US20070123867A1 - Capless multiaxial screw and spinal fixation assembly and method - Google Patents

Abstract

A bone fixation assembly and capless multi-axial screw system and method are shown. The assembly comprises a receiver having a rotary lock which in one embodiment includes a plurality of channels which urge and lock the elongated member to the screw using a bayonet type connection.

Description

RELATED APPLICATION DATA
• This application is a continuation-in-part of application Ser. No. 11/193,523, filed Jul. 29, 2005, which is incorporated herein by reference and made a part hereof.
BACKGROUND OF THE INVENTION
• This invention relates to a capless multiaxial screw and spinal fixation assembly and method, particularly useful for fixing and/or aligning vertebrae of the spine. The invention permits multiple angular orientations of an elongated member or rod with respect to a screw that is screwed into a vertebra.
• Various methods of spinal immobilization have been known and used in the past. The preferred treatment for spinal stabilization is immobilization of the joint by surgical fusion or anthrodesis. This method has been known since development in 1911 by Hibbs and Albe. However, in many cases, in particular cases involving fusion across the lumbosacral articulation and where there are many levels involved, pseudorarthrosis is a problem. It was discovered that immediate immobilization was necessary in order to allow a bony union to form. Post operative external immobilization, such as the use of splints and casts, was a favored method of treatment, however, as surgical techniques have become more sophisticated, various methods of internal and external fixation have been developed.
• Internal fixation refers to therapeutic methods of stabilization which are wholly internal to the patient and include commonly known devices such as bone plates and pins. External fixation, in contrast, involves at least some portion of stabilization device which is external to the patient's body. Internal fixation is now the favored method of immobilization because the patient is allowed greater freedom with the elimination of the external portion of the device and the possibility of infection, such as a pin tract infection is reduced.
• There have been numerous systems and methods developed in the past for correcting and stabilizing and aligning the spine for facilitating, for example, fusion at various levels or areas of the spine, such as those devices are shown in U.S. Pat. Nos. 4,085,744; 4,269,178; 4,805,602; 5,466,237; 5,474,555; 5,891,145; and 6,869,433 B2. Bone screws with a polyaxial head are commonly used in spine surgery today. They are used chiefly in the lumbar spine and screwed into bone (pedicle) posteriorly. The head of the screw is attached to the shaft of the screw by means of a ball and socket. The top of the screw is machined into a ball, and the head contains a socket into which the ball fits. The screw head further contains a receiver for receiving a separate rod. The rod is fastened to the screw head receiver via a threaded cap. The rod is then fastened to screws placed in adjacent vertebrae thus providing stabilization. The polyaxial head allows the rod to be placed in a variety of angles with respect to the screw allowing conformance to local anatomy.
• When the threaded cap is tightened upon the rod, a frictional pressure is transmitted from the threaded cap to the rod thence to the top of the ball, thus locking the ball-in-socket and preventing motion after tightening has occurred. This concept is demonstrated in U.S. Pat. Nos. 5,466,237 and 5,474,555, which illustrate this type of screw.
• U.S. Pat. No. 5,466,237 to Bird et al. discloses a bone screw having a spherical projection on the top of the bone screw. An externally threaded receiver member supports the bone screw and spinal rod on top of the spherical projection. An outer nut is tightened onto the receiver member to press the spinal rod against the spherical projection to accommodate various angular orientations of the bone screw relative to the rod.
• In another approach shown in U.S. Pat. No. 4,946,458 to Harms, a spherical headed bone screw supported within separate halves of a receiving member. The bottom of the halves are held together by a retaining ring. The top of the receiver halves are compressed about the bone screw by nuts threaded onto a threaded spinal rod.
• In still another approach taken by Harms et al. in U.S. Pat. No. 5,207,678, a receiver member is flexibly connected about a partially spherical head of a bone screw. Conical nuts on opposite sides of the receiver member threaded onto a threaded rod passing through the receiver. As the conical nuts are threaded toward each other, the receiver member flexibly compresses around the head of the bone screw to clamp the bone screw in its variable angular position. One detriment of the systems in the two Harms et al. patents is that the spinal rod must be threaded in order to accept the compression nuts.
• U.S. Pat. No. 6,869,433 discloses the use of a pedicle screw assembly that comprises a screw having a head with a convex portion and a receiver that receives the head. The receiver also receives an elongated member, such as a spinal fixation rod. The receiver has a concave portion which has a radius of curvature which is less than the radius of curvature of the convex portion of the head whereby to create an interference fit between the convex portion of the head and the concave portion of the receiver. The device also includes an internal nut and external nut that compresses the rod against a pressure disc which in turn compresses the head convex portion of the screw into the receiver concave portion and locks the angular position of the receiver with respect to the screw.
• One of the problems with the prior art devices is the number of parts and components, especially those components that utilize a threaded cap screw to secure the rod to the anchoring screw, whether internal or external, to fix the rod relative to the screw. Problems with the threaded fastener, that is, threaded cap or set screw, are numerous and include risk of cap loosening, loss of cap intra-operatively, cross threading, thread failure, failure of the cap in driving instrument and limitations upon torque application.
• What is needed, therefore, is a system and method that provide a lock or connection between the rod and screw without the use of external nuts, screws, caps or threads of the type shown in the prior art.
SUMMARY OF THE INVENTION
• The present invention improves the spinal fixation and the locking between an elongated member or rod and a screw.
• One object of the invention is to provide a system and method that reduces or eliminates the need for external or internal caps or screws to lock the relative position of a rod to a screw.
• Another object of the invention is to provide a simple bayonet-type connection that eliminates the fixation systems of the past and/or simplifies the spinal fixation procedure.
• In one aspect, this invention discloses a capless multiaxial screw system comprising a receiver comprising a receiver end comprising a receiver bore for receiving a threaded portion of a screw having a screw head; and a sleeve having a sleeve end for situating against at least a portion of the screw head after the threaded portion is received in the receiver bore, the sleeve having a sleeve bore associated with the sleeve end; the receiver having a channel for receiving an elongated member; the sleeve being adapted to permit the elongated member to engage the at least of portion of the screw head when the elongated member is received in the channel and the receiver is rotated to a locked position.
• In another aspect, this invention discloses a spinal fixation assembly comprising a receiver having a receiver bore for receiving a screw having a screw head and a receiver channel in communication with the receiver bore for receiving an elongated member; and a stabilizer dimensioned to be received in the receiver bore, the stabilizer having a stabilizer channel associated with a first end of the stabilizer for receiving the elongated member and a stabilizer bore through a second end of the stabilizer, the second end being adapted to permit direct contact between at least a portion of the screw head and the elongated member; the receiver being capable of rotating relative to the elongated member after the elongated member is received in the receiver channel to force the elongated member into contact with the at least a portion of the screw head.
• In yet another aspect, this invention relates to a receiver for use with a polyaxial screw comprising a body having a bore; and a channel for receiving an elongated member and for compressing it into engagement with a screw head of the polyaxial screw when the receiver is rotated.
• In still another aspect, this invention relates to a spinal fixation assembly comprising a receiver having a bore for receiving a screw having a screw head; and an intermediate member dimensioned to be received in the bore and having a first end and a second end; the receiver comprising an integral rotary lock for forcing and locking an elongated member directly against the screw head when the receiver is rotated.
• In another aspect, this invention discloses a spinal fixation assembly comprising a receiver having an opening for receiving a screw having a screw head; and an intermediate member dimensioned to be received in the opening and having an intermediate member receiving channel for receiving an elongated member and a screw head receiving opening adapted to receive at least a portion of the screw head; the receiver comprising a receiver channel for receiving the elongated member, the receiver channel forcing the elongated member into contact with the screw head when the receiver is rotated from an unlocked position to a locked position.
• In another aspect, this invention relates to a capless multiaxial screw system comprising a screw having a threaded portion and a screw head; a receiver having a receiver bore for receiving the threaded portion and a receiving channel for receiving an elongated member, the receiver further comprising a locking channel in communication with the receiving channel; an intermediate member adapted to be situated in the receiver bore, the intermediate member comprising an intermediate member bore for receiving at least a portion of the screw head; and the intermediate member bore being adapted to permit the at least a portion of the screw head to extend into the locking channel so that the elongated member may engage and compress against the at least a portion of the screw head when the elongated member is received in the receiving channel and the receiver is rotated.
• In still another aspect, this invention discloses a capless multiaxial screw fixation assembly comprising a screw having a threaded portion and a screw head; a receiver having a bore for receiving the threaded portion and a receiving channel for receiving an elongated member, the receiving channel further comprising a locking channel in communication with the receiving channel; and a guide for situating in the bore, the guide comprising a second receiving channel associated with a first end of the guide and a seat area associated with a second end of the guide; the guide being adapted to permit at least a portion of the screw head to extend into the second receiving channel so that the elongated member may engage the screw head to lock the elongated member to the screw when the elongated member is received in the first and second receiving channels and the receiver is rotated from an unlocked position to a locked position.
• In yet another aspect, this invention relates to a spinal fixation assembly comprising a receiver having a receiver bore for receiving a screw having a screw head, the receiver further comprising a locking channel and a receiving channel in communication with the locking channel; and an intermediate member dimensioned to be received in the receiver bore, the intermediate member comprising a body having a first end having an intermediate member channel and a second end having an intermediate member opening; the intermediate member opening being adapted to permit at least a portion of the screw head to engage an elongated member after the elongated member is received in the receiving, locking and intermediate member channels and the receiver is moved to a locked position.
• These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a fragmentary perspective view of a capless multiaxial screw and fixation assembly mounted on a spinal column having a plurality of vertebrae;
• FIG. 2 is a perspective view of the system shown inFIG. 1;
• FIG. 3 is an exploded fragmentary perspective view of the system shown inFIGS. 1 and 2;
• FIG. 4 is a fragmentary perspective view illustrating a rod received in a receiving channel of a receiver;
• FIG. 5 is a fragmentary plan view of the illustration shown inFIG. 4;
• FIG. 6 is a fragmentary view similar toFIG. 4, but showing the receiver rotated approximately 30 degrees about its axis relative to the rod;
• FIG. 7 is a fragmentary plan view similar toFIG. 5 and showing the receiver in the position illustrated inFIG. 6;
• FIG. 8 is fragmentary perspective view showing the receiver in a fully locked position;
• FIG. 9 is a plan view similar toFIGS. 5 and 7 showing the receiver in a fully locked position;
• FIG. 10 is a view taken along the line10-10 inFIG. 4;
• FIG. 11 is a view illustrating the rod after it has been received in the channel of the receiver and supported above a bottom surface of a compression member;
• FIG. 12 is a sectional view taken along the line12-12 inFIG. 8;
• FIG. 13 is a fragmentary view showing the rod in cross-section and in a fully locked position;
• FIG. 14 is a fragmentary view illustrating various features of the locking channels;
• FIG. 15 is a plan view showing a compression member received in a bore of the receiver and illustrating the aperture through which a tool may be inserted to rotate the screw head before the rod is positioned in a channel of both the receiver and the compression member;
