Expandable bone or tissue fastener and contour-adaptive modular locking plate

Abstract

A locking plate assembly comprising : at least two locking plates, each locking plate comprising a coupling feature configured to interlock with a coupling feature of another locking plate; wherein each locking plate is configured to be delivered through a minimally invasive incision and assembled intraoperatively into an interconnected construct; and wherein at least one of the locking plates further comprises an aperture configured to receive a bone fastener for securing the locking plate to a bone.

Description

[0001] EXPANDABLE BONE OR TISSUE FASTENER

[0002] AND CONTOUR-ADAPTIVE MODULAR LOCKING PLATE

[0003] Applicant

[0004] OrthoSpine Advance Health, Inc .

[0005] Inventors

[0006] Gabriel Garcia-Diaz , MD

[0007] Edward Franco

[0008] Gabriel Garcia-Correa

[0009] Reference To Pending Prior Patent Application

[0010] This patent application claims benefit of pending prior U . S . Provisional Patent Application Serial No .

[0011] 63 / 754 , 187 , filed 02 / 05 / 2025 by OrthoSpine Advance Health, Inc . for EXPANDABLE BONE OR TISSUE FASTENER (Attorney' s Docket No . OSPINE-2 PROV) .

[0012] The above-identified patent application is hereby incorporated herein by reference .

[0013] Field Of The Invention

[0014] This invention relates to medical devices in general , and more particularly to fasteners and associated fixation plates for percutaneous bone and tissue fixation .

[0015] Background Of The Invention

[0016] OSPINE-0207Fasteners (sometimes also referred to as "screws") find wide use in various surgical procedures . By way of example but not limitation, bone fasteners are commonly deployed in bone in order to provide a point for mounting another element used in a surgical procedure, such as a suture to connect soft tissue to bone, or a plate for connecting bone to bone (e . g. , for effecting fracture fixation, etc . ) .

[0017] Screw-style fasteners comprising a standard screw thread (i . e . , a helical thread) on the outer surface of the fastener may be simply "screwed" into bone by the surgeon, with the fastener being advanced into bone in the same manner that the fastener would be advanced into any other material (e . g. , wood, plastic, etc . ) . However, human bone presents a material that is somewhat different than other, homogenous materials . By way of example but not limitation, human bone typically comprises a hard outer surface made of cortical bone that provides strength and rigidity, and a porous inner material made of cancellous bone containing bone marrow for blood cell production. As a result, when a standard fastener comprising an external screw thread is advanced into bone, the distal portion of such a standard fastener does not find significant purchase in the cancellous bone, leading to a fastener that can "back out" of the hole in the bone in which it is installed, leading to compromised surgical procedures .

[0018] OSPINE-0207In addition, fasteners are commonly used to secure bone plates to the anatomy. By way of example but not limitation, bone plates are commonly utilized for fracture fixation, where such a bone plate is installed in the anatomy so as to span and reduce (under tension) the fracture in the bone . Complex, compound fractures may require bone plates of varying geometries to accommodate the native bone geometry. Prior art bone plates tend to be large, rigid (e . g. , stainless steel, titanium, etc . ) structures that must be carefully chosen / tailored for a particular application. Moreover, large bone plates (e . g. , for reduction of large fractures in long bones such as the femur, etc. ) are typically installed in an open procedure, requiring significant tissue trauma to the patient in order to obtain access to the surgical site . Such rigid prior art bone plates are large and challenging to deliver percutaneously via smaller incisions .

[0019] Thus there exists a need in the art for a new and improved fastener that can be more securely attached to bone than prior art fasteners .

[0020] There also exists need in the art for a new and improved bone plate that can be delivered percutaneously as well as a bone plate that can conform to the complex geometry of native bone .

[0021] Summary Of The Invention

[0022] OSPINE-0207The present invention comprises the provision and use of a new and improved fastener that can be more securely attached to bone than prior art fasteners .

[0023] The present invention also comprises the provision and use of a new and improved bone plate that can be delivered percutaneously .

[0024] The present invention further comprises a bone plate that is configured to conform to the complex geometry of native bone to which the novel bone plate is attached.

