US20140128917A1 - Inter-vertebral orthopedic device placement - Google Patents

Abstract

An orthopedic device is adapted to fixate the spinous processes of vertebral bones. The device includes at least one bone engagement member. When implanted, a bone engagement member is located on each side of a spinous process and adapted to forcibly abut the side of each spinous process.

Description

REFERENCE TO PRIORITY DOCUMENTS
• This application is a divisional of and claims priority to U.S. patent application Ser. No. 12/011,772 issuing as U.S. Pat. No. 8,568,453 on Oct. 29, 2013, which is incorporated herein by reference in its entirety, and which claims priority of co-pending U.S. Provisional Patent Application Ser. No. 60/898,010 filed Jan. 29, 2007, and U.S. Provisional Patent Application Ser. No. 60/921,570 filed Apr. 3, 2007. Priority of the aforementioned filing dates is hereby claimed and the disclosures of the Provisional patent applications are hereby incorporated by reference in their entirety.
BACKGROUND
• The present disclosure relates to devices and methods that permit fixation and stabilization of the bony elements of the skeleton. The devices permit adjustment and maintenance of the spatial relationship(s) between neighboring bones. Depending on the specifics of the embodiment design, the motion between adjacent skeletal segments may be limited or completely eliminated.
• Spinal degeneration is an unavoidable consequence of aging and the disability produced by the aging spine has emerged as a major health problem in the industrialized world. Alterations in the anatomical alignment and physiologic motion that normally exists between adjacent spinal vertebrae can cause significant pain, deformity, weakness, and catastrophic neurological dysfunction.
• Surgical decompression of the neural tissues and immobilization of the vertebral bones is a common option for the treatment of spinal disease. Currently, vertebral fixation is most frequently accomplished by anchoring bone screws into the pedicle portion of each vertebral body and then connecting the various screw fasteners with an interconnecting rod. Subsequent rigid immobilization of the screw/rod construct produces rigid fixation of the attached bones.
• The growing experience with spinal fusion has shed light on the long-term consequences of vertebral immobilization. It is now accepted that fusion of a specific spinal level will increase the load on, and the rate of degeneration of, the spinal segments immediately above and below the fused level. As the number of spinal fusion operations have increased, so have the number of patients who require extension of their fusion to the adjacent, degenerating levels. The rigidity of the spinal fixation method has been shown to correlate with the rate of the degenerative progression of the adjacent segments. In specific, implantation of stiffer instrumentation, such as rod/screw implants, produced a more rapid progression of the degeneration disease at the adjacent segment than use of a less stiff fixation implant.
• An additional shortcoming of the traditional rod/screw implant is the large surgical dissection required to provide adequate exposure for instrumentation placement. The size of the dissection site produces unintended damage to the muscle layers and otherwise healthy tissues that surround the diseased spine. A less invasive spinal fixation implant would advantageously minimize the damage produced by the surgical exposure of the spine.
SUMMARY
• The preceding discussion illustrates a continued need in the art for the development of a minimally invasive method of vertebral fixation of reduced rigidity.
• In a first embodiment, there is disclosed an orthopedic device adapted to fixate the spinous processes of vertebral bones. The implant includes at least one bone engagement member located on each side of a spinous process and adapted to forcibly abut the side of each spinous process. The engagement member only abuts a single spinous process and does not abut another surface of a second spinous process. The implant further includes a connector member adapted to interconnect the bone engagement members on each side of a spinous processes. The connector member is defined by a long axis that is substantially longitudinal and parallel to the spinous processes. The implant further includes a connection between the bone engagement members and the connector member. The connection is capable of reversibly transitioning between a first state, wherein the orientation between the engagement member and the connector member is changeable in at least one plane and a second state, wherein the orientation between the engagement member and the connector member is rigidly affixed. The implant further includes a cross member extending across the vertebral midline and adapted to adjustably couple the longitudinal connector members that are located on each side of the vertebral midline. The cross member reversibly transitions between a first state, wherein the orientation between the longitudinal connector members and the cross member is changeable and a second state, wherein the orientation between the longitudinal connector members and the cross member is rigidly affixed.
• In a second embodiment, there is disclosed an orthopedic device adapted to fixate the spinous processes of vertebral bones. The orthopedic device includes at least one bone engagement member located on each side of at least two adjacent spinous processes and adapted to forcibly abut the side of the spinous processes. The engagement member is substantially comprised of a contoured rod and contains at least one side aperture that permits contact between bone graft material and the spinous processes. The device further includes a cross member extending across the vertebral midline and adapted to adjustably couple the longitudinal bone engagement members that are located on each side of the vertebral mid line. The cross member is capable of reversibly transitioning between a first state, wherein, the orientation between the longitudinal bone engagement members and the cross member is changeable in at least one plane and a second state, wherein the orientation between the longitudinal bone engagement members and the cross member is rigidly affixed.
