USRE48870E1 - Systems and methods for delivering bone cement to a bone anchor - Google Patents

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

More than one reissue application has been filed for the reissue of U.S. Pat. No. 9,265,548, issued Feb. 23, 2016. This application is a continuation reissue of U.S. application Ser. No. 15/238,947, filed Aug. 17, 2016, now U.S. Pat. No. RE47,871. This application is also a broadening reissue of U.S. Pat. No. 9,265,548, which issued from U.S. application Ser. No. 13/832,054, filed Mar. 15, 2013. U.S. application Ser. No. 13/832,054 is a divisional of U.S. patent application Ser. No. 12/608,333, filed Oct. 29, 2009 (now abandoned), which claims priority to U.S. Provisional Patent Application No. 61/109,661, filed Oct. 30, 2008. Each of the aforementioned patent applications is incorporated herein by reference.

BACKGROUND

Bone anchors may be used in orthopedic surgery to temporarily fix bone during the healing or fusion process. One problem with the use of bone anchors is that bone anchors may pullout or otherwise be displaced from the bone prior to the healing or fusion process completing. This problem is particularly common when a bone anchor is positioned in poor quality bone such as osteoporotic bone. Accordingly, there is need for improved instruments and techniques for securing bone anchors to bone that minimize instances of anchor pull out.

SUMMARY

Disclosed herein are systems and methods for delivering bone cement or other materials to one or more bone anchors, such as one or more spinal anchors. In accordance with one aspect, an instrument system for delivering bone cement to a bone anchor may comprise an anchor connection instrument for releasably connecting to a proximal end of the bone anchor. The anchor connection instrument may include a first member coupled to an opposed second member. The first member and/or the second member may have a distal end configured to releasably connect to the proximal end of the bone anchor. The first member is movable between a release position to facilitate release of the anchor connection instrument from the proximal end of the bone anchor and a connect position in which at least one of the first member and the second member is connected to the proximal end of the bone anchor. The first member and the second member define a passage therebetween. The system includes a cement delivery tube positionable in the passage between the first member and the second member of the anchor connection instrument and a bone cement delivery system coupled to the tube.

In accordance with another aspect, a bone anchor system may include a plurality of bone anchors, each of the plurality of bone anchors including a proximal end, a distal bone engaging end, a passage extending from an opening at the proximal end to the distal bone engaging end, and an opening in a sidewall of the distal bone engaging end that communicates with the passage. The bone anchor system may include a bone cement delivery system and a tube connectable to the bone cement delivery system, the tube being sized to fit within the passage of each of the plurality of bone anchors. The bone anchor system may include an anchor connection instrument for releasably connecting to a proximal end of one of the plurality of bone anchors, the anchor connecting instrument including a first member pivotally coupled to an opposed second member. At least one of the first member and the second member may have a distal end configured to releasably connect to an exterior of the proximal end of one of the bone anchors. The first member and the second member may be pivotable between a spaced apart first position to facilitate release of the anchor connection instrument from the proximal end of one of the bone anchors and a second position in which the first member and the second member connect to the proximal end of one of the plurality of bone anchors. The bone anchor system may include a tube connector positionable within a passage provided between the first member and the second member of the anchor connecting mechanism for connecting the tube to the anchor connection instrument. The tube connector may have an opening sized to receive the tube therethrough that may be sized to permit the tube to move along a longitudinal axis of the tube and may be sized to restrict motion of the tube in a direction transverse to the tube.

In accordance with another aspect, a method of stabilizing a first vertebra and a second vertebra of a patient may comprise implanting a first bone anchor into the first vertebra, the first bone anchor having a proximal portion for engaging a spinal rod and a distal bone engaging portion. The method further comprises implanting a second bone anchor into the second vertebra, the second bone anchor having a proximal portion for engaging a spinal rod and a distal bone engaging portion. The method further comprises connecting an anchor connection instrument to the proximal portion of the first bone anchor and positioning the distal end of a cement delivery tube into a passage provided through at least a portion of the bone engaging portion of the first bone anchor, the anchor connection instrument connecting the cement delivery tube to the first bone anchor. The method further comprises delivering bone cement from a bone cement delivery system coupled to the bone cement delivery tube through the passage in the first bone anchor to the first vertebra, removing the anchor connection instrument and the cement delivery tube from the first bone anchor, connecting the anchor connection instrument and the cement delivery tube to the second bone anchor, delivering bone cement from the bone cement delivery system coupled to the bone cement delivery tube through a passage in bone engaging portion of the second bone anchor to the second vertebra, and connecting a spinal connection element to the first bone anchor and the second bone anchor.

BRIEF DESCRIPTION OF THE FIGURES

These and other features and advantages of the systems and methods disclosed herein will be more fully understood by reference to the following detailed description in conjunction with the attached drawings in which like reference numerals refer to like elements through the different views. The drawings illustrate principles of the systems and methods disclosed herein and, although not to scale, show relative dimensions.

FIG. 1 is a perspective view of an exemplary system for delivering bone cement to a bone anchor, illustrating the system connected to a bone anchor;

FIG. 2 is a perspective view of the system ofFIG. 1, illustrating the anchor connection instrument and the cement delivery tube prior to connection to the bone anchor;

FIG. 3 is a perspective view of the system ofFIG. 1, illustrating the bone cement delivery tube inserted into the passage of the bone anchor;

FIG. 4 is a perspective view of the system ofFIG. 1, illustrating the distal end of the anchor connection instrument connected to the bone anchor;

FIG. 5 is a side view in cross section of the system ofFIG. 1, illustrating the anchor connection instrument connected to the bone anchor;

FIG. 6 is a side view in cross section of the system ofFIG. 1, illustrating the anchor connection instrument connected to the bone anchor and the cement delivery tube positioned with the passage of the bone anchor;

FIGS. 7A-7D are perspective views of another exemplary system for delivering bone cement to a bone anchor, illustrating the connection of the system to a bone anchor;

FIGS. 8A-E are perspective views of another exemplary system for delivering bone cement to a bone anchor, illustrating the connection of the system to a bone anchor;

FIG. 9 is a perspective view of the system ofFIGS. 8A-8E;

FIG. 10 is a perspective view of the connection member of the system ofFIGS. 8A-8E;

FIGS. 11A-11B are perspective views of another exemplary system for delivering bone cement to a bone anchor, illustrating the connection of the system to a bone anchor;