• FIG. 16A-16E are various views of the receiver in accordance with one illustration of the invention;
• FIG. 17 is a sectional view of a compression member in accordance with one illustration of the invention;
• FIG. 18 is a fragmentary sectional view of another illustration of the invention, showing a channel having walls that are generally non-planar to define an intermediate area for loosely capturing the rod;
• FIG. 19 is a side elevation view of the embodiment shown inFIG. 18;
• FIG. 20 is a fragmentary sectional view that has been rotated relative toFIGS. 18 and 19;
• FIG. 21 is an elevational view rotated relative toFIG. 19;
• FIGS. 22-24 are plan views illustrating rotational movement of the receiver relative to the rod;
• FIGS. 25-27 are side elevation views that generally correspond toFIGS. 22-24, respectively, illustrating the receiver in various positions, but with the rod removed for ease of illustration and understanding;
• FIGS. 28-30 are views similar toFIGS. 25-27, respectively, illustrating the receiver in various rotational positions relative to the rod as the rod is moved from a receiving position to a locked position;
• FIGS. 31-33 are fragmentary sectional views somewhat enlarged and diagrammatic to simply illustrate the intermediate capturing step of receiving area for loosely capturing the rod in the receiver;
• FIG. 34 is a diagrammatic view which is presented for purposes of illustrating various dimensions of the channels in the receiver or the second illustrative embodiment;
• FIG. 35A is a perspective view of another embodiment of a capless multiaxial screw and fixation assembly in accordance with another embodiment of the invention;
• FIG. 35B is a sectional view of the embodiment illustrated inFIG. 35A;
• FIG. 35C is a perspective view of sleeve or guide used in the embodiment illustrated inFIG. 35A;
• FIG. 35D is a sectional view taken along theline35D-35D inFIG. 35C;
• FIG. 35E is a plan or top view of a sleeve or guide in accordance with another embodiment of the invention;
• FIG. 36A is a perspective fragmentary view of screw used in the embodiment illustrated inFIG. 35A;
• FIG. 36B is a plan or top view of the polyaxial screw shown inFIG. 36A;
• FIGS. 36C-36H illustrate other representative polyaxial screw head configurations that may be used to permit maximal polyaxial movement;
• FIGS. 36I-36L illustrate various tools used to drive the screws shown inFIGS. 36A-36H;
• FIGS. 37-42 are various views of the embodiments shown inFIG. 36A illustrating the rotation of the receiver relative to the rod and the guide or sleeve;
• FIGS. 43-46 are fragmentary sectional views illustrating various features of the receiver in an unlocked position and a locked position;
• FIGS. 47-48 illustrate the polyaxial tilting of the receiver and the rod engaging the screw head directly;
• FIGS. 49-57 are various views illustrating various receiver positions with and without the rod and using the intermediate channel or embodiment of the type illustrated inFIGS. 18-34;
• FIG. 58 is a fragmentary perspective view of the capless multiaxial screw fixation assembly in accordance with the embodiment illustrated inFIG. 35A mounted on the spinal column having the plurality of vertebra; and
• FIG. 59 is an exploded fragmentary perspective view of the system shown inFIG. 58.
DETAILED DESCRIPTION OF THE INVENTION
• Referring now toFIGS. 1-3, a capless multi-axial screw andspinal fixation assembly10 and method are shown. Theassembly10 comprises ascrew12 having a threadedportion12aand ahead12bthat in the embodiment being described, has a rounded profile or curvature, as best illustrated inFIGS. 3 and 10-13. Thescrew head12bcomprises a hexfemale opening12cfor receiving a tool (not shown) for screwing thescrew12 into an aperture14aof aspinal bone14, such as a vertebra of a spine.
• As illustrated inFIGS. 1 and 2, one feature of the invention is that it enables a user to fix a relative position of a plurality of vertebrae, such asvertebrae14,16 and18 inFIG. 1, in a fixed and stabilized position.
• Thesystem10 comprises a retainer orreceiver20 having a generallycylindrical receiver wall20c(FIG. 4) that defines an aperture or bore22 that traverses or extends along a receiver axis A (FIG. 11) the entire length of thereceiver20, as best illustrated inFIGS. 4, 10, and12. Thereceiver20 comprises afirst end20aand asecond end20b, and although not shown, may comprise a chamfer21 of about 45 degrees. It should be understood that theinternal wall20cdefines aseat20dtoward the bottom of the receiver20 (as viewed inFIGS. 10 and 15) that is arcuate or curved in cross section. Theseat20dhas a radius or curved surface R1 (FIG. 10). Note that a diameter or distance D1 (FIG. 10) ofbore22 at theend20bof the receiver orretainer20 is slightly smaller than both a diameter or distance D2 (FIGS. 7 and 10) of thebore22 atend20aand a diameter D3 (FIG. 12) of therounded screw head12bso that it defines thereceiver seat20d(FIGS. 10 and 15) for receiving or capturing thescrew head12b. In this regard, thescrew head12bhas anend12b1 that is configured and dimensioned to be received or captured in theseat20dand that can be rotated or screwed while in the bore22 (FIGS. 10 and 15). Theend12b2 has a curved or arcuate shape that generally complements the shape of theseat20dto permit polyaxial and relative movement between thereceiver20 andscrew12.
• As shown inFIGS. 3 and 11-13, thebore22 receives the threadedportion12aof thescrew12 until thehead12bis received in theseat20d(as illustrated inFIGS. 10-13). It should be understood that theseat20dcooperates with theend12b1 ofhead12band permits the retainer orreceiver20 to move polyaxially about a center ofhead12bso that position of thereceiver20 may be altered relative to thehead12bofscrew12. This allows a user, such as a surgeon or physician, to change the polyaxial position of thereceiver20 relative to thescrew12 in order to adjust an angular position of an elongated member orrod24 relative to, for example, thevertebrae14,16 and18 illustrated inFIG. 1. Therod24 may be any suitable shape in cross section, such as circular, hexagonal, octagonal, polygonal or the like.
• Note that thereceiver20 comprises a receiving channel or slot26 (FIG. 15) defined bywall surfaces21a,21b,21cand21d(FIG. 4). Thereceiver20 further comprises a lock, locking means, locking channel, or rotary lock28 (FIGS. 11 and 12) which is integral with thereceiver20. In the embodiment being described, thereceiver20 is manufactured of titanium and is machined to provide the receivingchannel26,lock28 and thebore22 using conventional machining techniques. Other potential materials include biocompatible load bearing material, such as metals, metal alloys, carbon fibers, composites, plastics or hybrid materials.
• In one embodiment, thelock28 cooperates and is in communication with the receivingchannel26 to provide acontinuous channel30 for receiving the elongated member orrod24. Thelock28 cooperates with the receivingchannel26 and urgesrod24 toward thescrew head12band vertebra, such as one of the vertebra14-18 inFIG. 1, when thereceiver20 is rotated in a clockwise direction (as viewed inFIG. 3). Thecontinuous channel30 comprises afirst channel32, thechannel26, and thesecond channel34. Thelock28 andcontinuous channel30 provides a bayonet-type connection for coupling or fixing thereceiver20, therod24 and screw12 together in the manner described herein.
• Note that thelock28 comprises thefirst channel32 and a second channel34 (FIGS. 12 and 13) that extend or spiral, as illustrated inFIGS. 16A-16E, about the receiver axis A (FIG. 11) ofreceiver20. The first andsecond channels32 and34 generally spiral or revolve from thefirst end20aofreceiver20 toward thesecond end20b, as shown inFIGS. 10-13 and16A-16D. Thus, in the embodiment being described, the first andsecond channels32 and34 are non-linear and spiral or revolve in a general helix about the axis A of thereceiver20. In the illustration, thechannels32 and34 spiral or revolve in the same direction about the axis A, as shown inFIGS. 16A-16D. Note that thechannels32 and34 are in communication with both the receiver bore22 and receivingchannel26 ofreceiver20. During operation, the channels32 (FIG. 11) and34 (FIG. 12) receive therod24 after it has been received inchannel26 and urge or force therod24 toward thescrew head12band vertebra, such asvertebra14 inFIG. 1, when thereceiver20 is rotated in a clockwise direction in the illustration being described.
• As illustrated inFIGS. 11 and 16A, thefirst channel32 is defined by a first surface orwall20e, a generally opposing second surface or wall20g, and athird surface wall20fthat joins thewalls20eand20gin thereceiver20. A fourth surface orwall20h, a generally opposingfifth wall20i, and a sixth surface orwall20jthat joinswalls20hand20icooperate to define the second channel34 (FIGS. 12 and 16D). Note that thewalls20eand20gare generally parallel andwalls20hand20iare generally parallel. In the illustration being described, thewalls20eand20gand20hand20iare generally planar and have generally constant distance D4 (FIG. 13) and D5 (FIGS. 11 and 12) therebetween. However, in the illustration described later herein relative toFIGS. 18-32, the opposingwalls20e,20g,20hand20imay be non-planar so that the distance or dimensions D9 and D10 vary along the length of thechannels32 and34.
• Thechannels32 and34 generally lay in planes P1 and P2 that are at the angles C (FIG. 14) and D, respectively, relative to the axis A of thereceiver20. As described later herein, thewalls20eand20hengage and cam against therod24 and force or urge it downward (as viewed inFIGS. 10-15) in response to the rotary movement of thereceiver20. In another embodiment described later herein, thewalls20eand20gandwalls20hand20imay comprise a curved or arcuate area and may cooperate to define an intermediate rod capturing area, as described below relative toFIGS. 18-34.
• As illustrated inFIGS. 4 and 11, note that thechannel32 is defined by thewalls20e,20f,20gand generally curved orarcuate wall portion50 that couples wall20gto surface21b(FIGS. 4 and 16A) ofchannel26. The generally curvedarcuate wall portion50 also generally defines an intersection or transition from the receivingchannel26 to thefirst locking channel32 oflock28. Thechannel34 is defined by20h,20iand20jand a third generally curved orarcuate wall52 that joins thewall20itowalls21d(FIGS. 4 and 16C). Thewall52 provides an intersection or transition betweenchannel26 and thesecond locking channel34. Notice that thewall portions20f(FIG. 11) and20j(FIG. 12) also each have a radius of curvature that generally complements the radius of curvature or circumference of therod24 so that when therod24 is moved from the unlocked position (illustrated inFIGS. 4, 5,10 and11) to a locked position (illustrated inFIGS. 8, 9,12 and13), therod24 is received and positioned against thewall portions20fand20jas shown.
• Thesystem10 may further comprise a compression member40 (FIGS. 3 and 17). Thecompression member40 comprises awall40athat defines a second generally U-shaped receivingchannel42. Thecompression member40 also comprises a frusto-conical seat or concave area41 (FIGS. 10 and 17), defined by a tapered wall or surface40b, that engages the rounded shape of theend12b1 (FIG. 3) ofscrew head12b. Although not shown, thesystem10 could be provided without thecompression member40, so that therod24 would engage thescrew head12bdirectly, for example, when thereceiver20 is rotated as described later herein.
• Thecompression member40 comprises a length D6 (FIGS. 3 and 17) and a diameter D7 (FIG. 17) dimensioned to be received in thebore22 as shown. Thechannel42 defined bywall40acomprises abottom surface40c. Thechannel42 is generally U-shaped in cross section and has a width or dimension D8 (FIGS. 3, 7 and17) andsurface40ccomprises a radius of curvature R5 (FIG. 17) that generally complements or is slightly larger than the circumference D9 (FIG. 3) of therod24.
• During operation, thecompression member40 is urged downward (as shown inFIGS. 10-13) in response to the rotary movement of thereceiver20. Therod24 engages thebottom surface40c(FIGS. 12 and 17) ofchannel42 ofcompression member40. This in turn causes surface40bto engage and apply a compressive force against theend12b1 ofscrew head12bas therod24 is driven in the downward direction (as viewed inFIGS. 10-13) and into thesecond channel42. This movement forces and compresses theseat20dagainst theend12b2 ofscrew head12bof thereceiver20, thereby locking thescrew head12bto therod24 and fixing the relationship of thereceiver20 relative to thescrew head12b.
• Note that the compression member40 (FIG. 17) also comprises a bore oraperture43 defined bywall40d. Thebore43 has a dimension or diameter D10 (FIG. 17). A surgeon or physician may insert a tool, such as a hex head screwdriver (not shown), throughchannel26, through bore22 ofreceiver20 and through thebore43 and into the hexfemale opening12c(FIG. 15), for example, to tighten or loosen thescrew12. Thus, it should be understood, as illustrated inFIG. 15, that the hexfemale opening12cofscrew12bis accessible after thescrew12 is inserted through thebone22 andcompression member40 is situated in thebore22.
• Referring back toFIGS. 10-16E, the receiving channel26 (FIG. 11) ofreceiver20 extends from anend20aofreceiver20 in an axial direction and lies in a plane P3 (FIG. 15) that is generally planar and extends downward along the axis A (as viewed inFIG. 14). In contrast, thelock28 defined by the lockingchannels32 and34 revolve, spiral or extend laterally or radially at distances that are generally constant relative to axis A and that vary, such as increase, relative to end20aofreceiver20. As mentioned earlier, each of thechannels32 and34 spiral in a general helix downward from the receivingchannel26 and about the axis A of thereceiver20 as shown in FIGS.10-13 and16A-16D. Note that thechannels32 and34 lay in the planes P1 and P2 (FIG. 14), respectively, that intersect axis A at the predetermined angles indicated by double arrows C and D. The predetermined angles C and D are acute angles in the embodiment being described.
