compressible material, such as a polymer, and may be selectively encased or enclosed by a coaxial sleeve 672 of a rigid material, such as a rigid polymer or a metal. A section of the length of the inner tube 671 may be exposed, e.g., not enclosed, to provide the compressible section 670 which may operate as a valve. The compressible section 670 may be provided at any point along the length of the tube 614.

The anchor connection instrument or other instrument may be used to selectively compress the wall of the inner tube 671 at the compressible section 670 to obstruct the inner tube 671. For example, the anchor connection instrument may include a longitudinally adjustable valve member 674 that includes a projection 676 or the like for compressing the wall of the inner tube 671 at the compressible section 670. The valve member 674 may be a prong, analogous to the prongs 308A, B and 408, described above, and may also be used to engage the instrument to the bone anchor. In the exemplary embodiment, when the valve member 674 is in a proximal position, the projection 676 compresses the wall of the inner tube 671 to obstruct the inner tube 671. In a distal position, the projection 676 abuts the rigid out sleeve 672 and the inner tube remains unobstructed.

FIGS. 17A-17E illustrate another exemplary embodiment of a system for delivering bone cement or other material to a bone anchor. The exemplary system includes an anchor connection instrument 600 including an instrument body 601 having a proximal end 602 for connection to a cement delivery tube, such as, for example, cement delivery tube 14 or cement delivery tube 614, described below, a distal end 604 sized and shaped to fit within the proximal portion 30 of the bone anchor 16, and passage 606 between the proximal end 602 and the distal end 604 through which the cement delivery tube may be positioned to connect to the passage 34 in the bone anchor 16.

The proximal end 602 of the exemplary instrument body 601 may include an annular collar 608 defining an opening to the passage 606 of the instrument 600. The collar 608 may include a connection feature to facilitate connection to the proximal end of the cement delivery tube. The connection feature may be an external thread, an internal thread, a groove or opening for receiving a projection or the like, or other known connection features. Alternatively, the collar 608 may connect to the proximal end of the tube by a simple friction fit. In the illustrated embodiment, the collar 608 includes a single pin 610 extending from the outer surface of the collar 608 that engages an internal thread provided on the proximal end 656 of the tube 614. The proximal end 602 of the instrument body 601 further includes a flange 615 having an outer diameter greater than the outer diameter of the collar 608. The proximal end 656 of the tube 614 may be advanced into contact with the flange 615, as illustrated in FIGS. 17B-D.

The distal end 604 of the anchor connection instrument 600 includes two spaced-apart arms 617A, 617B that are sized and shaped to fit within the rod receiving slot 31 of the bone anchor 16. For example, the distal end of the arms 617A, 617B are generally arcuate in shape having a curvature approximating the curvature of the rod contacting surfaces of the rod receiving slot 31.

The exemplary anchor connection instrument 600 further includes a first member 620A that is adjustable relative to the instrument body 601 of the instrument 600. For example, the first member 620A may be pivotally connected to the instrument body 601 and may be pivotable between a release position, in which the distal end 622A of the first member 620A is pivoted away from the instrument body to facilitate removal of the instrument 600 from the proximal end 30 of the bone anchor, and a connect position in which the distal end 622A of the first member 620A is pivoted toward the instrument body and the distal end 622A can engage the proximal end 30 of the bone anchor 16 to connect the instrument 600 to the bone anchor 16. The first member 620A is connected to the instrument body 601 by a pivot pin 619 positioned between the proximal handle 626A of the first member 620A and the distal end 622A of the first member 622A. A spring 621 or other biasing mechanism may be interposed between the instrument body 601 and the first member 620A to bias the first member 620A to the connect position. The distal end 622A of the first member 620A includes a ramped surface 623A that is effective to pivot the distal end 622A away from the instrument body 601, toward the release position, as the distal end 622A is advanced distally into engagement with the proximal end 30 of the bone anchor 16. The distal end 622A may include a feature, such as a projection, for engaging one of the slots 35 provided on the proximal end 30 of the bone anchor 16. In the exemplary embodiment, the proximal terminus of the ramped surface 623A engages one of the slots 35 provided on the proximal end 30 of the bone anchor 16. In alternative embodiments, the instrument 600 may include a second member, analogous in construction to the first member 620A, pivotally connected to the instrument body 601 at a location diametrically opposed to the first member 620A for engaging a second one of the slots 35 on the bone anchor 16.