FIGS. 12A-12C are perspective views of another exemplary system for delivering bone cement to a bone anchor, illustrating the connection of the system to a bone anchor;

FIGS. 13A-F are perspective views of another exemplary system for delivering bone cement to a bone anchor, illustrating the connection of the system to a bone anchor;

FIG. 14 is a side view in cross section of the system ofFIGS. 13A-E, illustrating the anchor connection instrument connected to thebone anchor16;

FIG. 15 is a side view in cross section of the distal end of the anchor connection instrument ofFIG. 14;

FIGS. 16A-16B are side views in cross section of an exemplary bone cement delivery tube including a valve at a distal end thereof, illustrating the valve in an open and a closed position;

FIG. 17A is an exploded view of another exemplary system for delivering bone cement to a bone anchor, illustrating the anchor connection instrument and the cement delivery tube of the system and a bone anchor;

FIG. 17B is a front view of the system ofFIG. 17A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the bone anchor;

FIG. 17C is a side view of the system ofFIG. 17A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the bone anchor;

FIG. 17D is a side view in cross section of the system ofFIG. 17A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the bone anchor;

FIG. 17E is an exploded view of the anchor connection instrument of the system ofFIG. 17A;

FIG. 18A is an exploded view of another exemplary system for delivering bone cement to a bone anchor, illustrating the anchor connection instrument and the cement delivery tube of the system and a bone anchor;

FIG. 18B is a front view of the system ofFIG. 18A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the bone anchor;

FIG. 18C is a side view of the system ofFIG. 18A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the bone anchor;

FIG. 18D is a side view in cross section of the system ofFIG. 18A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the bone anchor;

FIG. 18E is an exploded view of the anchor connection instrument of the system ofFIG. 18A;

FIG. 19A is an exploded view of another exemplary system for delivering bone cement to a bone anchor, illustrating the anchor connection instrument and the cement delivery tube of the system and a screw extension and a bone anchor;

FIG. 19B is a side view of the system ofFIG. 19A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the screw extension and the bone anchor;

FIG. 19C is a side view in cross section of the system ofFIG. 19A, illustrating the anchor connection instrument and the cement delivery tube of the system connected to the screw extension and the bone anchor;

FIG. 19D is side view of the anchor connection instrument of the system ofFIG. 19A;

FIG. 19E is side view of the cement delivery tube of the system ofFIG. 19A;

FIG. 20A is an exploded view of another exemplary system for delivering bone cement to a bone anchor, illustrating the anchor connection instrument, the cement delivery tube, and the counter-torque instrument of the system and a bone anchor;

FIG. 20B is a side view of the system ofFIG. 20A, illustrating the anchor connection instrument, the cement delivery tube, and the counter-torque instrument of the system connected to the bone anchor;

FIG. 20C is a side view in cross section of the system ofFIG. 20A, illustrating the anchor connection instrument, the cement delivery tube, and the counter-torque instrument of the system connected to the bone anchor;

FIG. 20D is front view of the counter-torque instrument of the system ofFIG. 20A;

FIG. 20E is side view of the counter-instrument of the system ofFIG. 20A;

FIG. 21 is an exploded view of another exemplary system for delivering bone cement to a bone anchor, illustrating the anchor connection instrument, the cement delivery tube, and a counter-torque instrument of the system and a bone anchor;

FIG. 22A is a front view of another exemplary embodiment of a cement delivery tube, illustrating the distal end of the tube;

FIG. 22B is a side view in cross section of the distal end of the tube ofFIG. 22A;

FIG. 22C is a side view of the distal end of the tube ofFIG. 22A;

FIG. 23 is a perspective view of another exemplary embodiment of a cement delivery tube, illustrating the distal end of the tube;

FIG. 24A is a side view in cross section of another exemplary embodiment of a cement delivery tube; and

FIG. 24B is a side view in cross section of another exemplary embodiment of a cement delivery tube.

DETAIL DESCRIPTION OF EXEMPLARY EMBODIMENTS

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the instruments and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the systems and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

The articles “a” and “an” are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

The terms “comprise,” “include,” and “have,” and the derivatives thereof, are used herein interchangeably as comprehensive, open-ended terms. For example, use of “comprising,” “including,” or “having” means that whatever element is comprised, had, or included, is not the only element encompassed by the subject of the clause that contains the verb.

FIGS. 1-6 illustrate an exemplary embodiment of a system for delivering bone cement or other materials to a bone anchor. Theexemplary system10 includes ananchor connection instrument12, adelivery tube14 connected to thebone anchor16 by theanchor instrument12, and acement delivery system18 coupled to the cement delivery tube for supplying bone cement to thebone anchor16. Theexemplary system10 facilitates rapid attachment and removal of thesystem10 from a bone anchor such that multiple bone anchors may be provided with bone cement prior to the bone cement setting. Thesystem10 may be used with any type of bone anchors, including, for example, bone screws used in spine surgery to fix or connect the vertebra of the spine. Such spinal bone screws may include, for example, polyaxial bone screws, monoaxial bone screws, and uniplanar bone screws.

Continuing to refer toFIGS. 1-6, theanchor connection instrument12 of theexemplary system10 connects thedelivery tube14 to abone anchor16. Theexemplary bone anchor16 is a polyaxial spinal anchor designed for posterior implantation in the pedicle or lateral mass of a vertebra. Theexemplary bone anchor16 includes aproximal portion30 configured to receive a spinal connection element such as a rigid or dynamic spinal rod and adistal portion32 configured to engage bone. For example, theproximal portion30 of the exemplary bone anchor includes a U-shaped rod-receivingslot31 for receiving a spinal rod. Theproximal portion30 may be configured to receive a closure mechanism, such as, for example, an external nut or cap or an internal setscrew that engages aninternal thread33 provided on the interior of theproximal portion30 of thebone anchor16. Theproximal portion30 of thebone anchor16 may also include features for engaging instruments such as theanchor connection instrument12. Such features may include one or more openings, such as a slot or the like, for receiving a complementary projection provided on an instrument. In theexemplary bone anchor16, theproximal portion30 includes two spaced apart, diametricallyopposed slots35.

