초록 ▼

A polyaxial bone screw assembly includes a threaded shank body having an upper portion, a receiver member or head, a retaining and articulating structure, and a pressure insert disposed between the shank upper portion and a rod. The receiver has a U-shaped cradle defining a channel for receiving a s

A polyaxial bone screw assembly includes a threaded shank body having an upper portion, a receiver member or head, a retaining and articulating structure, and a pressure insert disposed between the shank upper portion and a rod. The receiver has a U-shaped cradle defining a channel for receiving a spinal fixation rod and a receiver cavity. The retaining and articulating structure attaches to the shank and rotates with the shank in the cavity during positioning. The pressure insert presses upon the shank upper portion and not the retaining and articulating structure.

대표청구항 ▼

1. A bone anchor assembly comprising a shank for attaching to a bone, a receiver in pivotal relation with an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having a partial inner thread form,

1. A bone anchor assembly comprising a shank for attaching to a bone, a receiver in pivotal relation with an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having a partial inner thread form, a closure, and a compression insert positioned above and in direct downward locking contact with an integral top spherical surface of the shank, the closure including: a) a closed outer fastener having a body with a continuous outer thread form extending along at least a portion thereof and engaging the receiver inner thread form and a central bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a top surface thereof and an opening along a central axis opening onto the top surface of the inner set screw having a sole internal drive structure to receive a tool, the opening terminating at a lower interior tool abutment surface located nearer the bottom surface than the top surface thereof, the inner set screw is threadingly received in the central bore with the inner set screw insertable into the outer fastener from the bottom surface thereof, and whereinc) in a final position, the outer fastener and the inner set screw do not extend above top surfaces of the receiver first pair of arms. 2. The closure according to claim 1, wherein the outer fastener includes a break-off head drive structure. 3. The closure according to claim 1, wherein the outer fastener is driven by a first tool, and the inner set screw is driven by a second tool. 4. The bone anchor assembly of claim 1, wherein the integral top spherical surface of the shank has a central opening. 5. The bone anchor assembly of claim 1, wherein the shank has polyaxial motion with respect to the receiver. 6. The bone anchor assembly of claim 1, wherein the compression insert includes a second pair of upward extending arms that extend around the connecting member when the connecting member is in the channel. 7. The bone anchor assembly of claim 1, further comprising a retaining and articulating structure. 8. The bone anchor assembly of claim 1, wherein the compression insert remains spaced apart from a separate ring structure positionable within the receiver when the shank is in a non-pivotable position with respect to the receiver, the separate ring structure remaining in contact with a head of the shank. 9. The bone anchor assembly of claim 8, wherein the separate ring structure is inserted into the receiver before the shank. 10. The bone anchor assembly of claim 8, wherein the separate ring structure restrains the head of the shank from moving out of the receiver. 11. A bone anchor assembly comprising: a shank for attachment to a bone, a receiver with a cavity that receives an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces, a closure, and a compression insert positioned above an upper end of the shank, so as to engage the shank upper end and lock the shank in a position with respect to the receiver, and including a second pair of upward extending arms that extend around the connecting member when the connecting member is in the channel, the closure including: a) a closed outer ring fastener having an outer thread form and a central through bore with an internal surface guide and advancement thread form extending along a portion thereof and opening onto a bottom surface thereof, the outer fastener exerting pressure on the compression insert by rotation of the outer fastener with threaded advancement of the outer fastener within the receiver; andb) an inner set screw having an outer surface guide and advancement thread form and a bore with a central axis opening onto a top surface of the inner set screw, the bore terminating at a tool engagement abutment surface located nearer a bottom surface than the top surface, the inner set screw being threadedly received in the outer fastener with the inner set screw being insertable into the outer fastener from the bottom surface thereof, and wherein the inner set screw bottom surface engages and locks the connecting member, the shank frictionally maintained in an angular position relative to the receiver until the bone anchor assembly is locked by the closure. 12. The closure according to claim 11, wherein the outer fastener is driven by a first tool, and the inner set screw is driven by a second tool. 13. The bone anchor of claim 11, wherein the integral top radiused surface has a central opening which is continuous with an opening extending entirely through the shank. 14. The bone anchor of claim 11, wherein the shank is pivotal with respect to the receiver. 15. The bone screw assembly of claim 11, wherein the shank is cannulated. 16. The bone screw assembly of claim 11, further comprising a retaining and articulating structure. 