The proximal end 656 of the cement delivery tube 614 is generally annular in shape and includes an internal thread for engaging the pin 610 provided on the collar 608 of the instrument body. The proximal end 656 thus may be rotated into and out of engagement with the collar 608 of the instrument body 601 to thereby connect the tube 614 to the instrument 600 and position the distal end 654 of the tube 614 within the channel 34 of the bone anchor 16. The proximal end 656 of the tube 614 may also include a luer lock connector or other connector to connect the tube 614 to the cement delivery system 18.

In use, the cement delivery tube 614 may be connected to the anchor connection instrument 600. The instrument 600 may be connected to a bone anchor 16 by advancing the arms 617A, 617B into the rod receiving slot 31 of the proximal end 30 of the bone anchor 16. During this advancement, the ramped surface 623A of the distal end 622A of the first member 620A engages the outer surface of the proximal end 30 of the bone anchor 16 causing the first member 620A to pivot from the connect position toward the release position against the spring force provided by spring 621. When the arms 617A, 617B are seated in the rod receiving slot, the proximal terminus of the ramped surface 623A snaps into the groove 35 to thereby connect the anchor connection instrument 600 and the cement delivery tube 614 to the bone anchor 16. Cement from the cement delivery system 18 may then be provided to the bone anchor 16 through the tube 614.

In procedures in which multiple bone anchors are employed, a plurality of anchor connection instruments, including anchor connection instrument 600, may be connected to some or all of the bone anchors. A single cement delivery tube, such as a cement delivery tube 614, may be used to provide a connection to the cement delivery system 18 and deliver cement to the plurality of bone anchors. For example, the cement delivery tube 614 may be connected to a first anchor connection instrument 600 connected to a first bone anchor and cement delivered to the first bone anchor. The cement delivery tube 614 may be disconnected from the first anchor connection instrument, while remaining connected to the cement delivery system 18, and connected to a second anchor connection instrument connected to a second bone anchor. Once the desired amount of cement is delivered to the second bone anchor, the cement delivery tube 614 may be disconnected from the second anchor connection instrument 600 and the above process may be repeated for other anchor connection instruments connected to the other bone anchors. Thus, a system for delivering cement to a plurality of bone anchors may include a plurality of anchor connection instruments 600 and a cement delivery tube 614 connectable to each of the plurality of anchor connection instruments 600.

Alternatively, the anchor connection instrument 600 and the cement delivery tube 614 can be collectively connected and disconnected as a single unit from a plurality of bone anchors in the manner described above in connection instrument 12 and tube 14.

FIGS. 18A-18E illustrate another exemplary embodiment of a system for delivering bone cement or other material to a bone anchor. The exemplary system includes an anchor connection instrument 700 that is analogous in construction to the anchor connection instrument 600 described above except that the distal end 704 of the instrument body 701 includes a connection member 705 that is longitudinally adjustable relative to the instrument body 701. In the exemplary instrument 700, the distal end 704 of the instrument body 701 includes floating connection member 705 having a generally cylindrical body 707 and an enlarged distal end 709 configured to be seated in the rod receiving slot 31 of the proximal end 30 of the bone anchor 16. The connection member 705 is positioned within the central passage 706 of the instrument body 701 and movable along the length of the central passage 706 relative to the instrument body 701 between an extended position in which the distal end 709 of the connection member 705 is extended distally away from the instrument body 701 and a retracted position in which the distal end 709 of the connection member 705 is positioned proximate the instrument body. FIG. 18A illustrates the connection member 705 in the extended position. FIGS. 18B-D illustrate the connection member 705 in the retracted position. A spring 711 or other biasing member may be provided to bias the connection member 705 into the extended position. The connection member 705 and the instrument body 701 may include a retaining feature to inhibit separation of the connection member 705 from the instrument body 701. For example, the instrument body 701 may include one or more projections, e.g. pins 713A, B, that project into the central passage 706 of the instrument body 701 and engage the connection member 705. For example, the pins 713A, 713B may be seated in longitudinal slots 771 provided on diametrically opposed locations of the connection member 705.

