WO 2021/041889
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`PCT/US2020/048516
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`TITLE
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`Decorticating Screw
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`CROSS-REFERENCE TO RELATED APPLICATIONS
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`This application is entitled to priority to U.S. Provisional Patent
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`Application No. 62/893,672, filed August 29, 2019, the contents of which are
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`incorporated by reference herein in its entirety.
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`BACKGROUND OF THE INVENTION
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`Sacroiliac (SD) pain is a common cause of low back pain. One solution is
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`minimally invasive SI joint fusion. However, existing SI joint fusion hardware
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`inadequately addresses the SI joint space, resulting in deficient joint fusion and continued
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`pain. True SI arthrodesis calls for the SI joint space to be decorticated and compressed in
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`addition to the placement of stabilizing screws for positive long-term patient outcomes
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`and significant reduction in pain scores.
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`Thus, there is a need in the art for improved screwsthat are capable of
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`decorticating a joint space and applying compression to the fusion site. The present
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`invention satisfies this need.
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`SUMMARYOF THE INVENTION
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`In oneaspect, the present invention relates to a decorticating screw device,
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`comprising: a substantially cylindrical body, the body having a distal threaded section, a
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`proximal threaded section, a central ring having one or more decorticating elements.
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`In one embodiment, the screw further comprises a lumen running between
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`a proximal opening and a distal opening.
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`In one embodiment, the screw device further comprises a cap having a
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`threaded lumensized to fit over the proximal threaded section of the body and a proximal
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`lip having a diameter greater than a diameter of the cap.
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`In one embodiment, the central ring of the screw device is independently
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`rotatable from the threaded distal section.
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`In one embodiment, the screw device further comprises one or more
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`lateral openings fluidly connected to the lumen.
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`In one embodiment, the screw device comprises one or morecutting flutes
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`at a distal end.
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`In one embodiment, the screw device comprises one or more pointed tips
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`at a distal end.
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`In one embodiment, the proximal threaded section comprises a threading
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`selected from the group consisting of: knuckle threads, trapezoidal threads, square
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`threads, and buttress threads.
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`In one embodiment, the proximal threaded section
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`comprises a rounded or tapered proximal end.
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`In one embodiment, the central ring is attached to the proximal section,
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`such that the central ring and proximal section are independently rotatable from the
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`threaded distal section. In one embodiment, the central ring is movable in proximal and
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`distal directions to increase the reach of the one or more decorticating elements.
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`In one embodiment, the screw device comprises two or more external slots
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`formed between the distal threaded section, the central ring, and the one or more
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`decorticating elements, such that each external slot is sized to receive a pin of a screw
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`driving device.
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`In one embodiment, the one or more decorticating elements each comprise
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`one or more surface voids configured to accept graft material or tissue ingrowth. In one
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`embodiment, the cap comprises one or more surface voids configured to accept graft
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`material or tissue ingrowth.
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`In one embodiment, the cap comprises a thread-locking insert positioned
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`at a proximal end of the threaded lumen. In one embodiment, the cap lip comprises a
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`distal-facing surface having a rounded convex shape. In one embodiment, the cap
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`comprises a locking nut in alignment with the threaded lumenof the cap, the locking nut
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`being connected to the cap by one or more connecting bridges configured to break with
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`an application of a torque on the locking nut.
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`In one embodiment, the one or more decorticating elements are moveable
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`between a closed position and an open position. In one embodiment, the closed position
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`positions the decorticating elements adjacent to the central ring such that they have a
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`diameter substantially equal to a diameter ofthe threaded distal section, and wherein the
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`open position positions the decorticating elements away from the central ring such that
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`the decorticating elements extend beyond the diameter of the threaded distal section. In
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`one embodiment, the one or more decorticating elements are hingedly connected to the
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`central ring along an axis that is in parallel with a long axis of the body andarelaterally
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`swung from the closed position to the open position. In one embodiment, the one or
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`more decorticating elements are hingedly connected to the central ring along an axis that
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`is perpendicular to a long axis of the body and splay outwards from the closed position to
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`the open position. In one embodiment, the one or more decorticating elements are
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`flexible wire blades retracted into the central ring in a closed position and are pushable
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`outwards from the central ring to the open position. In one embodiment, the one or more
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`decorticating elements are sheathed within the central ring in a closed position and are
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`slideable outwards from the closed position to the open position. In one embodiment, the
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`one or more decorticating elements are at least partially pliable and are bendable from a
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`closed position to an open position. In one embodiment, the one or more decorticating
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`elements comprises at least one serration.