[0025] In a preferred form of the invention, there is provided an orthopedic fixation system comprising: a bone screw comprising a body having a distal end, a proximal end, and a central cavity defined by a sidewall disposed between the distal end and the proximal end of the body;

[0026] a rod configured to be disposed within the central cavity, the rod comprising a distal end and a proximal end;

[0027] wherein the sidewall of the central cavity comprises at least one radial restriction, wherein the diameter of the central cavity at the at least one radial restriction is smaller than the diameter of the central cavity proximal to the at least one radial restriction, such that distal advancement of the rod engages the at least one radial restriction of the sidewall of the central cavity and effects radially-outboard movement of the sidewall of the central

[0028] OSPINE-0207cavity, such that a portion of the body of the bone screw assumes a radially-expanded configuration when the rod engages the radial restriction.

[0029] In another preferred form of the invention, there is provided a locking plate assembly comprising:

[0030] at least two locking plates, each locking plate comprising a coupling feature configured to interlock with a coupling feature of another locking plate;

[0031] wherein each locking plate is configured to be delivered through a minimally invasive incision and assembled intraoperatively into an interconnected construct; and

[0032] wherein at least one of the locking plates further comprises an aperture configured to receive a bone fastener for securing the locking plate to a bone .

[0033] In another preferred form of the invention, there is provided a method for performing orthopedic fixation through a minimally invasive approach, the method comprising:

[0034] positioning a first locking plate against a surface of bone, wherein the first locking plate comprises a coupling feature configured to interlock with a coupling feature of a second locking plate and an aperture for receiving a first bone fastener;

[0035] positioning the second locking plate against the surface of the bone adj acent the first locking plate, wherein the second locking plate comprises a coupling

[0036] OSPINE-0207feature configured to interlock with the coupling feature of the first locking plate and an aperture for receiving a second bone fastener;

[0037] locking the second locking plate to the first locking plate by connecting the couple features;

[0038] passing a first bone fastener through the aperture in the first locking plate to lock the first locking plate to the bone; and

[0039] passing a second bone fastener through the aperture in the second locking plate to lock the second locking plate to the bone .

[0040] In another preferred form of the invention, there is provided a method for performing orthopedic fixation through a minimally invasive approach, the method comprising:

[0041] providing an orthopedic fixation system comprising :

[0042] a bone screw comprising a body having a distal end, a proximal end, and a central cavity defined by a sidewall disposed between the distal end and the proximal end of the body;

[0043] a rod configured to be disposed within the central cavity, the rod comprising a distal end and a proximal end;

[0044] wherein the sidewall of the central cavity comprises at least one radial restriction, wherein the diameter of the central cavity at the at least one radial restriction is smaller than the diameter of the

[0045] OSPINE-0207central cavity proximal to the at least one radial restriction, such that distal advancement of the rod engages the at least one radial restriction of the sidewall of the central cavity and effects radially-outboard movement of the sidewall of the central cavity, such that a portion of the body of the bone screw assumes a radially-expanded configuration when the rod engages the radial restriction;

[0046] inserting the bone screw into a hole formed in bone ;

[0047] inserting the rod into the central cavity of the bone screw; and

[0048] moving the rod distally so as to radially expand the distal end of the screw.

[0049] Brief Description Of The Drawings

[0050] These and other obj ects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:

[0051] Figs . 1-7 are schematic views of a novel orthopedic fixation system formed in accordance with the present invention;

[0052] OSPINE-0207Figs . 8 and 9 are schematic views showing another novel orthopedic fixation system formed in accordance with the present invention;

[0053] Figs . 10-13 are schematic views showing another novel orthopedic fixation system formed in accordance with the present invention;

[0054] Figs . 14-17 are schematic views showing a novel locking plate mounted to a novel orthopedic fixation system formed in accordance with the present invention;

[0055] Figs . 18A and 18B are schematic views showing a novel polyaxial mount for use with a novel contour-adaptive plate and novel orthopedic fixation system formed in accordance with the present invention;

[0056] Figs . 19 and 20 are schematic views showing a novel contour-adaptive plate for use with a novel orthopedic fixation system formed in accordance with the present invention; and

[0057] Figs . 21-25 are schematic views showing another novel contour-adaptive plate for use with a novel orthopedic fixation system formed in accordance with the present invention.