The enlarged distal end 709 of the connection member 705 may have an arcuate contact surface 773 sized to span the length of the rod receiving slot 31 of the bone anchor 16. The arcuate contact surface 773 may have a curvature that is approximately equal to the curvature of the rod contacting surfaces of the rod receiving slot 31 of the proximal end 30 of the bone anchor 16. In addition, the arcuate contact surface 773 may have a curvature that is approximately equal to the curvature of the rod to be positioned within the rod receiving slot 31 of the proximal end 30 of the bone anchor 16.

In use, the instrument 700 may be connected to the bone anchor 12 by positioning the connection member 705 of the instrument 700, in the extended position, into the rod receiving slot 31 of the proximal end 30 of the bone anchor 16, as illustrated in FIG. 18A. Preferably, the cement delivery tube 614 is connected to the instrument 700 prior to connecting the instrument 700 to the bone anchor 16. The distal end 654 of the cement delivery tube 614 is positioned within the connection member 705 such that only a portion of the distal end 654 if the tube 614 extends beyond the arcuate contact surface 773. The connection member 705 thereby serves to shield the tube 614 during the connection process while concomitantly permitting adjustment of the proximal end 30 of the bone anchor 16 relative to the bone engaging portion 32 of the bone anchor 16. This adjustability facilitates alignment of the distal end 654 of the tube 614 with the passage 34 of the bone anchor 16. As the connection instrument 700 is advanced distally relative to the bone anchor 16 to connect to the bone anchor 16, the connection member 705 is adjusted to the retracted position thereby exposing more of the tube 614 for insertion into the passage 34 of the bone anchor 16.

FIGS. 19A-19E illustrate another exemplary embodiment of a system for delivering bone cement or other material to a bone anchor. In the exemplary system, an anchor connection instrument 700 is configured to be positioned through a tubular screw extension connected to the bone anchor 16. The screw extension may be a minimally invasive screw extension such as the open screw extension 516 described above in connection with FIGS. 13A-15, or may be the closed minimally invasive screw extension 517 illustrated in FIGS. 19A-19E. The minimally invasive screw extension may be connected to the bone anchor 30 and may be used to percutaneously place a bone anchor, such as bone anchor 16, over a guide wire in a minimally invasive procedure.

The exemplary anchor connection instrument 800 includes a generally tubular instrument body 802 having a proximal end 806 for connection to the proximal end of a cement delivery tube, such as the proximal end 856 of the cement delivery tube 814, a distal end 804 configured to connect to a bone anchor, such as bone anchor 30, and a central passage spanning from the proximal end 806 to the distal end 804 through which the cement delivery tube may be delivered to the bone anchor. The proximal end 806 of the instrument 800 may include an annular collar 808 having an annular side wall spaced apart from the outer wall of the tubular instrument body 802. The annular collar 808 may be positioned about the screw extension and optionally may include a connection feature, such as a projection or a groove, to connect with a mating connection feature on the proximal end of the screw extension 517. The proximal end 806 may also include a connection feature to permit the proximal end of the cement delivery tube to be connected to the instrument 800. In the exemplary embodiment, for example, the proximal end 806 of the instrument body 802 includes an annular groove 809 for receiving the prongs 882A, 882B of the proximal end 856 of the cement delivery tube 814.

The distal end 804 of the instrument body 802 may include a first connection feature for connecting to the proximal end 30 of the bone anchor 16 and a second connection feature to connect with the bone engaging portion 32 of the bone anchor 16. The first connection feature 810, in the exemplary embodiment, is an externally threaded section 810 that threadingly engages the internal thread 33 provided on the proximal portion 30 of the bone anchor 16 to receive a closure mechanism. The second connection feature is a drive tip 812 that engages the drive feature provided on the proximal head of the bone engaging portion 32 to permit the bone engaging portion 32 to be anchored into bone. The first connection feature and the second connection feature permit the instrument 800 to hold the proximal rod receiving portion 30 of the bone anchor 16 relative to the bone engaging portion 32 of the bone anchor 16 which allows the distal tip 854 of the cement delivery tube 814 to be more easily placed in the passage 34 of the bone anchor 16.