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`In one embodiment, the threaded proximal section has diameterthat is less
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`than a diameter of the threaded distal section. In one embodiment, the diameter of the
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`cap is substantially equal to a diameter of the threaded distal section. In one
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`embodiment, the device further comprises a lock screw having a diameterlarger than a
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`diameter of the screw device lumen, the lock screw being drivable into the proximal
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`opening of the screw device to expand a proximal end of the screw device.
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`In one embodiment, the screw has a length between about 10 mm and
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`about 100 mm. In one embodiment, the screw has an outer diameter between about 5
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`25
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`mm and about 50 mm.
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`In another aspect, the present invention relates to a method of fusing a
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`joint between a first bone and a second bone, comprising the steps of: providing a
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`decorticating screw having a threaded distal section, a threaded proximal section, a
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`rotatable central ring having one or more blades, a lumen running between a proximal
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`opening and a distal opening, and one or more lateral openings fluidly connected to the
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`lumen; inserting the screw into a joint in need offixation, such that the distal section 1s
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`positioned in a first bone, the proximal section is positioned in a second bone, and the
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`central ring is positioned in a joint space betweenthefirst bone and the second bone;
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`rotating the central ring, such that the one or more blades decorticate the joint space
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`between the first bone and the second bone; packing at least one graft material into the
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`proximal opening of the screw, such that the at least one graft material enters the lumen
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`and exits the one or more lateral openings of the screw; placing a cap onto the proximal
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`section of the screw; and screwing a lock screw into the proximal opening of the screw.
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`In one embodiment, the graft material is selected from the group
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`consisting of: autologous bonegrafts, allogeneic bone grafts, xenogeneic bonegrafts,
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`hydroxyapatite, calcium phosphate, calcium sulphate, bioactive glass, polymers, cements,
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`and combinations thereof.
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`The following detailed description of exemplary embodiments of the
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`invention will be better understood when read in conjunction with the appended
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`drawings.
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`It should be understood, however, that the invention is not limited to the
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`precise arrangements and instrumentalities of the embodiments shown in the drawings.
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`FIG. 1A and FIG. 1B depict perspective views of an exemplary screw.
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`FIG. 2A through FIG. 2D depict various views of an exemplary screw
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`assembly. FIG. 2A is a cross-sectional side view of a distal screw componentattached to
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`a proximal screw component. FIG. 2B is a proximal view of a distal screw component.
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`FIG. 2C is a partially transparent view of a proximal screw component. FIG. 2D is a
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`partially transparent view of a distal screw componentattached to a proximal screw
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`component.
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`FIG.3 depicts various varieties and views of exemplary screw blades
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`FIG.4A and FIG. 4B depict an exemplary screw with blades in a closed
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`(FIG. 4A) and an open (FIG.4B)position.
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`FIG. 5A and FIG. 5B depict an exemplary screw with a cap component
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`attached (FIG. 5A) and cap component with a lock screw attached (FIG. 5B).
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`FIG. 6is a schematic depicting a cross-sectional side view ofan
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`exemplary screw inserted into a first bone, a second bone,and a joint space in between.
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`FIG. 7A through FIG. 7D depict a sequence of decortication using an
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`exemplary screw.
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`FIG. 8A through FIG. 8D depict an exemplary screw driving tool. FIG.
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`8A is a perspective view of the screw driving tool. FIG. 8B is a perspective view of an
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`exemplary locking tube. FIG. 8C is a perspective view of an exemplary screw
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`highlighting engagement points with a screw driving tool. FIG 8D is a magnified view of
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`the distal tip of a screw drivingtool.
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`FIG. 9A and FIG. 9B depict partially transparent views of the engagement
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`of an exemplary screw driving tool with an exemplary screw.
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`FIG. 10A through FIG. 10C depict an exemplary blade deploying tool.
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`FIG. 10A is a perspective view of the blade deploying tool. FIG. 10Bis a perspective
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`view of an exemplary screw highlighting engagement points with a blade deployingtool.
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`FIG. 10C is a magnified view of the distal tip of a blade deployingtool.
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`FIG. 11A through FIG. 11C depict a sequence of deploying the blades of
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`an exemplary screw using an exemplary blade deploying tool.
