Tool system for dynamic spinal implants

[0001] This application claims the benefit of U.S. Provisional Application No. 60/873,819 filed Dec. 8, 2006 and incorporated by reference herein. This application is a continuation-in-part of U.S. patent application Ser. No. 11/328,481 filed Jan. 9, 2006 that is a continuation-in-part of U.S. patent application Ser. No. 10/789,149, filed Feb. 27, 2004, now U.S. Pat. No. 7,160,300, all of which are incorporated herein by reference. U.S. patent application Ser. No. 11/328,481 is also a continuation-in-part of U.S. patent application Ser. No. 10/996,289 filed Nov. 23, 2004, also incorporated by reference herein.

[0002] The present invention relates to apparatuses and methods for use in performing spinal surgery using minimally or less invasive techniques and, in particular, to tools and methods of using such tools, especially for implanting and manipulating spinal screws and for implanting flexible or otherwise dynamic longitudinal connecting members for spinal support and alignment to create, as much as possible, a more normal or natural loading pattern between the vertebrae in flexion, extension, distraction, compression, side bending and torsion.

[0003] For many years, spinal osteosynthesis apparatuses have been utilized to correct spinal deformities, injuries or disease. In such procedures, substantially rigid longitudinal connecting members, for example, elongate solid rods, are surgically attached to vertebrae of the spine to provide support and/or to realign or reposition certain vertebrae. The longitudinal connecting members are typically secured to vertebrae utilizing bone screws and other spinal implants. In order to reduce the impact of such surgery on the patient, a desirable approach is to insert such implants percutaneously or with surgical techniques that are less invasive to the body of the patient. In order to provide for protected motion with more normal or natural spinal flexibility, more flexible or dynamic longitudinal connecting members may be chosen over solid rigid rods.

[0004] Problems arise when implant deployment and insertion tools designed for traditional open surgery that is more invasive are utilized in percutaneous or less invasive surgery or with dynamic stabilization longitudinal connecting members. The tools may be bulky, oversized or have irregular surfaces or protrusions that can catch and traumatize tissues. A projecting actuator arm or fastening member may be useful with respect to the spinal screw implantation process or the rod reduction process, but there may be insufficient clearance to use such structure and/or such structure may produce additional unwanted trauma which the percutaneous surgery is attempting to avoid.

[0005] A percutaneous or less invasive procedure also presents a problem with implantation of elongate connecting members that have historically required a long incision and open wound in order to provide for the length of the connecting member and the space required for the surgeon's hands as well as the tools needed to manipulate the rod. Such problems are then compounded by the implants and insertion tools used with the connecting member.

[0006] Consequently, it is desirable to develop apparatuses and techniques that allow for the insertion of bone screws or other bone attachment structures, the insertion and reduction of longitudinal connecting members into the bone screws and the securing of the connecting member to the bone screws with significantly less invasion into the body of the patient.

[0007] Historically, it also has been common to fuse adjacent vertebrae that are placed in fixed relation by the installation therealong of bone screws or other bone anchors and cooperating longitudinal connecting members or other elongate members. Fusion results in the permanent immobilization of one or more of the intervertebral joints. Because the anchoring of bone screws, hooks and other types of anchors directly to a vertebra can result in significant forces being placed on the vertebra, and such forces may ultimately result in the loosening of the bone screw or other anchor from the vertebra, fusion allows for the growth and development of a bone counterpart to the longitudinal connecting member that can maintain the spine in the desired position even if the implants ultimately fail or are removed. Because fusion has been a desired component of spinal stabilization procedures, longitudinal connecting members have been designed that are of a material, size and shape to largely resist bending (flexion, extension and sideways), twisting (torsion), compression and distraction, and thus substantially immobilize the portion of the spine that is to be fused. Thus, longitudinal connecting members are typically uniform along an entire length thereof, and usually made from a single or integral piece of material having a uniform diameter or width of a size to provide substantially rigid support.

[0008] Fusion, however, has some undesirable side effects. One apparent side effect is the immobilization of a portion of the spine. Furthermore, although fusion may result in a strengthened portion of the spine, it also has been linked to more rapid degeneration and even hyper-mobility and collapse of spinal motion segments that are adjacent to the portion of the spine being fused, reducing or eliminating the ability of such spinal joints to move in a more normal relation to one another. In certain instances, fusion has also failed to provide pain relief.

[0009] An alternative to fusion and the use of more rigid longitudinal connecting members or other rigid structure has been a “soft” or “dynamic” stabilization approach in which more elastic materials and/or shapes are utilized for a longitudinal connecting member fixed between a pair of bone anchors, such as pedicle screws, in an attempt to create, as much as possible, a more normal loading pattern between the vertebrae in flexion, extension, compression, distraction, side bending and torsion. Tools utilized with traditional rods or other more rigid structure may not be appropriate for manipulating more flexible and variously sized connecting members and cooperating bone attachment structures. The dynamic conditions associated with spinal movement therefore provide a challenge not only for the design of more flexible or elastic longitudinal connecting members, but also for the design of cooperating tooling.

[0010] A tool assembly and a set of tools according to the invention is provided for percutaneous or less invasive methods of implanting bone screws and an associated spinal connecting member in a patient. The tool assembly includes an elongate guide tool having structure at a lower end thereof that is operably mateable with opposed sides of a bone attachment receiver. The elongate guide tool includes first and second discreet, independently attachable and movable parts or members. The independent members allow for movement toward and away from one another, aiding insertion and manipulation of manipulation tools and other bone attachment structure.

[0011] Also according to the invention, a stabilizer is provided for placing the first and second members into a set spaced relation with one another when desired, for example, during driving of a bone screw shank into a vertebra and/or reducing a longitudinal connecting member and closure structure down between the first and second members and into the bone attachment structure. Both an independent stabilizer and a stabilizer attached to a bone screw driver may be included in a tool set according to the invention. Further tools include a cooperating bone screw driver with an attached stabilizer, a closure starter/reduction tool, a closure driver and a counter torque tool.

[0012] Therefore, the objects of the present invention include: to provide a compact tool assembly for supporting and installing bone attachment structures, such as bone screws, hooks and dynamic stabilization connecting members and other spinal implants with minimal or less surgical invasion to the patient; to provide such an assembly in which elongate holding members may be independently manipulated and form an open, expandable channel when desired and may also be placed into set spatial relation when desired; to provide a set of tools for implanting a dynamic spinal fixation connecting member for support or alignment along a human spine with minimal or less surgical invasion of the patient; to provide such a set of tools including an insertion tool, driving, reduction and manipulation tools for use in implanting a bone attachment implant, directing a longitudinal connecting member downwardly into such an implant and capturing the longitudinal connecting member within a receiver of the bone attachment implant; to provide such a set of tools including a closure reduction and installation tool for securing the dynamic fixation connecting member to the bone attachment implant; to provide such a set of tools wherein the insertion, driving and manipulation tools are easily attached to and disengaged from the bone attachment implants; to provide such a set of tools wherein the insertion tools, supports or stabilizers, deployment tools, reduction tools, bone implant installation tools and closure installation tools are all easily aligned, positioned, and engaged, if necessary, with respect to the bone implants and are disengaged from the bone implants and other tools in the installation assembly by manual manipulation of the surgeon; to provide a method of implanting a dynamic stabilization connecting member into bone implants within a patient with minimal or less surgical invasion of the patient; to provide such a method utilizing the previously described tools for implantation of such a connecting member; and to provide such a set of tools and methods that are easy to use and especially adapted for the intended use thereof and wherein the tools are comparatively inexpensive to produce.