The distalbone engaging portion32 of theexemplary bone anchor16 includes one or more screw threads. Theexemplary bone anchor16 is polyaxial, e.g., theproximal end portion30 is connected to the distalbone engaging portion32 in a polyaxial relationship such that the distalbone engaging portion32 may be positioned in a plurality of orientations relative to theproximal end portion30. Exemplary polyaxial spinal anchors include EXPEDIUM polyaxial pedicle screws, VIPER polyaxial pedicle screws, MOSS MIAMI and MOSS MIAMI SI polyaxial pedicle screws, and MOUNTAINEER polyaxial pedicle screws, all of which are available from DePuy Spine, Inc., of Raynham, Mass. Alternative exemplary spine screws include DePuy Spine's EXPEDIUM monoaxial pedicle screws and uniplanar pedicle screws. In addition, exemplary polyaxial pedicle screws are described in U.S. Patent Application Publication Nos. US 2005/0131408 and US 2005/0228388, each of which is incorporated herein by reference.

Theexemplary bone anchor16 is configured to permit bone cement or other materials to be injected into bone through thebone engaging portion32. Apassage34 extends from therod receiving slot31 in theproximal portion30 of thebone anchor16 into the distalbone engaging portion32. The distalbone engaging portion32 includes one ormore openings36 in the sidewall of the distalbone engaging portion32. Theopenings36 communicate with thepassage34 and extend radially from thepassage34 through the sidewall of the distalbone engaging portion32. Bone cement or other materials may be injected into bone through thepassage34 and theopenings36.

The anchor connection instrument may be configured to engage aproximal portion30 of thebone anchor16 and may connect to an exterior of the bone anchor or, in other embodiments, may connect to the interior of the bone anchor. Exemplary anchor connection instruments are described in US Patent Application Publication Nos. US20050149036, US20050149053, US20060079909, and US20070260261, each of which are incorporated herein by reference. In the illustrated embodiment, theanchor connection instrument12 connects to the exterior of theproximal portion30 of thebone anchor16. The exemplaryanchor connection instrument16 includes afirst member20A andsecond member20B that cooperate to selectively connect the instrument to thebone anchor16. Thefirst member20A and thesecond member20B havedistal ends22A,22B configured to releasably connect theinstrument12 to the exterior of theproximal portion30 of thebone anchor16. For example, the distal ends22A and22B may include aprojection24A,24B for engaging a feature, such asslots35, in theproximal portion30 of thebone anchor16. Alternatively, the distal ends22A,22B may include openings to receive a mating feature, such as a projection, provided on the proximal portion of thebone anchor16. Moreover, in alternative embodiments, the distal end of only one of the members may be configured to engage the bone anchor.

In the exemplary embodiment, thefirst member20A is coupled to the opposedsecond member20B. Thefirst member20A and thesecond member20B are pivotally connected and pivot about a pivot axis between a release position, in which thefirst member20A and thesecond pivot member20B pivot away from one another to facilitate removal of the distal ends22A,22B of thefirst member20A and thesecond member20B from the bone anchor and a connect position in which thefirst member20A and thesecond member20B pivot towards one another and the distal ends22A,22B can engage theproximal portion30 of thebone anchor16.FIGS. 1-6 illustrate theanchor connection instrument12 in the connect position. Thefirst member20A includes aproximal handle26A and thesecond member20B includes aproximal handle26B. Manipulation of theproximal handles26A,26B can effect pivoting of thefirst member20A and thesecond member20B between the release position and the connect position. For example, movement of theproximal handles26A and26B towards one another, in the direction of arrows X inFIG. 3, causes the distal ends22A,22B away from one another, in the direction of arrows Y inFIG. 3, to move toward the release position. Thefirst member20A and thesecond member20B may be biased to the release position or to the connect position by a spring or other biasing mechanism.

Theanchor connection instrument12 may be constructed of any biocompatible material suitable for use in medical instruments or implants. For example, theanchor construction instrument12 may be constructed from a metal, such as stainless steel, or a polymer, such as Radel®. Theanchor construction instrument12 may be a single use device or may be configured for multiple uses after sterilization.

At least a portion of thefirst member20A may be spaced apart from thesecond member20B to form apassage28 therebetween for receiving thecement delivery tube14. Atube connector40 may be positioned within thepassage28 between thefirst member20A and thesecond member20B, as illustrated inFIG. 5. Thetube connector40 may have an opening sized to receive thecement delivery tube14 therethrough. The opening in thetube connector40 is preferably sized to permit thecement delivery tube14 to move along a longitudinal axis of thetube14 relative to theanchor connection instrument12 while concomitantly restricting motion of thetube14 in a direction transverse to the longitudinal axis of thetube14. For example, the opening in thetube connector14 has an extent, e.g., a diameter, approximate to the extent, e.g. the outer diameter, of thecement delivery tube14. In the exemplary embodiment, thetube connector40 is generally disk shaped, is constructed of an elastomeric polymer material, and has a central opening having a diameter less than or equal to the outer diameter of thecement delivery tube14.

Thecement delivery tube14 is removably coupled to acement delivery system18. Thecement delivery system18 may include areservoir50 or other container for holding and/or mixing the cement and apressure source52, such as a pump, for applying pressure to the bone cement in thereservoir50 to move the bone cement through thesystem18, and thetube14, relative to thereservoir50. A suitablecement delivery system50 is the CONFIDENCE spinal cement system, available from DePuy Spine, Inc. of Raynham, Mass., and the cement delivery systems described in the following U.S. patents and patent applications: U.S. Pat. No. 7,097,648 and U.S. Patent Application Publication Nos. U.S. 2008/0228192, U.S. 2006/0264967, U.S. 2006/0079905, U.S. 2007/0027230, U.S. 2008/0212405, U.S. 2007/0032567, and U.S. 2008/0200915 and U.S. patent application Ser. Nos. 09/890,172 and 11/561,969, each of which is incorporated herein by reference.

The bonecement delivery tube14 is coupled to the bonecement delivery system18 to permit bone cement to be introduced to thedelivery tube14 from thesystem18. In the exemplary embodiment, the bonecement delivery tube14 is an elongated hollow tube having adistal end54 sized for insertion into thepassage34 in thedistal portion32 of thebone anchor16 and aproximal end56 having ahandle58 to facilitate manipulation of thetube14. Theproximal end56 of the tube may extend through thehandle58 and terminate at connection feature, such as a luer lock connection, that permits connection to the bonecement delivery system18. Thecement delivery tube14 may be a needle or stylet having a diameter less than the diameter of thepassage34 in thedistal portion32 of thebone anchor16. Thecement delivery tube14 may be constructed from any biocompatible material suitable for use in medical instruments or implants. For example, thecement delivery tube14 may be constructed from a metal, such as stainless steel, or a polymer, such as Radel®. Thecement delivery tube14 may be a single use device or may be configured for multiple uses after sterilization. In one exemplary embodiment, theanchor connection instrument12, including thetube connector40, and thecement delivery tube14, may be prepackaged in an assembled, sterilized state with thecement delivery tube14 positioned with theanchor connection instrument12 and through thetube connector40.

