Upload shank swivel head bone screw spinal implant

Abstract

A polyaxial bone screw having a bone implantable shank, a head and a retaining ring. The retaining ring includes an outer partial hemispherical surface and an inner bore with radially extending channels and partial capture recesses. The shank includes a bone implantable body with an external helical wound thread and an upwardly extending capture structure. The capture structure includes at least one spline which extends radially outward and has a wedged surface that faces radially outward therefrom. The capture structure operably passes through a central bore of the retaining ring while the spline passes through a suitably shaped channel so that the spline becomes positioned above the head at which time the shank is rotated appropriately and the shank is drawn back downwardly so that the spline engages and seats in the capture recess. The head includes an internal cavity having a spherical shaped surface that mates with the ring surface and has a lower restrictive neck that prevents passage of the ring once the ring is seated in the cavity.

1 . A polyaxial bone screw comprising:
 a) a head having a channel adapted to receive an elongate longitudinal member and having a lower restrictive neck;   b) a shank having a lower portion adapted to be implanted in a bone of a patient and an upper portion; said shank upper portion being sized and shaped to be positioned in said head so as to extend through said lower restrictive neck;   c) a retainer ring separate from said shank and received in said head; said retainer ring mating with and non-pivotably coupled to said shank upper portion to form a subassembly; said subassembly being polyaxially rotatable relative to said head prior to locking of the position of said shank relative to said head, said retainer ring width being larger than a width of said head lower restrictive neck so as to hold said shank upper portion in said head while allowing polyaxial movement of said subassembly relative to said head during positioning; and   d) said shank upper portion being sized, shaped and positioned so as to directly receive a downward force from said longitudinal member after said longitudinal member is received in said head channel, so as to lock the position of the shank relative to the head.   
   
   
       2 . The bone screw according to  claim 1  wherein:
 a) the shank having an upper end; and   b) said retaining ring engages said shank upper portion substantially below said shank upper end, such that between the shank and the retainer ring only said shank receives said direct downward force.   
   
   
       3 . The bone screw according to  claim 1  wherein:
 a) said shank is cannulated.   
   
   
       4 . The bone screw according to  claim 1  wherein:
 a) said shank upper portion includes an engagement end positioned and shaped so as to be adapted to abut against a longitudinal member placed in said channel.   
   
   
       5 . The bone screw according to  claim 4  wherein:
 a) said engagement end is convex.   
   
   
       6 . The bone screw according to  claim 1  wherein:
 a) said shank upper portion is sized and shaped to extend into said head channel when the bone screw is fully assembled.   
   
   
       7 . The bone screw according to  claim 1  including:
 a) a closure having mating structure for mating with said head and closing said channel so as to be adapted to capture said rod in said channel.   
   
   
       8 . The bone screw according to  claim 7  wherein:
 a) said closure having a helically wound mating guide and advancement structure and said head including a complimentary guide and advancement structure sized and shaped to allow said closure to be rotated into and torqued in said head.   
   
   
       9 . The bone screw according to  claim 8  in combination with:
 a) an elongate member.   
   
   
       10 . The bone screw according to  claim 9  wherein:
 a) said shank upper portion is shaped and positioned such that upon assembly of said bone screw and said elongate member, said shank upper portion has an engagement region that directly and frictionally engages said elongate member so as to secure said shank in a selected fixed angular configuration relative to said head.   
   
   
       11 . In a polyaxial bone screw assembly having a shank and a head with an upward opening receiving channel wherein the channel is sized and shaped to receive a rod located above the shank during use and having a lower restrictive neck; the improvement comprising:
 a) said shank being sized and shaped to be loaded upwardly through said head lower restrictive neck and thereafter being captured in said head by a separate retainer ring secured to said shank such that said shank and said retainer ring together pivot relative to said head while said shank is in said head and during positioning of the head relative to the shank, said shank being sized, shaped and positioned in said head so as to receive a downward force from above when a rod is placed in said channel so as to lock the position of the shank and head relative to each other.   
   
   
       12 . The screw according to  claim 11  wherein:
 a) said shank includes an upper portion that extends into said channel when said shank is loaded into said head.   
   
   
       13 . The bone screw according to  claim 12  wherein:
 a) said retainer ring engages said shank substantially below said upper portion, such that only said shank receives said direct downward force from above.   
   
   
       14 . The bone screw according to  claim 12  wherein:
 a) said retainer ring is sized and shaped to be uploaded into said head through said lower restrictive neck.   
   