• In another embodiment, there is disclosed an orthopedic device adapted to fixate the spinous processes of vertebral bones. The device includes at least one bone engagement member located on each side of at least two adjacent spinous processes and adapted to forcibly abut the side of the spinous processes. The bone engagement member is substantially comprised of a plate that contains a curvilinear end surface adapted to engage a connecting member, wherein the curvilinear end surface is not located on a bone engaging surface of the plate. The device further includes a cross member extending across the vertebral midline and adapted to adjustably couple the longitudinal bone engagement members that are located on each side of the vertebral mid line. The cross member has a complimentary surface adapted to engage the curvilinear end surfaces of the longitudinal bone engagement members and to provide a changeable attitude between them. The cross member is further adapted to reversibly transition between a first state, wherein the orientation between the longitudinal bone engagement members and the cross member is changeable in at least one plane and a second state, wherein the orientation between the longitudinal bone engagement members and the cross member is rigidly affixed.
• In another embodiment, there is disclosed an orthopedic device adapted to fixate the spinous processes of the vertebral bones wherein the device is adapted to accepted an additional bone fastener that is placed into the base of the spinous process in a substantially horizontal trajectory.
• In yet another aspect, for fixation of at least a first vertebral bone, a second vertebral bone and a third vertebral bone is disclosed. In one embodiment, the method comprises: (i) positioning a first implant onto a posterior aspect of the first vertebral bone and the second vertebral bone, the first implant comprises at least four bone abutment surfaces, a first abutment surface attached to a second abutment surface via a first interconnecting member, a third abutment surface attached to a fourth abutment surface via a second interconnecting member, the first and third bone abutment surfaces being aligned to substantially face one another, and the second and fourth bone abutment surfaces being aligned to substantially face one another, a third interconnecting member configured to movably couple the first and the second interconnecting members, and a first locking mechanism disposed at an intersection of the third interconnecting member and the first interconnecting member and configured to transition to a configuration that limits movement between the third interconnecting member and the first interconnecting member; (ii) advancing the first bone abutment surface of the first implant onto a first side of a spinous process of the first vertebral bone, and the third bone abutment surface of the first implant onto an opposing second side of the spinous process of the first vertebral bone; (iii) advancing the second bone abutment surface of the first implant onto a first side of a spinous process of the second vertebral bone, and the fourth bone abutment surface of the first implant onto an opposing second side of the spinous process of the second vertebral bone; (iv) applying a compressive force onto the first implant, the force causing entrapment of the spinous process of the first vertebral bone between the first and third bone abutment surfaces, and causing entrapment of the spinous process of the second vertebral bone between the second and fourth bone abutment surfaces; (v) actuating the first locking mechanism of the first implant to rigidly immobilize the first interconnecting member to the third interconnecting member; (vi) positioning a second implant onto a posterior aspect of the second vertebral bone and the third vertebral bone, the second implant comprises at least two bone abutment surfaces being aligned to substantially face one another, a first one of the at least two bone abutment surfaces comprising an extension configured to couple onto the third bone abutment surface of the first implant, the coupling transitioning from a first state to a second state, the first one of the at least two bone abutment surfaces being movable relative to the third bone abutment surface of the first implant when the coupling is in the first state, and being rigidly affixed to the third bone abutment surface of the first implant when the coupling is in the second state, at least one interconnecting member configured to movably couple the at least two bone abutment surfaces, and at least one locking mechanism configured to transition to a configuration that limits movement between the at least two bone abutment surfaces; (vii) advancing the first one of the at least two bone abutment surfaces of the second implant onto a first side of a spinous process of the third vertebral bone, and a second one of the at least two bone abutment surfaces of the second implant onto an opposing second side of the spinous process of the third vertebral bone; (viii) coupling the extension of the first one of the at least two bone abutment surfaces of the second implant onto the third abutment bone abutment surface of the first implant; (ix) applying a compressive force onto the second implant, the force causing entrapment of the spinous process of the third vertebral bone between the at least two bone abutment surfaces of the second implant; (x) actuating the at least one locking mechanism of the second implant to rigidly immobilize the at least two bone abutment surfaces relative to one another; and (xi) actuating the at least one interconnecting member of the second implant to rigidly affix the first one of the at least two bone abutment surfaces of the second implant onto the third bone abutment surface of the first implant.
• In another embodiment, the method comprises: (i) advancing a first bone abutment surface of a first implant onto a first side of a spinous process of the first vertebral bone, and a second bone abutment surface of the first implant onto an opposing second side of the spinous process of the first vertebral bone, the first and second bone abutment surfaces being aligned to substantially face one another; (ii) advancing a third bone abutment surface of the first implant onto a first side of a spinous process of the second vertebral bone, and a fourth bone abutment surface of the first implant onto an opposing second side of the spinous process of the second vertebral bone, the second and fourth bone abutment surfaces being aligned to substantially face one another, the third abutment surface configured to be attached to the first abutment surface via a first interconnecting member, and the fourth abutment surface configured to be attached to the second abutment surface via a second interconnecting member; (iii) applying