[0013] Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.

[0014] The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.

[0069] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.

[0070] It is also noted that any reference to the words top, bottom, up and down, and the like, in this application refers to the alignment shown in the various drawings, as well as the normal connotations applied to such tools and cooperating devices, and is not intended to restrict positioning of the tools in actual use. It is also noted that reference to words such as front, back, anterior and posterior used in this application also refer to the alignment shown in the various drawings, and in particular, when possible, with reference to the human spine and human body, but also is not intended to restrict positioning of the tools in actual use.

[0071] With particular reference to FIGS. 1-11, the reference numeral 1 generally designates a guide tool assembly according to the present invention that may be used alone or in combination with a variety of cooperating tools described herein that may make up a tool set 2 (see, e.g., FIGS. 12, 22, 25, 33 and 43) according to the invention for use in installing at least one and up to a plurality of bone screws 4 into a patient's spine 6, followed by the installation of a longitudinal member, such as the member generally 8 and up to a plurality of closure members or tops 9, into the bone screws 4 in a process according to the present invention.

[0072] The guide tool assembly 1 is open, having a first elongate member 10 and a separate or discrete second elongate member 12, each of the members 10 and 12 being engageable with the bone screw 4 as will be described more fully below. The open arrangement of the guide tool assembly 1 allows for independent manipulation of the elongate members 10 and 12 and insertion of a variety of tools, implants and longitudinal connecting members, some with sleeves or spacers having various widths or diameters. When more stability is desired, for example, during installation of the bone screw 4 into a vertebra 16 of the patient's spine 6, a driver 18 or other manipulating tool being used in connection with the guide tool assembly 1 may include a stabilizer 20 (described more fully below) for keeping the elongate members 10 and 12 in fixed spaced relation to one another. Furthermore, according to the invention, the assembly 1 may include a discrete or independent stabilizer 22 for use with a variety of tools, including, but not limited to the following illustrated tools: a closure starter/connecting member reducer 24, a closure driver 26 and a counter torque tool 28, all of which will be described more fully below.

[0073] The guide tool assembly 1 elongate members 10 and 12 are substantially similar to one another, sized and shaped for attachment to respective first and second arms 30 and 32 of the bone screw 4, the first arm having a top surface 31 and the second arm having a top surface 33. The elongate members 10 and 12 are generally sized and shaped to be sufficiently long to extend from an implanted bone screw 4 through an exterior of a patient's skin so as to provide an outwardly extending and upper handling portion that allows and provides for gripping by a surgeon during procedures utilizing the guide tool assembly 1, with or without the other cooperating tools. Specifically, the elongate member 10 is a singular discrete structure generally including an inner wall or surface 40 and an opposed outer wall or surface 42. The member 10 further includes opposed substantially parallel sides 44 and 46. The member 10 has a substantially constant width as measured between the sides 44 and 46, such width being substantially the same as a width of a cooperating bone screw arm 30. The sides 44 and 46 may be beveled along an entire length thereof as illustrated in the drawing figures. The back wall 42 is substantially planar along an entire length thereof. The front wall 40 has a concave curvature that substantially matches or corresponds to the inner curvature of the bone screw arm 30 that is in turn sized and shaped for mating cooperation with the substantially cylindrical closure member or top 9. The front wall 40 also is sized and shaped to receive and allow passage of both tools and implants as will be described more fully below. Running along a length of the member 10 and near respective sides 44 and 46 are a pair of substantially cylindrical through channels 47 and 48, each sized and shaped to receive one of a pair of cooperating lock pins 49.

[0074] The elongate members 10 and 12, stabilizer 22, lock pins 49 and other cooperating tooling may be made from a variety of suitable materials, including but not limited to metals, metal alloys, plastics, polymers, composites and blends thereof. For example, the tool components may be made from stainless steel, titanium, polymer blends that may be carbon reinforced, such a polyetheretherketone (PEEK) and or other radiolucent or non-radiolucent materials. In certain embodiments the members 10 and 12 may be rigid and in other embodiments, more flexible, allowing for bending of the members 10 and 12 and associated pins 49 without compromising strength of the components or attachment to a cooperating bone anchor.

[0075] The member 10 may further be described as having an upper, handling portion 50, an intermediate portion 52 and a lower implant engaging portion 54. The upper handling portion 50 includes a top surface 56 and a cut-out or recessed portion 58 substantially formed in the front wall or surface 40 and sized and shaped to provide access for tools and/or bone attachment components, the recessed portion 58 cooperating with a similar or identical recessed portion 58a on the member 12 as illustrated, for example, in FIGS. 11, 25 and 26. The channels 47 and 48 open to the top surface 56. Also, near the top surface, wall portions 60 forming the channels 47 and 48 are threaded for mating cooperation with a threaded portion of the lock pin 49 as will be described in greater detail below.

[0076] The lower implant engaging portion 54 includes a bottom surface 64 and a cut-out or recess 66 near such bottom surface that is formed in the wall 40 and also extends through a portion of the sides 44 and 46. With particular reference to FIGS. 6, 8 and 9, the cut-out 66 is defined by an upper surface 70 disposed substantially perpendicular to the outer surface 42, an inner planar surface 72 disposed substantially parallel to the outer surface 42 and a substantially planar lip surface 74 disposed at an acute angle with respect to the surface 72. With particular reference to FIG. 8, in the illustrated embodiment, the lip surface 74 is substantially parallel with the bottom surface 64, forming a narrow strip that projects away from the inner wall 40 and is sized and shaped to engage and fit within a groove 76 of the arm 30 of the bone screw 4.

[0077] With particular reference to FIGS. 6 and 7, the inner surface 72 further includes a raised strip or projection 78 that runs perpendicular to the lip surface 74 and is sized, shaped and positioned to slidingly engage with a slit 80 in a ledge 82 that partially defines the groove 76 disposed on the arm 30 of the bone screw 4. The raised strip 78 and the slit 80 are designed to ensure proper mating of the insertion tool 10 and the bone screw arm 30 and differentiate between the elongate member 10 and the elongate member 12 such that the member 10 only fits on the bone screw arm 30 and the member 12 only fits on the bone screw arm 32. The member 12 also includes a raised strip (not shown), similar to the strip 78, that is sized, shaped and positioned to slidingly engage with a slit 86 of the arm 32. The slits 80 and 86 may be disposed indirectly opposite of one another and the cooperating strips positioned on the tool 1 such that the member 10 only mates with the arm 30 and the member 12 only mates with the arm 32. The cooperation between the strip 78 and the slit 80 and the similar strip on the member 12 and the slit 86 ensures proper overall alignment and mating of the tool 1 and the bone screw 4 when both members 10 and 12 are in engagement with the bone screw 4, and further prohibits front to back movement of the bone screw 4 with respect to the insertion tool 1 when the members 10 and 12 are mounted on the screw 4 and the lock pins 49 are in contact with the bone screw 4. With reference to FIG. 5, the back wall 42 of the member 10 may include a laser etched alignment stripe 90 that aids a surgeon in properly aligning and mating the member 10 with the arm 30 by simply aligning the stripe 90 with a stripe 92 that is located on only the arm 30. It is noted that bone screws 4 and members 10 and 12 according to the invention may be configured to include uniform and opposite cooperating strips and slits so that the members 10 and 12 may be engaged with either the arm 30 or the arm 32 of the bone screw 4.

