Patent Publication Number: US-11648039-B2

Title: Spinal fixation tool attachment structure

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/662,826, filed Oct. 24, 2019, which a continuation of U.S. patent application Ser. No. 14/601,834 filed Jan. 21, 2015, now U.S. Pat. No. 10,485,588, which a continuation of U.S. patent application Ser. No. 11/272,508, filed Nov. 10, 2005, which claims the benefit of U.S. provisional patent application Ser. No. 60/630,536, filed Nov. 23, 2004, and which is also a continuation-in-part of U.S. patent application Ser. No. 10/996,289, filed Nov. 23, 2004, now U.S. Pat. No. 8,152,810 and is also 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, each of which are incorporated entirely by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to apparatuses and methods for use in performing spinal surgery and, in particular, to tools and methods of using such tools, especially for percutaneously implanting spinal screws and for implanting a rod for spinal support and alignment, using minimally invasive techniques. 
     For many years, spinal osteosynthesis apparatuses have been utilized to correct spinal deformities, injuries or disease. In such procedures, elongate rods are surgically attached to vertebrae of the spine to provide support and/or to realign or reposition certain vertebrae. Such rods are 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 minimally invasive to the body of the patient. 
     Problems arise when implantation tools designed for traditional surgery that is highly invasive are utilized in percutaneous surgery. The tools may be bulky, oversized or have irregular surfaces or protrusions. 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 is insufficient clearance to use such structure and/or such structure may produce additional invasive trauma which the percutaneous surgery is attempting to avoid. 
     A percutaneous procedure also presents a problem with implantation of rods that are elongate and have historically required a long incision and open wound in order to provide for the length of the rod and the space required for the surgeon&#39;s hands to manipulate the rod. Such problems are then compounded by the implants and insertion tools used with the rod. 
     Consequently, it is desirable to develop apparatuses and techniques that allow for the insertion of bone screws, the insertion and reduction of a rod into the bone screws and the securing of the rod to the bone screws with significantly less invasion into the body of the patient and with minimal surgical incision of the skin over the operational site. 
     SUMMARY OF THE INVENTION 
     A tool assembly and a set of tools according to the invention is provided for percutaneously implanting bone screws and an associated spinal rod in a patient. The tool assembly includes an elongate guide tool with implant engaging members and a multi-purpose installation tool. The multi-purpose tool is a stabilizer for the guide tool implant engaging members which also functions as a rod stabilizer tang container and deployer and a rod pusher and reducer. The guide tool has a lower end configured with opposed implant engaging members for releasable attachment to a spinal implant bone screw, hook, etc. The multi-purpose installation tool is elongate, and preferably includes a translation nut and attached sleeve which has a lower end for engaging and containing the rod stabilizer tang prior to rod insertion and later pushing on the rod for reduction. The translation nut is coaxial and freely rotatable with respect to the sleeve. The nut is configured for rotatable attachment to an upper end of the guide tool. The multi-purpose installation tool sleeve is attachable or securable to the guide tool in a first bone screw implantation orientation and in an alternative second rod pushing orientation. In the first, bone screw implantation orientation, the sleeve is disposed in a fixed, stationary position with respect to the guide tool, with the sleeve substantially surrounding the guide tool and retaining a flexible tang. In the second or rod pushing orientation, the sleeve is slidable along an axis of the guide tool and the nut can be rotated, thereby translating the rod pushing end between a first location substantially spaced from the guide tool end and a second location near the guide tool end for rod reduction. 
     The tool assembly may further include a driver having a handle, a guide tool attachment portion and a stem, the stem having an end configured for rotatable engagement with a spinal implant screw. The driver is in coaxial relationship with both the guide tool and the multi-purpose installation tool when the stem is disposed within the guide tool with the guide tool attached to the multi-purpose installation tool. The attachment portion of the driver is configured for rigid attachment to the guide tool, preventing rotation of the driver in relation to the guide tool. 
     A tool set according to the invention includes at least a pair of end guide tools. Each end guide tool includes an elongate body having opposed implant engaging members with lower attachment structure adapted for attachment to a respective bone screw. The body has an inner surface defining an elongate and laterally opening channel. Preferably, the guide tool body further defines an elongate opening communicating with the channel and a back wall with a flexible holding structure, the wall and holding structure disposed opposite the lateral opening. The back wall flexible holding structure includes first and second elongate and parallel slits in the lower back wall portion creating a movable tab or tang disposed between the first and second slits. The flexible flap or tang partially defines the elongate channel. Furthermore, during insertion procedures, the tang may be pushed so as to flex, hinge or spring at an upper end thereof and so that a lower end angulates and translates outwardly or to a location lateral relative to a remainder of the back wall, with the channel adapted to receive a respective rod therein. When an end of the rod is inserted in the lower end channel, the tang may be resiliently flexed further outwardly to accommodate the length of the rod while maintaining, containing and stabilizing the rod in a desired position relative to bone screws. 