[0058] Detailed Description Of The Preferred Embodiments The present invention comprises the provision and use of a new and improved fastener that can be more securely attached to bone than prior art fasteners .

[0059] OSPINE-0207The present invention also comprises the provision and use of a novel bone plate that can be delivered percutaneously .

[0060] The present invention further comprises a bone plate that is configured to conform to the complex geometry of native bone to which the novel bone plate is attached.

[0061] More particularly, and looking now at Figs . 1 and 2, there is shown a novel orthopedic fixation system 5 formed in accordance with the present invention.

[0062] Orthopedic fixation system 5 generally comprises an orthopedic screw 10 and a deployment rod 15.

[0063] Orthopedic screw 10 comprises a body 20 having a distal end 25, a proximal end 30, and a central cavity 35 formed between distal end 25 and proximal end 30 which opens on proximal end 30. If desired, central cavity 35 may also comprise a distal opening that opens on distal end 25 for accommodating a guidewire to aid in guiding screw 10 into the anatomy, as will be apparent to one of skill in the art in view of the present disclosure . A plurality of radially-outboard-extending ridges 40 are preferably formed on an outer surface 45 of body 20 of screw 10. In one preferred form of the present invention, ridges 40 comprise a generally helical screw thread for aiding insertion of screw 10 into bone, as will be apparent to one of skill in the art in view of the present disclosure .

[0064] OSPINE-0207Looking now at Fig. 2, a plurality of expansion slots 50 (e . g. , 2 expansion slots, 4 expansion slots, etc . ) are formed in body 20 of screw 10 so as to extend from, and open onto, outer surface 45 of body 20 and central cavity 35 of screw 10, whereby to permit radial expansion of body 20, as will hereinafter be discussed in further detail . Expansion slots 50 may be configured to extend substantially the entire distance of body 20 between distal end 25 and proximal end 30 thereof, or, if desired, expansion slots 50 may be configured to extend only from distal end 25 proximally a small distance (e . g. , one-quarter, one-half, etc . ) of the distance between distal end 25 and proximal end 30 of body 20.

[0065] Looking now at Figs . 3 and 4, central cavity 35 of screw 10 is defined by a sidewall 55. Sidewall 55 is formed so as to comprise one or more ramps 60 inwardly angled towards a central longitudinal axis 65 such that the diameter of central cavity 35 is reduced in the region of central cavity 35 where ramps 60 are formed in sidewall 55. In a preferred form of the invention, ramps 60 and sidewall 55 are formed out of a single piece of the same material (e . g. , integrally machined) .

[0066] In one preferred form of the invention, screw 10 comprises four expansion slots 50 and four ramps 60, with each ramp radially disposed on sidewall 55 of central cavity 35 such that each segment 70 (Fig. 4)

[0067] OSPINE-0207defined by expansion slots 50 comprises a ramp 60. Ramps 60 are configured to create a radial restriction 75 at a location in central cavity 35 intermediate distal end 25 and proximal end 30 of body 20, whereby to permit deployment rod 15 to engage ramps 60 and effect radial outboard movement of sidewall 55 in the region of radial restriction 75, as will hereinafter be discussed in further detail . In a preferred form of the present invention, a screw thread 80 is formed on the proximal portion of sidewall 55 extending proximally from ramps 60 to proximal end 30 of screw 10 which is configured to mate with a counterpart screw thread formed on deployment rod 15, as will hereinafter be discussed in further detail .

[0068] Proximal end 30 of body 20 of screw 10 may comprise a head 85 extending radially outboard of body 20. See Fig. 2. Head 85 may comprise one or more driver-engaging features 90 for mounting screw 10 to an inserter / driver , as will be apparent to one of skill in the art in view of the present disclosure .