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`FIG. 12A and FIG. 12B depict an exemplary graft funnel tool. FIG. 12A
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`is a perspective view of the graft funnel tool engaged to an exemplary screw. FIG. 12B is
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`a partially transparent magnified view of the graft funnel tool engaged to the screw.
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`FIG. 13A through FIG. 13C depict various views of an exemplary screw
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`highlighting graft entry and exit points.
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`FIG. 14 depicts an exemplary cap driving tool engaged to an exemplary
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`screw.
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`FIG. 15A through FIG. 15C depict magnified views of an exemplary cap
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`driving tool. FIG 15A is a magnified view of the distal end of the cap driving tool. FIG.
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`15B is a magnified view of the cap driver engaged to the cap of an exemplary screw.
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`FIG. 15C is a partially transparent magnified view of the cap driving tool engaged to the
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`proximal stem ofthe screw.
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`FIG. 16A and FIG. 16B depict an exemplary lock screw driver. FIG. 16A
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`iS a perspective view of the lock screw driver engaged to an exemplary screw. FIG. 16B
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`is a magnified view of the lock screw driver engaged to the screw.
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`FIG. 17A and FIG. 17B depict partially transparent magnified viewsof an
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`exemplary blade deploying tool engaged to an exemplary screw.
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`FIG. 18A and FIG. 18B depict an exemplary blade deploying tool. FIG.
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`18A is a perspective view of the blade deploying tool. FIG. 18B is a magnified view of
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`the distal end of the blade deployingtool.
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`FIG. 19A and FIG. 19B depict an exemplary blade deploying tool engaged
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`10
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`to an exemplary screw.
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`FIG. 20A and FIG. 20B depict perspective views of an exemplary screw.
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`FIG. 21A through FIG. 21C depict an exemplary blade deploying tool and
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`blade deployment in an exemplary screw. FIG. 21A is a magnified view of the distal end
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`of the blade deploying tool. FIG 21B is a perspective view of the screw with blades held
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`15
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`in blade retainers. FIG. 21C is a perspective view of the screw with blades released from
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`the bladeretainers.
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`FIG. 22A and FIG. 22B depict perspective views of an exemplary screw
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`with blades deployed.
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`FIG. 23A through FIG. 23D depict a sequence of deploying blades in an
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`exemplary screw.
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`FIG. 24A and FIG. 24B depict an exemplary cap driving tool and an
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`exemplary screw highlighting engagementpoints with the cap driving tool.
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`FIG. 25A and FIG. 25B depict a perspective view of an exemplary screw
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`and the screw engagedto the distal end of an exemplary blade deploying tool.
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`25
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`FIG. 26A and FIG. 26B depict partially transparent side views of an
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`exemplary blade deploying tool engaged to an exemplary screw.
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`FIG. 27A through FIG. 27C depict an exemplary screw. FIG. 27A isa
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`perspective view of the screw. FIG. 27B is a proximal view of the screw with blades in a
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`closed position. FIG. 27C is a proximal view of the screw with blades in an open
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`FIG. 28A through FIG. 28D depict a sequence of deploying blades in an
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`exemplary screw. The central ring of the screw is shownpartially transparentto illustrate
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`the movementof the blades.
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`FIG. 29A through FIG. 29F depict an exemplary screw. FIG. 29A through
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`FIG. 29C depict the screw with blades in a closed position. FIG 29D through FIG. 29F
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`depict the screw with blades in an open position.
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`FIG. 30 depicts an exemplary decorticating screw having a proximal shaft
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`with knuckle threading.
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`FIG. 31 depicts an exemplary decorticating screw having a tapered or
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`rounded proximal shaft lead in.
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`FIG. 32 depicts an exemplary decorticating screw having serrated blades.
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`FIG. 33 depicts an exemplary decorticating screw having pointed distal
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`tips.
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`FIG. 34 depicts an exemplary screw driving tool having dovetail-shaped
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`15
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`pins fitting into external slots embeddedin a distal screw and central ring of a
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`decorticating screw.
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`FIG. 35 depicts the exemplary screw driving tool of FIG. 34, wherein the
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`dovetail-shaped pins slide over the blades of a decorticating screw.
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`FIG. 36 depicts an exemplary cap having a thread-lockinginsert.
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`FIG. 37 depicts an exemplary cap having a convexcap lip surface.
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`FIG. 38 depicts an exemplary cap having a locking nut.
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`FIG. 39 depicts an exemplary cap drivingtool.