   
       15 . The bone screw according to  claim 12  wherein:
 a) said retainer ring is sized and shaped to be downloaded into said head through said channel.   
   
   
       16 . The bone screw according to  claim 15  wherein:
 a) said retainer ring has a radiused surface adapted to pivotally mate with a radiused mating surface in a chamber in said head.   
   
   
       17 . In a polyaxial bone screw assembly having a shank and a head with a channel sized and shaped to receive a rod; the improvement comprising:
 a) said shank being sized and shaped to allow uploading of said shank into said head such that said shank is positioned directly beneath and receives a downward force from a rod located in said channel;   b) a retaining ring that is non-integral with said head and said shank for capturing said shank in said head; said ring being secured to said shank while in said head and pivoting together with said shank during positioning of said shank relative to said head, wherein said ring receives downward force from said shank for frictionally securing said ring against said head in a locked configuration.   
   
   
       18 . In a polyaxial bone screw having a shank and a head wherein said head includes a rod receiving channel; the improvement comprising:
 a) said shank being sized and shaped to allow for said shank to be uploaded into said head;   b) said shank having an upper engagement region sized and shaped to project sufficiently into said channel after said shank is loaded into said head so as to directly engage a rod received in said channel and to be biased into locking engagement against said head due to application of force to such a rod on a side of said rod opposite said shank; and   c) a retaining ring that is non-integral with the shank; the retaining ring being joined with the shank in the head and thereafter pivoting with said shank relative to said head.   
   
   
       19 . The bone screw according to  claim 18  wherein:
 a) said retaining ring engages said shank substantially below said upper engagement region, such that only said shank receives a direct force from above.   
   
   
       20 . The bone screw according to  claim 18  in combination with a rod and a closure operably closing said channel and biasing against said rod opposite said shank and wherein said closure is rotatably joinable to said head by flangeforms. 
   
   
       21 . A polyaxial bone screw and rod assembly comprising:
 a) a head having a channel adapted to receive a rod and having a lower bore;   b) a shank having a threaded lower portion adapted to be implanted in a bone and an upper portion with a capture structure;   c) said shank upper portion being sized and shaped to be uploaded through said head lower bore and thereafter extend into said channel so as to engage a rod in said channel;   d) a retaining structure having a retainer ring that mates with and secures to said capture structure to form a subassembly inside said head; said retainer ring being non-integral with said shank; said retainer ring being downloaded from a top of the said head; said subassembly polyaxially rotating relative to said head during positioning of said shank relative to said head;   e) a rod that is sized and shaped to be received in said channel; and   f) said shank upper portion further including an upper convex surface sized, shaped and positioned such that when said bone screw is fully assembled and said rod is located in said channel, said convex surface engages said rod to urge said subassembly into a non-moveable configuration relative to said head.   
   
   
       22 . The bone screw according to  claim 21  wherein:
 a) said retainer ring engages said shank upper portion substantially below said upper convex surface, such that only said shank receives a direct downward force.   
   
   
       23 . The bone screw according to  claim 21  wherein:
 a) said retaining ring is a continuous ring.   
   
   
       24 . The bone screw according to  claim 21  wherein:
 a) said retaining ring is a discontinuous ring.   
   
   
       25 . A polyaxial bone screw and rod assembly comprising:
 a) an elongate rod;   b) a head having a rod receiving channel for operably receiving said rod; said channel being positioned between a pair of upstanding and spaced arms with each arm having a first of a guide and advancement structure thereon; said head having a lower bore and a chamber located between said channel and said bore;   c) a shank having a lower portion adapted to be secured to a bone and an upper capture portion sized and shaped to extend through said bore and be polyaxially rotatably held within said head chamber during positioning of said head relative to said shank;   d) a non-integral retainer sized and shaped to secure to said shank upper capture portion of said shank so as to polyaxially rotate with said shank relative to said head during positioning;   e) said shank having an integral upper rod engaging structure that is sized and shaped to project into said channel and be engaged by said rod when said rod is in said channel; and   f) a closure for closing between said arms and having second guide and advancement structure thereon that rotatably mates with said first guide and advancement structure; said closure upon advancement operably biasing said rod against said shank so as to lock said shank in position relative to said head.   
   
   
       26 . The assembly according to  claim 25  wherein:
 a) said first and second guide and advancement structures are selected from a group consisting of reverse angle threads, buttress threads and flangeforms.   
   
   
       27 . The assembly according to  claim 25  wherein:
 a) said first and second guide and advancement structures are flangeforms.   
   