[0069] Looking now at Figs . 1-5, deployment rod 15 comprises a distal end 95, a proximal end 100, and a body 105 extending therebetween (Fig. 5) . Body 105 of deployment rod 15 preferably comprises a helical screw thread 110 (Figs . 1 and 2 ) configured to mate with helical screw thread 80 of central cavity 35, whereby to permit deployment rod 15 to be advanced into central cavity 35 and moved distally relative to screw

[0070] OSPINE-020710 by selective rotation of deployment rod 15, as will hereinafter be discussed in further detail .

[0071] Proximal end 100 of deployment rod 15 preferably comprises a head 115. Head 115 preferably comprises an opening 120 for receiving a driver (not shown) whereby to permit selective rotation of deployment rod 15 relative to screw 10, as will be apparent to one of skill in the art in view of the present disclosure . Opening 120 may comprise a non-circular cross-section characterized by one or more flats for engaging a driver, as will be apparent to one of skill in the art in view of the present disclosure . By way of example but not limitation, opening 120 may comprise a hexagonal cross-section for receiving a hex driver. Additionally, it should be appreciated that, if desired, a central opening may extend entirely through deployment rod 15 between, and opening upon, proximal end 100 / opening 120 and distal end 95, whereby to permit deployment rod 15 to be passed over a guidewire, as will be apparent to one of skill in the art in view of the present disclosure .

[0072] In an exemplary use, and looking now at Figs . 3-7, a bone hole is formed in a bone sized to receive screw 10. Screw 10 is inserted into the bone hole formed in the bone (e . g. , using a guidewire, etc . ) . With screw 10 disposed in the bone hole, deployment rod 15 is inserted into central cavity 35 of screw 10 and advanced distally (e . g. , via rotating deployment

[0073] OSPINE-0207rod 15) . It will be appreciated that screw thread 110 of deployment rod 15 mates with screw thread 80 of central cavity 35, whereby to permit deployment rod 15 to be advanced distally within central cavity 35 by selective rotation of deployment rod 15.

[0074] When distal end 95 of deployment rod 15 contacts ramps 60 of screw 10, continued distal movement of deployment rod 15 effects radial outboard displacement of ramps 60 and hence, radial outboard displacement of body 20 of screw 10 in the region of ramps 60. The maximum degree of radial outboard displacement is achieved as distal end 95 of deployment rod 15 engages radial restriction 75. It will be appreciated that as body 20 is displaced radially outboard in the region of ramps 60 / radial restriction 75, outer surface 45 of body 20 is also moved radially outboard, whereby to change the outer geometry of screw 10. Specifically, the distal portion of screw 10 separates at expansion slots 50 into segments 70 as the distal portion of screw 10 is forced radially outboard by the action of deployment rod 15 contacting ramps 60. As a result, the portion of outer surface 45 moved radially-outboard by the distal advancement of deployment rod 15 acts to engage the cancellous bone and present a distally-disposed, radially-enlarged region of screw 10 that resists backing out of the bone hole .

[0075] In one preferred form of the invention, the outer diameter of the distal portion of body 20 of screw 10

[0076] OSPINE-0207can be expanded from approximately 3 / 8 inches to about 7 / 16 inches, i . e . , a total expansion of about 4-8 mm.

[0077] Looking now at Figs . 8 and 9, if desired, head 85 of screw 10 may comprise a radially-extending flange 125 comprising a distal surface 130 and a proximal surface 135. One or more teeth 140 may be mounted to distal surface 130 so as to extend distally therefrom, whereby to engage the surface of the bone that screw 10 is inserted into and resist rotation of screw 10 relative to the bone . Furthermore, if desired, one or more openings 145 may be formed in flange 125, extending therethrough and configured to accommodate one or more fixation screws 150 (Fig. 9) for aiding in securing flange 125 / screw 10 to bone, as will be apparent to one of skill in the art in view of the present disclosure .

[0078] It will be appreciated that, if desired, body 20 of screw 10 may further comprise one or more fenestrations (not shown) for receiving bone graft material and / or boney ingrowth-promoting material to increase healing and fusion rates (e . g. , to facilitate the addition of bone graft material to the fenestrations prior to insertion of screw 10 into the anatomy and radial expansion of body 20 of screw 10 in the manner discussed above) .