[0078] Each lock pin 49 is elongate, having a top surface 94 a curved bottom surface 95, a hex-shaped upper driving portion 96 disposed near the top surface 94 and a threaded portion 97 disposed near the driving portion 96 and on a smooth cylindrical body portion 98 of the lock pin 49. The smooth body portion 98 extends from the driving portion 96 to the bottom surface 95. As illustrated in FIG. 1, near the bottom surface 95, the body portion 98 may be of slightly reduced diameter as shown by the portion 99 to result in the bottom surface 95 being of a size and shape to fully contact the bone screw 4 without overhanging the arm 30 or 32. The lock pin 49 is sized and shaped to be received in either of the cylindrical channels 47 and 48 in either of the members 10 and 12, with the threaded portion 97 rotatably receivable in the threaded inner wall 60. The lock pin 49 is sized and shaped to extend along and completely through the channels 47, 48 until the curved bottom 95 abuts the top surface 31 or 33 of the bone screw 4 with the upper driving portion 96 extending above the top 56 of the member 10 as illustrated, for example, in FIG. 3.

[0079] The lock pins 49 are rotated and driven downwardly into the member 10 by a socket driver (not shown). A suitable driver includes a substantially cylindrical elongate body and an elongate hex-shaped aperture or driving socket sized and shaped to receive and mate with the hex-shaped upper driving portion 96 of each of the lock pins 49.

[0080] As illustrated in FIGS. 11 and 12, the member 12 is substantially similar to the member 10 in size and shape, having an inner wall 40a, and outer wall 42a, sides 44a and 46a, channels 47a and 48a, upper intermediate and lower portions 50a, 52a and 54a, respectively, a top surface 56a, a recessed portion 58a, a bottom surface 64a and a recess 66a, identical or substantially similar to respective elements 40, 42, 44, 46, 47, 48, 50, 52, 54, 56, 58, 64 and 66, described herein with respect to the member 10. The member 12 channels 47a and 48a cooperate with the lock pins 49 in a manner identical to that described herein with respect to the member 10 with each channel including a threaded portion (not shown) identical or substantially similar to the threaded channel portion 60. The recess 66a is identical to the recess 66 with the exception of the inner strip that is similar to the strip 78 but disposed at a different location to cooperate with the slit 86 of the bone screw arm 32 as already described herein.

[0081] With reference to FIGS. 11 and 12, when the members 10 and 12 are mated with respective arms 30 and 32 of the bone screw 4, the members 10 and 12 may be independently manipulated toward and away from one another, as will be described in greater detail below. Also a through channel 101 is formed between the members 10 and 12 extending along the entire length of the tool 1 from the bone screw 4 to the lock pin top surfaces 94. The channel 101 is sized and shaped to receive and allow passage of both tools and implants. As will be discussed more fully below, an opening formed between the recessed portions 58 and 58a provide clearance to readily receive a driving end of the bone screw driver 18 as well as the closure top 9 and the longitudinal connecting member 8.

[0082] With reference to FIGS. 12-22, the bone screw driver 18 includes an upper elongate handle 130; an elongate shaft 132; and a driving end portion 134 integral with or fixedly attached to the shaft 132; all extending along an axis of rotation A. The handle 130 is somewhat triangular when viewed on end as shown in FIG. 19. The handle 130 may include shallow apertures to aid a surgeon in gripping and rotating the handle 130. The handle 130 is fixed to and coaxial with the shaft 132. A screw driver lock limit 136 and the stabilizer 20 are disposed on the shaft 132. The driving end portion 134 extends from the shaft 132 and is of reduced diameter. Integral or attached to the end portion 134 is a hex-shaped driving socket 140 sized and shaped to mate with a hex drive 144 formed in a shaft of the bone screw 4. Although a socket type driver is shown, a driver according to the invention may have any of a variety of driving features designed to mate with a driving head, socket, or other external or internal driving feature of a cooperating bone screw. The driving tool 18 may include a longitudinal through bore formed along an entire length thereof to cooperate with cannulated bone screws, allowing for insertion of the driver 18 and cooperating engaged bone screw over guide wires or pins.

[0083] With particular reference to FIGS. 13-18, the stabilizer 20 is located on the shaft 132 between the handle 130 and the lock limit 136. The stabilizer 20 includes a substantially central through bore 150 through which the driver shaft 132 extends, the stabilizer 20 being slidingly received on the shaft 132 along the axis A between the handle 130 and the lock limit 136. The stabilizer 20 further includes four smaller, uniformly shaped through bores 152 positioned evenly about the bore 150 and running substantially parallel to the bore 150 (and the shaft 132). The bores 152 are substantially circular in cross-section, being sized, shaped and positioned to slidingly receive four lock pins 49 and hold such pins in spaced alignment when the lock pins 49 are attached to the elongate members 10 and 12 and contact the bone screw 4 and the stabilizer 20 is seated on the members 10 and 12. The stabilizer 20 further includes an upper portion 154 and an attached lower portion 156, the upper and lower portions shaped to engage one another in a dovetail arrangement as shown in FIGS. 16 and 18. As illustrated in FIG. 18, the upper and lower portions are attached by means of an assembly pin 158 that extends through the upper and lower portions 154 and 156 near one side 159 and a laterally loaded spring retainer 160 at an opposite side 161. At the side 161, the upper portion 154 extends beyond the lower portion 156 in a lateral direction perpendicular to the axis A, providing a ledge for ease in moving the stabilizer 20 up and down the shaft 132 along the axis A. It is foreseen that the stabilizer 20 may be constructed in other ways, for example, of singular molded construction. The stabilizer 20 further includes substantially planar parallel top and bottom surfaces 162 and 164, respectively. The bottom surface 164 contacts and seats upon the upper surfaces 56 and 56a of respective members 10 and 12 and in slidable engagement therewith when the stabilizer 20 is slid downwardly along the shaft 132 and received over the lock pins 49, placing the members 10 and 12 into a parallel arrangement with one another, providing control over the device 1 during rotation of the driver 18 about the axis A when the driver 18 is used to implant the bone screw 4 into a vertebra 16.