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`FIG.40 is a flowchart of an exemplary method of using a decorticating
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`screw.
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`DETAILED DESCRIPTION
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`The present invention provides decorticating screws and insertion tools for
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`implanting the decorticating screws. The screws anchorinto a first and a second boneto
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`fuse the two bones together. The screwsinclude a rotatable bladed section to decorticate
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`30
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`a joint space between the first and second bone. The screwsalso optionally include a cap
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`to secure the screws in the bone and apply compression to the joint to be fused. In some
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`embodiments, the decorticating screwsare useful for sacroiliac (SD joint fusion.
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`Definitions
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`It is to be understoodthat the figures and descriptions of the present
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`invention have been simplified to illustrate elements that are relevant for a clear
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`understanding of the present invention, while eliminating, for the purposeofclarity,
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`many other elements typically found in the art. Those of ordinary skill in the art may
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`recognize that other elements and/or steps are desirable and/or required in implementing
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`10
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`the present invention. However, because such elements and steps are well knownin the
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`art, and because they do notfacilitate a better understanding of the present invention, a
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`discussion of such elements and steps is not provided herein. The disclosure herein is
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`directed to all such variations and modifications to such elements and methods known to
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`those skilled in theart.
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`Unless defined elsewhere, all technical and scientific terms used herein
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`have the same meaning as commonly understood by one ofordinary skill in the art to
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`whichthis invention belongs. Although any methods and materials similar or equivalent
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`to those described herein can be used in the practice or testing of the present invention,
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`the exemplary methods and materials are described.
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`Asused herein, each of the following terms has the meaning associated
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`with it in this section.
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`Thearticles “a” and “an” are used herein to refer to one or to more than
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`one (i.e., to at least one) of the grammatical object of the article. By way of example, “an
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`element” means one element or more than one element.
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`“About” as used herein when referring to a measurable value such as an
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`amount, a temporal duration, and the like, is meant to encompassvariations of +20%,
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`10%,
`+5%,
`+1%, and +0.1% from the specified value, as such variations are
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`appropriate.
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`Throughoutthis disclosure, various aspects of the invention can be
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`presented in a range format. It should be understood that the description in range format
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`is merely for convenience and brevity and should not be construed as an inflexible
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`limitation on the scope of the invention. Accordingly, the description of a range should
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`be considered to have specifically disclosed all the possible subranges as well as
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`individual numerical values within that range. For example, description of a range such
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`as from | to 6 should be considered to have specifically disclosed subranges such as from
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`1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as
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`individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any whole
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`and partial increments there between. This applies regardless of the breadth of the range.
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`First Decorticating Screw
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`Referring now to FIG. 1A and FIG. 1B, an exemplary decorticating screw
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`100 is now described. Screw 100 comprises a proximal end 102 and a distal end 104,
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`wherein a distal screw 106 is engaged to the distal end of a proximal screw 118. A cap
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`146 fits over the proximal end of proximal screw 118 and is locked in place by a lock
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`15
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`screw 158.
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`Referring now to FIG. 2A through FIG. 2D, distal screw 106 and proximal
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`screw 118 are now described. Distal screw 106 comprises a substantially cylindrical
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`shape having a tapered distal end ending in distal opening 110, a proximal end having a
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`proximal opening 108, and a lumen 112 extending betweendistal opening 110 and
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`20
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`proximal opening 108. Distal screw 106 comprises a threaded exterior.
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`In some
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`embodiments, distal screw 106 comprises one or more cutting flutes at the distal end,
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`suchthat distal screw 106is self-tapping. Visible in FIG. 2B, the proximal end ofdistal
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`screw 106 comprises two or more pin slots 116. Distal screw 106 further comprises one
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`or more pins 114 extending laterally across proximal opening 108.
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`Proximal screw 118 comprises a substantially cylindrical shape with a
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`lumen 130 extending between a proximal opening 126 and a distal opening 128, wherein
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`lumen 130 is alignable with lumen 112 to form a single continuous lumen. The
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`continuous lumen can be sized to fit commonly used guide wires and Steinmannpins.