[0079] In addition, it should also be appreciated that, if desired, surface roughening, a porous coating and / or nano surface technology may be added to outer

[0080] OSPINE-0207surface 45 of body 20 of screw 10 to increase fusion and / or promote healing (e . g. , 3-D printed, sprayed on, coated, etc . ) .

[0081] Looking now at Fig. 10, if desired, ridges 40 disposed on outer surface 45 of body 20 may comprise a helical screw thread 155 extending between distal end 25 and proximal end 30 of body 20 of screw 10. If desired, the pitch of helical screw thread 155 may be varied as the helical screw thread 155 extends distally along the length of body 20 (e . g. , such that a proximal portion of body 20 comprises more turns of helical screw thread 155 than a distal portion of body 20) .

[0082] In another embodiment of the present invention, and looking now at Figs . 11-13, there is provided an orthopedic fixation system 5A. Orthopedic fixation system 5A is substantially identical to orthopedic fixation system 5 discussed above, however, with orthopedic fixation system 5A there is provided an orthopedic screw 10A and a deployment rod 15A that differ from orthopedic screw 10 and deployment rod 15 discussed above .

[0083] More particularly, and still looking at Figs . Ills, orthopedic screw 10A comprises a head 85A comprising a screw thread 156 extending about head 85A. Screw thread 156 is configured to mate with a counterpart screw thread formed on the sidewall defining a lumen in a locking plate as will

[0084] OSPINE-0207hereinafter be discussed in further detail . In addition, with this embodiment of the invention, screw thread 80 formed on the sidewall 55 of central cavity 35 of orthopedic screw 10 is omitted, such that sidewall 55A of orthopedic screw 10A comprises a smooth surface .

[0085] Deployment rod 15A comprises a body 105A substantially similar to the aforementioned body 105 of deployment rod 15 discussed above, however, with this embodiment of the invention screw thread 110 is omitted, with body 105A of deployment rod 15A comprising a smooth outer wall between distal end 95 and proximal end 100 of deployment rod 15A. With this embodiment of the present invention, deployment rod 15A is sized to be received within central cavity 35 of orthopedic screw 10A such that distal end 95 of deployment rod 15A contacts ramps 60 and effects outboard pivoting of ramps 60 when deployment rod 15A is disposed in a distalmost position. Furthermore, if desired, deployment rod 15A may be sized such that proximal end 100 of deployment rod 15A is substantially flush with the proximalmost surface of head 85A when deployment rod 15A is in its distalmost position relative to orthopedic screw 10A. See Fig.

[0086] 13 .

[0087] Although screw thread 80 formed on the sidewall 55 of central cavity 35 of orthopedic screw 10 and screw thread 110 of deployment rod 15 are omitted in

[0088] OSPINE-0207the embodiment shown in Figs . 12 and 13, one, or both, of central cavity 35 of orthopedic screw 10A and deployment rod 15A could be formed with screw threads without departing from the scope of the present invention (e . g. , if it is desired to advance deployment rod 15A through central cavity 35 of screw 10A by rotating deployment rod 15A) .

[0089] Looking now at Figs . 14-17, in another form of the present invention, there is provided one or more novel locking plates 160 configured to be mounted to orthopedic screw 10. Locking plate 160 comprises at least one opening 165 for passing screw 10 therethrough such that head 85 engages locking plate 160, whereby to mount locking plate 160 to bone . With this form of the invention, it will be appreciated that head 85 comprises a radial dimension that is larger than the diameter of the at least one opening 165 formed in locking plate 160. Locking plate 160 may comprise one or more keyholes 170 for receiving elements of other locking plates 160, as will be apparent to one of skill in the art in view of the present disclosure .

[0090] Looking now at Figs . 18A and 18B, it should also be appreciated that, if desired, head 115 of deployment rod 15 may comprise a polyaxial mount 175 for mounting to a contour-adaptive plate 180 mounted thereto . Polyaxial mount 175 is configured to move (e . g. , to rotate in multiple dimensions) as necessary

[0091] OSPINE-0207to accommodate the desired positioning of contour-adaptive plate 180. By way of example but not limitation, polyaxial mount 175 can be configured to permit angular correction between the screw 10 and contour-adaptive plate 180 of up to 30 degrees .