• As shown inFIGS. 16A and 16B, thechannel32 is inclined relative to a radial line ofreceiver20 at a third angle (indicated by double arrow E inFIG. 16A) relative to end20a.Channel34 is also inclined relative to a radial line at a fourth angle F (FIG. 16B). Although not shown, it is contemplated that other designs, configurations or arrangements ofchannels32 and34 and thelock28 may be provided, such as channels (not shown) that extend about axis A, but that do not spiral and/or that are not at the inclined angles E and F, such as channels that extend at distances that are generally constant relative to end20a.
• An operation or method regarding this illustration will now be described. As illustrated inFIGS. 3-9 and15, thescrew12, together withreceiver20 are screwed intovertebra14 during which a physician or surgeon screws the threadedportion12bofscrew12 in the aperture14aof thevertebra14 using a tool (not shown), such as a hex wrench or screwdriver (not shown), that is inserted throughchannel26, bore22 and bore43. In one embodiment, thereceiver20,screw12 andcompression member40 may be provided in a pre-assembled unit prior to surgery, so no assembly is required by the physician. Thescrew12 is screwed substantially all the way intovertebrae14, but is left with space between thereceiver20 andvertebrae14 so that an angular or polyaxial position of thereceiver20 may be adjusted or changed during the operation.
• Thechannel26 ofreceiver20 andchannel42 ofcompression member40 are provided or arranged in a common plane P3, as shown inFIGS. 4, 5 and15. The surgeon then places therod24 into thechannels26 and42 and adjusts the multi-axial or polyaxial position of thereceiver20 relative to therod24. As mentioned earlier, thechannel26 and bores22 (FIG. 10) and43 (FIG. 17) provide a continuous opening orarea49 through which the physician or surgeon may insert a tool, such as a hex tool, to turn, rotate and/or tighten or loosen thescrew12 in the desired direction prior to placing therod24 intochannel26. At this point, therod24 remains in an unlocked position.
• Note that therod24 is supported by and between the arcuate or roundedwall portions50 and52, which causes therod24 to be situated above thebottom surface40cof thechannel42 ofcompression member40, as illustrated inFIGS. 10 and 11. Note that the arcuate orcurved wall portions50 and52 each comprise a radius of curvatures R2 (FIGS. 11, 14 and16a) and R3 (FIGS. 13 and 14), respectively, that generally complements or is larger than a radius of curvature or circumference of therod24, as illustrated inFIGS. 11 and 13.
• The camming or bayonet type action of therotary lock28 onreceiver20 forces therod24 in an axial direction parallel with axis A ofreceiver20 when thereceiver20 is turned or rotated with a tool, such as a screwdriver (not shown), placed inchannel26, as illustrated inFIGS. 6 and 7. This rotary movement or action forces therod24 downward (as viewed inFIG. 10) and into thechannels32 and34. As thereceiver20 is rotated further, as shown inFIGS. 8 and 9, thewalls20eand20g(FIG. 11) ofchannel32 andwalls20hand20i(FIG. 12) ofchannel34 act upon, force or urge therod24 downward (as viewed inFIGS. 10-13) and into thesecond channel42 ofcompression member40 until it engages thesurface40cofcompression member40. As thereceiver20 is rotated further, therod24 urges thecompression member40 toward thescrew head12b1 and forces wall40bof thecompression member40 against thescrew head12bofscrew12 with a compressive force which causes thescrew head12bto become fastened or locked to therod24, thereby fixing thereceiver20 androd24 to thescrew12.
• It should be appreciated that when therod24 is in the locked position shown inFIGS. 8, 9,12 and13, therod24 engagessurfaces20e,20f, and20gofchannel32 and surfaces20h,20iand20jofchannel34 andsurface40cofsecond channel42. Theseat40dofcompression member40 engagesscrew head12b2. These surfaces cooperate to retainrod24 in the locked position. Thesurfaces20fand20jcomprise a radius of curvature R4 of about Φ.100-Φ.130 inch. A raised detent portion or bump59 (which is only shown inFIG. 13 for ease of illustration) may be provided in eachchannel32 and34, as shown inFIG. 13 relative to channel32. Thedetent59 is provided to facilitate retaining therod24 in the locked position.
• Thus, as illustrated inFIGS. 1, 2 and4-9, a surgeon may use one or a plurality ofspinal fixation assemblies10 during a spinal fixation procedure. For example, the surgeon may use aplurality receivers20 and screws12 with onerod24, as illustrated inFIGS. 1 and 2. In the illustration, the surgeon screws thescrews12 into a plurality of vertebrae, such asvertebrae14,16 and18 illustrated inFIG. 1, and generally aligns thechannels26 ofreceivers20. The surgeon then inserts the tool, such as a hex tool (not shown), throughbores22 and43 and intofemale slot12cinscrew head12 and screws thescrew12 until the bottom20bof thereceiver20 engages or is proximately located against its respective vertebra.
• If thecompression member40 is being used,compression member40 is located in each bore22 of eachreceiver20 and generally aligns thechannels42 and26, as illustrated inFIGS. 4, 10 and15. It should be understood that when thespinal fixation assembly10 is in the unlocked position, thechannels26 and42 are generally parallel or lie in the common plane P3 as shown inFIG. 15. Therod24 is then placed inchannel26, whereupon it becomes supported bywalls50 and52 (FIG. 4) and bywall portions50 and52 (FIGS. 4 and 11). This causesrod24 to be supported slightly above the bottom40cofchannel42 ofreceiver40, as mentioned earlier and as illustrated inFIGS. 10 and 11.
• At this point in the procedure, the surgeon aligns therod24 in thereceiver20 to the desired position relative to the spine, vertebrae andother receivers20 that are being used. He positions therod24 and polyaxial or angular position of each receiver(s)20 relative thereto. It should be understood that the screws and position of the vertebrae, such as vertebrae14-18, relative to each other may also be adjusted. Once the bones14-18 are adjusted and angular or polyaxial position of eachreceiver20 is adjusted, the surgeon locks eachreceiver20 torod24 by rotating or turning thereceiver20 with a tool, such as a screwdriver (not shown), placed inslot26. This causes thereceivers20 to become fixed or locked onto theirrespective screws12 and the spinal bones14-18 (FIG. 1) to become aligned and fixed into the desired position.
• It should be understood that before therod24 is placed in the receivingchannel26 and thereceiver20 is rotated, the surgeon may tighten one ormore screws12 to a tighter or fixed seated position by situating the tool, such as a hex wrench (not shown), through the aperture43 (FIG. 15) defined by thewall40dof thecompression member40 and into the hexagonalfemale slot12cin thescrew head12b. After thescrew12 is tightened to the desired tightness or torque, the surgeon places therod24 into thechannels26 and42 (FIGS. 4, 5,10 and11) of the one or more of thereceivers20 being used.
• As mentioned, the surgeon rotates thereceiver20 about its axis, as illustrated inFIGS. 3, 6 and7 using a tool, such as a screwdriver (not shown), in the clockwise direction, as illustrated inFIGS. 6 and 7. During this rotation ofreceiver20, thecompression member40 androd24 do not rotate. As alluded to earlier,walls20eand20g(FIG. 11) andwalls20hand20i(FIG. 12) urge therod24 toward the bottom ofchannels32 and34 and urge therod24 to move downward (as viewed inFIGS. 10 and 12) toward thesurface40cor bottom of thechannel42 where it engages thesurface40c, as illustrated inFIGS. 4-9 and10-13. Therod24 is also supported by and compresses against thesurface40cofcompression member40. Theseat40dis caused to engage thescrew head12b2.
• Thus, when it is desired to lock thereceiver20 and thescrew12 to therod24, the surgeon rotates thereceiver20 in the clockwise direction, as illustrated inFIGS. 6 and 7, using the conventional tool, such as a regular screwdriver. Thereceiver20 is rotated until it is moved from the unlocked to the locked position, as illustrated inFIGS. 8, 9,12 and13. Note that in the locked position, therod24 is received and engages thewalls20fand20jassociated with the ends ofchannels32 and34, respectively.
• Thus, it should be understood that whenreceiver20 is rotated, thewalls20eand20hprovide the camming force necessary to cam and urge therod24 against thereceiver40. This, in turn, causes the surface or wall40bofreceiver40 to compress and lock against theend portion12b2 (FIG. 3) ofscrew head12b. The wall40bofcompression member40 cooperates with the curved seat defined bywall20d(FIG. 10) and traps or locks thescrew head12bto therod24.
• As illustrated inFIGS. 8, 9,12 and13, notice that thechannel26 lies in an imaginary plane that is generally perpendicular to the imaginary plane in which thechannel42 and an axis ofrod24 when thereceiver20 is in the locked position.
• It should be appreciated from the foregoing that the receivingchannel26 is in communication with thechannels32 and34 oflock28 and that thelock28 cooperates with therod24 to not only lock therod24 to thescrew12, but also to fix a position of thevertebrae14,16 and18.
• When it is desired to unlock therod24 from thescrew12, the surgeon simply rotates thereceiver20 in a counterclockwise direction in the illustration and reverses the procedure.
• Referring now toFIGS. 18-34, another illustrative embodiment is shown. Those parts that are the same as the parts relative toFIGS. 1-17 have been labeled with the same part number, except that the part numbers in the embodiment described inFIGS. 18-34 have a prime mark (“′”) associated therewith. TheFIGS. 31-34 are diagrammatic enlarged sectional views for ease of illustration.
• Note in the embodiment inFIGS. 18-34, thereceiver20′ compriseschannels32′ and34′ that each have a cross-sectional dimension that varies over the length of thechannels32′ and34′ to provide anintermediate holding area60 where therod24′ is loosely captured in thechannels32′ and34′. Thechannels32′ and34′ each have an introducingarea60a, an intermediate holding or receivingarea60band a lockingarea60c. For ease of illustration and description, the receivingarea60bwill be described relative to channel32′; however, it should be understood that thechannel34′ in the second illustration comprises substantially the same configuration.
• It should be appreciated that theintermediate area60bin thechannels32′ and34′ enable an intermediate step betweeninitial rod24′ insertion andfinal rod24′ locking. In other words, this is arod24′ capturing step during which therod24′ is loosely captured in thereceiver20′, but it is not rigidly locked into place againstscrew12′ yet. This allows the surgeon greater ease and flexibility when he adjusts thescrews12′ position with respect to therod24′ while therod24′ is in place. For example, the surgeon may move thescrews12′ closer together (compression) or In the illustration being described, the intermediate capturing step is accomplished by rotating thereceiver20′ partially, such as approximately 30 degrees in the illustration as shown inFIGS. 23, 26 and29, which forces therod24′ from the introducingarea60ainto theintermediate area60b.
• The introduction area comprises an associated dimension D13 (FIG. 34) and the lockingarea60chas an associated dimension D14 (FIG. 34). Theintermediate area60bhas an associated intermediate dimension D15 (FIG. 34) between thewall62 andwall64 that is slightly larger than the diameter of therod24′ and the dimensions D13 and D14 associated with theintroduction area60aand lockingarea60c, respectively. It is dimensioned to accommodate therod24′ and to capture therod24′ loosely so that therod24′ can easily slide between thewalls62 and64 and is not locked. This facilitates the surgeon adjusting a position of thescrews12′ in vertebrae, such asvertebrae14′-18′, relative to a position of therod24. Once thescrews12′ are adjusted to the desired position, the physician or surgeon may then lock thereceiver20′ onto thescrew12′ by inserting a tool, such as a screwdriver (not shown), into theslot26′ and rotate thereceiver20′ in the clockwise direction as illustrated inFIGS. 22-30.
• In the illustration shown inFIGS. 31-34, thechannel32′ is defined by awall62, a generally opposingsecond wall64 and a joiningwall63 that joinswalls62 and64 as shown. Note that unlike the embodiment described relative toFIGS. 1-17, thechannel wall62 has a first wall portion62a, asecond wall portion62band anintermediate wall portion62cthat couples thewall portions62aand62bas shown. The opposingchannel wall64 comprises the first wall portion64a, asecond wall portion64band anintermediate wall portion64cthat couples the first andsecond wall portions64aand64bas shown. In this regard, note that anintersection66 is defined between thewall portions64aand64c. Asecond intersection68 is defined between thewall portion62band62cas shown. Theintersections66 and68 generally define an entrance to theintermediate area60. Theintermediate wall portions62cand64ccooperate to define theintermediate area60bwhich receives therod24′ and loosely captures therod24′ in thereceiver20′.
• Thechannels32′ and34′ are configured such that they comprise or define theintroduction area60afor receiving therod24′ in thereceiver20′, as illustrated inFIGS. 22, 25 and28. The first wall portion64aprovides a ramp64a1 for directing therod24′ into theintermediate area60bwhen thereceiver20′ is rotated about 20-40 degrees as shown inFIGS. 23, 26 and29. As shown in the illustration, thesurfaces62 and64 are not generally planar and have areas, such asintermediate wall portions62cand64cthat are curved or recessed to facilitate defining theintermediate area60b.