In the exemplary embodiment, thereservoir50 of thecement delivery system18 is directly connected to thecement delivery tube14 and thepressure source52 may be positioned remote from thecement reservoir50 and thecement delivery tube14. Remote placement of thepressure source52 permits a medical professional to inject cement into thebone anchor16 outside of the imaging field of the imaging system (e.g., a fluoroscopy or x-ray system) used to monitor the cement volume injected into the patient's bone thorough the bone anchor. In this manner, the medical professional is not exposed to radiation from the imaging system during the bone cement injection procedure.

Thecement delivery system18 may include avalve60 for controlling cement delivery to thecement delivery tube14. For example, thevalve60 may be used to selectively interrupt flow of bone cement to the bonecement delivery tube14. In the exemplary embodiment, thevalve60 is positioned at the interface between thecement delivery system18 and thetube14, e.g., between thecement reservoir50 and theproximal end56 of thecement delivery tube14. In alternative embodiments, a valve may be provided as part of thecement delivery tube14, for example, in thehandle58 or at thedistal end54 of thetube14. For example, in one exemplary embodiment, at least a portion of thedistal end54 or other portion of the tube, may be compressible and the valve may be operated to selectively compress the compressible portion and thereby restrict cement flow through the tube. Such an embodiment is described in more detail below.

An exemplary method of stabilizing a first vertebra and second vertebra of a patient, including delivering of bone cement to a bone anchor, will be described in more detail below. Initially, a first bone anchor, such asbone anchor16 described above, may be implanted into a first vertebra and a second bone anchor, such as anotherbone anchor16, may be implanted in a second vertebra. For example, the first and second bone anchors may be implanted into the respective pedicles of adjacent vertebrae through a posterior approach. The implantation procedure may be an open procedure, in which, for example, the bone anchors are implanted through a single incision, or a minimally invasive procedure in which the first bone anchor and the second bone anchor are implanted through separate percutaneous incisions.

Theanchor connection instrument12 may be connected to theproximal portion30 of the first bone anchor. For example, thedistal end22A of thefirst member20A of theanchor connection instrument12 may be moved, e.g., pivoted, away from thedistal end22B of thesecond member20B of theanchor connection instrument12 to separate thedistal end22A of thefirst member20A from thedistal end22B of thesecond member20B. The separateddistal ends20A and20B may then be positioned about theproximal end30 of the bone anchor. Thedistal end22A of thefirst member20A of theanchor connection instrument12 may be moved, e.g., pivoted, toward thedistal end22B of thesecond member20B of theanchor connection instrument12 until the distal ends22A and22B contact theproximal end30 of the first bone anchor to connect theanchor connection instrument12 to the first bone anchor.

As illustrated inFIG. 2, thecement delivery tube14 may be coupled to theanchor connection instrument12 via thetube connector40 prior to attachment of theanchor connection instrument12 to thefirst bone anchor12. Thedistal end54 of thecement delivery tube14 may be positioned in thepassage34 of the distalbone engaging portion32 of thefirst bone anchor12. In one exemplary embodiment, thedistal end54 of thecement delivery tube14 may be adjusted relative to one ormore openings36 in thedistal portion34 of the first bone anchor to select the opening or openings through which to deliver cement to the first vertebra.

Thecement delivery tube14 may be coupled to thecement delivery system18 before or after connection of thecement delivery tube14 and theanchor connection instrument12 to the bone anchor. In one embodiment, the bone cement may be mixed in thereservoir50 of thecement delivery system18 prior to connection to thecement delivery tube14. Incement delivery systems18 including avalve60, the valve may be opened to permit cement flow through thecement delivery tube14. Thepressure source52 may be operated to deliver a fluid, such as saline, under pressure to thereservoir50 which forces bone cement from thereservoir50 into the bonecement delivery tube14, through thepassage54 in the first bone anchor to the first vertebra.

The medical professional operating thepressure source52 may monitor the delivery of cement to the first vertebra using an imaging system such as a fluoroscopy system. Because thepressure source52 is remote from theanchor connection instrument14 and is outside the imaging field, the medical professional is not exposed to radiation from the imaging system.

Once the desired amount of bone cement is delivered to the first vertebra, theanchor connection instrument12 andcement delivery tube14 may be removed from the first bone anchor and connected to the second bone anchor, preferably while thecement delivery tube14 remains connected to thecement delivery system18. Prior to disconnecting theanchor connection instrument12 and thecement delivery tube14 from the first bone anchor, thevalve60, if provided, may be closed to interrupt cement delivery to the first bone anchor and thecement delivery tube14. In addition, thepressure source52 may be operated in reverse, for example to provide for fluid flow in the direction of the pressure source, to reduce pressure of the bone cement incement delivery tube14 and to minimize leaking of cement from thedistal end54 of thecement delivery tube14 during removal. The fluid pressure in thecement delivery system18 may be monitored through apressure indicator62.

Once theanchor connection instrument12 andcement delivery tube14 are connected to the second bone anchor, bone cement may be delivered to the second bone anchor and the second vertebra in accordance with the procedure described above in connection with the first bone anchor and the first vertebra. Once the desired amount of cement is delivered to the second vertebra, theanchor connection instrument12 and thecement delivery tube14 may be removed from the second bone anchor. A spinal connection element, such as a spinal rod may then be connected to the first bone anchor and the second bone anchor to stabilize the first vertebra relative to the second vertebra. In a minimally invasive procedure, the spinal connection element may be delivered to first bone anchor through the percutaneous incision in which first bone anchor is implanted and the spinal connection element may be positioned beneath the skin and the lamina to the second bone anchor. Such a minimally invasive procedure may be carried out using the VIPER and VIPER II Spinal Fixation Systems available from DePuy Spine of Raynham, Mass.