17. A bone screw assembly comprising: a shank for implanting in a bone, a receiver with a cavity that receives an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces and a splay preventing inner thread form, a closure to close and lock the assembly, and a compression insert operably positioned above and in direct downward locking contact with an upper end of the shank having an integral top radiused surface for insert engagement, the closure comprising: a) an outer fastener having a closed body with a drive structure on a top surface thereof and a continuous splay preventing outer thread form engaging the receiver inner thread form and a central bore with a continuous internal surface guide and advancement thread extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form and a central multi-surface aperture opening onto only a substantially flat top surface of the inner set screw configured to slidably receive a tool, the aperture terminating at a tool engagement abutment surface located nearer a bottom surface than the flat top surface, the bottom surface of the inner set screw being closed off, and wherein in a final locking position the outer fastener is located between the first pair of arms, so as to not extend above the top surfaces of the receiver first pair of arms, the inner set screw remaining spaced apart from the receiver arms, the set screw being insertable into the outer fastener from the bottom surface of the outer fastener. 18. The bone anchor assembly of claim 17, wherein the shank has an integral top radiused surface having a central opening. 19. The bone anchor assembly of claim 17, wherein the shank is pivotal with respect to the receiver. 20. The bone anchor assembly of claim 17, wherein the shank is cannulated. 21. The bone screw assembly of claim 17, further comprising a retaining and articulating structure. 22. A pivotal bone screw assembly comprising: a shank for implanting in a bone, a receiver with a cavity that operably receives an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween adapted to receive a connecting member, the first pair of arms having top surfaces and an inner splay preventing thread form thereon, a closure, and a compression insert operably positioned above and in direct downward locking contact with an upper end of the shank having an integral top radiused surface and including a second pair of upward extending arms that extend around the connecting member when the connecting member is in the channel, the closure including: a) a closed outer ring fastener with an external splay preventing thread form and having a drive structure on a top thereof and a through bore with a continuous internal surface guide and advancement thread extending along at least a portion thereof and opening onto a bottom surface thereof, the outer ring fastener being positioned entirely between the first pair of arms of the receiver; andb) an inner set screw having a continuous outer surface guide and advancement thread and a central multi-surface bore opening onto only a substantially flat top surface of the inner set screw, the bore terminating at a tool engagement abutment surface that is closed off and located nearer a bottom surface than the flat top surface, the inner set screw being threadedly insertable in the outer ring fastener from the bottom surface, the bottom surface of the inner set screw being closed off and substantially flat. 23. The closure according to claim 22, wherein the bottom surface of the inner set screw engages and locks the connecting member. 24. A bone anchor assembly comprising: a bone anchor structure with an upper portion, a receiver with a cavity that receives the upper portion of the bone anchor structure and a first pair of upward extending arms forming a channel therebetween, the first pair of arms having top surfaces and an inner splay preventing thread form, a closure, and a compression insert positioned above a top end of the bone anchor structure upper portion, the closure including: a) a closed outer fastener having a body with a top drive structure and at least one continuous helically wound outer splay preventing thread form engaging the receiver inner splay preventing thread form and a through bore with an internal surface helically wound guide and advancement thread form extending to and opening onto a bottom surface thereof, the bottom surface configured to engage a structure positioned within the receiver channel; andb) an inner set screw having an outer surface helically wound thread form, and a tool engagement structure comprising an opening with a central drive structure opening onto only a top surface of the inner set screw and slidably receiving a tool therein, the opening terminating at a lower interior closed off tool engagement abutment surface, the lower interior closed off tool engagement abutment surface being located nearer a bottom surface than the top surface of the inner set screw, and wherein;c) the inner set screw is threadedly insertable in the outer fastener through bore from the bottom surface of the outer fastener such that in a final position the outer fastener and the inner screw do not extend above the top surfaces of the first pair of arms. 25. The bone anchor assembly of claim 24, wherein the bone anchor structure is pivotal with respect to the receiver. 26. The bone anchor assembly of claim 24, wherein the bone anchor structure is cannulated. 27. The bone anchor assembly of claim 24, further comprising a retaining and articulating structure. 