• During a surgical procedure, the surgeon may make the desired adjustments of therod24′ relative to thescrews12′ andvertebrae14′-18′ while therod24′ is loosely captured in theintermediate area60b. The surgeon then uses the tool, such as a screwdriver (not shown), to rotate thereceiver20′ to the locked position shown inFIGS. 24, 27 and29. Similar to the embodiment described earlier herein relative toFIGS. 1-17, thereceiver20′ urges or forces therod24′ from theintermediate area60bto the lockingarea60c. Therod24′ becomes situated in the lockingarea60c, whereupon therod24′ becomes locked therein. Note that the distance or dimension D12 (FIG. 8) between thesecond wall portions64band62bis substantially the same or may be smaller than the diameter of therod24′. As thereceiver20′ is rotated in the clockwise direction in the illustration being described, thewall62 slightly deflects upward (as viewed inFIG. 31, for example) to permit therod24 to be captured and locked in the lockingarea60c. Note that awall portions62,63 and64 comprises various radii of curvature R5-R9 having the illustrative dimensions or ranges of dimensions set forth in the Table I below. For example, the radius of curvature R8 generally corresponds to the cross sectional circumference of therod24′ so that therod24′ becomes captured in the lockingarea60c. As in the prior illustration, the detent59 (FIG. 33) may be provided inchannels60 and62 to further facilitate retaining therod24′ in the lockingarea60c.
• Advantageously, this system and method facilitates providing a lockingreceiver20 that reduces or eliminates the need for threading, internally or externally.
• Advantageously, theimmediate areas60bofchannels32′ and34′ of the second embodiment are dimensioned and configured to facilitate locking therod24′ onto thescrews12′ while permitting ease of adjustment between thereceiver20′ and therod24′ when therod24′ andreceiver20′ are situated in theintermediate area60b′, as illustrated inFIGS. 23, 26 and29.
• In the embodiments being described, therod24,screw12,receiver20 andcompression member40 are all made of titanium alloy. Other materials may be used such as metals, metal alloys, carbon fibers, composites, plastics or hybrid materials.
• For example, thescrew12 may have a length D11 (FIG. 3) ranging from 10 mm-60 mm, and thereceiver20 may have a diameter D12 (FIG. 8) ranging between 2 mm-10 mm. Thecompression member40 may define thechannel42 having the width D8 ranging between 2 mm-12 mm. Thechannels32 and34 may comprise dimensions D5, D6 (FIGS. 3 and 17) ranging between 2 mm-10 mm. It should be understood, however, the other shapes and dimensions may be used without departing from the true spirit and scope of the invention.
• Referring now toFIGS. 35-59, another illustrative embodiment is shown. As with prior embodiments, those parts that are the same or similar to the parts shown and described relative toFIGS. 1-34 have been labeled with the same part number, except that the part numbers described inFIGS. 35-59 have a double prime number (“″”). As with the prior embodiments, theFIGS. 35-59 are diagrammatic in large sectional views for ease of illustration.
• In the embodiment being described, an assembly orsystem100″ is shown. As illustrated inFIGS. 58 and 59, theassembly100″ may be used alone or in combination withother assemblies100″, with one or more of theassemblies10 of the embodiments described earlier herein, or with other spinal fixation devices or assemblies (not shown). As with prior embodiments, the function of the assembly is to fix or secure one or more bones, such as thevertebrae14″,16″ and18″ in the spinal column illustrated inFIG. 58, in a fixed and stabilized position relative to each other. As with the prior embodiments, it should be understood that the embodiment could be used in any environment where it is desired to fix and stabilize one or more bones or bone segments together.
• In the embodiment illustrated inFIGS. 35-59, note that thereceiver20″ is substantially the same as in the prior embodiments shown and described relative toFIGS. 1-34. Also, it should be understood as with the embodiments illustrated inFIGS. 1-16E, the embodiment could comprise a substantially straight orplanar channel32 and34, alternatively, it could comprise the stepped ormultidimensional channels32′ and34′ (FIGS. 17-34) inreceiver20′. Thechannels32′ and34′ have a cross-sectional dimension that varies over the length of thechannels32′ and34′ to provide theintermediate holding area60′ where the elongated member orrod24′ is loosely captured in thechannels32′ and34′. As mentioned earlier, thechannels32′ and34′ each have the introducingarea60a′, the intermediate holding or receivingarea60b′ and the lockingarea60c′. Thechannels32′ and34′ of the embodiment illustrated inFIGS. 18-34 receive therod24′ and facilitate positioning of therod24′ to the spinal bones, such asbones14′,16′ and18′, prior to thereceiver20′ being rotated to the locked position as being described herein.Channel32″ and34″ may have configurations that are the same or similar to thechannel32,32′,34, and34′.
• Referring now toFIGS. 35A and 35B, thesystem100″ comprises a stabilizer, intermediate member, second receiver, guide or sleeve, which shall be referred to as guide orsleeve104″ for ease of description, rather than acompression member40″ of the type shown inFIGS. 1-34. The guide orsleeve104″ is received in thebore22″ ofreceiver20″ and is adapted to receive therod24″, which may be cylindrical and elongated as illustrated. In the embodiment illustrated inFIGS. 35A-59, it should be understood that thesleeve104″ is adapted and dimensioned to be received in the aperture or bore22″ defined by thereceiver wall20c″. Theguide104″ is a guide or sleeve that is slidable and rotatable in thebore22″.
• Theguide104″ comprises or defines abore110″ (FIGS. 35A and 35E) in communication with achannel121″ that receives therod24″ and facilitates aligning therod24″ in thereceiver20″. In this regard, thesleeve104″ guides therod24″ into the receiving channel orslot26″ of thereceiver20″. After thereceiver20″ is rotated as described herein, therod24″ is cammed, urged or moved toward ahead102a″ of apolyaxial screw102″ when thereceiver20″ is rotated to the locked position illustrated inFIGS. 45 and 46. Unlike the embodiment ofFIG. 1, note that thescrew102″ has a ball or head102a″ that has a full radius. The full radius and bore110″ are adapted or dimensioned such that at least a part of thehead102a″ extends into thebore110″. The operation and use of theassembly100″ will be described in more detail later herein.
• It should be understood that in this illustrative embodiment, the guide orsleeve104″ does not function as a compression member like thecompression member40 and40′ described earlier herein. Thus, one feature of this embodiment is that therod24″ engages and compresses directly against at least a portion of thehead102a″ after thereceiver20″ is rotated to the locked position as described herein.
• The sleeve or guide104″ comprises afirst wall portion112″ and a generally opposedsecond wall portion114″ that are curved about an axis B (FIG. 35B) of theguide104″ (FIG. 35B). The guide orsleeve104″ comprises generally cylindrical joiningportions117″ and119″ that join the first andsecond wall portions112″ and114″ as illustrated inFIG. 35A. Thewall portions112″ and114″ cooperate with the joiningportions117″ and119″ to define thechannel121″. A pair ofedges112a″ and114a″ (FIG. 35C) cooperate with joiningportion119″ to define a first channel opening111″ to channel121″. A second pair of edges112b″ and114b″ cooperate with joiningportion117″ to define a second channel opening113″ to theopening121″ for receiving therod24″.
• The guide orsleeve104″ comprises thebore110″ having an inner diameter D16 (FIG. 35D). As illustrated inFIG. 35D, thewall portions112″ and114″ haveinner surfaces112c″ and114c″, respectively, that lie in a generally cylindrical or curved plane and have a diameter D17 (FIG. 35D) that generally corresponds to a diameter ofbore110″. In the illustration being described, thechannel121″ has a channel width D18 (FIG. 35E) that generally corresponds to the diameter of thebore110″. Unlike the embodiment illustrated inFIG. 17 described earlier herein, notice that thebore110″ is in fluid communication with thechannel121″ and has the dimension D16 that generally corresponds to dimension D18. Thus, in the illustration being described, thebore110″ has the dimension B16 (FIG. 35D) that is generally constant along its length and the diameter of thebore110″ generally corresponds or is smaller than the distance betweenwalls112″ and114″. In contrast, in the embodiment ofFIGS. 1-34, thecompression member40″ comprises the wall40b″ that is curved or tapered inwardly and the dimension D10 is smaller than the dimension D8.
• Notice that thefirst wall portion112″ comprises a first end112d″ having a chamfer surface and thesecond wall portion114″ comprises a second end114d″ having a chamfer surface as shown. The chamfer ends112d″ and114d″ facilitate guiding therod24″ into the receivingarea22″ andchannel121″ as described herein.
• A second end104b″ (FIG. 35D) of thereceiver104″ comprises asurface105″ in thewall portions112″ and114″ and the joiningportions117″ and119″ that define a generally continuous frusto-conical surface in cross-section that extends around thebore110″, as shown inFIGS. 35A and 35E. Alternatively,surface105″ could comprise a curved, semispherical or spherical shape in cross-section or otherwise be shaped to complement a shape of thescrew head102a″.
• Thefirst wall portion112″ and generally opposedsecond wall portion114″ have outer surfaces112d″ and114d″ that lie in a cylindrical or circumferential plane that is generally cylindrical and adapted and dimensioned to be slidably and rotatably received in thebore22″ defined by thewall22c″ of thereceiver20″, as illustrated inFIGS. 37-57.
• Notice that edges112a″,112b″ and114a″,114b″ of thewall portions112″ and114″, respectively, and surfaces117a″ (FIG. 35A) and119a″ (FIG. 35B) of the joiningportions117″ and119″, respectively, cooperate with thesurface112c″ of firstcurved wall portion112″ and thesurface114c″ of the secondcurved wall portion114″, respectively, to define thechannel121″ (FIGS. 35C-35E). The guide orsleeve channel121″ receives therod24″ as described herein. Thesurfaces112c″ and114c″ could be curved as illustrated inFIGS. 35A-35C or they could be straight or generally planar, as illustrated inFIGS. 35D and 35E.
• As illustrated inFIGS. 35D-35E, the joiningportions117″ and119″ each have a dimension D17. The dimension D17 and the dimension D16 (FIG. 35D) ofbore110″ and shape or radius ofhead102a″ are adapted and dimensioned so that at least a portion of thepolyaxial screw head102a″ protrudes or extends at least partly into thebore110″ and intochannel121″ above a plane P5 (FIG. 35E) defined by surfaces117a″ (FIG. 35C) and119a″ (FIG. 35D). As will be described later herein, this permits or enables therod24″ to directly engage and compress against at least a portion, such as a portion orarea120″ (FIG. 36A), of thehead102a″, so that therod24″ can become locked directly against thehead102a″ when thereceiver20″ is rotated as described herein.
• Notice inFIGS. 35A-35B and36A and36B that thehead102a″ has the first engaging surface orcontact area120″, which in the illustration being described is generally centrally located along an axis SA (FIGS. 35A and 36A) of a threaded portion102b″ (FIG. 35A) of thescrew102″.
• The overall shape or configuration of anouter surface102a1″ (FIG. 36A-36B) of thehead102″ is generally curved, arcuate or spherical. Notice inFIG. 36B that thehead102″ comprises a plurality of recessedareas122″,124″,126″ and128″ that are separated by or define a plurality of curved portions orwalls130″,132″,134″ and136″ as shown. Notice that thecurved walls130″,132″,134″ and136″ are joined by a generally cylindrical post orportion138″ that cooperate to define amale member129″ that extends upwardly (as viewed inFIG. 35A) from a plane P4 (FIG. 35B) defined by thesurfaces140″,142″,144″ and146″ (FIG. 36B).
• In the illustration being described, the engaging surface orportion120″ has asurface120a″ that is curved in the illustration being described. Thewalls130″,132″,134″, and136″ each have surfaces orportions150″,152″,154″ and156″, respectively, that are also curved in the illustration being described.
• It should be understood that thehead102a″ may comprise any suitable configuration or surface shape as may be necessary to permit the at least aportion120″ of thehead102a″ to engage or be engaged by therod24″. Although not shown, if therod24″ had a non-curved surface, then it may be desirable to provide a head (not shown) having a shape that is adapted to directly complement and engage the non-curved surface. For example, if therod24″ were hexagonal, octagonal, square or rectangular in cross section, then thehead102a″ may have a mating or engaging portion to facilitate directly engaging therod24″ when thereceiver20″ is moved or rotated to the locked position. Moreover, a radius of curvature of each of thesurfaces120a″,150″,152″,154″ and156″ may be generally constant, may vary over its surface, or may be non-constant if desired. Also, the curvatures or shapes of the surfaces may be larger or smaller if desired, and they may be different among them.
• Thesurface105″ may be straight or it may comprise a curvature, arcuate or spherical shape in order to adapt to and complement the curvature or shape of thehead102a″ and/orsurfaces150″,152″,154″ or156″ as shown.
• As illustrated inFIGS. 43 and 44, notice that therod24″ is received in the receiving area orchannel22″ in thearea110″ andchannel121″ (FIG. 43). Therod24″ becomes positioned in thereceiver20″ and against the generally curved orarcuate wall portions50″ and52″ ofreceiver20″ as shown. After thereceiver20″ is rotated from the unlocked position, illustrated inFIGS. 43 and 44, to a locked position, illustrated inFIGS. 45 and 46, therod24″ becomes cammed or urged downward (as viewed in the Figures) until at least a portion of therod24″ engages at least a portion of thehead102a″, such as one or more of thesurfaces120a″,150″,152″,154″, or156″ as shown. For example, notice inFIGS. 45 and 46 that therod24″ engages thesurface120a″. Note that thereceiver20″ cams, urges or forces therod24″ downward (as viewed in theFIGS. 45 and 46) until therod24″ engages thesurface120a″ and thereby locks therod24″ to thehead102″ after thereceiver20″ is rotated to the locked position shown inFIGS. 45 and 46.