Bone cement may be injected through any number of bone anchors, e.g., one or more bone anchors depending on, for example, the procedure being performed and the quality of the bone of the vertebra being stabilized. The exemplary systems and methods described above allow multiple anchors and their respective vertebrae to be quickly and easily filled with bone cement. Moreover, since bone cement typically has a limited working time in which the cement is flowable and suitable for injection, the system and methods described above allow an increased number of anchors to be injected with cement during the bone cement working time.

The exemplary systems and methods described above are particularly suited for delivering bone cement. Although any type of bone cement or bone filler may be used with these systems and methods, a high viscosity bone cement, such as high viscosity polymethylmethacrylate based cement available from DePuy Spine, Inc., of Raynham Mass. (CONFIDENCE Spinal Cement), is particularly suited for delivery using the above systems and methods. Alternatively, the systems and methods described above may be used to deliver other materials, such as irrigation fluid or biologics to bone through a bone anchor.

FIGS. 7A-7D illustrate another exemplary embodiment of a system for delivering bone cement or other materials to a bone anchor. In the exemplary system, thecement delivery tube14 includes aconnection member100 positioned between theproximal end56 of thetube14 and thedistal end54 of thetube14. Theconnection member100 is configured to engage theinternal thread33 provided on theproximal portion30 of thebone anchor16. In the exemplary embodiment, theconnection member100 is generally disk shaped and includes anexternal thread102 complementary to theinternal thread33 provided on theproximal portion30 of thebone anchor16. Theconnection member100 may be spaced a distance D from the tip of thedistal end54 of thetube14 selected to allow thedistal end54 of thetube14 to advance into thepassage34 provided in thebone anchor16, as illustrated inFIG. 7A. In use, thecement delivery tube14 may be connected to thebone anchor16 by advancing thedistal end54 of thetube14 into thepassage34 of the bone anchor, as illustrated inFIG. 7B, and rotating thetube14 to engage thethread102 on theconnection member100 with theinternal thread33 of thebone anchor16, as illustrated inFIG. 7C. Thetube14 may be rotated until thedistal end54 of thetube14 reaches the desired depth within thepassage34 of thebone anchor16, as illustrated inFIG. 7D. Thetube14 may be quickly removed from thebone anchor16 by rotating thetube14 in the opposite direction to disengagethread102 fromthread33. Thetube14 may be connected to a cement delivery system such as thecement delivery system18 described above and cement may be injected through one or more bone anchors in a manner analogous to the methods described above.

FIGS. 8A-10 illustrate another exemplary embodiment of a system for delivering bone cement or other materials to a bone anchor. In the exemplary system, thecement delivery tube14 includes aconnection member200 positioned between theproximal end56 of thetube14 and thedistal end54 of thetube14. Like theconnection member100 described above, theconnection member200 is configured to engage theinternal thread33 provided on theproximal portion30 of thebone anchor16. In the exemplary embodiment, theconnection member200 is generally disk shaped and includes anexternal thread202 complementary to theinternal thread33 provided on theproximal portion30 of thebone anchor16. In the exemplary embodiment, thethread202 of theconnection member200 is interrupted at two spaced apart, opposed unthreadedsections204A and204B. The unthreaded sections202A and202B 204A and 204B are positioned diametrically opposed to one another. Thus, theconnection member200 has a threadedsection206 interposed between each unthreaded section202A and202B 204A and 204B. Theconnection member200 may be spaced a distance F from the tip of thedistal end54 of thetube14 selected to allow thedistal end54 of thetube14 to be advanced into thepassage34 provided in thebone anchor16, as illustrated inFIG. 8A.

In use, thecement delivery tube14 may be connected to thebone anchor16 by advancing thedistal end54 of thetube14 into thepassage34 of thebone anchor16, as illustrated inFIG. 8B. During insertion of thetube14, theconnection member200 is oriented such that the unthreadedsections204A and204B face the internally threaded portions of theproximal portion30 of thebone anchor16 and the threadedsections206 are aligned with therod slot31 of theproximal portion30 of the oneanchor16, as illustrated inFIGS. 8C-D. Once thedistal end54 of thetube14 reaches the desired depth within thepassage34 of thebone anchor16, thetube14 may be rotated approximately 90° to engage thethread202 on the threadedportions206 with theinternal thread33 on the threaded portions of thebone anchor16, as illustrated inFIG. 8E. Thetube14 may be quickly removed from thebone anchor16 by rotating thetube14 approximately 90° in the opposite direction to disengage thethread202 on the threadedportions206 fromthread33. Thetube14 may be connected to a cement delivery system such as thecement delivery system18 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, thecement delivery tube14 may be connected tobone anchor16 with ananchor connection instrument300 configured to engage the interior of theproximal portion30 of thebone anchor16. The exemplaryanchor connection instrument300 is generally tubular in shape and has aproximal end302, adistal end304, and an internal lumen orpassage306 extending from theproximal end302 and thedistal end304 for receiving thecement delivery tube14 therein. Thedistal end304 of theanchor connection instrument300 includes two spaced-apart prongs orfingers308A and308B configured to selectively engage thethread33 on theproximal portion30 of thebone anchor16. Theprongs308A and308B are diametrically opposed to each other and are connected at aproximal end310A,310B to theanchor connection instrument300. Theprongs308A and308B have a freedistal end312A,312B opposite the proximal ends310A,310B. Eachprong308A,308B may pivot or flex about itsproximal end310A,B between a first, spaced-apart position, illustrated inFIG. 11A and a second, compressed position in which theprongs308A,308B pivot towards one another to facilitate insertion of thedistal end304 of theinstrument300 into the bone anchor. Theprongs308A,308B are biased to the first position. The distal ends312A,312B of eachprong308A,308B includes aprojection314A,314B for engaging theinternal thread33 of thebone anchor16.