The exemplary cement delivery tube 814 includes a proximal end 856 configured to connect to the proximal end 806 of the instrument 800 and to the cement delivery system 18 and a distal end 865 854 sized to be positioned within the passage 34 of the bone anchor 16 and deliver cement from the cement delivery system 18 to the bone anchor 16. The proximal end 856 includes a connection feature for connecting to a mating connection feature on the proximal end 806 of the instrument 800. For example, the proximal end 856 of the exemplary tube 814 includes two spaced-apart flexible, resilient prongs 882A, 882B that may be snapped into the groove 809 on the proximal end 806 of the instrument 800. The proximal ends 884A, 884B of the prongs 882A, 882B may be compressed together to release the distal ends 886A, 886B of the prongs from the groove 809. In addition, the tube 814 may include a connection feature, such as a leur luer lock connector, to connect the tube 814 to the cement delivery system 18.

Referring to FIG. 19E, the cement delivery tube 814 may taper from an increased inner diameter at the proximal end to 856 a reduced diameter at the distal end 854 to maximize the flow of cement within the tube 814 and thereby extend the working time of the cement. In the exemplary embodiment, for example, the tube 814 includes a first section 890, a second section 892 distal to the first section 890, and a third section 894 distal to the second section 892. The first section 890 has a first inner diameter that is greater than the second inner diameter of the second section 892, which is greater than the third inner diameter of the third section 894. A first tapering section 896 interposed between the first section 890 and the second section 892 provides a tapering inner diameter from the first diameter to the second diameter. A second tapering section 898 interposed between the second section 892 and the third section 894 provides a tapering inner diameter from the second diameter to the third diameter. Any number of different diameter sections may be provided. Alternatively, the inner diameter of the tube may taper continuously from a diameter at the proximal end 856 to a second diameter at the distal end 854.

The exemplary anchor connection instrument 800 and the cement delivery tube 814 may also be used in open procedures or procedures in which a screw extension is not connected to the bone anchor. Referring to FIGS. 20A-E, for example, the exemplary instrument 800 and the cement delivery tube 814 may be used in connection with a counter-torque instrument 900 which allows the distal end 804 of the instrument 800 to be rotated into engagement with the proximal end 30 of the bone anchor 16. The counter-torque instrument 900 includes a generally tubular body 902 having a central passage through which the connection instrument 800 and the cement delivery tube 814 may be positioned. The body 902 of the instrument 900 may include a number of slots or openings therein to reduce the weight of the instrument 900 and to facilitate cleaning of the instrument. The distal end 904 of may include two spaced apart, diametrically opposed fingers 904A, 904B for positioning within the rod receiving slot 31 of the bone anchor 16.

In use, fingers 904A, 904B of the counter-torque instrument 900 are positioned within the rod receiving slot 31 of the bone anchor 16 during rotational engagement and disengagement of the externally threaded section 810 of the anchor engagement instrument 800 with the internal thread 33 provided on the proximal portion 30 of the bone anchor 16. The counter-torque instrument 900 prevents rotation of the proximal end 30 of the bone anchor 16 relative to the anchor connection instrument 800.

In open procedures, the length of the counter-torque instrument 900 and the anchor connection instrument 800 may be reduced, as illustrated in FIG. 21. FIG. 21 further illustrates another exemplary embodiment of a bone cement delivery tube 916 having a connection feature that permits the proximal end 956 of the tube 914 to be internally connected to the collar 808 of the anchor connection instrument 800. The connection feature, in the illustrated embodiment, includes one or more flexible, resilient prongs 959 that snap fit into a groove or opening in the inner wall of the collar 808. The distal end of the bone cement delivery tube may be configured to occlude a portion of the passage 34 in the bone anchor 16 to direct bone cement through selective openings 36 in the bone anchor 16. In one exemplary embodiment, the distal end of a bone cement delivery tube (e.g., tube 14, tube 614, tube 814, or tube 914) may be configured to occlude the distal end of the passage 34 thereby directing cement through only the openings 36 in the side wall of the bone engaging portion 32. The distal end 54 of the cement delivery tube 14 may include occlusion 1002 that prevents further cement flow and one or more slots or openings in the sidewall of the tube 14 that permit cement flow from the sidewalls rather than through a distal opening in the tube 14. In the exemplary embodiment, two diametrically opposed slots 1004A, 1004B are provided. The size, shape, and position of the slots may be varied depending on the desired cement flow.