[0084] With reference to FIGS. 13, 14 and 19, for example, the illustrated lock stop 136 is annular and extends outwardly radially from the shaft 132 generally in a direction perpendicular to the axis A and includes a top outwardly and downwardly sloping or conical surface 167. The stop 136 is fixed to the shaft 132 at a location such that the stabilizer 20 does not slide completely down the shaft 132 prior to being positioned between the members 10 and 12 and over the lock pins 49. With reference to FIGS. 20 and 21, the stop 136 is also positioned at a location along the shaft 132 so that when the stabilizer 20 abuts against the slanted surface 167 of the lock stop 136, the stabilizer 20 also squarely and evenly seats on the members 10 and 12 with the hex socket driving head 140 being in engagement with the bone screw hex drive 144 of the bone screw 4 that is attached to the members 10 and 12. When in such position, the stabilizer 20 places the members 10 and 12 into set spatial relationship with one another, preventing outward or inward movement of the members 10 and 12 away or toward the axis A, allowing for ease in rotation of the driver 18 during implantation of the bone screw 4.

[0085] It is noted that the present invention is not intended to be restricted for use with a particular type of bone screw 4 or other bone attachment structure, bone screw closure mechanism, or longitudinal connecting member. It is foreseen that the guide tool assembly 1 and the tool set 2 of the present invention can be used with virtually any type of bone screw, including, but not limited to, fixed monoaxial, hinged and polyaxial bone screws and hooks of many different types that include features for engagement with the members 10 and 12 as described herein.

[0086] With respect to the illustrated polyaxial bone screw 4 shown in FIGS. 1, 2, 7, 9 and 10, in addition to the arms 30 and 32, the bone screw 4 further includes a threaded shank 170 in pivotal relationship with a receiver 172. The previously described arms 30 and 32 define a portion of the receiver 172. As previously described herein, the arm 30 includes the V-shaped or undercut tool engagement groove 76 that engages the lip surface 74 of the elongate member 10. The arm 32 includes a similar undercut or groove 76a that engages the lip surface 74a of the elongate member 12. The arms 30 and 32 also define a longitudinal connecting member receiving channel 174 passing therethrough between outer substantially planar surfaces 175 and 175a. The bone screw shank 170 includes an upper portion 176 that extends into the receiver 172 and is operationally secured therein, so that the receiver 172 is rotatable on the shank 170 until locked in position through engagement with the longitudinal connecting member 8 or compression insert (not shown) disposed between the connecting member 8 and the upper portion 176 under pressure. For example, the shank 170 may be connected to the head utilizing a spline capture connection as illustrated in the drawing figures and disclosed in U.S. Pat. No. 6,716,214 from U.S. patent application Ser. No. 10/464,633, which is incorporated by reference herein. The illustrated bone screw 4 is also cannulated, having a through bore 178 extending from a top of the shank upper portion 176 to a bottom or tip 179 of the shank.

[0087] With reference to FIGS. 25, 35 and 36, the illustrated closure structure, top or fastener 9 closes between the spaced bone screw arms 30 and 32 to secure the longitudinal connecting member 8 in the channel 174. The closure top 9 can be any of many different plug type closures. Preferably the closure top 9 has a cylindrical body 180 with a helically wound mating guide and advancement structure 182. The guide and advancement structure 182 can be of any type, including V-type threads, buttress threads, reverse angle threads, or square threads. Preferably the guide and advancement structure 182 is a helically wound flange form that interlocks with a reciprocal flange form as part of a guide and advancement structure on an interior of the bone screw arms 30 and 32. A suitable locking guide and advancement structure of this type is disclosed in U.S. Pat. No. 6,726,689 from U.S. patent application Ser. No. 10/236,123 which is incorporated by reference herein. The illustrated closure 9 is provided with a non-round driving feature that is illustrated as an opening 184, such as an Allen or Torx type of opening, to receive the similarly shaped closure starter/reduction tool 24 and closure driver 26, as will be described more fully below, to advance the closure top 9 into the receiver 172. Alternatively, the closure top 9 may be equipped with a break-off head (not shown) that breaks from the threaded cylindrical body 180 upon the application of a preselected torque, such as 95 to 120 inch-pounds. Such a break-off head would include an inner drive feature or a faceted exterior configured to mate with a similarly shaped driver of a final closure driving or torquing tool (not shown). The closure top 9 further includes a bottom surface 185 having a point 186 and outer rim 187 extending therefrom. In some embodiments an insert may be provided for placement between the closure top 9 and the longitudinal connecting member 8, such as a compression insert having a curved surface to closely grip a cooperating curved surface of the member 8.

[0088] With particular reference to FIGS. 23-29, the illustrated longitudinal connecting member 8 cooperates with two or more bone screws 4 and is a non-fusion dynamic stabilization longitudinal connecting member assembly having an elongate flexible rod-like inner core 188 and at least one and up to a plurality of cannulated outer spacers or sleeves 190 slidably received on the core 188 and placable between implanted bone screws 4 as illustrated, for example, in FIG. 49. The longitudinal connecting member 8 is elongate, with the inner core 188 being an elastic substantially solid, smooth and uniform cylinder or rod having an outer cylindrical surface 192 and a substantially circular cross-section. However, it is foreseen that the core may be of a variety of different cross-sections, including but not limited to oval, rectangular or other curved or polygonal configurations. The illustrated core 188 is made from natural or synthetic elastomers, including, but not limited to polyisoprene (natural rubber), and synthetic polymers, copolymers, and thermoplastic elastomers, for example, polyurethane elastomers. The illustrated sleeve 190 is also made from a plastic, such as a thermoplastic elastomer, for example, polycarbonate-urethane having a greater stiffness than the elastomer of the core 188. In order to have low or no wear debris, the sleeve 190 inner surfaces and/or cooperating core 188 outer surfaces may be coated with an ultra thin, ultra hard, ultra slick and ultra smooth coating, such as may be obtained from ion bonding techniques and/or other gas or chemical treatments.

[0089] The illustrated core 188 is sized and shaped to be received in the U-shaped channel 174 of the bone screw receiver 172 with the sleeves 190 sized and shaped to extend between bone screws 4, providing limitation and protection of movement of the core 188 at such location. Thus, the sleeve 190 is sized and shaped for substantially even and precise alignment and substantial frictional contact between flat end surfaces 194 and 195 of the sleeve 190 and cooperating flat side surfaces 175 and 175a of bone screws 4.

[0090] Furthermore, when the longitudinal connecting member 8 is implanted with the sleeves 190 disposed between bone screws 4, and the closure structures 9 are tightened in place in the receivers 172, the implantation tool assembly 1 may be manipulated to direct the pair of adjacent receivers 172 toward one another so as to axially compress the elastic sleeve 190 between facing side surfaces 175 and 175a of the adjacent receivers 172. Such compression due to frictional engagement and compression of the sleeve 190 between the bone screws 4 during installation results in some tension and distraction of the core 188 when the implantation tools are removed from the bone screws 4, as the sleeve end surfaces 194 and 195 then press against the facing bone screw surfaces 175 and 175a, but the core 188 is otherwise fixed with respect to each of the bone screws 4 within respective receiver channels 174. Such dynamic tension/compression relationship between the sleeve 190 and the elastic core 188 provides further strength and stability to the overall assembly and also allows for the entire connecting member assembly 8 to elongate, if needed, in response to spinal movement. The increased stability and strength of the assembly advantageously allows for use of a smaller, more compact, reduced volume, lower profile longitudinal connecting member 8 and cooperating bone anchors than, for example, flexible cord and spacer type longitudinal connecting member assemblies.