In use, theanchor connection instrument300 and thetube14 may be advanced toward thebone anchor16 to position thedistal end54 of thetube14 within thepassage34 of thebone anchor16, as illustrated inFIG. 11A. As thedistal end304 of theinstrument300 engages theproximal portion30 of thebone anchor16, theprongs308A and308B are compressed to the first, compressed position. Theprojections314A and314B may include a ramped surface to compress theprongs308A,308B toward the second position. In the second position, theprojections314A,314B may pass the leading edge of thethread33 of thebone anchor16 and then snap into place beneath a crest of thethread33 as theprongs308A,308B move to the first position thereby connecting theanchor connection instrument300 and thetube14 to the bone anchor. Theanchor connection instrument300 may be removed from thebone anchor16 by compressing theprongs308A,308B to the second position and retracting thedistal end304 from theproximal portion30 of thebone anchor16. Thetube14 may be connected to a cement delivery system such as thecement delivery system18 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, thecement delivery tube14 may be connected tobone anchor16 with ananchor connection instrument400 configured to engage the interior of theproximal portion30 of thebone anchor16. The exemplaryanchor connection instrument400 is analogous in construction and use to theanchor connection instrument300 described above except theanchor connection instrument400 has asingle prong408 rather twoprongs308A,308B. In addition, thedistal end404 of theanchor connection instrument400 is shaped to fit within therod slot31 of thebone anchor16. For example, thedistal end404 of theinstrument400 is generally T-shaped having a pair ofopposed extensions420A,420B that extend from the instrument and that each have an arcuate lower surface for engaging the arcuate surface on theproximal portion30 of thebone anchor16 that bounds therod slot31. Theextensions420A,420B, when positioned in therod slot31 of thebone anchor16, provide stability and limit rotation of theanchor connection instrument400 relative to thebone anchor16. Theanchor connection instrument300 described above in connection withFIGS. 11A and 11B may also be provided with extensions analogous toextensions420A,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, acement delivery tube514 may be connected tobone anchor16 with ananchor connection instrument500 configured to engage the interior of theproximal portion30 of thebone anchor16 through a screw extension connected516 to thebone anchor16. Theexemplary screw extension516 is used to percutaneously place a bone anchor, such asbone anchor16, 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 exemplaryanchor connection instrument500 is sized to fit within theexemplary screw extension516, e.g., having an external diameter less than the inner diameter of the screw extension.

Theanchor connection instrument500 includes an inner longitudinallyadjustable member502 that receives thecement delivery tube514 and an outer sleeve504 positioned about theinner member502. Ahandle506 is connected to the inner member504. Theinner member502 may be adjusted between a proximal position and a distal position relative to the outer sleeve504. The outer sleeve504 has adistal end508 having two laterallyadjustable prongs510A,510B. Advancement of theinner member502 relative to the outer sleeve504 from the proximal position to the distal position causes theprongs510A,510B to move laterally, in a direction transverse to the longitudinal axis, which facilitates engagement with bone anchor. For example, theprongs510A,510B may enter therod slot31 in theproximal portion33 of the bone anchor thereby connecting theouter sleeve508, and thecement delivery tube514 to thebone anchor30. Handle506 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 acement delivery tube614 that includes an integral valve at the distal end of the cement delivery tube. The exemplarycement delivery tube614 includes acompressible section670 in which a portion of the wall of thetube614 may be compressed to selectively interrupt flow of cement through thecement delivery tube14. In one embodiment, for example, thecement delivery tube14 may include aninner tube671 constructed from a resilient compressible material, such as a polymer, and may be selectively encased or enclosed by acoaxial sleeve672 of a rigid material, such as a rigid polymer or a metal. A section of the length of theinner tube671 may be exposed, e.g., not enclosed, to provide thecompressible section670 which may operate as a valve. Thecompressible section670 may be provided at any point along the length of thetube614.

The anchor connection instrument or other instrument may be used to selectively compress the wall of theinner tube671 at thecompressible section670 to obstruct theinner tube671. For example, the anchor connection instrument may include a longitudinallyadjustable valve member674 that includes aprojection676 or the like for compressing the wall of theinner tube671 at thecompressible section670. Thevalve member674 may be a prong, analogous to theprongs308A, B and408, described above, and may also be used to engage the instrument to the bone anchor. In the exemplary embodiment, when thevalve member674 is in a proximal position, theprojection676 compresses the wall of theinner tube671 to obstruct theinner tube671. In a distal position, theprojection676 abuts the rigid outsleeve672 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 ananchor connection instrument600 including aninstrument body601 having aproximal end602 for connection to a cement delivery tube, such as, for example,cement delivery tube14 orcement delivery tube614, described below, adistal end604 sized and shaped to fit within theproximal portion30 of thebone anchor16, andpassage606 between theproximal end602 and thedistal end604 through which the cement delivery tube may be positioned to connect to thepassage34 in thebone anchor16.

Theproximal end602 of theexemplary instrument body601 may include anannular collar608 defining an opening to thepassage606 of theinstrument600. Thecollar608 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, thecollar608 may connect to the proximal end of the tube by a simple friction fit. In the illustrated embodiment, thecollar608 includes asingle pin610 extending from the outer surface of thecollar608 that engages an internal thread provided on theproximal end656 of thetube614. Theproximal end602 of theinstrument body601 further includes aflange615 having an outer diameter greater than the outer diameter of thecollar608. Theproximal end656 of thetube614 may be advanced into contact with theflange615, as illustrated inFIGS. 17B-D.

Thedistal end604 of theanchor connection instrument600 includes two spaced-apartarms617A,617B that are sized and shaped to fit within therod receiving slot31 of thebone anchor16. For example, the distal end of thearms617A,617B are generally arcuate in shape having a curvature approximating the curvature of the rod contacting surfaces of therod receiving slot31.

The exemplaryanchor connection instrument600 further includes afirst member620A that is adjustable relative to theinstrument body601 of theinstrument600. For example, thefirst member620A may be pivotally connected to theinstrument body601 and may be pivotable between a release position, in which thedistal end622A of thefirst member620A is pivoted away from the instrument body to facilitate removal of theinstrument600 from theproximal end30 of the bone anchor, and a connect position in which thedistal end622A of thefirst member620A is pivoted toward the instrument body and thedistal end622A can engage theproximal end30 of thebone anchor16 to connect theinstrument600 to thebone anchor16. Thefirst member620A is connected to theinstrument body601 by apivot pin619 positioned between theproximal handle626A of thefirst member620A and thedistal end622A of thefirst member622A. Aspring621 or other biasing mechanism may be interposed between theinstrument body601 and thefirst member620A to bias thefirst member620A to the connect position. Thedistal end622A of thefirst member620A includes a rampedsurface623A that is effective to pivot thedistal end622A away from theinstrument body601, toward the release position, as thedistal end622A is advanced distally into engagement with theproximal end30 of thebone anchor16. Thedistal end622A may include a feature, such as a projection, for engaging one of theslots35 provided on theproximal end30 of thebone anchor16. In the exemplary embodiment, the proximal terminus of the rampedsurface623A engages one of theslots35 provided on theproximal end30 of thebone anchor16. In alternative embodiments, theinstrument600 may include a second member, analogous in construction to thefirst member620A, pivotally connected to theinstrument body601 at a location diametrically opposed to thefirst member620A for engaging a second one of theslots35 on thebone anchor16.