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`Proximal screw 118 has three regions: a distal nose 120, a central ring 122, anda
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`proximal stem 124. Distal nose 120 has a diameter sizedto fit through proximal opening
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`108 ofdistal screw 106. Inserting pins 114 throughdistal screw 106 prevents distal nose
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`120 from backing outof distal screw 106. In this manner, proximal screw 118 is free to
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`rotate about commonaxis 101 shared between proximal screw 118 and distal screw 106
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`while engaged to distal screw 106. In some embodiments, distal nose 120 is sized
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`slightly shorter than proximal opening 108 of distal screw 106 such that a gap 121 is
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`provided, permitting proximal screw 118 with room to shift in proximal and distal
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`directions. Proximal stem 124 has a threaded exterior and at least one stem slot 132
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`extending from proximal opening 126 in a distal direction. In some embodiments,
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`proximal stem 124 has a diameter smaller than a diameterof distal screw 106.
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`Central ring 122 comprises one or more blades 134. Each blade 134 has a
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`curved construction ending in a sharp or beveled tip. Blades 134 can haveasolid
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`construction, or have one or more voids 138 positioned on a side or throughout(FIG.3).
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`Voids 138 can include graft material or encourage ingrowth of tissue. Each blade 134 is
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`hingedly connected to central ring 122 by a pin 136, such that blade 134 can fold against
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`central ring 122 ina closed position (FIG. 4A) and swing away from central ring 122 in
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`an open position (FIG. 4B). The hinged connection is in parallel alignment with a long
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`axis of screw 100.
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`In a closed position, blade 134 forms a tool space 145 with central
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`ring 122. Central ring 122 can further comprise a blade stop 140 adjacent to pin 136,
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`whichis a surface that limits the swinging angle of blade 134. Central ring 122 further
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`comprises two or more pin slots 142. Pin slots 142 are alignable with pin slots 116 of
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`distal screw 106 to form a continuous lumen. In some embodiments, central ring 122 has
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`a diameter substantially equal to a diameter of distal screw 106.
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`Referring now to FIG. 5A and FIG. 5B, cap 146 and lock screw 158 are
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`now described. Cap 146 comprises a substantially cylindrical shape having a lumen
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`25
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`extending between proximal opening and a distal opening. The lumen of cap 146 has a
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`threaded surface sized to screw onto the threaded exterior of proximal stem 124. Cap 146
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`has a proximal surface having one or more tab slots 154. The proximal surface comprises
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`a lip 153 that extends beyond a diameter of cap 146 to catch onto a bonesurface andaid
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`in bone compression. Cap 146 has an exterior surface that can include one or more
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`apertures 156 that can accept graft material or tissue ingrowth. In some embodiments,
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`cap 146 has a diametersubstantially equal to a diameter ofdistal screw 106. Lock screw
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`158 is sized to screw within proximal opening 126 of proximal stem 124. Lock screw
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`158 comprises an outer diameterthat is slightly larger than the inner diameter of lumen
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`130, such that inserting lock screw 158 into proximal opening 126 expands proximal
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`stem 124 and prevents cap 146 from loosening.
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`In essence, screw 100 is a decorticating screw device comprising a
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`substantially cylindrical body, the body having a distal threaded section, a proximal
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`threaded section, a central ring having one or more decorticating elements, and a lumen
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`running between a proximal opening and a distal opening, and one or morelateral
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`openings fluidly connected to the lumen; and a cap having a threaded lumensizedto fit
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`over the proximal threaded section of the body and a proximal lip having a diameter
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`greater than a diameter of the cap; wherein the central ring is independently rotatable
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`from the threaded distal section. In one embodiment, the screw comprises one or more
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`cutting flutes at a distal end.
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`In one embodiment, the central ring is attached to the
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`proximal section, such that the central ring and proximal section are independently
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`rotatable from the threaded distal section. In one embodiment, the central ring is
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`movable in proximal and distal directions to increase the reach of the one or more blades.
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`In one embodiment, the one or more blades each comprise one or more surface voids
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`configured to accept graft material or tissue ingrowth. In one embodiment, the cap
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`20
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`comprises one or more surface voids configured to accept graft material or tissue
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`ingrowth. In one embodiment, the one or more blades are moveable between a closed
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`position and an openposition. In one embodiment, the closed position positions the
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`blades adjacent to the central ring such that they have a diameter substantially equal to a
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`diameter of the threaded distal section, and wherein the open position positions the blades
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`away from the central ring such that the blades extend beyond the diameter of the
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`threadeddistal section.