[0091] The sleeve 190 further includes a pair of substantially flat parallel and opposite lateral surfaces 196 and 197 and a pair of curved opposite posterior/anterior surfaces 198 and 199. Each of the surfaces 196, 197, 198 and 199 extend between the flat end surfaces 194 and 195. The geometry of the sleeve 190 allows for a narrower width between the parallel surfaces 196 and 197 than a distance or diameter between the curved surfaces 198 and 199. Such geometry provides adequate stiffness or support for the flexible core 188 in flexing due to the distance between the posterior/anterior curved surfaces 198 and 199, while the more narrow width or distance between the flat surfaces 196 and 197 allows for placement of the sleeve 190 between adjacent vertebrae without engagement with such vertebrae. Stated in another way, a cylindrical sleeve having a diameter large enough to produce a desired limit of bending or flexing movement of the core 188 would most likely have a diameter large enough to result in interference of the sleeve cylindrical surface with portions of adjacent vertebrae. The flat surfaces 196 and 197 allow for adequate clearance but do not detract from an overall strength of the sleeve 190.

[0092] Extending along the substantially central axis of the sleeve 190 is an internal substantially cylindrical and smooth surface that defines a bore 200 with a circular cross section, the bore 200 extending through the sleeve 190 and sized and shaped to receive the core 188. The internal surface defining the bore 200 is of a slightly greater diameter than an outer diameter of the cylindrical surface 192 of the core 188, allowing for axially directed sliding movement of the sleeve 190 with respect to the core 188 during installation of the core 188 into the sleeve 190 and also when both the core 188 and the sleeve 190 are implanted with the sleeve 190 located between adjacent bone screws 4.

[0093] In the illustrated embodiment, the sleeve 190 further includes a compression groove 201. Sleeves 190 according to the invention may include one, none or any desired number of grooves 201. The groove 201 extends substantially uniformly about the sleeve 190, being formed in the external surfaces 196, 197, 198 and 199 of the sleeve 190. The groove or grooves 201 may be added as desired to advantageously increase a longitudinal compressibility of the sleeve 190 during installation between a pair of bone screws 4.

[0094] It is foreseen that the core 188 may be sized and made from such materials as to provide for a relatively more rigid longitudinal connecting member 8 or a relatively more flexible member 8 with respect to flex or bendability along the member 8. Also, since the distance between the bone screw receivers or heads 172 can vary, the core 188 may be desirably more or less stiff. As stated above, the illustrated longitudinal connecting member 8 is one of a variety of connecting members, including, but not limited to, rigid rods, rod/coil combinations and chord and spacer combinations, that may cooperate with tools according to the invention.

[0095] With reference to FIGS. 26 and 29-34, the independent stabilizer 22 according to the invention is similar to the stabilizer 20, including a central bore 250, four uniformly sized small bores 252 for receiving lock pins 49, an upper portion 254, a lower portion 256, an assembly pin 258, a first side 259, a spring retainer 260, a second side 261, a top 262 and a bottom 264 for seating on the elongate members 10 and 12, such features being substantially similar in shape and function to the respective central bore 150, four uniformly sized small bores 152, upper portion 154, lower portion 156, assembly pin 158, first side 159, spring retainer 160, second side 162, top 162 and bottom 164 of the driver stabilizer 20. Furthermore, the central bore 250 communicates with a lateral channel 270 that opens to a discontinuous face 272 of the stabilizer 22, the channel 270 being defined by substantially parallel spaced walls 274 and 275. As will be described in greater detail below, the walls 274 and 275 are spaced a distance to provide clearance for receiving selected upper and lower portions of the shaft of the closure starter/reduction tool 24 therebetween. Also, a substantially cylindrical surface 278 that defines the central bore 250 includes a discontinuous guide and advancement structure 280 designed for rotational mating engagement with a cooperating guide and advancement structure 282 of the closure starter/reduction tool 24. The guide and advancement structures 280 and 282 may be a v-thread as illustrated in the drawing figures or other guide and advancement structures known in the art. As compared to the through bores 152 formed in the stabilizer 20 that are circular and function to closely set or lock the members 10 and 12 in a particular spaced relation to one another during rotation of the bone screw driver 18, in the illustrated stabilizer 22, the four through bores 252 that are sized and shaped to receive lock pins 49 therethrough are oval, each being wider in a direction running between the sides 259 and 261, allowing some movement of the members 10 and 12 toward and away from one another when the stabilizer 22 is mounted on the guide tool assembly 1 as illustrated in FIG. 29 with the bottom surface 264 in contact with upper surfaces 56 and 56a of the members 10 and 12, respectively, and thus providing for some additional width of the through channel 101 formed between the members 10 and 12 to allow some play and additional clearance when manipulating the members 10 and 12 and inserting tools and implants utilizing the tool assembly 1.

[0096] With reference to FIGS. 25, 26, 29,30, 33, 34, 37 and 38, the closure starter/reduction tool 24 of the tool set 2 of the invention is elongate, having an axis of rotation C and including a handle 290 fixed to an elongate cylindrical stem or shaft 292 and a driving tip 294 fixed to or integral with the shaft 292. The handle 290, shaft 292 and tip 294 are coaxial along the axis of rotation C. The handle 290 includes grooves or shallow apertures to aid a surgeon in gripping and rotating the starter 24 about the axis C when, for example, the starter/reduction tool 24 is engaged with the guide and advancement structure 280 of the stabilizer 22. The closure starter/reduction tool 24 is sized and shaped to be used in cooperation with the tool assembly 1, with the tip 294 in engagement with the closure top 9 and the starter 24 extending through the tool assembly 1 with the handle 290 initially located laterally of the assembly 1 as illustrated in FIG. 25 and thereafter located above the lock pins 49 to allow for adequate clearance between the handle 290 and the assembly 1 to allow for the rotation of the closure top 9 into the bone screw receiver 172 by turning the handle 290. For insertion and removal of the closure starter/reduction tool 24 into and out of the assembly 1, the shaft 292 is reduced in width at two locations; a lower width reduction portion or length 296 and an upper width reduction portion or length 298. The lower width reduction portion 296 is located between the driving tip 294 and the guide and advancement or threaded portion 282. The upper width reduction portion is located between the threaded portion 282 and the handle 290. With particular reference to FIGS. 25 and 30, both the lower portion 296 and the upper portion 298 have a width running perpendicular to the axis C that is less than a distance between the walls 274 and 275 of the stabilizer 22 that define the lateral channel 270 while a remainder of the shaft 292 has a diameter that is larger than the width of the channel 270. The illustrated reduced portions 296 and 298 are formed by cutouts or recesses that result in a pair of parallel walls formed in the otherwise cylindrical shaft 292. It is foreseen that the reduced portions 296 and 298 may also be made by reducing the diameter of the shaft 292 in the desired locations. The reduced portion 296 allows for insertion of the closure starter/reduction tool 24 into the stabilizer 22 and between the members 10 and 12 during a process of inserting the closure top 9 between the members 10 and 12 between the cut-out surfaces 58 and 58a as shown in FIGS. 25, 26 and 30. The reduced portion 298 allows for removal of the tool 24 from the members 10 and 12 after reduction of the longitudinal connecting member 8 and mating of the closure top 9 to the receiver of the bone screw 4 as evident from FIGS. 33 and 34. During a process of reduction of the longitudinal connecting member 8 down the assembly 1, the remainder of the shaft 292 is of a diameter large enough to keep the tool 24 between the members 10 and 12 as desired for reduction of the longitudinal connecting member 8 into the receiver 172 and attachment of the closure top 9 to the bone screw 4.