Theproximal end656 of thecement delivery tube614 is generally annular in shape and includes an internal thread for engaging thepin610 provided on thecollar608 of the instrument body. Theproximal end656 thus may be rotated into and out of engagement with thecollar608 of theinstrument body601 to thereby connect thetube614 to theinstrument600 and position thedistal end654 of thetube614 within thechannel34 of thebone anchor16. Theproximal end656 of thetube614 may also include a luer lock connector or other connector to connect thetube614 to thecement delivery system18.

In use, thecement delivery tube614 may be connected to theanchor connection instrument600. Theinstrument600 may be connected to abone anchor16 by advancing thearms617A,617B into therod receiving slot31 of theproximal end30 of thebone anchor16. During this advancement, the rampedsurface623A of thedistal end622A of thefirst member620A engages the outer surface of theproximal end30 of thebone anchor16 causing thefirst member620A to pivot from the connect position toward the release position against the spring force provided byspring621. When thearms617A,617B are seated in the rod receiving slot, the proximal terminus of the rampedsurface623A snaps into thegroove35 to thereby connect theanchor connection instrument600 and thecement delivery tube614 to thebone anchor16. Cement from thecement delivery system18 may then be provided to thebone anchor16 through thetube614.

In procedures in which multiple bone anchors are employed, a plurality of anchor connection instruments, includinganchor connection instrument600, may be connected to some or all of the bone anchors. A single cement delivery tube, such as acement delivery tube614, may be used to provide a connection to thecement delivery system18 and deliver cement to the plurality of bone anchors. For example, thecement delivery tube614 may be connected to a firstanchor connection instrument600 connected to a first bone anchor and cement delivered to the first bone anchor. Thecement delivery tube614 may be disconnected from the first anchor connection instrument, while remaining connected to thecement delivery system18, 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, thecement delivery tube614 may be disconnected from the secondanchor connection instrument600 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 ofanchor connection instruments600 and acement delivery tube614 connectable to each of the plurality ofanchor connection instruments600.

Alternatively, theanchor connection instrument600 and thecement delivery tube614 can be collectively connected and disconnected as a single unit from a plurality of bone anchors in the manner described above inconnection instrument12 andtube14.

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 ananchor connection instrument700 that is analogous in construction to theanchor connection instrument600 described above except that thedistal end704 of the instrument body701 includes aconnection member705 that is longitudinally adjustable relative to the instrument body701. In theexemplary instrument700, thedistal end704 of the instrument body701 includes floatingconnection member705 having a generallycylindrical body707 and an enlargeddistal end709 configured to be seated in therod receiving slot31 of theproximal end30 of thebone anchor16. Theconnection member705 is positioned within thecentral passage706 of the instrument body701 and movable along the length of thecentral passage706 relative to the instrument body701 between an extended position in which thedistal end709 of theconnection member705 is extended distally away from the instrument body701 and a retracted position in which thedistal end709 of theconnection member705 is positioned proximate the instrument body.FIG. 18A illustrates theconnection member705 in the extended position.FIGS. 18B-D illustrate theconnection member705 in the retracted position. Aspring711 or other biasing member may be provided to bias theconnection member705 into the extended position. Theconnection member705 and the instrument body701 may include a retaining feature to inhibit separation of theconnection member705 from the instrument body701. For example, the instrument body701 may include one or more projections, e.g. pins713A, B, that project into thecentral passage706 of the instrument body701 and engage theconnection member705. For example, thepins713A,713B may be seated inlongitudinal slots771 provided on diametrically opposed locations of theconnection member705.

The enlargeddistal end709 of theconnection member705 may have anarcuate contact surface773 sized to span the length of therod receiving slot31 of thebone anchor16. Thearcuate contact surface773 may have a curvature that is approximately equal to the curvature of the rod contacting surfaces of therod receiving slot31 of theproximal end30 of thebone anchor16. In addition, thearcuate contact surface773 may have a curvature that is approximately equal to the curvature of the rod to be positioned within therod receiving slot31 of theproximal end30 of thebone anchor16.

In use, theinstrument700 may be connected to thebone anchor12 by positioning theconnection member705 of theinstrument700, in the extended position, into therod receiving slot31 of theproximal end30 of thebone anchor16, as illustrated inFIG. 18A. Preferably, thecement delivery tube614 is connected to theinstrument700 prior to connecting theinstrument700 to thebone anchor16. Thedistal end654 of thecement delivery tube614 is positioned within theconnection member705 such that only a portion of thedistal end654 if thetube614 extends beyond thearcuate contact surface773. Theconnection member705 thereby serves to shield thetube614 during the connection process while concomitantly permitting adjustment of theproximal end30 of thebone anchor16 relative to thebone engaging portion32 of thebone anchor16. This adjustability facilitates alignment of thedistal end654 of thetube614 with thepassage34 of thebone anchor16. As theconnection instrument700 is advanced distally relative to thebone anchor16 to connect to thebone anchor16, theconnection member705 is adjusted to the retracted position thereby exposing more of thetube614 for insertion into thepassage34 of thebone anchor16.

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, ananchor connection instrument700 is configured to be positioned through a tubular screw extension connected to thebone anchor16. The screw extension may be a minimally invasive screw extension such as theopen screw extension516 described above in connection withFIGS. 13A-15, or may be the closed minimallyinvasive screw extension517 illustrated inFIGS. 19A-19E. The minimally invasive screw extension may be connected to thebone anchor30 and may be used to percutaneously place a bone anchor, such asbone anchor16, over a guide wire in a minimally invasive procedure.

The exemplaryanchor connection instrument800 includes a generallytubular instrument body802 having aproximal end806 for connection to the proximal end of a cement delivery tube, such as theproximal end856 of thecement delivery tube814, adistal end804 configured to connect to a bone anchor, such asbone anchor30, and a central passage spanning from theproximal end806 to thedistal end804 through which the cement delivery tube may be delivered to the bone anchor. Theproximal end806 of theinstrument800 may include anannular collar808 having an annular side wall spaced apart from the outer wall of thetubular instrument body802. Theannular collar808 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 thescrew extension517. Theproximal end806 may also include a connection feature to permit the proximal end of the cement delivery tube to be connected to theinstrument800. In the exemplary embodiment, for example, theproximal end806 of theinstrument body802 includes anannular groove809 for receiving theprongs882A,882B of theproximal end856 of thecement delivery tube814.