In an alternative embodiment illustrated in FIG. 23, the distal end 54 of a bone cement delivery tube 14 may include an occlusion in the form of a plug 1006 spaced from the distal opening 1008 in the tube 14 by a wire or other reduced diameter structure 1010. The plug 1006 may have any shape suitable to occlude the passage 34 in the bone anchor 16. The plug 1006, in the exemplary embodiment, is generally spherical in shape.

The distal end of a bone cement delivery tube may be flexible to facilitate placement of the tube in the passage 34 of the bone anchor 16. For example, the distal end 1054 of an exemplary cement delivery tube 1104 may include lengthwise sections of increased flexibility, as illustrated in FIG. 24A. The distal end 1054 of the exemplary tube 1104 includes a first lengthwise section 1056 and a second lengthwise section 1058 connected to and distal from the first section 1056. The first section 1056 may be constructed from a material having increased flexibility compared to the second section 1058 and compared to the proximal section 1050. For example, the first section 1056 may be constructed of a flexible polymer material, the second section 1058 may be constructed from a stiffer material, such as a metal (e.g., stainless steel), and the proximal section 1050 may be constructed of a stiffer material and/or have an increased wall thickness providing increased stiffness. Any number of lengthwise sections constructed from materials of differing flexibility may be provided. In an alternative embodiment of a bone cement delivery tube 1114, the continuous length of the distal end 1154 of the tube may be constructed from a flexible material while the proximal end 1150 of the tube 1114 may be constructed of from a stiffer material, such as a metal (e.g., stainless steel) and/or may have an increased wall thickness to provide increased stiffness.

While the systems and methods of the present invention have been particularly shown and described with reference to the exemplary embodiments thereof, those of ordinary skill in the art will understand that various changes may be made in the form and details herein without departing from the spirit and scope of the present invention. Those of ordinary skill in the art will recognize or be able to ascertain many equivalents to the exemplary embodiments described specifically herein by using no more than routine experimentation. Such equivalents are intended to be encompassed by the scope of the present invention and the appended claims.

Claims

1. A method of delivering cement to a spinal anchor anchored in a vertebra of a patient, the method comprising:

advancing a distal end of an anchor connection instrument through an opening in a proximal portion of a spinal anchor, the proximal portion of the spinal anchor having a slot for receiving a spinal rod and a thread for receiving a closure mechanism for securing the rod in the proximal portion, the distal end of the anchor connecting instrument including a first connection feature spaced apart from a second connection feature, the first connection feature comprising an external thread, the second connection feature comprising a drive tip located at a distal tip of the distal end of the anchor connection instrument,

advancing the drive tip of the anchor connection instrument into a drive feature at a proximal opening in a passage formed in a distal bone engaging portion of the spinal anchor, the passage communicating with the opening in the proximal portion of the spinal anchor,

rotating the first connection feature to engage the external thread of the first connection feature with the thread on the proximal portion of the spinal anchor, the first connection feature being positioned between the proximal end and the distal end of the anchor connection instrument a distance from the drive tip, the distance selected to allow the drive tip to be advanced into the drive feature of the distal bone engaging portion of the spinal anchor when the first connection feature engages the proximal portion of the spinal anchor, the anchor connection instrument holding the proximal portion of the spinal anchor relative to the distal bone engaging portion of the spinal anchor when the first connection feature engages the proximal portion of the spinal anchor and the second connection feature is advanced into the drive feature of the distal bone engaging portion of the spinal anchor,

positioning a bone cement delivery tube through the anchor connection instrument,

advancing a distal end of the bone cement delivery tube into the passage of the distal bone engaging portion of the spinal anchor,

connecting a proximal end of the bone cement delivery tube to a bone cement delivery system, and

injecting cement into the passage of distal bone engaging portion of the spinal anchor through the bone cement delivery tube.