a compressive force onto the first implant, the force causing entrapment of the spinous process of the first vertebral bone between the first and second bone abutment surfaces, and causing entrapment of the spinous process of the second vertebral bone between the third and fourth bone abutment surfaces; (iv) actuating a first locking mechanism to rigidly immobilize the first and the second interconnecting members of the first implant relative to one another; (v) advancing a fifth bone abutment surface of a second implant onto a first side of a spinous process of the third vertebral bone, and a sixth bone abutment surface of the second implant onto an opposing second side of the spinous process of the third vertebral bone, the fifth and sixth bone abutment surfaces being aligned to substantially face one another; (vi) coupling an extension of the fifth bone abutment surface of the second implant onto the second bone abutment surface of the first implant; (vii) applying a compressive force onto the second implant, the force causing entrapment of the spinous process of the third vertebral bone between the fifth and sixth bone abutment surfaces of the second implant; (viii) actuating a second locking mechanism of the second implant to rigidly immobilize the fifth and sixth bone abutment surfaces relative to one another; and (ix) causing the fifth bone abutment surface of the second implant to be rigidly affixed to the second bone abutment surface of the first implant.
• In another aspect, an orthopedic implant is disclosed. In one embodiment, the orthopedic device is configured to attach onto at least a first, second bone, and third bone and comprises: a first abutment surface, a second abutment surface configured to attach to the first abutment surface via a first interconnecting member, a third abutment surface, the third bone abutment surface being aligned to substantially face the first bone abutment surface, a fourth abutment surface configured to attach to the third abutment surface via a second interconnecting member, the fourth bone abutment surface being aligned to substantially face the second bone abutment surface, a third interconnecting member configured to movably couple the first and the second interconnecting members, a first locking mechanism configured to be disposed at an intersection of the third interconnecting member and the first interconnecting member and configured to transition to a configuration that limits movement between the third interconnecting member and the first interconnecting member, a fifth abutment surface comprising an extension configured to couple onto the third abutment surface, the coupling transitioning from a first state to a second state, a sixth abutment surfaces configured to be aligned to substantially face the fifth abutment surface, a fourth interconnecting member configured to movably couple the fifth and sixth abutment surfaces, and a second locking mechanism configured to transition to a configuration that limits movement between the fifth and the sixth abutment surfaces. The fifth abutment surface is movable relative to the third bone abutment surface when the coupling is in the first state, and the fifth abutment surface is rigidly affixed to the third bone abutment surface when the coupling is in the second state.
• Other features and advantages will be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosed devices and methods.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows perspective views of an exemplary embodiment of an orthopedic implant.
• FIG. 2A shows an exploded view of the implant embodiment.
• FIG. 2B illustrate multiple views of a locking member of the implant.
• FIG. 3A shows a section of a locking mechanism of the implant in the locked and rigid position.
• FIG. 38 shows a section of a locking mechanism of the implant in the un-locked and non-rigid position.
• FIG. 4 shows a section of another locking mechanism of the implant.
• FIG. 5A andFIG. 58 show a perspective view of the embodiment prior to screw placement and after screw placement, respectively.
• FIG. 6 shows a second embodiment of the implant attached to a vertebral bone model.
• FIG. 7 A shows a side perspective of the embodiment ofFIG. 6.
• FIG. 7B shows a cross-sectional view of the device ofFIG. 7 A.
• FIG. 8 shows an alternative locking mechanism of the implant.
• FIG. 9 shows a member of the alternative locking mechanism.
• FIG. 10 illustrates a cross-sectional view of the alternative locking mechanism.
• FIG. 11 illustrates a perspective view of another embodiment of an orthopedic implant.
• FIG. 12 shows the device ofFIG. 11 in multiple orthogonal planes.
• FIG. 13A shows an exploded view of the implant.
• FIG. 13B illustrates a cross-sectional view of the locking mechanism.
• FIG. 14 shows a perspective view of another embodiment of an orthopedic implant.
• FIG. 15 shows an exploded view of the implant inFIG. 14.
• FIG. 16 shows a cross-section view of the locking mechanism of the implant embodiment ofFIG. 14.
• FIG. 17 shows a modular attachment device.
• FIG. 18 illustrates an exploded view of the modular attachment device ofFIG. 17.
• FIGS. 19A and 19B show a locking mechanism between the modular attachment device ofFIG. 17 and the device ofFIG. 14. The locking mechanism is shown in the unlocked state inFIG. 19 A and in the locked state inFIG. 19B.
• FIG. 20 shows a perspective view of another embodiment attached to vertebral bones.
• FIG. 21 illustrates the device ofFIG. 20 in an exploded view.
• FIG. 22 shows a cross-sectional view through the locking mechanism of the device.
DETAILED DESCRIPTION
• FIG. 1 shows a perspective view of an exemplary embodiment of a vertebral fixation implant. The implant can be anchored across multiple levels of vertebral bones via one or more spiked anchor members, such asmembers105. For clarity of illustration, the device is shown attached to two adjacent vertebral bones. The vertebrae are represented schematically and those skilled in the art will appreciate that actual vertebral bones may include anatomical details that differ from those shown inFIG. 1. An exploded view of the implant is shown inFIG. 2A.
• In a device intended to immobilize two vertebral bones, fouranchor members105 are interconnected by “H’ shapedrod connector109. Therod connector109 includes a pair of rods that extend generally parallel to the vertebral midline and a single cross rod that crosses the vertebral midline. The cross rod interacts with a locking element that can be used to adjust the position of the cross rod relative to the pair of rods that extend generally parallel to the vertebral midline.