• As mentioned earlier, the arcuate orcurved wall portions112c″ and114c″ cooperate with the joiningportions117″ and119″ to define the aperture or bore110″. As mentioned earlier herein, note that the dimension D16 generally corresponds to or is generally the same as the dimension D18 (FIG. 35E) between thesurfaces112c″ and114c″ ofwalls112″ and114″, respectively, but it could be smaller or larger so that it is adapted and dimensioned to permit at least a portion of thehead102a″ to be engages by therod24″.
• The dimensions D16 (FIG. 35D), and D18 (FIG. 35E) and the guide orsleeve member104″ are selected, adapted and configured to permit at least a portion, such as the engagingportion120a″ and/or all of or at least a portion of one or more of the surfaces of150″,152″,154″ and156″ to extend through the aperture or bore110″ and intochannel121″ and above the plane P5 (FIG. 35D). Thus, the adaptation or configuration of the guide orsleeve112″, bore110″ andchannel112″ permits at least a portion of thehead102a″ to protrude or extend into thechannel121″ so that it may engage or be engaged byrod24″ when thereceiver20″ is rotated to the locked position illustrated inFIGS. 45 and 46.
• Unlike prior embodiments described herein, notice that nocompression member40 is necessary in this embodiment, and although not shown, the guide orsleeve104″ is also optional in this embodiment. In the illustration being described, the guide orsleeve104″ comes into direct contact with thehead102a″ of thescrew102″ when thereceiver20″ is rotated to the locked position, but thesleeve104″ itself does not compress against thehead102a″ to lock therod24″ to thehead102a″ as does thecompression member40″ in the embodiments illustrated inFIGS. 1-34, for example.
• It should be understood that the embodiment being described relative toFIGS. 35A-59, may be used with areceiver20 havingchannels32 and34 of the type shown inFIGS. 1-16E. Alternatively, the embodiment may be used with areceiver20′ having thechannels32″ and34″ having the steps or channel areas that are of the type shown inFIGS. 18-34, namelychannels32″ and34″ that each have a cross-sectional dimension that varies over the length of thechannels32″ and34″. As mentioned earlier, such shape facilitates providing theintermediate holding area60″ where therod24″ is loosely captured in thechannels32″ and34″. The use of and installation of thesystem100″ is similar to the use and installation of the embodiments earlier relative toFIGS. 1-34, which will now be described.
• As with the prior embodiment and as illustrated inFIGS. 1 and 2, one or more of the assemblies orsystems100 may be used during a surgical procedure as shown inFIGS. 58 and 59. For example, the surgeon may use a plurality ofreceivers20″ and screws102″ with arod24″ similar to the illustration shown inFIGS. 1 and 2. In the illustration being described relative to the embodiment ofFIGS. 35A-59, the surgeon positions thescrew102″ intobore110″ and screws thescrews102″ for eachassembly100″ into each of the plurality of vertebrae, respectfully, such asvertebrae14″,16″ and18″ illustrated inFIG. 58. He then situates the guide orsleeve104″ intobore22″ and generally aligns thechannel121″ of the sleeve or guide104″ with the receivingchannel26″ of thereceiver20″ as illustrated inFIGS. 37, 38,43,44,49 and55. The surgeon then inserts atool125″ (FIG. 36I) that is capable of rotatably driving thescrew102″ into bone or into thebore110″ and drives screw102″ until the bottom20b″ of thereceiver20″ engages or is approximately located adjacent to or against its respective vertebrae.
• Note that theguide sleeve104″ is located in thebore22″ of thereceiver20″ and provides a guide for therod24″ to become aligned and positioned inreceiver20″, as illustrated in FIGS.37,43-46,49-51 and55-57. Thewalls112″ and114″ of the guide orsleeve104″ perform lateral stabilization and alignment of therod24″. It should be understood that when theassembly100″ is in the unlocked position (as illustrated, for example, inFIGS. 37, 38,43,44,49 and55), thechannels121″ and26″ become generally parallel and lie in a common plane P6 (FIG. 38). After therod24″ is placed in thechannels26″ and121″, it is supported by thewalls50″ and52″ ofreceiver20 and betweenwalls112″ and114″, as best illustrated inFIGS. 43 and 44. This causes therod24″ to be supported slightly above the surfaces117a″ (FIG. 35C) and119a″ (FIG. 35D). As mentioned earlier, the shape and configuration ofscrew head102aand the dimension ofbore110″ allows for the screw ball or head102a″ to protrude through thebore110″. Thelower portion102c″ has been further truncated or indented to allow for maximal exposure of the screw-ball.
• As mentioned earlier herein, thereceiver20″ may have generallystraight channels32″ and34″ of the type illustrated inFIGS. 18-32 or channels of varying dimensions of the type illustrated inFIGS. 49-57, in which case therod24″ would be positioned in thereceiver20′ as illustrated inFIGS. 49 and 55. For ease of discussion, it will be assumed thatreceiver20″ comprises thechannels32″ and34″ of the type illustrated inFIGS. 37-42.
• After the screw(s)102″ are screwed into the bone a desired distance and the guide orsleeve104″ is inserted into thereceiver20″, the surgeon aligns therod102″ in thereceiver20″ to the desired position relative to the spine, vertebrae or bone and also relative to one or moreother receivers20″, if any, that are being used during the procedure. It should be understood that thescrews102″ and the position of thevertebrae14″-18″, relative to each other may be adjusted by the surgeon. Once thebones14″-18″ are adjusted and the angular or polyaxial position of thereceiver20″ is adjusted, therod102″ is adjusted within thereceiver20″ and in theguide sleeve104″. The surgeon or technician may then lock thereceiver20″ to therod24″ by rotating or turning thereceiver20″ with the tool, such as a flat-head screw driver (not shown), placed in theslot26″. This causes therod24″ to directly engage at least a portion of thescrew head102a″, such as surfaces orportions120a″,150″,152″,154″ or156″, thereby causing therod24″ to become locked or fixed onto thescrew102″. This causes thereceiver20″ to become affixed to its respective bone, such as spinal bones14-18 (FIG. 1).
• As illustrated inFIGS. 37-42 and49-57, notice that as thereceiver20″ is rotated, therod24″ is cammed, forced or urged downward (as viewed inFIGS. 43-46) and in a direction parallel to the axis SA (FIG. 43) until therod24″ comes into direct engagement with the at least a portion of thehead102a″. In the illustration being described, notice inFIGS. 45 and 46 that therod24″ comes into direct contact and engagement with the portion in120″ of thehead102a″.
• FIGS. 39 and 40 illustrate therod24″ situated in thereceiver20″ after it is rotated between unlocked and locked positions.FIGS. 50 and 56 also illustrate an intermediate position after thereceiver20″ has been rotated slightly and therod24″ is captured in thechannels32″ and34″ and upon rotation ofreceiver20″, being urged downward toward thehead102a″ of thescrew102″. Finally, theFIGS. 41, 42,45 and46 illustrate theassembly100″ after thereceiver20″ has been rotated clockwise in the illustration, showing therod24 directly engaging at least portion, such asportion120a″, of thehead102a″ of thescrew102″. As best illustrated inFIGS. 37-42, after thereceiver20″ is rotated from the unlocked position (shown inFIGS. 37, 38,43 and44) to the locked position (shown inFIGS. 41, 42,45 and46), therod24″ engages, compresses and becomes locked against at least a portion, such asportion120a″, of thehead102a″ of thescrew102″.
• If thereceiver20″ comprises thechannels32″ and34″ having the configurations of the type illustrated inFIGS. 18-34, then the operation is similar. In this regard, thescrew102″ is received in thebore110″ and the guide orsleeve104″ is situated in thebore110″ after which thescrew102 is driven by a tool, such astool125″ inFIG. 36I, into bone, such asvertebrae14″. In other words, as with the embodiment described earlier herein relative toFIGS. 18-34, therod24″ is loosely captured in thechannel32″ and34″ as illustrated. InFIGS. 49 and 55 recall that thechannels32″ and34″ each have the introducingarea60a″, theintermediate holding area60b″ and the lockingarea60c″. As illustrated inFIGS. 49, 52 and55, theguide sleeve104″ andreceiver20″ are aligned such that theirrespective channels121″ and26″, respectively, become generally aligned so that therod24″ may be inserted therein. As illustrated inFIGS. 50, 53 and56, as thereceiver20″ is rotated about its axis RA (FIG. 56), therod24″ becomes captured in the intermediate holding or receivingarea60b″ as illustrated inFIGS. 50 and 56. Theintermediate holding area60b″ in thechannels32′ and34′ enable the intermediate step between theinitial rod24″ insertion andfinal rod102″ locking.
• As with the embodiment described earlier herein, relative toFIGS. 18-34, therod24″ capturing step during which therod24″ is loosely captured in thereceiver20″, but is not yet rigidly locked in place against at least aportion120a″ ofscrew head102a″. This allows the surgeon greater ease and flexibility when he adjusts the relative position of the rod relative to thescrew head102a″. For example, and as mentioned earlier herein, the surgeon may cause or move thescrews102″ closer together (compression) or further apart and then rotate thereceiver20″ using the tool, such as a screwdriver placed in theslot26″, to lock therod24″ in direct engagement with thescrew head102a″.
• Notice inFIGS. 51, 54 and57, thereceiver20″ has been rotated to the locked position, thereby locking therod24″ directly to at least a portion, such asportion120a″, of thescrew head102″.
• It should be understood, however, that as with prior embodiments, thereceiver20″ may be situated such that its axis RA is not coaxial with the screw axis SA (FIG. 43) ofscrew102″. The relative position of thereceiver20″ and thehead102″ enables the polyaxial position of thereceiver20″ and the corresponding position of therod24″ relative to thehead102a″ to be adjusted by the surgeon during use. For example, notice thereceiver20″ may be tilted or pivoted as shown inFIGS. 47 and 48, after therod24″ is positioned in the desired position, thereceiver24″ is rotated from, for example, the unlocked position and intermediate positions, illustrated inFIGS. 49 and 50, to the locked position illustrated inFIGS. 51 and 57, whereupon therod24″ engages and compresses against at least a portion of thehead102a″ as described herein. Notice that after thereceiver20″ has been moved or rotated to the locked position, therod24″ engages, compresses and becomes locked against the at least a portion of thescrew head102a″, such as portions orsurfaces120a″,150″,152″,154″ and156″ (FIG. 36A). Thereceiver20″ remains in the tilted position relative to thehead102a″.
• Advantageously, thescrew head102a″ is configured and adapted to have a desired shape, such as a curved, arcuate or spherical shape or other desired shape, so that thereceiver20″ can be positioned in a desired polyaxial position, even if its axis RA (FIG. 56) is not coaxial with the axis SA (FIG. 43) of thescrew102″. This permits the polyaxial position of therod24″ relative to thescrew head102a″ to be changed. In this regard, note inFIGS. 35A, 35B,45 and46 that thescrew102″ has a truncated orindented area102c″ to permit or allow for maximal exposure of the screw ball or head102a″, which in turn facilitates a wide range of polyaxial movement
• It should be appreciated that therecesses122″,124″,126″ and128″ (FIG. 36B) could also comprise more or fewer recesses or apertures and could comprise other configurations or shapes.FIGS. 36C-36D,36E-36F and36G-36H illustrate other representative or illustrative configurations of thehead102a″ of thescrew102″ that also permit polyaxial movement and locking of thereceiver20″ to therod24″. Notice, for example, ascrew170″ (FIG. 36C) has ahead172 having a shape or surface that is also curved, arcuate or spherical. However, the recessedareas174″ and176″ provide at least one or a plurality of female openings that receiveelongated engagement members180″,182″ of atool184″ (FIG. 36J) used to rotate thescrew102″.
• FIGS. 36E and 36F Illustrate ascrew head188″ having asquare aperture189″ in the curved orspherical head188a″ (FIG. 36E) for receiving atool178″ (FIG. 36K) having a squarehollow tip178a″. Similarly, ascrew head190″ (FIGS. 36G and 36H) having ahexagonal aperture192″ for receiving a hollow malehexagonal tip194″ (FIG. 36L) of atool196″ (FIG. 36L) for rotating thehead190a″ and thescrew190″. Notice that theheads188″ and190″ in the embodiments illustrated inFIGS. 36E-36H each have surfaces188a1″ and190a1″, respectively, that are arcuate, curved or spherical and also provide a plurality of areas, portions, surfaces or surface area contact points against which therod24″ may be compressed or engaged after thereceiver20″ has been rotated to the locked position mentioned herein.
• Advantageously, this system and method provides apparatus, method and means for providing a capless and polyaxial positionable andmoveable receiver20″ which reduces or eliminates the need for a compression member, such as thecompression member40″ of the type described earlier herein relative to the embodiments shown inFIGS. 1-34. In this embodiment, theguide sleeve104″ provides means for receiving therod24″ and guiding it into thereceiver20″ and also for guiding therod24″ toward thehead102″ as thereceiver20″ is moved or rotated from the unlocked or intermediate positions shown, for example,43 and44 to the locked position45 and46, respectively. Thus, in the illustration being described, therod24″ directly engages thehead102a″ and becomes locked there against.
• Advantageously, this system and method provide a capless multiaxial screw which eliminates the need for caps or screws or threads of the type used in the prior art. This system and method combine a very simplified yet effective means for locking an elongated member or rod to a screw and bones, such as spinal bones or other human bones, in the manner described and shown herein.
• While the apparatus, system and method herein described, and the form of apparatus for carrying this method into effect, constitute several illustrative embodiments of this invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the inventions, which is defined in the appended claims.