     The multi-purpose installation tool is attachable to the end guide tool in a first, bone screw implantation configuration position and in an opposite second, rod pushing configuration or position. In the first position, an elongate slot or opening in the sleeve of the tool support is aligned with and fixed in adjacent relationship to the channel opening of the end guide tool, with the sleeve of the tool being held adjacent to the back wall portion and retaining the spring tang. In the second, rod pushing position, the end guide tool back wall portion and the tool sleeve opening are fixed in adjacent relationship with the back wall tang portion protrudeable into the tool sleeve opening. 
     An intermediate guide tool according to the invention includes an end with opposed first and second implant engaging legs defining a longitudinal pass-through opening, passageway or slot for receiving a rod therethrough. When attached to a multi-purpose installation tool in the first, bone screw implantation orientation, the tool sleeve is disposed in a fixed, stationary position substantially surrounding and supporting both the intermediate guide tool legs. In the second or rod pushing orientation, the sleeve is in sliding relation along an axis of the intermediate guide tool, with the sleeve and associated rod pushing end translatable along the first and second legs between a first location spaced from the intermediate guide tool end and a second location adjacent or near the guide tool end. 
     A vertebral support rod implantation kit according to the invention, adapted for use with a plurality of vertebrae, includes a plurality of polyaxial bone screws, each bone screw being adapted for implantation in one vertebra, each of the bone screws having an attachment structure. It is foreseen that the polyaxial bone screws can be cannulated and/or fixed. The kit also includes an elongate rod having first and second ends, the rod sized and shaped to extend between a pair of end bone screws of the plurality of bone screws, which can be fixed, polyaxial and cannulated or not cannulated. The kit further includes a plurality of closure tops with each closure top being sized and shaped to mate with a respective bone screw and capture or retain the elongate rod within a cavity or channel defined by the respective arms of the bone screw. Additionally, the kit includes a pair of end guide tools, and may include one or more intermediate guide tools, each guide tool being attachable to multi-purpose installation tools, as described herein and bone screw drivers, the drivers being configured to be rigidly attached to a respective end guide tool or intermediate guide tool. 
     In a method according to the invention, a spinal fixation tool assembly is assembled by first attaching a bone screw head of a spinal implant screw to a mating attachment structure disposed at a first end of an elongate guide tool implant engaging member, the guide tool defining a laterally opening channel and having a second attachment structure disposed at a second end thereof. The guide tool and attached spinal implant screw may then be inserted into a multi-purpose installation tool, the tool having a translation nut, or the like, and a sleeve-like structure. The nut or similar part is rotated or manipulated in a first direction to mate the tool support with the second attachment structure on the guide tool and translate the sleeve or similar surrounding structure to a location near the guide tool first end. Then, a driver is inserted into the guide tool channel, the driver having a handle and a spinal implant screw engagement end. In the illustrated embodiment, the driver is attached to the guide tool at the second attachment structure with the driver engagement end engaging the spinal implant screw. It is foreseen that the guide tool could be attached to the screw and the screw inserted with the driver without the need for additional tools. 
     A method according to the invention may also include the steps of inserting the attached driver, guide tool and spinal implant screw into an incision, especially a minimally invasive incision sized to snugly or closely receive the assembled tools and bone screw, and into contact with a vertebra, followed by turning the driver handle. By turning the handle, the driver, the associated tools and the spinal implant screw are rotated as one assemblage or unit, driving the spinal implant screw into the vertebra. 
     Further method steps according to the invention include detaching the drivers from the attached guide tool and multi-purpose installation tool, if used, and withdrawing the drivers from the incisions, followed by detaching the multi-purpose installation tools, if used, from the end guide tools and thereby deploying the end tangs. If used, it may also be desirable to detach the multi-purpose installation tools from the intermediate guide tools, if any. 
     According to one embodiment of the invention, during rod insertion, a respective multi-purpose installation tool may be utilized for rod reduction and accordingly replaced on each end guide tool with the sleeve opening thereof aligned with the end guide tool flexible wall or tang to allow the tang to remain flexed outward. Then a rod first end may be inserted into an incision through which one of the end guide tools has been inserted, and then guided into a channel of an adjacent end or intermediate guide tool. The rod is then guided into and through all remaining channels with first and second ends of the rod each in contact with a flexible wall or deployed tang of a respective end guide tool with the tangs biasing against the rod ends, and with the rod extending through all associated guide tools. The multi-purpose installation tool sleeve is then utilized as a rod pusher by rotating the nut and sliding the closed end of the sleeve toward the lower guide tool end, the sleeve end contacting the rod and pushing the rod toward the bone screw. 