28. A bone anchor assembly comprising: a bone attachment structure for attachment to a bone, a receiver with a cavity that receives an upper portion of the bone attachment structure and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces, a closure, and a compression insert positioned above an upper end of the bone attachment structure, the closure including: a) a closed outer ring fastener having a drive structure on a top thereof and an outer thread form and a central bore with an internal surface guide and advancement thread form extending along a portion thereof and opening onto a bottom surface thereof, the outer fastener being positioned entirely between the first pair of arms of the receiver and configured to engage the connecting member and an inner set screw; andb) an inner set screw having an outer surface guide and advancement thread form and a bore with a central axis opening onto a top surface of the inner set screw, the bore terminating at a tool engagement abutment surface located nearer a bottom surface than the top surface, the inner set screw being threadedly insertable into in the outer fastener from the bottom surface of the outer fastener and having a bottom portion configured to engage and lock the connecting member. 29. A bone anchor assembly comprising: a shank for attaching to a bone, a receiver with a cavity that receives an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces, a closure, and a compression insert positioned above and in direct downward locking contact with an integral top radiused surface on an upper end of the shank and including a second pair of upward extending arms that extend around the connecting member when the connecting member is in the channel, the closure including: a) a closed outer fastener having a body solely engaging the receiver, an inner set screw, and the connecting member within the channel, and having a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) the inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a flat top surface thereof and an opening along a central axis opening onto the top surface of the inner set screw having a sole internal drive structure to receive a tool, the opening terminating at a lower interior tool engagement abutment surface located nearer the bottom surface thereof, and whereinc) the inner set screw is threadedly insertable in the outer fastener through bore from the bottom surface thereof. 30. A bone anchor assembly comprising: a bone attachment structure having an integral radiused top surface, a receiver with a cavity that receives an upper portion of the bone attachment structure and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces, a closure, and a compression insert positioned above and in direct downward locking contact with the integral radiused top surface of the bone attachment structure and including a second pair of upward extending arms that extend around the connecting member when the connecting member is in the channel, the closure including: a) a closed outer fastener having a body solely engaging the receiver, an inner set screw, and the connecting member within the channel, and having a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) the inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a flat top surface thereof and an opening along a central axis opening onto the top surface of the inner set screw having a sole internal drive structure to receive a tool, the opening terminating at a lower interior tool engagement abutment surface located nearer the bottom surface than the top surface thereof, and whereinc) the inner set screw is threadedly insertable in the outer fastener through bore from the bottom surface thereof. 31. A bone anchor assembly comprising a shank for attaching to a bone, the shank having an upper portion with a partially radiused surface, a receiver with a cavity that receives the upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces and a partial inner thread form, a closure, and a compression insert positioned above and in direct downward locking contact with the upper portion radiused surface of the shank, the closure including: a) a closed outer fastener having a body with a drive structure on a top thereof and a continuous outer thread form extending along at least a portion thereof and engaging the receiver inner thread form and a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a flat top surface thereof and an opening along a central axis opening onto the top surface of the inner set screw having a sole internal drive structure to receive a tool, the opening terminating at a lower closed off interior tool engagement abutment surface located nearer the bottom surface than the top surface thereof, the inner set screw being insertable into the outer fastener from the bottom surface of the outer fastener. 32. The bone screw assembly of claim 31, wherein the shank is cannulated. 33. The bone anchor assembly of claim 31, further comprising a retaining and articulating structure. 34. A bone anchor assembly comprising a shank for attaching to a bone, the shank having a radiused top surface, a receiver with a cavity that receives an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces and a partial inner splay preventing thread form, a closure, and a compression insert positioned above and in direct downward locking contact with an upper end of the shank and including a second pair of upward extending arms that extend around the connecting member when the connecting member is in the channel, the closure including: a) a closed outer fastener having a body with a drive structure on a top thereof and a continuous outer splay preventing thread form extending along at least a portion thereof and engaging the receiver inner thread form and a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a flat top surface thereof and an opening along a central axis opening onto the top surface of the inner set screw having a sole internal drive structure to slidably receive a tool, the opening terminating at a closed off lower interior tool engagement abutment surface located nearer the bottom surface than the top surface thereof providing a non-through opening, and whereinc) the inner set screw is threadedly insertable in the outer fastener through bore from the bottom surface of the outer fastener, such that, in a final position, the inner set screw exerts pressure to lock the connecting member. 