• The rod connector interacts with a plurality ofanchor members105 that are positioned so that each can be affixed onto each side surface of a spinous process of each vertebra. Theanchor member105 is adapted to affix onto the side surface of the spinous process and can have various structures suited for such a purpose. In the illustrated embodiment, the anchor member contains aninner abutment surface1052 that contains structures adapted to attach to the spinous process, such asspiked projections1053. Eachanchor member105 also has anouter surface1055 that contains areceptacle member1056 adapted to receive a segment ofrod connector109. A locking member110 (FIG. 28) is adapted to interact withreceptacle member1056 and rigidly affixrod connector109 onto ananchor member105. As described below, the lockingmember110 is sized and shaped to be positioned inside a central cavity of receptacle member and locked in place therein. Eachanchor member105 can optionally contain abore hole1058 that is adapted to accept a bone screw or other fastener that, when applied, can increase the fixation strength of the device onto bone.
• Through its interaction with lockingmember110,receptacle member1056 ofanchor member105 is adapted to allow adjustable placement ofrod connector109 relative tomember105 and provide an adjustable orient forspike members1053 relative to the spinous process. In use, theanchor members105 are attached to the spinous processes by driving thespike members1053 into the spinous processes. After each of twomembers105 are forcibly driven into opposing sides of a spinous process of a single spinal vertebra, lockingmember110 is compressed into the central cavity ofreceptacle member1056. The lockingmember110 interacts with thereceptacle member1056 and therod connector109 such that a segment ofrod connector109 is rigidly affixed within thereceptacle member1056. The lockingmember110 is adapted to reversibly transition from a first un-locked state in whichmember1056,member110 and the interacting segment ofrod connector109 are movable to a second locked state wherein the device members are rigidly affixed to another, as described more fully below.
• FIG. 2B shows various views of an exemplary embodiment of lockingmember110. In the illustrated embodiment, lockingmember110 has a sphericalinner cavity1102 adapted to accept aspherical end segment1092 of connectingrod109. Outer surface1104 of lockingmember110 is adapted to fit within and interact with a conical inner surface ofreceptacle member1056 ofanchor member105. Anouter wall relief1109 is adapted to accept a retention pin. A second relief,1106, is located on an open end of lockingmember110 and allows the formation of deformable flap withprotrusion tip1108.
• A cross-sectional view of the locking mechanism is shown inFIG. 3A (locked state) and inFIG. 3B (unlocked state). In the unlocked state shown inFIG. 3B,spherical end segment1092 of connectingrod109 is non-rigidly retained withincavity1102 ofmember110, permitting movement of connectingrod109 relative tomember110 in one or more planes. With the application of a compressive load by a locking device (not shown),member110 is forcibly advanced into the conical inner surface ofreceptacle member1056. The advancement of lockingmember110 intoreceptacle1056 produces a centripetal force that rigidly immobilizes the connectingrod109 to anchormember105. The interaction ofprotrusion tip1108 of lockingmember110 with a relief on the inner wall of receptacle member1056 (FIG. 3A) will maintain the construct in the locked position even after the locking instrument is removed.
• While theinner cavity1102 ofmember110 can accept aspherical end segment1092 of connectingrod109, the flat surroundingsegment1103 of the inner aspect ofmember110 can alternatively accommodate and interact with a cylindrical segment ofrod109. Withmember110 in the unlocked position and a cylindrical segment ofrod109 engaged,member110 can translate along the cylindrical segment ofrod109 and produce a device of variable length. In this configuration, rotational movement betweensegment105 and interconnectingrod109 occurs at the interface between member11 O andreceptacle1056 as well as within the second locking mechanism shown inFIG. 4.
• A second locking mechanism can be used to maintain the device in a locked configuration. The second locking mechanism can be located within therod connector109 and actuated by the advancement of threadedscrews1094 into a complimentary threaded bore hole on connectingrod109, as shown inFIG. 4. For clarity of illustration, the threads are not shown inFIG. 4. This second locking mechanism exerts a compressive load onto lockingmember110 and maintains the device in the locked configuration. It also places a compressive load across each of the twoanchor members105 placed on apposing sides of a spinous process and keeps thespiked projections1053 rigidly affixed to bone.
• Bone fixation may be strengthened further by the placement of bone screws or similar fasteners through bore holes within theanchor members105, such asbore hole1058. The insertion of bone screws into theanchor members105 is illustrated inFIGS. 5A and 5B.Bores1058 are positioned inmember105 so as to provide a substantially axial (i.e., horizontal) screw trajectory and advance the distal screw segment into the base of the spinous process. Preferably, each of the two opposite screws anchored onto a single spinous process are adapted to follow a non-parallel trajectory so as to further enhance bone fixation. In addition, the screw top may be angled so as to provide a Morse-taper like fit within thebore hole1058. Alternatively, a secondary feature may be added to lock the bone screw ontoanchor member105 after the screws are fully seated into the underlying bone. Anadditional tab1057 may be used to connect twoanchor members105 across the mid line of the spinous process. This variation is shown inFIG. 6, which shows thetab1057 that extends over the spinous process. In an embodiment, thetab1057 has malleable sides that permit relative motion between eachanchor member105. Thetab1057 may also contain a central bore that is adapted to accept a bone fastener anchored into the spinous process.FIG. 7 A show a lateral view of the device ofFIG. 6, whileFIG. 7B illustrates a lateral cross sectional view that shows the bone screw extending along the long axis of the spinous process through thetab1057.