Claims (123)

1. A capless multiaxial screw system comprising:

a receiver comprising a receiver end comprising a receiver bore for receiving a threaded portion of a screw having a screw head; and

a sleeve having a sleeve end for situating against at least a portion of said screw head after said threaded portion is received in said receiver bore, said sleeve having a sleeve bore associated with said sleeve end;

said receiver having a channel for receiving an elongated member;

said sleeve being adapted to permit said elongated member to engage said at least of portion of said screw head when said elongated member is received in said channel and said receiver is rotated to a locked position.

2. The capless multiaxial screw system as recited inclaim 1 wherein said sleeve end comprises an outer end surface that is tapered or concave, said outer end surface engaging said at least a portion of said screw head.

3. The capless multiaxial screw system as recited inclaim 1 wherein said sleeve end comprises an inner end surface, said at least a portion of said screw head extending through said sleeve bore beyond said inner end surface when said receiver is in said locked position.

4. The capless multiaxial screw system as recited inclaim 1 wherein said receiver comprises a plurality of channels for receiving said elongated member.

5. The capless multiaxial screw system as recited inclaim 4 wherein each of said plurality of channels defines an intermediate area for capturing said elongated member to facilitate adjusting a position of said elongated member before it is locked in said receiver.

6. The capless multiaxial screw system as recited inclaim 5 wherein said plurality of channels are defined by a first surface and a second surface, each of said plurality of channels having an intermediate step for defining said intermediate area.

7. The capless multiaxial screw system as recited inclaim 6 wherein at least one of said first or second surfaces is not planar.

8. The capless multiaxial screw system as recited inclaim 1 wherein said channel is a helical channel defined by at least one surface of said receiver.

9. The capless multiaxial screw system as recited inclaim 1 wherein said sleeve end comprises a generally concave or semispherical seat, at least a second portion of said screw head having a curvature that generally complements said generally concave or semispherical seat.

10. The capless multiaxial screw system as recited inclaim 1 wherein said channel comprises a receiving area that is generally parallel to an axis of said receiver and comprises a locking area that spirals about said axis of said receiver when moving in an axial direction.

11. The capless multiaxial screw system as recited inclaim 10 wherein said locking area extends in a direction that is generally not parallel to said axis of said receiver.

12. The capless multiaxial screw system as recited inclaim 1 wherein said receiver comprises at least one camming surface that cooperates with an opposing surface for defining said channel, said at least one camming surface facilitates compressing said elongated member directly against said at least a portion of said screw head.