[0097] The driving tip 294 includes a slot 300 and faceted geometry 301 for capturing and holding the closure structure 9 driving feature 184 prior to and during insertion of the structure 9 into the receiver 172. In some embodiments, the tip 294 may further include a lateral projection or key (not shown) sized and shaped to mate with a key slot of the closure structure drive 184 for precise positioning of the closure structure 9 into the insertion tool 1 and the receiver 172 by the closure starter/reduction tool 24. Specifically, as the outer thread 282 formed on the closure starter/reduction tool 24 is sized and shaped to rotatably mate with the guide and advancement structure 280 of the stabilizer 22, a position of a leading surface of the thread 282 and the leading surface of the guide and advancement structure 280 may be synchronized along with the positioning of a key of the driving tip 294 so that a controlled, exact mating of the closure top 9 with the receiver 172 may be consistently accomplished. As will be described in greater detail below, according to the invention, the thread 282 of the tool 24 is of sufficient length that the longitudinal connecting member 8 (or other type of connecting member, such as a coil or rod) is moved downwardly in a controlled manner into the receiver 172 by rotating the tool 24.

[0098] The illustrated closure driver 26 according to the invention is sized and shaped to cooperate with the assembly 1 and the illustrated counter torque tool 28. As will be described in greater detail below, the closure driver 26 is inserted into the assembly 1 and engages the closure top 9 for tightening the same after removal of the closure starter/reduction tool 24 from the assembly 1. With particular reference to FIGS. 41, 42 and 47, the driver 26 includes a somewhat curved, T-shaped handle 310 fixed to an elongate cylindrical stem or shaft 312 and a driving tip 314 fixed to or integral with the shaft 312. The handle 310, shaft 312 and tip 324 are coaxial along an axis of rotation D. The handle 310 is sized and shaped to aid a surgeon in gripping and rotating the driver 26 about the axis D during tightening of the closure top 9 in the bone screw 4. The shaft 312 is of a desired length so that the tool 26 may be used in cooperation with the tool assembly 1, with the tip 314 in engagement with the closure top 9 and the shaft 312 extending through the tool assembly 1 with the handle 310 located above the lock pins 49 and the counter torque tool 28 with adequate clearance between the handle 310 and the assembly 1 to allow for the rotation of the closure top 9 in the bone screw receiver 172 by rotation of the handle 310 about the axis D. The driving tip 314 includes a slot 316 and faceted geometry 318 for engaging the closure structure 9 driving feature 184 during tightening of the structure 9 into the receiver 172.

[0099] With particular reference to FIGS. 39, 40 and 43-47, the illustrated counter torque tool 28 includes a hollow shaft 330 that is sized and shaped to be slidably received over the tool assembly 1. The shaft 330 has a lower end portion 332 that has a pair of diametrically spaced, curved bridges 334 and 336. With particular reference to FIGS. 44 and 46, each of the bridges 334 and 336 is sized and shaped to closely fit over the curved surface 198 and portions of the opposed flat surfaces 196 and 197 of the sleeve 190 and thus align the sleeve 190 of the longitudinal connecting member 8 with respect to the bone screw 4 in a desired orientation with the sides 196 and 197 parallel to the outer surfaces of the arms 30 and 32 of the bone screw 4. When seated squarely on at least one sleeve 190, as illustrated in FIGS. 46 and 47, the counter torque tool 28 allows a surgeon to counter a torque applied by the driver 26 during rotation and tightening of the closure top 9 in the receiver 172. The counter torque tool 28 also has an upper handle 340 disposed substantially perpendicular to the shaft 330 and having an upper opening 342 communicating with the hollow shaft through which the holding assembly 1 and the driver 26 passes in the manner suggested by FIGS. 43-47. The illustrated counter torque tool 28 further includes a lateral opening or side channel 350 formed in a surface 351, the channel 350 communicating with the hollow interior of the shaft 330 along an entire length of the shaft 330. The opening or channel 350 is disposed between substantially parallel walls 354 and 356 that define respective alignment bridges 334 and 336. The channel 350 is sized to receive the upper portion 254 of the stabilizer 22 that forms a ledge or overhang of the lower portion 256 at the side 261. Furthermore, the handle 340 includes a lower surface 360. Formed in the lower surface 360 is a recess 362 sized and shaped to receive the upper portion 254 of the stabilizer 22. The shaft 330 and the handle 340 are sized and shaped such that when the bridges 334 and/or 336 properly seat upon and align with one or two longitudinal connecting member sleeves 190 as illustrated in FIGS. 45 and 46, the top 262 of the stabilizer 22 makes contact with a substantially flat surface 362 that partially defines the recess 362. Lateral walls 366 that also define the recess 363 surround the stabilizer upper portion 254 near the side 261, limiting side to side and front to back movement of the stabilizer 22 and thus of the entire holding tool assembly 1 with respect to the counter torque tool 28.

[0100] In use, the previously described tools are utilized to attach one or more longitudinal connecting members 8 to the human spinal column 6. The procedure is begun by selection of a bone screw 4 in accordance with the size of the patient's vertebra 16 and the requirements of the spinal support needed. Bone screws 4 having a rotatable or polyaxial heads or receivers 172 are preferred but not required for the procedure, as such allow relatively easy adjustment of the longitudinal connecting member 8 in the tool assembly 1 and with respect to other tools included in the tool set 2 during placement and for movement of the tool assembly 1 or individual members 10 and 12, as described below. The bone screw 4 is also preferably cannulated so as to be receivable over and guided by a guide pin or wire as discussed more fully below.

[0101] Alternative polyaxial, hinged and monoaxial bone screws, for example, such as those described in U.S. patent application Ser. No. 11/328,481 filed Jan. 9, 2006, the disclosure of which is incorporated by reference herein, may also be used with tools according to the present invention. Furthermore, other types of longitudinal connecting members may be used according to the invention including, for example, chord/spacer combinations, rods and coils.