• An alternative locking member that reversibly locks connectingrod109 and receptacle1056 ofmember105 is shown inFIGS. 8 through 10. This embodiment has a modified version of the locking member, which is shown inFIG. 9. Lockingmember122 has aninner cavity1222 that is sized and shaped to acceptspherical end1092 of connectingrod109.Member122 has conicalouter wall1224 that fits withinreceptacle member1056.Relief1225 ofwall1224 is adapted to accept a retention pin. Another relief,1227, is located on the inferior surface of lockingmember122 and allows the formation of deformable flap withprotrusion tip1228. Akey hole relief1229 allows the superior aspect ofmember122 to angle inward in response to a compressive load and constrictinner cavity1222 of the lockingmember122.
• A cross-sectional view of the alternate embodiment of the locking mechanism is shown inFIG. 10 in the locked configuration. With the application of a compressive load by a locking device (not shown},member122 is forcibly advanced into the conical inner surface ofreceptacle member1056. Because of the difference in wall angle between the outer wall ofmember122 and the inner wall ofreceptacle1056, advancement ofmember122 intoreceptacle1056 produces a centripetal inclination of the walls ofmember122 and rigidly immobilizes the connectingrod109 to anchormember105. The interaction ofprotrusion tip1228 of lockingmember122 with a relief on the inner wall ofreceptacle member1056 will maintain the construct in the locked position even after the locking instrument is removed. As previously discussed with reference tomember110, a cylindrical segment ofconnector rod109 may be alternatively used to interact withmember122 and produce a device of variable length.
• The device may be also used to fixate more than two vertebral levels. In this procedure, the total length from the top-most to lower-most spinous process is measured and the number of spinous processes to be affixed is counted. An interconnecting longitudinal rod of the appropriate length is selected and coupled with the appropriate number ofbone anchor members105. Either one, both or none of the longitudinal interconnecting rod ends may be spherical.Members110 of theanchor member105 will couple and interaction with cylindrical portion of the longitudinal rod to provide an adjustable spacing betweenmembers105. An interconnecting rod with the appropriate number ofmember105 is placed on each side of the mid line.
• Starting at a selected level, a locking compression device (not shown) is used to drive the spikes of themembers105 into each side of the spinous process. The locking compression device is left in position and the procedure is repeated onto the next spinous process level. Prior to the rigid fixation ofmember110 withinreceptacle1056, the attitude ofmember105 may be adjusted by rotation and translation relative to the interconnecting rod. After anchoring the opposingmember105 into the spinous process, the locking device is left in place and the procedure is sequentially moved to another level. After fixation of a number of levels has been accomplished, the surgeon can place a cross member across the mid line and couple each of the longitudinal rods. This step can be performed after some or allmembers105 have been rigidly affixed to their designated vertebral level. After cross member placement, the locking compression device attached to each secured level is removed. If desired, an additional bone screw fastener may be placed throughbore hole1058.
• FIGS. 11 through 13 illustrate an additional device embodiment. A perspective view is shown inFIG. 11 while multiple orthogonal views are illustrated inFIG. 12. Thedevice1705 is comprised of twobone engaging members1710 that are each formed of a pair of contoured or curved rods that extend outwardly from acentral member1717. Thebone engaging members1710 are separated by a space that is sized and shaped to receive a bone structure, such as the spinous process of a vertebral body. Opposed surfaces of thebone engaging members1710 have attachment means such as spikes, knurls or other protrusions on the bone-facing aspect of each bone-engaging member. An interconnectingmember1720 comprised of an elongated rod is adapted to extend through a fitted bore hole within eachcentral member1717. A lockingscrew1725 is adapted to reversibly lock a segment of interconnectingmember1720 within eachcentral member1717.
• FIG. 13A shows an exploded view of the device.FIG. 138 illustrates a cross-sectional view through the locking mechanism.Central member1717 has acentral bore1728 along and the long access that is adapted to accept lockingscrew1725 and asecond bore1730 that is adapted to acceptinterconnecting ember1720. Compressiblespherical member1732 hasbore hole1734 andopen side notch1735. As shown inFIG. 138,member1732 is contained withinbore hole1728 ofcentral member1717 and surrounds a segment of interconnectingmember1720 in the assembled device. Lockingscrew1725 abuts a surface of compressiblespherical member1732. In the unlocked state, interconnectingmember1720 is freely movable withinmember1732.Spherical member1732 can also rotate withincentral hole1728, thereby proving an adjustable relationship between eachbone engaging members1710 andinterconnecting rod1720. With advancement of lockingscrew1725,spherical member1732 is forcibly compressed ontorod1720 and immobilized withincentral hole1728, thereby lockinginterconnecting rod1720 withinbone engaging member1710.
• In placement of the device onto bone, eachbone engaging member1710 is situated on an opposite side of the spinous processes to be immobilized. A compressive force is applied by a locking instrument (not shown) acrossmembers1710 so as to drive the spikes into the side of the spinous processes of neighboring vertebrae and immobilize them. The interconnectingmember1720 is used to maintain compression even after the locking instrument has been removed. In this regard, the threadedlocking screws1725 are advanced to provide a locked engagement between interconnectingmember1720 and eachmember1710. After implantation,multiple apertures1723 exist in this rod-based device that advantageously permit access to the underlying bone of the spinous processes. Bone graft material can be placed throughapertures1723 and into contact with the spinous processes in order to form and augment the bone fusion mass.