[0092] In use, fixation system 5 can be used as follows with polyaxial mount 175 to mount at least one contour-adaptive plate 180 to bone . First screw 10 is positioned into a hole formed in bone (e . g. , by passing screw 10 through a cannula and / or over a guidewire) . Then, deployment rod 15 is moved distally through central cavity 35 so as to radially expand the distal end of screw 10. Subsequently, a first contour-adaptive plate 180 is passed through the cannula (and / or over a guidewire) and mounted to polyaxial mount 175. If desired, additional screws 10 having polyaxial mounts 175 can be positioned in holes formed in the bone and additional contour-adaptive plates 180 can be passed through the cannula (and / or over a guidewire) and mounted to the additional screws . Once positioned in the bone, the contour-adaptive plates 180 can be connected together (e . g. , via at least one from a group consisting of a tab-and-slot, a dovetail and a puzzle contour) .

[0093] Looking now at Figs . 19 and 20, if desired, a plurality of contour-adaptive plates 180 may be linked together (i . e . , connected) so as to form a single structure which is configured to resist axial and

[0094] OSPINE-0207rotational disassembly. If desired, contour-adaptive plates 180 may be selectively mounted to one another via a coupling feature 185. By way of example but not limitation, coupling feature 185 may comprise at least one from a group consisting of tabs, slots, dovetails and puzzle contours, as will be apparent to one of skill in the art in view of the present disclosure . Contour-adaptive plates 180 are preferably formed out of a resilient flexible material such that contour-adaptive plates 180 can conform to the geometry of the native bone to which they are mounted, as will be apparent to one of skill in the art in view of the present disclosure . Furthermore, it should also be appreciated that contour-adaptive plates 180 are preferably sized to fit within the delivery lumen of a standard surgical cannula and / or passed over a guidewire, whereby to permit contour-adaptive plates 180 to be serially delivered percutaneously to a surgical site and assembled in vivo at the surgical site by mounting a plurality of contour-adaptive plates 180 to one another via coupling feature (s) 185, and by mounting the combined contour-adaptive plates to a bone (i . e . , via a plurality of orthopedic fixation systems 5, 5A) .

[0095] Looking now at Figs . 21-25, there is shown a contour-adaptive plate 190 formed in accordance with the present invention. Contour-adaptive plate 190 generally comprises a plurality (e . g. , three) of

[0096] OSPINE-0207securement washers 195 connected together via a plurality of linking bodies 200, as will hereinafter be discussed in further detail .

[0097] Each securement washer 195 comprises an opening 205 passing therethrough, with opening 205 being defined by a sidewall 210. A thread 215 is formed on sidewall 210 and configured to mate with screw thread 156 of head 85A of orthopedic screw 10A discussed above . As a result of this construction, when orthopedic fixation system 5A is passed into opening 205 of securement washer 195, screw thread 156 of orthopedic screw 10A mates with thread 215 of securement washer 195, whereby to mount securement washer 195 to orthopedic screw 10A.

[0098] Linking bodies 200 may be mounted to securement washer 195 via one or more pins 220 such that each securement washer 195 can pivot relative to the linking body (or bodies) 200 to which the securement washer 195 is mounted, whereby to accommodate the curved geometry of an anatomical structure (e . g. , a sacrum, an ilium or vertebral body) . See Fig. 23. It should also be appreciated that, if desired, a plurality of securement washers 195 may be selectively mounted to one another via a coupling feature 225. By way of example but not limitation, coupling feature 225 may comprise at least one from a group consisting of tabs, slots, dovetails and puzzle contours, as will

[0099] OSPINE-0207be apparent to one of skill in the art in view of the present disclosure .