Thedistal end804 of theinstrument body802 may include a first connection feature for connecting to theproximal end30 of thebone anchor16 and a second connection feature to connect with thebone engaging portion32 of thebone anchor16. Thefirst connection feature810, in the exemplary embodiment, is an externally threadedsection810 that threadingly engages theinternal thread33 provided on theproximal portion30 of thebone anchor16 to receive a closure mechanism. The second connection feature is adrive tip812 that engages the drive feature provided on the proximal head of thebone engaging portion32 to permit thebone engaging portion32 to be anchored into bone. The first connection feature and the second connection feature permit theinstrument800 to hold the proximalrod receiving portion30 of thebone anchor16 relative to thebone engaging portion32 of thebone anchor16 which allows thedistal tip854 of thecement delivery tube814 to be more easily placed in thepassage34 of thebone anchor16.

The exemplarycement delivery tube814 includes aproximal end856 configured to connect to theproximal end806 of theinstrument800 and to thecement delivery system18 and a distal end865 854 sized to be positioned within thepassage34 of thebone anchor16 and deliver cement from thecement delivery system18 to thebone anchor16. Theproximal end856 includes a connection feature for connecting to a mating connection feature on theproximal end806 of theinstrument800. For example, theproximal end856 of theexemplary tube814 includes two spaced-apart flexible,resilient prongs882A,882B that may be snapped into thegroove809 on theproximal end806 of theinstrument800. The proximal ends884A,884B of theprongs882A,882B may be compressed together to release the distal ends886A,886B of the prongs from thegroove809. In addition, thetube814 may include a connection feature, such as a leur luer lock connector, to connect thetube814 to thecement delivery system18.

Referring toFIG. 19E, thecement delivery tube814 may taper from an increased inner diameter at the proximal end to856 a reduced diameter at thedistal end854 to maximize the flow of cement within thetube814 and thereby extend the working time of the cement. In the exemplary embodiment, for example, thetube814 includes afirst section890, asecond section892 distal to thefirst section890, and athird section894 distal to thesecond section892. Thefirst section890 has a first inner diameter that is greater than the second inner diameter of thesecond section892, which is greater than the third inner diameter of thethird section894. Afirst tapering section896 interposed between thefirst section890 and thesecond section892 provides a tapering inner diameter from the first diameter to the second diameter. Asecond tapering section898 interposed between thesecond section892 and thethird section894 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 theproximal end856 to a second diameter at thedistal end854.

The exemplaryanchor connection instrument800 and thecement delivery tube814 may also be used in open procedures or procedures in which a screw extension is not connected to the bone anchor. Referring toFIGS. 20A-E, for example, theexemplary instrument800 and thecement delivery tube814 may be used in connection with acounter-torque instrument900 which allows thedistal end804 of theinstrument800 to be rotated into engagement with theproximal end30 of thebone anchor16. Thecounter-torque instrument900 includes a generallytubular body902 having a central passage through which theconnection instrument800 and thecement delivery tube814 may be positioned. Thebody902 of theinstrument900 may include a number of slots or openings therein to reduce the weight of theinstrument900 and to facilitate cleaning of the instrument. The distal end904 of may include two spaced apart, diametricallyopposed fingers904A,904B for positioning within therod receiving slot31 of thebone anchor16.

In use,fingers904A,904B of thecounter-torque instrument900 are positioned within therod receiving slot31 of thebone anchor16 during rotational engagement and disengagement of the externally threadedsection810 of theanchor engagement instrument800 with theinternal thread33 provided on theproximal portion30 of thebone anchor16. Thecounter-torque instrument900 prevents rotation of theproximal end30 of thebone anchor16 relative to theanchor connection instrument800.

In open procedures, the length of thecounter-torque instrument900 and theanchor connection instrument800 may be reduced, as illustrated inFIG. 21.FIG. 21 further illustrates another exemplary embodiment of a bone cement delivery tube916 having a connection feature that permits theproximal end956 of thetube914 to be internally connected to thecollar808 of theanchor connection instrument800. The connection feature, in the illustrated embodiment, includes one or more flexible,resilient prongs959 that snap fit into a groove or opening in the inner wall of thecollar808. The distal end of the bone cement delivery tube may be configured to occlude a portion of thepassage34 in thebone anchor16 to direct bone cement throughselective openings36 in thebone anchor16. In one exemplary embodiment, the distal end of a bone cement delivery tube (e.g.,tube14,tube614,tube814, or tube914) may be configured to occlude the distal end of thepassage34 thereby directing cement through only theopenings36 in the side wall of thebone engaging portion32. Thedistal end54 of thecement delivery tube14 may includeocclusion1002 that prevents further cement flow and one or more slots or openings in the sidewall of thetube14 that permit cement flow from the sidewalls rather than through a distal opening in thetube14. In the exemplary embodiment, two diametricallyopposed slots1004A,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 inFIG. 23, thedistal end54 of a bonecement delivery tube14 may include an occlusion in the form of aplug1006 spaced from thedistal opening1008 in thetube14 by a wire or other reduceddiameter structure 1010. Theplug1006 may have any shape suitable to occlude thepassage34 in thebone anchor16. Theplug1006, 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 thepassage34 of thebone anchor16. For example, thedistal end1054 of an exemplarycement delivery tube1104 may include lengthwise sections of increased flexibility, as illustrated inFIG. 24A. Thedistal end1054 of theexemplary tube1104 includes a firstlengthwise section1056 and a secondlengthwise section1058 connected to and distal from thefirst section1056. Thefirst section1056 may be constructed from a material having increased flexibility compared to thesecond section1058 and compared to theproximal section1050. For example, thefirst section1056 may be constructed of a flexible polymer material, thesecond section1058 may be constructed from a stiffer material, such as a metal (e.g., stainless steel), and theproximal section1050 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 bonecement delivery tube1114, the continuous length of thedistal end1154 of the tube may be constructed from a flexible material while theproximal end1150 of thetube1114 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 (31)

The invention claimed is:

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

6. The method ofclaim 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.

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