• FIGS. 14 through 16 illustrate an additional device embodiment. A perspective view is shown inFIG. 14 while an exploded view in shown inFIG. 15. Thedevice208 is comprised of twobone engaging members210 and212 that are opposed to one another. Thebone engaging members210 and212 are separated by a space that is sized and shaped to receive a bone structure, such as the spinous process of a vertebral body. Opposed surfaces of thebone engaging members210 and212 have attachment means such as spikes, knurls or other protrusions on the bone-facing aspect of each bone-engaging member. In application, each member is situated on an opposite side of the spinous processes to be immobilized. A compressive force is applied by a locking instrument (not shown) acrossmembers210 and212 so as to drive the spikes into the side of the spinous processes of neighboring vertebrae and immobilize them. A slotted interconnectingplate218 is used to maintain compression even after the locking instrument has been removed.
• A cross-sectional view of the implant's locking mechanism is shown in the locked position inFIG. 16. Aspherical member222 has threadedcentral bore2224 and accepts threaded screw226 (threads not shown for either member).Member222 resides within bores230 (FIG. 15) ofplate members210 and212.Bore230 is adapted to permit insertion ofmember222 from the bottom. A securement member, such as a protrusion withinbore230, preventsmember222 from emerging from the top. Retention pins234retain member222 withinbore230 and prevent its rotation relative to long axis ofbore230. The top surface of eachmember210 and212 contains aspherical protrusion240 that has the same center of rotation as seatedmember222. The inferior surface of interconnectingplate218 has a complimentary spherical indentation that compliments thespherical surface protrusion240 ofmembers210 and212. In this way, eachmember210 and212 can be independently oriented relative to interconnectingplate218. With advancement of threadedscrew226 intomember222, the interconnectingplate218 is locked relative tomembers210 and212.
• Amodular device1402 is shown inFIGS. 17 through 19. The modular device is adapted to reversibly lock onto an implanteddevice208 and thereby extend the affixing of an adjacent vertebral body to the implanteddevice208.FIG. 17 shows the modular device attached to an implanteddevice208.FIG. 18 shows the modular device in an exploded state adjacent to an assembleddevice208, which is substantially identical or similar to the device shown inFIGS. 14-16. A locking mechanism1405 is adapted to reversibly lock onto thedevice208 by interacting with ahole1407 in thedevice208. The locking mechanism1405 includes apin1410 that fits into anexpandable head1415 that is positionable within thehole1407.
• FIG. 19A shows the locking mechanism1405 in a unlocked state with thedevice208. The pin141 O is partially positioned within theexpandable head1415, which is located insidebore1407 of thebone engaging member210.Member210 has a curved inner surface that is adapted to interact with the complimentary outer surface ofhead1415 and permit movement therebetween. With thepin1410 in the unlocked position shown inFIG. 19A,modular device1402 and member21 O are movable relative to one another in one or more planes.FIG. 19B shows the locking mechanism1405 in a locked state such that thepin1410 has been fully inserted into theexpandable head1415. This has caused thehead1415 to expand outward withinbore hole1407 and provide an interfering, locked engagement between the modular device and thebone engaging member210. The two devices are thus locked relative to one another.
• FIGS. 20 through 22 illustrate an additional device embodiment.FIG. 20 shows the device attached to vertebral bones andFIG. 21 shows the device in an exploded state. The device is comprised of twobone engaging members2005 formed of elongated rods configures to be positioned adjacent the vertebral bodies. Thebone engaging members2005 are separated by a space that is sized and shaped to receive a bone structure, such as the spinous process of a vertebral body. Opposed surfaces of thebone engaging members2005 have attachment means such as spikes, knurls or other protrusions on the bone-facing aspect of each bone-engaging member.
• With reference toFIG. 20-22, thebone engaging members2005 are connected to acentral member2015 by a pair of curved connectingarms2025 withenlarged heads2030. The connectingarms2025 and thebone engaging members2005 are joined together byretention pins2050. Theheads2030 can pivot inside the cavity ofcentral member2015 such that thebone engaging members2005 can move toward and away from the spinous processes.
• A threadedlocking screw2035 engages threadedlocking nut2040 within the central cavity of central member201˜.Edges2042 ofmember2040 are contained withinindentions2032 ofheads2030. As lockingscrew2035 is rotated and locking nut is moved towards the head2037 ofscrew2035, heads2030 of connectingarms2025 are rotated within the central cavity ofmember2015. Rotation ofheads2030 cause thebone engaging members2005 to pivot inward by virtue of the curved shape of the connectingarms2025. Thebone engaging members2005 thereby are caused to exert a compressive force onto the spinous processes and to be secured thereto. Conversely, rotation of the locking2035 in the reverse direction will cause thebone engaging member2005 to move away from the spinous processes.
• The disclosed devices or any of their components can be made of any biologically adaptable or compatible materials. Materials considered acceptable for biological implantation are well known and include, but are not limited to, stainless steel, titanium, tantalum, shape memory alloys, combination metallic alloys, various plastics, resins, ceramics, biologically absorbable materials and the like. Any components may be also coated/made with osteo-conductive (such as deminerized bone matrix, hydroxyapatite, and the like) and/or osteo-inductive (such as Transforming Growth Factor “TGF-8,” Platelet-Derived Growth Factor “PDGF,” Bone-Morphogenic Protein “BMP,” and the like) bio-active materials that promote bone formation. Further, any surface may be made with a porous ingrowth surface (such as titanium wire mesh, plasma-sprayed titanium, tantalum, porous CoCr, and the like), provided with a bioactive coating, made using tantalum, and/or helical rosette carbon nanotubes (or other carbon nanotube-based coating) in order to promote bone in-growth or establish a mineralized connection between the bone and the implant, and reduce the likelihood of implant loosening. Lastly, the system or any of its components can also be entirely or partially made of a shape memory material or other deformable material.
• Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be strictly limited to the description of the embodiments contained herein.