   
       28 . The assembly according to  claim 25  wherein
 a) said shank is cannulated along the entire length thereof.   
   
   
       29 . The assembly according to  claim 25  wherein:
 a) said retainer having a first radiused surface such that said retainer rotates with said shank during positioning of said shank relative to said head; and   b) said head chamber having a second radiused surface operably receiving said first radiused surface and allowing polyaxial rotation between said shank and said head during positioning.   
   
   
       30 . The bone screw according to  claim 25  wherein:
 a) said capture structure engages said shank upper capture portion substantially below said integral upper rod engaging structure, such that only said shank receives a direct downward force when said rod is biased against said shank.   
   
   
       31 . In an implant assembly including a bone screw and a rod wherein said bone screw has a head with a rod receiving channel and a shank with an integral lower portion adapted to be secured to a bone and an integral upper portion pivotally received in said head during positioning, the improvement comprising wherein:
 a) said shank is uploaded into said head and said shank upper portion extends substantially into said channel when said shank upper portion is received in said head and directly engages said rod so that biasing of said rod downward against said shank operably locks said shank in position relative to said head before said rod fully seats in a bottom of said channel and such that said shank first receives a downward force thereon upon downward biasing of said rod and then transfers the downward force from the shank to lock the shank in a fixed position relative to the head; and   b) a capture ring sized and shaped to mate with said shank upper portion and pivoting with said shank upper portion during polyaxial rotation of said shank relative to said head.   
   
   
       32 . The assembly according to  claim 31  wherein:
 a) said shank is cannulated along the entire length thereof.   
   
   
       33 . In an implant assembly including a bone screw and a rod wherein said bone screw has a head with a rod receiving channel and a shank with a lower portion adapted to be secured to a bone and an upper portion pivotally received in said head during positioning, the improvement comprising wherein:
 a) said shank is cannulated along the entire length thereof; and   b) said shank upper portion projects into said channel so as to directly engage said rod when said rod is located in said channel and said shank is biased by said rod when fully lowered in said channel so as to lock said shank in a fixed position relative to said head; and   c) a capture ring sized and shaped to mate with said shank upper portion and pivoting with said shank upper portion during polyaxial rotation of said shank relative to said head.   
   
   
       34 . The assembly according to  claim 35  including
 a) a closure that is rotatably mated with said head so as to bias against said rod when rotated, such that said rod biases against said shank and locks said shank in position relative to said head.   
   
   
       35 . The assembly according to  claim 33  wherein:
 a) only said shank receives a downward force thereon upon downward biasing of said rod.   
   
   
       36 . A polyaxial bone screw comprising:
 a) a head having a channel adapted to receive an elongate rod and having a lower bore;   b) a shank having a lower portion adapted to be implanted in a bone of a patient and an upper portion; said shank being sized and shaped to be loaded into said head and through said bore;   c) a retainer ring separate from said shank and received in said head; said retainer ring cooperating with said shank upper portion so as to polyaxially rotate with said shank relative to said head during positioning of said shank relative to said head prior to locking of the position of said shank relative to said head, said retainer ring presenting a head engaging surface diameter larger than said head lower bore so as to hold said shank in said head while allowing polyaxial movement of said shank relative to said head during positioning;   d) said shank upper portion being sized and shaped so as to extend into said channel after said shank is received in said head; and   e) said shank upper portion includes an engagement end positioned and shaped so as to be adapted to abut against a rod placed in said channel.   
   
   
       37 . The bone screw according to  claim 36  wherein:
 a) said engagement end is convex.   
   
   
       38 . The assembly according to  claim 36  wherein:
 a) only said shank receives a downward force thereon upon downward biasing of said rod.   
   
   
       39 . A polyaxial bone screw assembly comprising:
 a) an elongate rod;   b) a head having a channel receiving said rod during use and having a lower bore and a lower opening;   c) a shank having a lower portion adapted to be implanted in a bone of a patient and an upper portion; said shank upper portion being sized and shaped to be loaded into said head and through said lower opening;   d) a retainer ring separate from said shank and received in said head; said retainer ring mating with and secured to said shank upper portion so as to rotate together with said shank relative to said head during positioning and so as to form a subassembly prior to locking of the position of said shank relative to said head, said subassembly presenting a head engaging surface diameter larger than said head lower bore so as to hold said shank in said head while allowing polyaxial movement of said shank relative to said head during positioning;   e) said shank upper portion being sized, shaped and positioned so as to receive a downward force transferred through a rod placed into said channel after said shank is received in said head;   f) a closure including a mating structure for mating with said head and closing said channel so as to be adapted to capture said rod in said channel;   g) said closure is positioned in said head and engages said head; and wherein   h) said shank upper portion is shaped and positioned such that upon assembly of said bone screw and said rod, said shank upper portion directly receives said force, said force being generated by said closure that causes frictional engagement of said ring with said head so as to secure said shank in a selected fixed angular configuration relative to said head.   
   