[0102] With particular reference to FIGS. 1-11, the tool assembly 1 may be placed into engagement with the polyaxial bone screw 4 as follows: With particular reference to FIG. 1, a pair of lock pins 49 are inserted in the elongate member 10 cylindrical channels 47 and 48 with each lock pin tip or bottom 95 being inserted into the channels at the top surface 56 and guided downwardly toward the bottom 64 of the tool 10. Once the threaded portion 97 makes contact with the threaded inner wall 60, the particular lock pin 49 is rotated and driven downwardly slightly, enough to place the lock pin 49 into engagement with the member 10. The bone screw receiver 172 is then aligned with an elongate tool member 10 by aligning the laser etched stripe 92 of the receiver arm 30 with the laser etched stripe 90 of the tool member 10. The lip surface 74 is then placed next to the bone screw arm 30 slightly beneath the groove 76 and then moved up into the groove as shown in FIGS. 8 and 9. The lock pin bottoms 95 are moved toward the receiver arm top surface 31 by mounting a lock pin driver socket (not shown) on a lock pin 49 with the driving portion 96 of the pin 49 received in an elongate socket of the driver. The lock pin driver is rotated about a center axis thereof until the bottom surface 95 of the pin 49 frictionally engages with the receiver surface 31 and the lip surface 74 is fully engaged with the bone screw arm 30 at the groove 76. The raised strip 78 disposed in the slit 80 of the receiver advantageously prohibits movement of the pin 49 between the surfaces 175 and 175a, but some movement toward and away from the channel 174 is possible. The lock pins 49 are inserted into the channels 47a and 48a of the member 12 in a similar fashion to what has been described herein with respect to the lock pins and channels 47 and 48 of the member 10. The member 12 is then engaged with the bone screw arm 32 at the groove 76a, with the lock pins 49 driven downward into engagement with the top surface 33 and the arm 32. It is noted that in certain embodiments according to the invention that do not include offset slits 80 and 86 in the bone screw arms 30 and 32, respectively, or cooperating offset alignment strips, such as the strip 78, the members 10 and 12 may be attached to either of the bone screw arms 30 or 32 as previously described herein. With reference to FIG. 11, both the members 10 and 12 are thus attached to the bone screw 4, forming the guide tool assembly 1 that provides some freedom of movement of the members 10 and 12 toward and away from the receiver channel 174 allowing for ease in insertion of longitudinal connecting members, tools and any other bone attachment structures.

[0103] With reference to FIGS. 12-22, after installation of the members 10 and 12 on the bone screw receiver 172, the driver 18 is inserted into the tool assembly 1 by downward or lateral insertion of the driving end portion 134 and a portion of the shaft 132 into the channel 101 formed between the members 10 and 12 with the stabilizer 20 initially disposed above the lock pins 49 as shown in FIG. 20. Thereafter, the driver 18 is moved downwardly toward the receiver 172 until the driving head 140 engages the drive feature 144 of the bone screw 4. The stabilizer 20 is then moved downwardly toward the members 10 and 12 with each of the lock pins 49 being received in a through bore 152 of the stabilizer 20. The stabilizer is moved toward the members 10 and 12 until the bottom surface 164 seats on top surfaces 56 and 56a of respective elongate members 10 and 12 and also upon the surface 167 of the lock limit 136. With reference to FIG. 22, the driver 18 is manually rotated about the axis A thereof to rotate and drive the bone screw shank 170 into the vertebra 16. The driver 18 may be removed by simply sliding the shaft 132 upwardly away from the receiver 172 until the stabilizer 20 clears the pins 49 and the driving end 140 is out of the incision, and then the driver 18 may be moved laterally out of the tool assembly 1 in either direction out of the through channel 101.

[0104] With further reference to FIG. 22, in a method according to the invention, a relatively minimally invasive incision or incisions 368 may be made in a patient's skin 369 and stretched so as to snugly receive the guide tool assembly 1 and other tools of the invention. A drill (not shown) is utilized to form a first guide bore in the vertebra 16 under guidance of non invasive imaging techniques, which procedure is well known and established. A thin pin or guide wire may then be inserted in the first guide bore, the pin and guide bore functioning to minimize stress on the vertebra 16 and providing an eventual guide for the placement and angle of the bone screw shank 170 with respect to the vertebra 16. Then the guide bore is enlarged utilizing a cannulated drilling tool or tap having an integral or otherwise attached cannulated and threaded bit with an outer surface sized and shaped to correspond to the size and shape of the chosen threaded bone screw 1.

[0105] With the pin fixed to the vertebra 16 and in place in an enlarged guide bore and extending upwardly through the bore and out of the incision 368, the pin is threaded into the bore 178 at the tip 179 of the shank 170 and out of the opening at the top surface 176 of the bone screw shank 170. The pin is then threaded through the driver 18. With the driver 18 installed in the tool assembly 1 as illustrated in FIG. 22 and as previously described herein, the bone screw 4 is then rotated and driven into the tapped bore in the vertebra 16. Depending upon the type of bone screw 4 utilized in connection with the tool assembly of the invention, the surgeon may drive the bone screw shank 170 independently of the receiver 172 and attached tool 1, or the surgeon may drive the bone screw shank 170 and the receiver 172 and attached tool 1 until the shank body 170 is disposed at a desired depth in the tapped bore of the respective vertebra 16. At least two and up to a plurality of bone screws 4 with attached insertion tool assemblies 1 are installed in each vertebra 16 to be attached to the longitudinal connecting member 8.

[0106] With reference to FIGS. 23-38, the closure starter/reduction tool 24 is then used to insert the closure top 9 between the members 10 and 12 and press or reduce the longitudinal connecting member 8 or other type of longitudinal connecting member, such as a rod or coil, downwardly into the receivers 172 of the implanted bone screws 4. With reference to FIG. 23, in the embodiment shown, a spacer or sleeve 190 is cut to length for engagement with each of two adjacent bone screws 4 and pre-loaded onto the inner core 188 then the core 188 of the longitudinal connecting member 8 is inserted into and through the channel 101 at the recessed portions 58 and 58a formed by the members 10 and 12 with a tail or end of the cord core 188 extending out of the channel 101. The core 188 is then manipulated downwardly manually to a location below the recessed portions 58 and 58a where the channel 101 narrows, thus generally aligning the core 188 with the bone screw channel with the sleeve 190 being in sliding contact with outer planar surfaces of the members 10 and 12 as illustrated in FIGS. 25, 26 and 29. A closure top 9 is placed upon and frictionally engaged with the closure starter/reduction tool 24 by inserting the driving tip 294 into the closure driving feature 184. Then, the closure top 9 may be laterally inserted between the members 10 and 12 through the channel 101 at the recessed portions 58 and 58a as illustrated in FIG. 25. To stabilize the members 10 and 12, the stabilizer 22 may then be engaged with the members 10 and 12 by downward insertion of the stabilizer 22 over the lock pins 49 as shown in FIGS. 26, 29 and 30, with each lock pin 49 being received in a bore 252 of the stabilizer 22. The stabilizer 22 is moved toward the members 10 and 12 until the bottom surface 264 seats on top surfaces 56 and 56a of respective elongate members 10 and 12. With further reference to FIGS. 26 and 30, thereafter, the closure starter/reduction tool 24 may be laterally angularly inserted into the channel 101, angled upwardly into a position parallel and centrally located between the members 10 and 12, with the reduced portion 296 of the tool 24 being receivable in and through the channel 270 of the stabilizer 22 as best illustrated in FIG. 30.

[0107] The tool 24 is then manually pushed downwardly along the channel 101 between the members 10 and 12 with the closure top 9 bottom surface 185 engaging and pressing the inner core 188 downwardly toward the bone screw 4 until the threaded portion 282 of the tool 24 makes contact with the guide and advancement structure 280 of the stabilizer 22. At the same time, the sleeve 190 is manually pressed downwardly through the incision 368 or along an extension thereof. Back muscle tissue separates to allow the insertion of the core and sleeve combination of the connecting member 8 and can be further separated by finger separation or cutting through of one or more incisions, if required.