13. The capless multiaxial screw system as recited inclaim 1 wherein said receiver comprises a plurality of camming surfaces that cooperate with a plurality of opposing surfaces, respectively, to define said channel, said plurality of camming surfaces for camming against said elongated member and forcing it into compression against said at least a portion of said screw head.

14. The capless multiaxial screw system as recited inclaim 13 wherein said locking channel comprises a first locking channel area and a second locking channel area, said receiver comprises a first camming surface generally opposed to a first opposing surface to define said first locking channel area and a second camming surface generally opposed to a second opposing surface to define said second locking channel area, said first and second camming surfaces camming against said elongated member to cause said elongated member to apply a compressive force against said screw head when said receiver is rotated.

15. The capless multiaxial screw system as recited inclaim 1 wherein said channel comprises a lock member associated therewith for facilitating retaining said receiver in a locked position.

16. The capless multiaxial screw system as recited inclaim 15 wherein said lock member cooperates with an end wall of said channel to define a locking area at which said receiving member is locked when it is in said locked position.

17. The capless multiaxial screw system as recited inclaim 1 wherein said channel lies in a first plane that is generally planar and said receiver further comprising a locking channel that lies in a second plane that is non-planar.

18. The capless multiaxial screw system as recited inclaim 1 wherein said receiver comprises a locking channel that spirals about an axis of said retainer.

19. The capless multiaxial screw system as recited inclaim 1 wherein said receiver comprises a seat, said screw head having a screw head end that is generally spherical or semispherical and said seat is adapted to receive and complement said screw head end.

20. The capless multiaxial screw system as recited inclaim 1 wherein said screw head comprises a plurality of recessed areas in at least a portion of said screw head adapted to receive a tool for driving said screw.

21. The capless multiaxial screw system as recited inclaim 1 wherein said screw head comprises a simple recessed area adapted to receive a tool for driving said screw.

22. The capless multiaxial screw system as recited inclaim 1 wherein said at least a portion of said screw head comprises an outer surface that is arcuate, curved, semispherical or spherical.

23. The capless multiaxial screw system as recited inclaim 22 wherein said outer surface is spherical.

24. The capless multiaxial screw system as recited inclaim 1 wherein said sleeve end is adapted to permit direct engagement or compression of said elongated member against said at least a portion of said screw head.

25. The capless multiaxial screw system as recited inclaim 1 wherein said screw head is adapted to permit point contact and compression of said elongated member against said at least a portion of said screw head when a screw axis of said screw is not coaxial with a receiver axis of said receiver.

26. The capless multiaxial screw system as recited inclaim 3 wherein said sleeve bore is adapted to permit said at least a portion of said screw head to extend into said sleeve bore a predetermined distance such that it extends into said channel.

27. The capless multiaxial screw system as recited inclaim 1 wherein said sleeve comprises two generally opposing walls that stabilize and align said elongated member in said receiver.

28. The capless multiaxial screw system as recited inclaim 27 wherein said at least a portion of said screw head comprises an outer surface that is arcuate, curved, semispherical or spherical in cross section.

29. A bone fixation assembly comprising:

a receiver having a receiver bore for receiving a screw having a screw head and a receiver channel in communication with said receiver bore for receiving an elongated member; and

a stabilizer adapted to be received in said receiver bore, said stabilizer having a stabilizer channel and a stabilizer bore through said stabilizer, said stabilizer adapted to permit direct contact between at least a portion of said screw head and said elongated member;

said receiver being capable of rotating relative to said elongated member after said elongated member is received in said receiver channel to force said elongated member into contact with said at least a portion of said screw head.

30. The bone fixation assembly as recited inclaim 29 wherein said receiver comprises at least one engaging surface for engaging said elongated member and for locking said elongated member to said at least a portion of said screw head when said receiver is rotated to a locked position.

31. The bone fixation assembly as recited inclaim 29 wherein said receiver is generally cylindrical and said receiver bore extends along an axis of said receiver, said receiver comprising a first locking aperture in communication with said receiver bore and a second locking aperture in communication with said receiver bore; said first and second locking apertures cooperating to define a locking channel.

32. The bone fixation assembly as recited inclaim 31 wherein said locking channel is defined by a first channel in a wall of said receiver and a second channel in said wall of said receiver, said first and second channels being generally opposed.

33. The bone fixation assembly as recited inclaim 32 wherein said first channel and said second channel extend away from said receiver channel about a receiver axis of said receiver such that rotation of the receiver will cause said elongated member to move to a locked position whereupon it engages said at least a portion of said screw head.

34. The bone fixation assembly as recited inclaim 32 wherein said first channel and said second channel spiral in a common direction about a receiver axis of said receiver.

35. The bone fixation assembly as recited inclaim 29 wherein said receiver comprises a wall that lies in a generally circular or arcuate plane about a receiver axis of said receiver and said receiver channel being by said wall.

36. The bone fixation assembly as recited inclaim 29 wherein said screw head comprises a plurality of recessed areas.

37. The capless multiaxial screw system as recited inclaim 29 wherein said screw head comprises a single recessed area adapted to receive a tool for driving the screw.

38. The bone fixation assembly as recited inclaim 29 wherein an outer surface of said at least a portion of said screw head is arcuate, curved, spherical or semispherical in cross section.

39. The bone fixation assembly as recited inclaim 29 wherein an outer surface of said at least a portion of said screw head is arcuate or spherical at said at least a portion of said screw head.

40. The bone fixation assembly as recited inclaim 39 wherein said screw has a truncated area for permitting maximal polyaxial movement of said receiver relative to said screw head.

41. The bone fixation assembly as recited inclaim 29 wherein said stabilizer bore of said stabilizer is adapted to permit point contact of said elongated member against said at least a portion of said screw head.

42. The bone fixation assembly as recited inclaim 39 wherein said stabilizer bore of said stabilizer is adapted to permit point contact of said elongated member against said at least a portion of said screw head.

43. The bone fixation assembly as recited inclaim 29 wherein said screw head and said stabilizer bore are adapted to permit point contact of said elongated member against said at least a portion of said screw head and when a screw axis of said screw is not coaxial with a receiver axis of said receiver.

44. The bone fixation assembly as recited inclaim 29 wherein said stabilizer bore is adapted to permit said at least a portion of said screw head to extend into said receiver bore a predetermined distance.

45. The bone fixation assembly as recited inclaim 29 wherein said stabilizer comprises an inner end surface, said at least a portion of said screw head extends beyond said inner end surface and into said stabilizer bore when said elongated member is in a locked position in said receiver.

46. The bone fixation assembly as recited inclaim 29 wherein said stabilizer comprises a first wall and a generally opposed second wall for defining a stabilizer receiving area or channel for receiving said elongated rod.

47. The bone fixation assembly as recited inclaim 46 wherein said stabilizer bore is in communication with said stabilizer receiving area, said stabilizer bore being adapted to permit said at least a portion of said screw head to be received in said stabilizing bore so that said elongated member directly engages or is engaged by said at least a portion of said screw head when said receiver is rotated to a locked position.

48. The bone fixation assembly as recited inclaim 47 wherein said stabilizer comprises a generally cylindrical wall that defines said stabilizer bore.

49. The bone fixation assembly as recited inclaim 48 wherein said generally cylindrical wall comprises an inner diameter that generally corresponds to a distance between said first and second walls.

50. An intermediate member for use with a polyaxial screw having a head that is generally spherical comprising:

a body having a bore; and

a channel for receiving an elongated member;

said bone being adapted to permit at least a portion of a screw head of the polyaxial screw to enter into said bore.

51. The intermediate member as recited inclaim 50 wherein a width of said channel is at least as large as a radius of said bore.

52. The intermediate member as recited inclaim 50 wherein said intermediate member comprises an end having a frusto-conical, or spherical or semispherical surface for engaging said screw head.

53. The intermediate member as recited inclaim 50 wherein said intermediate member comprises an end having an opening adapted to permit said elongated member to engage or be engaged by at least one portion of said screw head.

54. A bone fixation assembly comprising:

a receiver having a bore for receiving a screw having a screw head; and

an intermediate member dimensioned to be received in said bore and having a first end and a second end;

said receiver comprising an integral rotary lock for forcing and locking an elongated member directly against said screw head when said receiver is rotated.

55. The bone fixation assembly as recited inclaim 54 wherein said integral rotary lock comprises a continuous channel for receiving said elongated member and for urging said elongated member toward said screw head when said receiver is rotated.

56. The bone fixation assembly as recited inclaim 54 wherein said integral rotary lock comprises a first channel that extends about a receiver axis in a first direction and a second channel that extends about said receiver axis in a second direction and a receiver channel coupling said first and second channels.

57. The bone fixation assembly as recited inclaim 56 wherein said first and second directions extend away from said receiver channel about a receiver axis of said receiver such that rotation of said receiver will move said elongated member from an unlocked position to a locked position.

58. The bone fixation assembly as recited inclaim 56 wherein said receiver channel lies in a plane that generally extends along an axis of said receiver.

59. The bone fixation assembly as recited inclaim 56 wherein said first and second channels spiral about said receiver axis.

60. The bone fixation assembly as recited inclaim 56 wherein said first and second channels lie in imaginary planes that intersect an axis of said receiver at acute angles.

61. The bone fixation assembly as recited inclaim 56 wherein said receiver channel lies in a receiver plane, said first channel lies in a first plane and said second channel lies in a second plane, each of said first and second planes intersecting said receiver plane at an acute angle that extends toward a bone when said screw is screwed into the bone.

62. The bone fixation assembly as recited inclaim 54 wherein said receiver comprises a removable intermediate member for stabilizing said elongated member.

63. The bone fixation assembly as recited inclaim 62 wherein said removable intermediate member comprises an end having an opening, said screw head and said opening being adapted to enable said elongated member to contact at least one portion of said screw head.

64. The bone fixation assembly as recited inclaim 54 wherein said screw head is generally spherical.

65. The bone fixation assembly as recited inclaim 62 wherein said screw head is generally spherical.

66. A bone fixation assembly comprising:

a receiver having an opening for receiving a screw having a screw head; and

an intermediate member dimensioned to be received in said opening and having an intermediate member receiving channel for receiving an elongated member and a screw head receiving opening adapted to receive at least a portion of said screw head;

said receiver comprising a receiver channel for receiving said elongated member, said receiver channel compressing said elongated member against said screw head when said receiver is rotated from an unlocked position to a locked position.

67. The spiral fixation assembly as recited inclaim 66 wherein said receiver channel comprises a locking channel that spirals about an axis of said receiver.

68. The spiral fixation assembly as recited inclaim 67 wherein said locking channel provides a bayonet connection between said elongated member and said screw.

69. The bone fixation assembly as recited inclaim 66 wherein said receiving channel comprises at least a portion that lies in a first plane and said intermediate member receiving channel comprises at least a portion that lies in a second plane, said second plane and said first plane being generally parallel when said elongated member is in said unlocked position and generally perpendicular when said elongated member is in said locked position.

70. The bone fixation assembly as recited inclaim 66 wherein when said receiver is rotated from said unlocked position to said locked position, said elongated member directly engages said at least a portion of said screw head and becomes situated closer to said screw compared to when said elongated member is in said unlocked position.

71. The bone fixation assembly as recited inclaim 70 wherein said receiver channel is in communication with a locking channel so that when said receiver is in said unlocked position, said receiving channel becomes generally aligned with said intermediate member receiving channel in said intermediate member.