   
       40 . The polyaxial bone screw assembly according to  claim 39  wherein:
 a) said shank being sized, shaped and positioned in said head so as to directly receive said downward force from above when a rod is placed in said channel.   
   
   
       41 . The polyaxial bone screw assembly according to  claim 39  wherein:
 a) said ring engaging said shank upper portion substantially below a top surface thereof; wherein only said shank receives said downward force.   
   
   
       42 . In a polyaxial bone screw having a shank and a head having an inner chamber with an internal curvate surface and also having a lower opening; the improvement comprising:
 a) said chamber internal surface having a larger dimension than said opening;   b) said shank having an upper portion that has a smaller width than said opening to allow said shank to be uploaded through said opening;   c) a rod receiving channel located above said chamber; said shank extending into said channel so as to engage a rod in said channel during use; and   d) a retaining structure that loads separately from said shank into said chamber and captures said shank in said chamber; said retaining structure being secured to and rotating with said shank relative to said head and having a lower surface sized and shaped to slidingly mate and rotate with said chamber internal surface during positioning.   
   
   
       43 . In a polyaxial bone screw having a shank and a head; the improvement comprising:
 a) said head having a lower aperture and said shank being sized and shaped so as to allow uploading of an upper portion of said shank through said aperture into said head; and   b) retaining structure that is non-integral with said shank and loaded into said head separately from said shank; said retaining structure mating with and being secured to said shank so as to capture and pivot with said shank upper portion in said head so as to allow polyaxial movement of said shank relative to said head.   
   
   
       44 . A polyaxial bone screw assembly comprising:
 a) a head having a channel adapted to receive an elongate longitudinal member and having a lower restrictive neck;   b) a shank having a lower portion adapted to be implanted in a bone of a patient and an upper portion; said shank upper portion being sized and shaped to be positioned in said head so as to extend through said lower restrictive neck;   c) a retainer ring separate from said shank and received in said head; said retainer ring mating with and non-pivotably coupled to said shank upper portion said shank and said retainer ring when coupled being polyaxially rotatable together relative to said head prior to locking of the position of said shank relative to said head, said retainer ring width being larger than a width of said head lower restrictive neck so as to hold said shank upper portion in said head while allowing polyaxial movement of said shank relative to said head during positioning; and   d) said shank upper portion being sized, shaped and positioned so as to receive a downward force from said longitudinal member after said longitudinal member is received in said head channel, so as to lock the position of the shank relative to the head channel thereby locking the position of the shank and head relative to each other.   
   
   
       45 . A polyaxial bone screw assembly comprising:
 a) an elongate member;   b) a head having a channel to receive the elongate longitudinal member and having a lower restrictive neck;   c) a shank having a lower portion adapted to be implanted in a bone of a patient and an upper portion; said shank upper portion being sized and shaped to be positioned in said head so as to extend through said lower restrictive neck;   d) a retainer ring separate from said shank and received in said head; said retainer ring mating with and non-pivotably coupled to said shank upper portion; said upper shank and said retainer ring when coupled being polyaxially rotatable together relative to said head prior to locking of the position of said shank relative to said head, said retainer ring width being larger than a width of said head lower restrictive opening so as to hold said shank upper portion in said head while allowing polyaxial movement of said shank relative to said head during positioning; and   e) the upper portion being sized and shaped to extend upward and so as to be located beneath the elongate member, when the elongate member is received in the channel; when the assembly is fully assembled, the elongate member operably transferring a downward force to the shank upper portion, so as to urge the coupled shank and retainer ring into frictional contact with head and so as to lock the configuration of the shank with respect to the head.   
   
   
       46 . In a polyaxial bone screw having a shank and a head with a channel sized and shaped to receive a rod; the improvement comprising:
 a) said shank being sized and shaped to allow uploading of said shank into said head such that said shank is positioned directly beneath and receives a downward force from a rod located in said channel; a retaining ring that is non-integral with said head and said shank for capturing said shank in said head; said ring being secured to said shank while in said head and pivoting together with said shank during positioning of said shank relative to said head, wherein said ring only engages said shank and said head.