Claims (30)

1.-5. (canceled)

6. A method for fixation of at least a first vertebral bone, a second vertebral bone and a third vertebral bone, said method comprising:

positioning a first implant onto a posterior aspect of said first vertebral bone and said second vertebral bone, said first implant comprising:

at least four bone abutment surfaces, a first abutment surface attached to a second abutment surface via a first interconnecting member, a third abutment surface attached to a fourth abutment surface via a second interconnecting member, said first and third bone abutment surfaces being aligned to substantially face one another, and said second and fourth bone abutment surfaces being aligned to substantially face one another;

a third interconnecting member configured to movably couple said first and said second interconnecting members; and

a first locking mechanism disposed at an intersection of said third interconnecting member and said first interconnecting member and configured to transition to a configuration that limits movement between said third interconnecting member and said first interconnecting member;

advancing said first bone abutment surface of said first implant onto a first side of a spinous process of said first vertebral bone, and said third bone abutment surface of said first implant onto an opposing second side of said spinous process of said first vertebral bone;

advancing said second bone abutment surface of said first implant onto a first side of a spinous process of said second vertebral bone, and said fourth bone abutment surface of said first implant onto an opposing second side of said spinous process of said second vertebral bone;

applying a compressive force onto said first implant, said force causing entrapment of said spinous process of said first vertebral bone between said first and third bone abutment surfaces, and causing entrapment of said spinous process of said second vertebral bone between said second and fourth bone abutment surfaces;

actuating said first locking mechanism of said first implant to rigidly immobilize said first interconnecting member to said third interconnecting member;

positioning a second implant onto a posterior aspect of said second vertebral bone and said third vertebral bone, said second implant comprising:

at least two bone abutment surfaces being aligned to substantially face one another, a first one of said at least two bone abutment surfaces comprising an extension configured to couple onto said third bone abutment surface of said first implant, said coupling transitioning from a first state to a second state, said first one of said at least two bone abutment surfaces being movable relative to said third bone abutment surface of said first implant when said coupling is in said first state, and being rigidly affixed to said third bone abutment surface of said first implant when said coupling is in said second state;

at least one interconnecting member configured to movably couple said at least two bone abutment surfaces; and

at least one locking mechanism configured to transition to a configuration that limits movement between said at least two bone abutment surfaces;

advancing said first one of said at least two bone abutment surfaces of said second implant onto a first side of a spinous process of said third vertebral bone, and a second one of said at least two bone abutment surfaces of said second implant onto an opposing second side of said spinous process of said third vertebral bone;

coupling said extension of said first one of said at least two bone abutment surfaces of said second implant onto said third abutment bone abutment surface of said first implant;

applying a compressive force onto said second implant, said force causing entrapment of said spinous process of said third vertebral bone between said at least two bone abutment surfaces of said second implant;

actuating said at least one locking mechanism of said second implant to rigidly immobilize said at least two bone abutment surfaces relative to one another; and

actuating said at least one interconnecting member of said second implant to rigidly affix said first one of said at least two bone abutment surfaces of said second implant onto said third bone abutment surface of said first implant.

7. A method as inclaim 6, wherein said compressive force applied to said first implant is provided by a separate instrument.

8. A method as inclaim 6, wherein said compressive force applied to said second implant is provided by a separate instrument.

9. A method as inclaim 6, wherein one or more bone abutment surfaces of said first implant further comprise one or more surface projections configured to anchor onto bone.

10. A method as inclaim 6, wherein one or more bone abutment surfaces of said second implant further comprise one or more surface projections configured to anchor onto bone.

11. A method as inclaim 6, wherein said third interconnecting member is positioned to cross a mid-sagittal plane that bisects said first vertebral bone into a right half and a left half.

12. A method as inclaim 6, wherein said at least one interconnecting member of said second implant is positioned to cross a mid-sagittal plane that bisects said third vertebral bone into a right half and a left half.

13. A method as inclaim 6, wherein said coupling of said extension of said first one of said at least two bone abutment surfaces onto said third bone abutment surface of said first implant substantially immobilizes said first one of said at least two bone abutment surfaces of said second implant relative to said third bone abutment surface of said first implant in one of a plurality of possible orientations.

14. A method as inclaim 6, wherein said act of transitioning said first locking mechanism substantially immobilizes said first interconnecting member relative to said third interconnecting member of said first implant in one of a plurality of possible orientations.

15. A method as inclaim 6, wherein at least one of said first or second implants is at least partially manufactured of a metallic material.

16. A method as inclaim 6, wherein at least one of said first and second bone abutment surfaces of said first implant comprises a tapered projection configured to penetrate bone.

17. A method as inclaim 6, wherein at least one of said third and fourth bone abutment surfaces of said first implant comprises a tapered projection configured to penetrate bone.