     The attachment structure for joining the guide tool to the bone screw includes radial mating projections and receivers or grooves that allow the guide tool to be twisted on and twisted from the head of the bone screw. For example, an external attachment on the bone screw head can have tapered undercut upper surfaces. Additional attachment structures according to the invention include snap-on/twist off, snap-on/pry-off, slide-on/push-off, snap- or slide-on/slide off, and other combinations. It is foreseen that other attachment structure could be used such as clip-on/clip-off, clip-on/twist-off, snap-on/snap-off, spring-on/spring-off, spring-on/twist-off, set screws, etc. The attachment structure secures the guide tool to the bone screw during insertion of the screw into bone, but allows the tool to release from the bone screw for removal of the tool at the end of the procedure by rotation of the tool about a central axis thereof or by some other mechanism, as described herein. 
     OBJECTS AND ADVANTAGES OF THE INVENTION 
     Therefore, the objects of the present invention are: to provide a compact tool assembly for supporting and installing bone screws and other implants with minimal surgical invasion to the patient; to provide such an assembly wherein a tool providing support and stabilization for implant engaging members of the assembly during bone screw implantation may also be utilized for deployment of rod containment tangs and as a rod reducer; to further provide a set of tools for implanting a spinal rod for support or alignment along a human spine with minimal surgical invasion of the patient; to provide such a set of tools including a pair of end tool guides for slidably guiding opposed ends of the rod toward end bone screws attached to the end guide tools; to provide such a set of tools including intermediate guide tools for each intermediate bone screw that guide the rod in slots therethrough to respective bone screws; to provide such a set of tools including rod and closure top installation tools for assisting in securing the rod in the bone screws; to provide such a set of tools wherein the guide tools are easily attached to and disengaged from the bone screws; to provide such a set of tools wherein the guide tools, guide tool supports or stabilizers, tang containment and deployment tools, rod reduction tools, bone screw installation tools and closure top installation tools are all easily aligned, positioned, and engaged, if necessary, with respect to the bone screw and are disengaged from the bone screw and other tools in the installation assembly by manual manipulation of the surgeon; to provide a method of implanting a rod into bone screws within a patient with minimal or less surgical invasion of the patient; to provide such a method utilizing the previously described tools for percutaneous implantation of such a rod; 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. 
     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. 
     The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an exploded front elevational view of a tool assembly according to the present invention showing a driver tool, a multi-purpose installation tool implant engaging member stabilizer sleeve/tang container and deployer/rod pusher and reducer and an end guide tool shown with an attached polyaxial bone screw. 
         FIG.  2    is an enlarged front elevational view of an intermediate guide tool of the invention. 
         FIG.  3    is an enlarged side elevational view of the intermediate guide tool of  FIG.  2   . 
         FIG.  4    is an enlarged rear elevational view of the intermediate guide tool of  FIG.  2   . 
         FIG.  5    is an enlarged front elevational view of the end guide tool of  FIG.  1   . 
         FIG.  6    is an enlarged side elevational view of the end guide tool of  FIG.  5   . 
         FIG.  7    is an enlarged rear elevational view of the end guide tool of  FIG.  5   . 
         FIG.  8    is a cross-sectional view of the end guide tool, taken along the line  8 - 8  of  FIG.  5   . 
         FIG.  9    is an enlarged cross-sectional view of the intermediate guide tool, taken along the line  9 - 9  of  FIG.  2   . 
         FIG.  10    is an enlarged cross-sectional view of the intermediate guide tool, taken along the line  10 - 10  of  FIG.  2   . 
         FIG.  11    is an enlarged bottom plan view of the intermediate guide tool of  FIG.  2   . 
         FIG.  12    is an enlarged and fragmentary perspective view of a polyaxial bone screw of the invention. 
         FIG.  13    is an enlarged and fragmentary front elevational view of the polyaxial bone screw of  FIG.  12   . 
         FIG.  14    is an enlarged and fragmentary side elevational view of the polyaxial bone screw of  FIG.  12   . 
         FIG.  15    is an enlarged and fragmentary side elevational view of the polyaxial bone screw of  FIG.  12    disposed opposite the side shown in  FIG.  14   . 
         FIG.  16    is an enlarged top plan view of the polyaxial bone screw of  FIG.  12   . 
         FIG.  17    is an enlarged and fragmentary front elevational view of the polyaxial bone screw of  FIG.  12    and the intermediate guide tool of  FIG.  2   , shown at an early stage of a twist-on installation of the intermediate guide tool to the bone screw head. 