[0108] With particular reference to FIG. 33, the closure starter/reduction tool 24 is then rotated about the axis C by rotating the handle 290, mating the threads 280 and 282, providing mechanical advantage to move the closure top 9 and core 188 toward the receiver 172 in a controlled manner. During such rotation, the closure structure bottom surface makes contact with the core 188, moving and also holding the core 188 in a controlled manner at intermediate positions along the assembly 1, allowing for manipulation of the sleeve 190 in a downward direction without the need for manual pressure on the starter/reduction tool 24 as both the core 188 and the sleeve 190 are reduced downwardly toward the bone screw 4 and also as other portions of the core 188 and other sleeves 190 are being moved downwardly toward other cooperating bone screws 4 also utilizing the tool assembly 1 and other cooperating tools of the invention disclosed herein. Subsequent rotation of the tool 24 also rotates the closure top 9 into engagement with the guide and advancement structure located on inner surfaces of the bone screw arms 30 and 32, capturing the core 188 in the receiver 172 as illustrated in FIG. 34.

[0109] It is foreseen that in certain embodiments according to the invention, starting locations of the respective mating guide and advancement structures 280 and 282, as well as a projection or key on the driving tip 294 and a key slot on the closure top drive 184 may be positioned to precisely mate the closure structure guide and advancement structure 182 with a guide and advancement structure formed on inner surfaces of the arms 30 and 32 of the receiver 172. Also, such an embodiment may include cooperating guide and advancement structures sized and positioned such that once the closure top 9 is threaded fully into the receiver 172, but not otherwise tightened therein, further rotation of the tool 24 may be prohibited by abutment with a thread run out stop.

[0110] With reference to FIG. 34, the driving tip 294 of the closure starter/reduction tool 24 is then retracted by simply pulling the tool 24 upwardly away from the receiver 172. Then, the tool 24 may be removed from the assembly 1 by lifting the tool 24 upwardly between the members 10 and 12 or by lateral and angular movement, with the reduced portion 298 passing through the lateral channel 270 and the larger threaded portion 282 passing through the larger recess created by the cooperating recessed portions 58 and 58a of respective members 10 and 12.

[0111] With reference to FIGS. 39-47, once all of the closure tops 9 are in a seated position in respective bone screws 4 and the surgeon is satisfied with the position of all of the elements, the closure tops 9 may be locked into place with the elongate driving tool 26 and the counter torque tool 28. With particular reference to FIGS. 43-46, the counter torque tool 28 is inserted over the assembly 1 and moved downwardly toward the bone screw 4 with the end or side 261 of the stabilizer 22 extending through the side channel 350. With particular reference to FIGS. 44 and 46, as the tool 28 is pressed downwardly against the sleeve 190, contact between the bridge 336 and the spacer surfaces 196, 197 and 198 straightens the sleeve 190, aligning the surfaces 196 and 197 into substantially parallel relationship with outer surfaces of the receiver arms 30 and 32. Also, with reference to FIGS. 39 and 40, as the sleeve 190 becomes straightened, the stabilizer 22 top surface 262 makes contact with the surface 364 of the counter torque tool 28 ensuring alignment between the sleeve 190 and the bone screw receiver 172 without excess pressure being placed on the longitudinal connecting member 8 or the bone screw 4. With reference to FIGS. 41, 42 and 47, the closure driver 26 is then inserted into the upper opening 342 of the counter torque tool 28 and moved downwardly until the driving tip 314 engages the driving feature 184 of the closure top 9. The tool 28 is then rotated to tighten the closure top 9 in the receiver 172 by rotating the T-shaped handle 310 while the counter torque tool 28 is held stationary using the handle 340. By rotating the handle 310, a surgeon applies adequate tightening force, typically 70-120 inch pounds, to fully tighten and set the closure top 9 within the receiver 172 so that the bottom surface point 186 and rim 187 dig into the cylindrical surface 192 of the core 188.

[0112] As indicated previously herein, as the closure tops 9 are rotated and then tightened against the core 188 in a pair of cooperating bone screws 4, such bone screws 4 may be pressed toward one another by moving attached assemblies 1 toward one another, thereby frictionally engaging and then compressing the sleeve 190 between the adjacent bone screws 4. When all tooling is removed, the sleeve 190, pressing against facing surfaces of the cooperating bone screw receivers 172, stretches the elastic core 188. The resulting bone attachment assembly is thus substantially dynamically loaded and oriented relative to the cooperating vertebrae to provide relief (e.g., shock absorption) and protected movement with respect to flexion, extension, distraction and compressive forces placed on the longitudinal connecting member 8 and the two connected bone screws 4. The elasticity of the core 188 may also allow the core 188 to twist or turn, providing relief for torsional stresses. The sleeve 190 limits such torsional movement as well as bending movement of the core 188, providing spinal support. Furthermore, because the sleeve 190 is compressed during installation, the sleeve advantageously allows for some protected extension or distraction of both the core 188 and the sleeve 190.

[0113] After all of the closure tops 9 have been locked into place, the driver 26 and counter torque tools 28 are removed, followed by removal of each of the tool assemblies 1. The stabilizer 22 is first removed by sliding the stabilizer 22 upwardly and away from the member 10 and 12 and off of the lock pins 49. The lock pin driver (not shown) is then used on each lock pin 49 to loosen each pin 40 from the members 10 and 12 by rotating the driver to rotate each pin upwardly and away from the surface 31 or 33. Slight downward force is then placed on each of the members 10 and 12 by the surgeon to move the lip surfaces 74 and 74a out of the respective grooves 76 and 76a of the receiver 172. Then the members 10 and 12 are moved upwardly away from the receiver 172 and out of the incision 368. Such procedure is followed to remove each tool member 10 and 12 out of the incision or various incisions utilized to implant the bone screws 4 and longitudinal connecting member 8 after which the incision or incisions 368 are closed. Examples of fully assembled and implanted bone screw or screws 4 with a cooperating longitudinal connecting member 8 are illustrated in FIGS. 48 and 49.

[0114] If removal of the longitudinal connecting member 8 from any of the bone screws 4 is necessary, or if it is desired to release the member 8 at a particular location, disassembly is then accomplished in reverse order to the procedure described previously herein for assembly.

[0115] With reference to FIGS. 50-53, eventually, if the spine requires more rigid support, the longitudinal connecting member 8 may be removed and replaced with another longitudinal connecting member, such as a solid rigid rod 370, having the same diameter as the inner core 188, utilizing the same or same sized closure tops 9. Such is accomplished by using the driving tool 26 inserted in the aperture 184 to rotate and remove the closure tops 9 from the receivers 172 followed by removal of the connecting member 8. The replacement rod 370 is then implanted, followed by closure top 9a insertion and tightening using the same or similar tools previously described herein. With reference to FIG. 52, it is noted that the illustrated embodiment includes a counter torque tool 28a that includes curved bridges 334a sized and shaped to closely engage the replacement rod 370.

[0116] Alternatively, if less support is eventually required, a less rigid, more flexible assembly, for example, including a longitudinal connecting member made with a more flexible core, but otherwise having the same diameter as the inner core 188, may replace the connector 8 also utilizing the same bone screws 4.

[0117] It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.