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`Referring now to FIG. 6 and FIG. 7A through FIG. 7D,the operation of
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`screw 100 is now described. As described elsewhere herein, screw 100 is provided for
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`the locking ofa first bone to a second bone. To this end, screw 100 comprises three
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`distinct regions: a first region defined by distal screw 106 that securesinto a first bone
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`160; a second region defined by central ring 122 and blades 134 that decorticates a joint
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`space 164 betweenfirst bone 160 and second bone 162; and a third region defined by the
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`proximal end of proximal screw 118 and cap 146that secures into a second bone 162.
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`FIG. 7A through FIG. 7D depict the sequence in which screw 100 locksa first bone 160
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`to a second bone 162. In FIG. 7A, the blades 134 are retracted to allow for insertion of
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`screw 100, wherein screw 100 is screwed into first bone 160 such that distal screw 106
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`resides within first bone 160, proximal stem 124 resides within second bone 162, and
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`central ring 122 is positioned within joint space 164. In FIG.7B, blades 134 are
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`deployed from central ring 122. In FIG. 7C, proximal screw 118 is rotated to decorticate
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`joint space 164 using blades 134. The aforementioned gap 121 permits proximal screw
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`118 to be shifted in proximal and distal directions to allow blades 134 to decorticate
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`closer to first bone 160 and second bone 162.
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`In some embodiments, decorticated
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`material can be removed by suction through the apertures, lumens, and proximal opening
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`of screw 100.
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`In FIG. 7D, the decorticated space is packed with graft material and screw
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`15
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`100 is capped with cap 146, compressing second bone 162 against first bone 160 with lip
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`153. Lock screw 158 can then be optionally inserted into proximal opening 126 to
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`expand proximal stem 124 and prevent cap 146 from loosening.
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`Several tools are provided to drive screw 100 and to manipulate its
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`subcomponents. Referring now to FIG. 8A and FIG. 8B, an exemplary screw driving
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`20
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`tool 200 is now described. Screw driving tool 200 comprises an elongate shaft 206
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`having a lumen 214 running throughout. Shaft 206 has a handle 208 positioned at
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`proximal end 202, pins 212 positioned at a distal end 204, and a distal opening 210 sized
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`to fit proximal stem 124 of proximal screw 118. As described elsewhere herein, central
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`ring 122 comprises pin slots 142 that are alignable with pin slots 116 of distal screw 106
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`25
`
`to form a continuous lumen. Pins 212 are sized to fit within the continuous lumen
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`formed bypin slots 142 and pin slots 116. Locking tube 300 comprises an elongate
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`hollow cylindrical construction with a grip 302 at a proximal end and a threadeddistal
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`opening 304 sized to screw onto the threaded exterior of proximal stem 124. Locking
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`tube 300 has an outer diameter sized to fit within lumen 214 of screw driving tool 200.
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`Visible in FIG. 9A and FIG. 9B, screw driving tool 200 secures to screw
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`100 by fitting distal opening 210 of shaft 206 over proximal stem 124 such that pins 212
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`are inserted through pin slots 142 and pin slots 116. Screw driving tool 200 is locked to
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`screw 100 by screwing distal opening 304 of locking tube 300 onto proximal stem 124.
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`Screw driving tool 200 can thereby simultaneously drive distal screw 106 and proximal
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`screw 118 into a targetsite.
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`Referring now to FIG. 10A through FIG. 10C, an exemplary blade
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`deploying tool 400 is now described. Blade deploying tool 400 comprises an elongated
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`shaft 406 having a handle 408 at a proximal end 402 and a blade engagingtip 414 at a
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`10
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`distal end 404. Blade deploying tool 400 further comprises a lumen 412 extending
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`between a proximal opening and a distal opening 410, wherein lumen 412 is sized tofit
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`locking tube 300 described elsewhere herein and distal opening 410 is sized to fit over
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`proximal stem 124 of proximal screw 118. Blade engaging tip 414 comprises one or
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`more curved ramps 416 sized to fit within tool space 145 between blade 134 and central
`
`15
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`ring 122 of screw 100.
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`FIG. 11A through FIG. 11C illustrate the operation of blade deploying
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`tool 400. Between FIG. 11A and FIG. 11B, blade deploying tool 400 is fit over proximal
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`stem 124 of proximal screw 118, wherein each curved ramp 416 is wedgedinto tool
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`space 145 to force blades 134 away from central ring 122. While notvisible, locking
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`20
`
`tube 300 is inserted through lumen 412 of blade deploying tool 400 and screwed onto
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`proximal stem 124 to secure blade deploying tool 400 to screw 100.