2. The method of claim 1, wherein at least a portion the bone cement delivery system is positioned outside of a fluoroscopic imaging field about the patient.

3. The method of claim 1, further comprising

removing the anchor connection instrument and the bone cement delivery tube from the spinal anchor,

advancing a distal end of the anchor connection instrument through an opening in a proximal portion of a second spinal anchor,

advancing the drive tip of the anchor connection instrument into a drive feature at a proximal opening in a passage formed in a distal bone engaging portion of the second spinal anchor, the passage communicating with the opening in the proximal portion of the second spinal anchor,

rotating the first connection feature to engage the external thread of the first connection feature with the thread on the proximal portion of the second spinal anchor,

positioning the bone cement delivery tube through the anchor connection instrument,

advancing the distal end of the bone cement delivery tube into the passage of the distal bone engaging portion of the second spinal anchor, and

injecting cement into the passage of distal bone engaging portion of second the spinal anchor through the bone cement delivery tube.

4. The method of claim 1, wherein the thread of the first connection feature is interrupted at two spaced apart, opposed unthreaded sections and further comprising

inserting the first connection feature into the proximal portion of the bone anchor with the unthread sections facing the thread, and

rotating the first connection feature to engage the thread on the first connection feature with the thread on the proximal portion of the bone anchor.

5. The method of claim 1, further comprising connecting a spinal rod to the proximal portion of the bone anchor after injecting cement into spinal anchor.

6. The method of claim 5, further comprising connecting a connection mechanism to the proximal end of the bone anchor to capture to the spinal rod to the spinal anchor.

7. A method of delivering cement to a spinal anchor anchored in a vertebra of a patient, the method comprising:

advancing a distal end of an anchor connection instrument into a proximal portion of a spinal anchor, the proximal portion of the spinal anchor having a slot for receiving a spinal rod and a thread for receiving a closure mechanism for securing the rod in the proximal portion, the distal end of the anchor connection instrument including a first connection feature spaced apart from a second connection feature, the first connection feature comprising an external thread, the second connection feature comprising a distal tip of the distal end of the anchor connection instrument,

advancing the distal tip of the anchor connection instrument into a proximal opening in a passage formed in a distal bone engaging portion of the spinal anchor, the passage communicating with the proximal portion of the spinal anchor,

rotating the first connection feature to engage the external thread of the first connection feature with the thread on the proximal portion of the spinal anchor, the first connection feature being positioned between the proximal end and the distal end of the anchor connection instrument a distance from the distal tip, the distance selected to allow the distal tip to be advanced into the proximal opening of the distal bone engaging portion of the spinal anchor when the first connection feature engages the proximal portion of the spinal anchor, the anchor connection instrument holding the proximal portion of the spinal anchor relative to the distal bone engaging portion of the spinal anchor when the first connection feature engages the proximal portion of the spinal anchor and the second connection feature is advanced into the proximal opening of the distal bone engaging portion of the spinal anchor

positioning a bone cement delivery tube through the anchor connection instrument while the anchor connection instrument is engaged with the spinal anchor, and

injecting cement into the passage of the distal bone engaging portion of the spinal anchor through the bone cement delivery tube,

wherein the first connection feature and the second connection feature are advanced simultaneously.

8. The method of claim 7, further comprising removing the anchor connection instrument after injecting cement into the passage of the distal bone engaging portion of the spinal anchor.

9. The method of claim 7, wherein removing the anchor connection instrument includes rotating the first connection feature to disengage the external thread of the first connection feature from the thread of the proximal portion of the bone anchor.

10. The method of claim 9, wherein the tubular extension is connected to the bone anchor.

11. The method of claim 10, further comprising connecting a closure mechanism to the proximal end of the spinal anchor to capture the spinal rod to the spinal anchor.

12. The method of claim 7, further comprising positioning the anchor connection instrument through a tubular extension.

13. The method of claim 7, further comprising connecting a spinal rod to the proximal portion of the spinal anchor after injecting cement into the spinal anchor.

14. The method of claim 7, wherein the anchor connection instrument comprises a tubular instrument body having a protruding annular portion at a proximal end thereof.