35. A bone anchor assembly comprising: a bone attachment structure having a radiused top surface, a receiver with a cavity that receives an upper portion of the bone attachment structure and a first pair of upward extending arms forming a channel therebetween, the first pair of arms having top surfaces, and a closure, the closure including: a) a closed outer fastener having a body engaging the receiver and a structure positioned within the channel, and having a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a top surface thereof and an opening along a central axis opening onto the top surface of the inner set screw having a sole internal drive structure to slidably receive a tool, the opening terminating at a blind end formed by a lower interior tool engagement abutment surface located nearer the bottom surface than the top surface thereof, and whereinc) the inner set screw is threadedly insertable in the outer fastener through bore from the bottom surface thereof. 36. A bone anchor assembly comprising an attachment structure for connecting to a bone, a receiver with a cavity that receives an upper portion of the attachment structure and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces and a partial inner thread form, a closure, and a compression insert positioned above and in direct downward locking contact with an upper end of the attachment structure, the closure including: a) a closed outer fastener having a body and a continuous outer thread form extending along at least a portion thereof and engaging the receiver inner thread form and a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form extending from near a bottom surface thereof to near a flat top surface thereof and a central axis bore opening onto the top surface of the inner set screw having a sole internal drive structure to receive a tool, the bore terminating at a lower interior tool engagement abutment surface located nearer the bottom surface thereof than the top surface, and whereinc) the inner set screw is threadedly insertable in the outer fastener through bore from the bottom surface thereof. 37. A bone anchor assembly comprising: a shank for attachment to a bone, a receiver with a cavity that receives an upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces, a closure, and a compression insert positioned above an upper end of the shank, so as to engage the shank upper end and lock the shank in a position with respect to the receiver, the closure including: a) a closed outer ring fastener having an outer thread form and a central through bore with an internal surface guide and advancement thread form extending along a portion thereof and opening onto a bottom surface thereof, the outer fastener exerting pressure through the compression insert by rotation thereof so as to lock the bone anchor assembly; andb) an inner set screw having an outer surface guide and advancement thread form and an aperture positioned around a central axis opening onto a top surface of the inner set screw, the aperture terminating at an internal bottom tool engagement abutment surface that is closed off and located nearer a bottom surface than the top surface, the inner set screw is threadedly insertable in the outer fastener from the bottom surface thereof. 38. A bone anchor assembly comprising a shank for attaching to a bone, the shank having an upper portion with a partially radiused surface, a receiver with a cavity that receives the upper portion of the shank and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces and a partial inner thread form, a closure and a pressure insert positioned above and in direct downward locking contact with the upper portion radiused surface of the shank, the closure including: a) a closed outer fastener having a body and a continuous outer thread form extending along at least a portion thereof and engaging the receiver inner thread form and a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer splay preventing surface thread form extending from near a bottom surface thereof to near a flat top surface thereof and a central axis aperture opening onto the top surface of the inner set screw having a sole internal drive structure configured to receive a tool, the aperture terminating at a blind ending formed by a lower interior tool engagement abutment surface located nearer the bottom surface than the top surface, the inner set screw insertable into the outer fastener from the bottom surface thereof. 39. A bone anchor assembly comprising a bone attachment structure having a radiused top surface, a receiver with a cavity that receives an upper portion of the bone attachment structure and a first pair of upward extending arms forming a channel therebetween to receive a connecting member, the first pair of arms having top surfaces, and a closure, the closure including: a) a closed outer fastener having a body engaging the receiver and a structure positioned within the channel, and having a through bore with an internal surface guide and advancement thread form extending to and opening onto a bottom surface thereof; andb) an inner set screw having a continuous outer surface thread form extending from near a solid closed off bottom surface thereof to near a top surface thereof and a central axis recess opening onto the top surface of the inner set screw having a sole internal drive structure to slidably receive a tool, the recess terminating at a lower interior tool engagement abutment surface located nearer the bottom surface thereof than the top surface thereof, and whereinc) the inner set screw is threadedly insertable in the the fastener through bore from the bottom surface thereof.