18. An orthopedic implant configured to attach onto at least a first, second bone, and third bone, said implant comprising:

a first abutment surface;

a second abutment surface configured to attach to said first abutment surface via a first interconnecting member;

a third abutment surface, said third bone abutment surface being aligned to substantially face said first bone abutment surface;

a fourth abutment surface configured to attach to said third abutment surface via a second interconnecting member, said fourth bone abutment surface being aligned to substantially face said second bone abutment surface;

a third interconnecting member configured to movably couple said first and said second interconnecting members;

a first locking mechanism configured to be disposed at an intersection of said third interconnecting member and said first interconnecting member and configured to transition to a configuration that limits movement between said third interconnecting member and said first interconnecting member;

a fifth abutment surface comprising an extension configured to couple onto said third abutment surface, said coupling transitioning from a first state to a second state;

a sixth abutment surfaces configured to be aligned to substantially face said fifth abutment surface;

a fourth interconnecting member configured to movably couple said fifth and sixth abutment surfaces;

a second locking mechanism configured to transition to a configuration that limits movement between said fifth and said sixth abutment surfaces;

wherein said fifth abutment surface is movable relative to said third bone abutment surface when said coupling is in said first state, and said fifth abutment surface is rigidly affixed to said third bone abutment surface when said coupling is in said second state.

19. An orthopedic implant as inclaim 18, wherein said first abutment surface comprises one or more surface projections configured to anchor onto bone.

20. An orthopedic implant as inclaim 19, wherein at least one surface projection of said first abutment surface comprises a tapered tip configured to penetrate into bone.

21. An orthopedic implant as inclaim 18, wherein said second abutment surface comprises one or more surface projections configured to anchor onto bone.

22. An orthopedic implant as inclaim 18, wherein said third abutment surface comprises one or more surface projections configured to anchor onto bone.

23. An orthopedic implant as inclaim 18, wherein said fourth abutment surface comprises one or more surface projections configured to anchor onto bone.

24. An orthopedic implant as inclaim 18, wherein said fifth abutment surface comprises one or more surface projections configured to anchor onto bone.

25. An orthopedic implant as inclaim 18, wherein said sixth abutment surface comprises one or more surface projections configured to anchor onto bone.

26. An orthopedic implant as inclaim 18, wherein said first locking mechanism is configured to substantially immobilize said first interconnecting member relative to said third interconnecting member in one of a plurality of possible orientations.

27. An orthopedic implant as inclaim 18, wherein said coupling is configured to immobilize said fifth abutment surface relative to said third abutment surface in one of a plurality of possible orientations.

28. An orthopedic implant as inclaim 18, wherein said implant is at least partially comprised of a plastic material.

29. An orthopedic implant as inclaim 18, wherein said implant is at least partially comprised of a metallic material.

30. An orthopedic implant as inclaim 18, wherein said implant comprises a bioactive material configured to promote bone formation.

31. A method for fixation of at least a first vertebral bone, a second vertebral bone and a third vertebral bone, said method comprising:

advancing a first bone abutment surface of a first implant onto a first side of a spinous process of said first vertebral bone, and a second bone abutment surface of said first implant onto an opposing second side of said spinous process of said first vertebral bone, said first and second bone abutment surfaces being aligned to substantially face one another;

advancing a third bone abutment surface of said first implant onto a first side of a spinous process of said second vertebral bone, and a fourth bone abutment surface of said first implant onto an opposing second side of said spinous process of said second vertebral bone, said second and fourth bone abutment surfaces being aligned to substantially face one another, said third abutment surface configured to be attached to said first abutment surface via a first interconnecting member, and said fourth abutment surface configured to be attached to said second abutment surface via a second interconnecting member;

applying a compressive force onto said first implant, said force causing entrapment of said spinous process of said first vertebral bone between said first and second bone abutment surfaces, and causing entrapment of said spinous process of said second vertebral bone between said third and fourth bone abutment surfaces;

actuating a first locking mechanism to rigidly immobilize said first and said second interconnecting members of said first implant relative to one another;

advancing a fifth bone abutment surface of a second implant onto a first side of a spinous process of said third vertebral bone, and a sixth bone abutment surface of said second implant onto an opposing second side of said spinous process of said third vertebral bone, said fifth and sixth bone abutment surfaces being aligned to substantially face one another;

coupling an extension of said fifth bone abutment surface of said second implant onto said second bone abutment surface of said first implant;

applying a compressive force onto said second implant, said force causing entrapment of said spinous process of said third vertebral bone between said fifth and sixth bone abutment surfaces of said second implant;

actuating a second locking mechanism of said second implant to rigidly immobilize said fifth and sixth bone abutment surfaces relative to one another; and

causing said fifth bone abutment surface of said second implant to be rigidly affixed to said second bone abutment surface of said first implant.

32. A method as inclaim 31, wherein said acts of applying a compressive force further comprise utilizing a separate apparatus to apply said force.

33. A method as inclaim 31, wherein said act of actuating said first locking mechanism comprises transitioning said first locking mechanism from a first state to a second state, said second state limiting movement between a third interconnecting member configured to movably couple said first and said second interconnecting members and said first interconnecting member, said first locking mechanism being disposed at an intersection of said third interconnecting member and said first interconnecting member.

34. A method as inclaim 31, wherein said act of coupling an extension of said fifth bone abutment surface of said second implant onto said second bone abutment surface of said first implant further comprises substantially immobilizing said fifth bone abutment surface of said second implant relative to said second bone abutment surface of said first implant in one of a plurality of possible orientations.

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