[0100] In one exemplary method, two contour-adaptive plates 190 can be mounted to bone as follows . First, a first contour-adaptive plate 190 is positioned against a bone surface (e . g. , by passing contour-adaptive plate 190 through a cannula and / or over a guidewire) . Next, a second contour-adaptive plate 190 is mounted to the first contour-adaptive plate 190 (e . g. , by passing the second contour-adaptive plate 190 through a cannula and / or over a guidewire) and connecting the second contour-adaptive plate 190 to the first contour-adaptive plate 190. Next, fixation screws (e . g. , screw 10 and deployment rod 15, screw 10A and deployment rod 15A) can be passed through openings 205 in first and second contour-adaptive plates 190 to secure first and second contour-adaptive plates 190 to the bone . Alternatively, if desired, a fixation screw can be used to secure first contour-adaptive plate 190 to the bone, second contour-adaptive plate 190 can then be locked to first contour-adaptive plate 190, and then a second fixation screw can be used to lock second contour-adaptive plate 190 to bone after it has been connected to first contour-adaptive plate 190. If desired, additional contour-adaptive plates 190 can be passed through the cannula (and / or over a guidewire) , mounted to at least one of the first and second contour-adaptive plates

[0101] OSPINE-0207190 and then secured to the bone with a fixation screw. In this way, multiple contour-adaptive plates 190 can be connected together to make a locking plate of any desired size for positioning flush against a contoured surface (e . g. , the curved surface of a bone) .

[0102] It should be appreciated that the locking plates of the present invention can be formed out of a radiolucent material and / or include a radiopaque marker (not shown) to aid fluoroscopic alignment during percutaneous assembly.

[0103] Modifications Of The Preferred Embodiments It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.

[0104] OSPINE-0207

Claims

What Is Claimed Is :

1. An orthopedic fixation system comprising: a bone screw comprising a body having a distal end, a proximal end, and a central cavity defined by a sidewall disposed between the distal end and the proximal end of the body;a rod configured to be disposed within the central cavity, the rod comprising a distal end and a proximal end;wherein the sidewall of the central cavity comprises at least one radial restriction, wherein the diameter of the central cavity at the at least one radial restriction is smaller than the diameter of the central cavity proximal to the at least one radial restriction, such that distal advancement of the rod engages the at least one radial restriction of the sidewall of the central cavity and effects radially-outboard movement of the sidewall of the central cavity, such that a portion of the body of the bone screw assumes a radially-expanded configuration when the rod engages the radial restriction.

2. The orthopedic fixation system of claim 1, wherein the at least one radial restriction comprises a tapered portion of the central cavity configured to be engaged by the rod during distal advancement of the rod into the central cavity.OSPINE-02073. The orthopedic fixation system of claim 1, wherein the body of the bone screw further comprises at least one fenestration configured to receive bone graft or biologies .

4. The orthopedic fixation system of claim 1, wherein a pitch of the helical thread is varied as the helical thread extends distally along the length of the body of the bone screw.

5. The orthopedic fixation system of claim 1, wherein the sidewall defining the central cavity comprises a helical thread, and further wherein the rod comprises a helical thread configured to mate with the helical thread of the sidewall of the central cavity of the body of the bone screw.

6. The orthopedic fixation system according to claim 1 wherein the proximal end of the rod comprises a head.

7. The orthopedic fixation system according to claim 6 wherein the head comprises a polyaxial mount .

8. The orthopedic fixation system according to claim 7 wherein the polyaxial mount is configured to mount to a locking plate .OSPINE-02079. The orthopedic fixation system according to claim 8 wherein the locking plate comprises an interlocking contour configured for mounting to an adj acent locking plate .

10. The orthopedic fixation system of claim 8, wherein the polyaxial mount on the head of the rod permits angular correction between the bone screw and the locking plate of up to 30 degrees .

11. The orthopedic fixation system of claim 1, wherein the distal end of the bone screw comprises an enlarged head.

12. The orthopedic fixation system of claim 11, wherein the enlarged head of the bone screw comprises screw threads for mounting to a locking plate .

13. The orthopedic fixation system of claim 12, wherein the locking plate comprises a compression slot enabling dynamic bone compression when the bone screw is tightened to the locking plate .