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`In FIG. 11C, blade
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`deploying tool 400 is rotated, wherein blades 134 catch onto surrounding material and are
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`forced fully open to carve out the surrounding material. It should be understoodthat
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`blade deploying tool 400 is secured only to proximal screw 118, such that rotating blade
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`25
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`deploying tool 400 rotates only proximal screw 118 while distal screw 106 remains
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`stationary.
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`Referring now to FIG. 12A and FIG. 12B, an exemplary graft funnel tool
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`500 is now described. Graft funnel tool 500 comprises a shaft 506 having a handle 508 at
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`a proximal end 502 and a distal opening 512 at a distal end 504. Graft funnel tool 500
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`30
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`further comprises a lumen 514 running between a proximal opening and distal opening
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`512, wherein lumen 514 1s sized to fit packing rod 516. Packing rod 516 can include a
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`grip 518 positioned at a distal end. Distal opening 512 comprises a threadedinterior
`
`sized to screw onto the threaded exterior of proximal stem 124. In this manner, graft
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`material can be inserted into the proximal opening of graft funnel tool 500 and packed
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`into screw 100 using packing rod 516. The pathways for graft material is shown in FIG.
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`13A through FIG. 13C. Graft material enters proximal opening 126 of screw 100 and
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`fills lumen 130 of proximal screw 118 and lumen 112 ofdistal screw 106. Graft material
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`is able to exit screw 100 andfill any adjacent spaces by way of distal opening 110 and
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`apertures 144 positioned on central ring 122.
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`In particular, apertures 144 provide access
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`10
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`to the space decorticated by blades 134 for the inflow of graft material.
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`Referring now to FIG. 14 and FIG. 15A through FIG. 15C, an exemplary
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`cap driving tool 600 is now described. Cap driving tool 600 has a proximal end 602 and
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`a distal end 604 and comprises an outer shaft 606 having a proximal handle 608, a distal
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`cap driver 616, and a lumen extending between a proximal opening and a distal opening.
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`15
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`Cap driver 616 comprises one or more tabs 618, each tab 618 sized to fit within a tab slot
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`154 on cap 146. Cap driver 616 further comprises one or more spring clips 620, each
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`spring clip 620 also having a tab sized to fit within a tab slot 154 on cap 146. Spring clip
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`620 provides a spring force that releasably secures cap driver 616 to a proximal end of
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`cap 146. Cap driving tool 600 further comprises an inner shaft 622 positioned within the
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`20
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`lumen of outer shaft 606, inner shaft 622 comprising a proximal grip 624 and a distal tip
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`626. Distal tip 626 is sized to fit within lumen 130 of proximal screw 118. Distal tip 626
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`further comprises distal tabs 628 that are sized to fit within stem slots 132 of proximal
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`screw 118. Cap driving tool 600 thereby engages screw 100 bylinkingdistal tip 626 of
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`inner shaft 622 with proximal screw 118 and cap driver 616 of outer shaft 606 with cap
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`25
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`146. Inner shaft 622 and proximal screw 118 are held stationary, enabling outer shaft
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`606 to be actuated to drive cap 146 onto proximal stem 124.
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`Referring now to FIG. 16A and FIG. 16B, an exemplary lock screw driver
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`700 is now described. Lock screw driver 700 has a proximal end 702 and a distal end
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`704 and comprisesa distal handle 706 and a proximal screw bit 708 sizedto fit lock
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`30
`
`screw 158. Lock screw driver 700 can be usedto drive lock screw 158 into proximal
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`opening 126, whereupon lock screw 158 slightly expands the proximal end of proximal
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`stem 124 to prevent cap 146 from loosening and detaching from screw 100.
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`Second Decorticating Screw
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`Referring now to FIG. 17A through FIG. 19B, another exemplary screw
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`100 is depicted having a proximal screw 800 with central ring 802 and a complementary
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`blade deploying tool 900. Similar to central ring 122 of proximal screw 118, central ring
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`802 comprises one or more hingedly connected blades 804. Central ring 802 further
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`comprises curvedslots 806 positioned adjacent to each blade 804. Blades 804 are
`
`10
`deployable using blade deploying tool 900, which has a proximal end 902 andadistal
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`end 904 and comprisesa distal shaft 906 having a lumen 908 running between a proximal
`
`opening 910 and a distal cavity 912. Adjacent to distal cavity 912, blade deploying tool
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`900 comprises one or more