72. The bone fixation assembly as recited inclaim 66 wherein said receiver channel is generally perpendicular to an elongated member axis of said elongated member when said receiving member is in said locked position.

73. The bone fixation assembly as recited inclaim 66 wherein said receiver channel comprises a locking channel that spirals from a first end of said receiver toward a second end of said receiver.

74. The bone fixation assembly as recited inclaim 73 wherein said locking channel defines a helix.

75. The bone fixation assembly as recited inclaim 66 wherein said receiver channel extends from an end of said receiver in a direction that is generally parallel to an axis of said receiver and further comprises a locking channel that extends at least partially about said axis of said receiver.

76. The bone fixation assembly as recited inclaim 66 wherein said intermediate member receiving channel becomes generally aligned with said receiver channel when said elongated member is received in said receiver and said receiver channel and said intermediate member receiving channel become non-aligned when said receiver is rotated to said locked position.

77. The bone fixation assembly as recited inclaim 66 wherein said receiver channel comprises a locking channel, said receiver comprising at least one camming surface that cooperates with an opposing surface that cooperates to define said receiver channel, said at least one camming surface camming against said elongated member to move said elongated member against said screw head when said receiver is rotated.

78. The bone fixation assembly as recited inclaim 66 wherein said receiver comprises a plurality of camming surfaces that cooperate with a plurality of opposing surfaces, respectively, to define a locking channel, said plurality of camming surfaces camming against said elongated member to cause said elongated member to apply a compressive force against said screw head when said receiver is rotated.

79. The bone fixation assembly as recited inclaim 66 wherein said receiver comprises a locking channel comprising a first locking channel area and a second locking channel area

said receiver comprises a first camming surface generally opposed to a first opposing surface to define said first locking channel area and a second camming surface generally opposed to a second opposing surface to define said second locking channel area, said first and second camming surfaces camming against said elongated member to force said elongated member to apply a compressive force against said screw head when said receiver is rotated.

80. The bone fixation assembly as recited inclaim 79 wherein said receiver comprises a detent or protrusion or a plurality of detents or protrusions in communication with said locking channel.

81. The bone fixation assembly as recited inclaim 79 wherein said receiver comprises a surface that defines an end wall of said locking channel to define a locking area at which said elongated member is locked when it is in said locked position.

82. The bone fixation assembly as recited inclaim 66 wherein said receiver comprises a locking channel, said receiver channel lies in a first plane that is generally planar and said locking channel lies in a second plane that is non-planar.

83. The bone fixation assembly as recited inclaim 82 wherein said second plane spirals about an axis of said receiver.

84. The bone fixation assembly as recited inclaim 82 wherein said locking channel extends in a direction that is non-axial relative to an axis of said receiver.

85. The bone fixation assembly as recited inclaim 66 wherein said screw head is generally arcuate, spherical, semispherical or curved and said intermediate member comprises an end having an outer end surface that is generally complementary in shape and adapted to receive said screw head.

86. The bone fixation assembly as recited inclaim 66 wherein said screw head comprises a plurality of recessed areas surrounding said at least a portion of said screw head.

87. The bone fixation assembly as recited inclaim 66 wherein said at least a portion of said screw head is spherical in cross section.

88. The bone fixation assembly as recited inclaim 66 wherein said at least a portion of said screw head is spherical in cross section at an area where said elongated member directly engages said screw head.

89. The bone fixation assembly as recited inclaim 66 wherein said outer surface of said screw head is adapted to permit point contact of said elongated member directly against said at least a portion of said screw head.

90. The bone fixation assembly as recited inclaim 66 wherein said screw head is adapted to permit point contact of said elongated portion against said at least a portion of said screw head when a screw axis of said screw is not coaxial with a receiver axis of said receiver.

91. The bone fixation assembly as recited inclaim 66 wherein said intermediate member comprising an end having an opening adjusted to permit an engaging portion of said screw head to extend into said receiver opening a predetermined distance.

92. The bone fixation assembly as recited inclaim 66 wherein said intermediate member comprises a bottom surface, said at least a portion of said screw extending beyond said bottom surface and into said receiver channel when said elongated member is in said locked position.

93. The bone fixation assembly as recited inclaim 66 wherein said intermediate member comprises an end having an outer end surface that is frusto-conical.

94. The bone fixation assembly as recited inclaim 66 wherein said screw head comprises an outer surface and at least one tool aperture or area for receiving a tool.

95. A capless multiaxial screw system comprising:

a screw having a threaded portion and a screw head;

a receiver having a receiver bore for receiving said threaded portion and a receiving channel for receiving an elongated member, said receiver further comprising a locking channel in communication with said receiving channel;

an intermediate member adapted to be situated in said receiver bore, said intermediate member comprising an intermediate member bore for receiving at least a portion of said screw head; and

said intermediate member bore and said screw head being adapted to permit said at least a portion of said screw head to extend into said locking channel so that said elongated member may engage and compress against said at least a portion of said screw head when said elongated member is received in said receiving channel and said receiver is rotated.

96. The capless multiaxial screw system as recited inclaim 95 wherein said locking channel comprises a plurality of channels, each of said plurality of channels defining an intermediate area for capturing said elongated member to facilitate adjusting a position of said elongated member before it is locked in said receiver.

97. The capless multiaxial screw system as recited inclaim 96 wherein each of said plurality of channels are defined by a first surface and a second surface, each of said plurality of channels having an intermediate step on at least one of said first surface or said second surface for defining said intermediate area.

98. The capless multiaxial screw system as recited inclaim 97 wherein at least one of said first and second surfaces is not planar.

99. The capless multiaxial screw system as recited inclaim 95 wherein said locking channel is a helical channel defined by at least one surface in a body of said receiver.

100. The capless multiaxial screw system as recited inclaim 95 wherein said intermediate member comprises an end having a first side comprising a generally concave seat, at least a second portion of said screw head having a curvature that generally complements said generally concave seat.

101. The capless multiaxial screw system as recited inclaim 95 wherein said receiving channel is generally parallel along an axis of said receiver and said locking channel spirals about said axis of said receiver when moving in an axial direction.

102. The capless multiaxial screw system as recited inclaim 95 wherein said receiving channel extends from an end of said receiver in a direction that is generally parallel to said axis of said receiver and said locking channel extends in a direction that is generally not parallel to said axis of said receiver.

103. The capless multiaxial screw system as recited inclaim 95 wherein said receiver comprises at least one camming surface that cooperates with an opposing surface to define said locking channel, said at least one camming surface forcing said elongated member against said at least a portion of said screw head.

104. The capless multiaxial screw system as recited inclaim 95 wherein said receiver comprises a plurality of camming surfaces that cooperate with a plurality of opposing surfaces, respectively, to define said locking channel, said plurality of camming surfaces camming against said elongated member to lock said receiver to said at least a portion of said screw head.

105. The capless multiaxial screw system as recited inclaim 95 wherein said locking channel comprises a first locking channel area and a second locking channel area, said receiver comprises a first camming surface generally opposed to a first opposing surface to define said first locking channel area and a second camming surface generally opposed to a second opposing surface to define said second locking channel area, said first and second camming surfaces camming against said elongated member to force said elongated member against said at least a portion of said screw head when said receiver is rotated.

106. The capless multiaxial screw system as recited inclaim 95 wherein said receiving channel lies in a first plane that is generally planar and said locking channel lies in a second plane that is non-planar.

107. The capless multiaxial screw system as recited inclaim 106 wherein said second plane spirals about an axis of said receiver.

108. The capless multiaxial screw system as recited inclaim 95 wherein said locking channel spirals about an axis of said receiver.

109. The capless multiaxial screw system as recited inclaim 95 wherein said receiver comprises a seat defining a seat area said screw head being generally spherical, said seat being adapted to receive and complement said screw head.

110. The capless multiaxial screw system as recited inclaim 95 wherein said screw head comprises a plurality of recessed areas for receiving a tool used to turn said screw.

111. The capless multiaxial screw system as recited inclaim 95 wherein said at least a portion of said screw head is spherical or semispherical.

112. The capless multiaxial screw system as recited inclaim 95 wherein said at least a portion of said screw head is arcuate or spherical in cross section.

113. The capless multiaxial screw system as recited inclaim 95 wherein said intermediate member comprises a seat defining a seat area adapted to permit point contact between said elongated member and said at least a portion of said screw head.

114. The capless multiaxial screw system as recited inclaim 95 wherein said screw head and said screw head receiving opening are adapted to permit point contact of said elongated member against said at least a portion of said screw head when a screw axis of said screw is not coaxial with a receiver axis of said receiver.

115. The capless multiaxial screw system as recited inclaim 95 wherein said intermediate member comprises an end, said intermediate member bore being adapted to permit said at least a portion of said screw head to extend into said locking channel a predetermined distance.

116. The capless multiaxial screw system as recited inclaim 95 wherein said intermediate member comprises a first wall and a generally opposed second wall for defining an intermediate member receiving area for receiving said elongated member.

117. The capless multiaxial screw system as recited inclaim 95 wherein said intermediate member bore is in communication with said intermediate member receiving area, said intermediate member bore being dimensioned to permit said at least a portion of said screw head to be received in both said receiver bore and said intermediate member bore so that when said receiver is rotated, said elongated member engages and locks against said at least a portion of said screw head.

118. The capless multiaxial screw system as recited inclaim 95 wherein said intermediate member is generally cylindrical and defined by a generally cylindrical wall, an inner diameter of said generally cylindrical wall being greater than a diameter of said elongated member.

119. A capless multiaxial screw fixation assembly comprising:

a screw having a threaded portion and a screw head;

a receiver having an aperture for receiving said threaded portion and a receiving channel for receiving an elongated member, said receiving channel further comprising a locking channel in communication with said receiving channel; and

a guide for situating in said bore, said guide comprising:

a second receiving channel associated with a first end of said guide and a seat area associated with a second end of said guide;

said guide being adapted to permit at least a portion of said screw head to extend into said receiving channel and said second receiving channel so that said elongated member may engage said screw head to lock or compress said elongated member to said screw when said elongated member is received in said first and second receiving channels and said receiver is rotated from an unlocked position to a locked position.

120. A bone fixation assembly comprising:

a receiver having a receiver bore for receiving a screw having a screw head, said receiver further comprising a locking channel and a receiving channel in communication with said locking channel; and

an intermediate member dimensioned to be received in said receiver bore, said intermediate member comprising a body having a first end having an intermediate member channel and a second end having an intermediate member opening;

said intermediate member opening being adapted to permit at least a portion of said screw head to engage an elongated member after said elongated member is received in said receiving channel, said locking channel and said intermediate member channel and said receiver is moved to a locked position.

121. The bone fixation assembly as recited inclaim 120 wherein said intermediate member comprises a pair of generally opposed walls that cooperate with said second end to define stabilize and align the elongated member in said receiver channel.

122. The bone fixation assembly as recited inclaim 121 wherein said intermediate member bore is generally cylindrical and comprises a diameter substantially the same as a distance between said pair of generally opposed walls.

123. A method for stabilizing one or more bones, said method comprising the steps of:

placing an elongated member into a receiving channel of said receiver and channel of said intermediate member; and

rotating said receiver to cause said elongated member to directly engage at least a portion of said screw head.

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