14. The orthopedic fixation system according to claim 1 wherein the central cavity opens on the distal end of the body.OSPINE-020715. A locking plate assembly comprising:at least two locking plates, each locking plate comprising a coupling feature configured to interlock with a coupling feature of another locking plate;wherein each locking plate is configured to be delivered through a minimally invasive incision and assembled intraoperatively into an interconnected construct; andwherein at least one of the locking plates further comprises an aperture configured to receive a bone fastener for securing the locking plate to a bone .

16. A locking plate assembly according to claim 15 wherein the coupling feature comprises at least one from a group consisting of tabs, slots, dovetails and puzzle contours .

17. The locking plate assembly of claim 15, wherein the assembled locking plates are configured to conform to the surface of a curved anatomical structure .

18. The locking plate assembly of claim 15, wherein interlocked locking plates are configured to resist axial and rotational disassembly.OSPINE-020719. The locking plate assembly of claim 15, wherein at least a portion of the at least two locking plates is radiolucent, and further wherein at least one of the two locking plates comprises a radiopaque marker .

20. The locking plate assembly of claim 15, further comprising a locking insert configured to slide into a keyway to rigidly lock together two locking plates .

21. The locking plate assembly of claim 15, wherein the bone fastener comprises :an expandable bone screw having a cannulated body with external threads and a distal end including at least two expansion arms; andan internal rod disposed within the cannulated body, the rod comprising external threads configured to engage internal threads formed in the cannulated body, such that advancement of the internal rod causes radial displacement of the expansion arms to increase the outer diameter of the distal end of the bone screw .

22. The locking plate assembly of claim 21 wherein a proximal head portion of the bone fastener comprises a polyaxial mounting surface configured to mount to the aperture .OSPINE-020723. The locking plate assembly of claim 22 wherein at least one of a proximal end of the internal rod and a proximal end of the bone screw comprises the polyaxial mounting surface .

24. A method for performing orthopedic fixation through a minimally invasive approach, the method comprising :positioning a first locking plate against a surface of bone, wherein the first locking plate comprises a coupling feature configured to interlock with a coupling feature of a second locking plate and an aperture for receiving a first bone fastener;positioning the second locking plate against the surface of the bone adj acent the first locking plate, wherein the second locking plate comprises a coupling feature configured to interlock with the coupling feature of the first locking plate and an aperture for receiving a second bone fastener;locking the second locking plate to the first locking plate by connecting the couple features;passing a first bone fastener through the aperture in the first locking plate to lock the first locking plate to the bone; andpassing a second bone fastener through the aperture in the second locking plate to lock the second locking plate to the bone .OSPINE-020725. The method according to claim 24 wherein the first bone fastener comprises :an expandable bone screw having a cannulated body with external threads and a distal end including at least two expansion arms; andan internal rod disposed within the cannulated body, such that advancement of the internal rod causes radial displacement of the expansion arms to increase the outer diameter of the distal end of the bone screw .

26. The method according to claim 24 wherein positioning the locking plate comprises passing the locking plate through a cannula .

27. The method according to claim 24 wherein positioning the locking plate comprises passing the locking plate over a guidewire .

28. A method for performing orthopedic fixation through a minimally invasive approach, the method comprising :providing an orthopedic fixation system comprising :a bone screw comprising a body having a distal end, a proximal end, and a central cavityOSPINE-0207defined by a sidewall disposed between the distal end and the proximal end of the body;a rod configured to be disposed within the central cavity, the rod comprising a distal end and a proximal end;wherein the sidewall of the central cavity comprises at least one radial restriction, wherein the diameter of the central cavity at the at least one radial restriction is smaller than the diameter of the central cavity proximal to the at least one radial restriction, such that distal advancement of the rod engages the at least one radial restriction of the sidewall of the central cavity and effects radially-outboard movement of the sidewall of the central cavity, such that a portion of the body of the bone screw assumes a radially-expanded configuration when the rod engages the radial restriction;inserting the bone screw into a hole formed in bone ;inserting the rod into the central cavity of the bone screw; andmoving the rod distally so as to radially expand the distal end of the screw.

29. The method according to claim 28 further comprising :providing at least one locking plate configured to be mounted to the bone screw; andOSPINE-0207mounting at least one locking plate to the bone screw .OSPINE-0207

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