15. The method of claim 14, wherein the bone cement delivery tube includes a connector disposed between the two wings of the handle for connecting the bone cement delivery tube to a reservoir of bone cement.

16. The method of claim 7, wherein the bone cement delivery tube includes a handle comprising two wings extending laterally-outward from a proximal end of the bone cement delivery tube.

17. The method of claim 7, further comprising connecting the bone cement delivery tube to a reservoir of bone cement and applying pressure to bone cement in the reservoir to move the bone cement into the bone cement delivery tube.

18. The method of claim 7, further comprising injecting the cement through openings in a sidewall of the distal bone engaging portion of the spinal anchor and into surrounding bone.

19. A method of delivering cement to a spinal anchor anchored in a vertebra of a patient, the method comprising:

advancing a distal end of an anchor connection instrument into a proximal portion of a spinal anchor, the proximal portion of the spinal anchor having a slot for receiving a spinal rod and a thread for receiving a closure mechanism for securing the rod in the proximal portion, the distal end of the anchor connection instrument including a first connection feature spaced apart from a second connection feature, the first connection feature comprising an external thread, the second connection feature comprising a distal tip of the distal end of the anchor connection instrument,

advancing the distal tip of the anchor connection instrument into a proximal opening in a passage formed in a distal bone engaging portion of the spinal anchor, the passage communicating with the proximal portion of the spinal anchor,

rotating the anchor connection instrument to engage the external thread of the first connection feature with the thread on the proximal portion of the spinal anchor, the first connection feature being positioned between the proximal end and the distal end of the anchor connection instrument a distance from the distal tip, the distance selected to allow the distal tip to be advanced into the proximal opening of the distal bone engaging portion of the spinal anchor as the anchor connection instrument is rotated, the anchor connection instrument holding the proximal portion of the spinal anchor relative to the distal bone engaging portion of the spinal anchor when the first connection feature engages the proximal portion of the spinal anchor and the second connection feature is advanced into the proximal opening of the distal bone engaging portion of the spinal anchor

positioning a bone cement delivery tube through the anchor connection instrument,

placing a distal end of the bone cement delivery tube into fluid communication with the passage of the distal bone engaging portion of the spinal anchor, and

injecting cement into the passage of the distal bone engaging portion of the spinal anchor through the bone cement delivery tube while the anchor connection instrument is engaged with the spinal anchor,

wherein rotating the first connection feature simultaneously rotates the second connection feature.

20. The method of claim 19 further comprising removing the anchor connection instrument after injecting cement into the passage of the distal bone engaging portion of the spinal anchor.

21. The method of claim 19, wherein removing the anchor connection instrument includes rotating the anchor connection instrument to disengage the external thread of the first connection feature from the thread of the proximal portion of the bone anchor.

22. The method of claim 21, wherein the tubular extension is connected to the bone anchor.

23. The method of claim 22, further comprising connecting a closure mechanism to the proximal end of the spinal anchor to capture the spinal rod to the spinal anchor.

24. The method of claim 19, further comprising positioning the anchor connection instrument through a tubular extension.

25. The method of claim 19, further comprising connecting a spinal rod to the proximal portion of the spinal anchor after injecting cement into the spinal anchor.

26. The method of claim 19, wherein the anchor connection instrument comprises a tubular instrument body having a protruding annular portion at a proximal end thereof.

27. The method of claim 19, wherein the bone cement delivery tube includes a proximal connector for connecting the bone cement delivery tube to a cement delivery system.

28. The method of claim 27, wherein the bone cement delivery tube includes a connector disposed between the two wings of the handle for connecting the bone cement delivery tube to a reservoir of bone cement.

29. The method of claim 19, wherein the bone cement delivery tube includes a handle comprising two wings extending laterally-outward from a proximal end of the bone cement delivery tube.

30. The method of claim 19, further comprising connecting the bone cement delivery tube to a reservoir of bone cement and applying pressure to bone cement in the reservoir to move the bone cement into the bone cement delivery tube.

31. The method of claim 19, further comprising injecting the cement through openings in a sidewall of the distal bone engaging portion of the spinal anchor and into surrounding bone.