         FIG.  18    is an enlarged and fragmentary cross-sectional view of the intermediate guide tool and polyaxial bone screw installation, taken along the line  18 - 18  of  FIG.  17   . 
         FIG.  19    is an enlarged and fragmentary cross-sectional view similar to  FIG.  18   , showing a later stage of the twist-on installation of the intermediate guide tool to the bone screw head. 
         FIG.  20    is an enlarged and fragmentary cross-sectional view similar to  FIGS.  18  and  19   , showing the intermediate guide tool installed on the bone screw head. 
         FIG.  21    is an enlarged, fragmentary and cross-sectional view, taken along the line  21 - 21  of  FIG.  20   , showing the intermediate guide tool installed on the bone screw head. 
         FIG.  22    is an enlarged front elevational view of the multi-purpose tool shown in  FIG.  1   . 
         FIG.  23    is a cross-sectional view of the multi-purpose tool taken along the line  23 - 23  of  FIG.  22   . 
         FIG.  24    is an enlarged bottom plan view of the multi-purpose tool of  FIG.  22   . 
         FIG.  25    is an enlarged and fragmentary cross-sectional view of a portion of the multi-purpose tool shown in  FIG.  23   . 
         FIG.  26    is an enlarged and fragmentary side elevational view of the driver shown in  FIG.  1    having a handle, a nut fastener and a stem, with the nut fastener being shown in a first, unengaged position. 
         FIG.  27    is an enlarged and fragmentary front elevational view of the driver tool similar to  FIG.  26   , showing the nut fastener in a second or intermediate position. 
         FIG.  28    is an enlarged and fragmentary side elevational view similar to  FIG.  27    and further showing a cross-sectional view of the nut fastener, taken along the line  28 - 28  of  FIG.  27   . 
         FIG.  29    is an enlarged cross-sectional view similar to  FIG.  23   , showing an early stage of the installation of the multi-purpose tool to the end guide tool (shown in side elevation as in  FIG.  6   ). 
         FIG.  30    is an enlarged cross-sectional view similar to  FIG.  29   , showing the multi-purpose tool installed to the end guide tool (shown in side elevation). 
         FIG.  31    is an enlarged cross-sectional view of the multi-purpose tool, taken along the line  31 - 31  of  FIG.  30   , showing the end guide tool in front elevation. 
         FIG.  32    is an enlarged and fragmentary cross-sectional view of the multi-purpose tool similar to  FIG.  31   , shown attached to the end guide tool and also showing a sliding engagement stage of attachment to the driver (shown in front elevation). 
         FIG.  33    is an enlarged and fragmentary front elevational view similar to  FIG.  32   , showing the driver nut fastener in the intermediate position shown in  FIG.  27   . 
         FIG.  34    is an enlarged and fragmentary front elevational view similar to  FIG.  33   , showing the driver in fixed engagement with the guide tool. 
         FIG.  35    is an enlarged and fragmentary view similar to  FIG.  34   , showing the driver in fixed engagement with the guide tool and with the driver nut fastener shown in cross-section as in  FIG.  28   , and the multi-purpose tool shown in cross-section as in  FIG.  32   . 
         FIG.  36    is a partial and generally schematic cross-sectional view of a patient&#39;s spine, showing a thin guide pin installed at a first side thereof and a bone screw tap tool and threaded bore made thereby at a second side thereof. 
         FIG.  37    is a partial and generally schematic view of a patient&#39;s spine showing a tool assembly according to the invention with attached bone screw being guided toward the threaded bore in a vertebra in an early stage of a process according to the invention. 
         FIG.  38    is a partial and generally schematic view of a patient&#39;s spine, showing an end guide tool and the multi-purpose tool of the present invention being positioned for use in a process according to the invention. 
         FIG.  39    is a partial and generally schematic view of a patient&#39;s spine, showing a pair of end tools and a pair of intermediate tools of the present invention being positioned for use in a process according to the invention. 
         FIG.  40    is a partial and generally schematic view of a patient&#39;s spine, showing a pair of end tools with the flexible tangs containing a rod which has now been inserted and a pair of intermediate tools of the present invention with one of the intermediate tools shown with an attached multi-purpose tool in a rod reduction application and one of the end guide tools shown partially cut-away, illustrating a closure top installation tool disposed within the end tool and cooperating with a bone screw closure member, the tools being utilized in an early stage of rod implantation to guide the rod toward the bone screws. 
         FIG.  41    is a partial and generally schematic cross-sectional view of the spine, taken along the line  41 - 41  of  FIG.  40   , showing an early stage of implanting a rod according to a process of the invention. 
         FIG.  42    is a partial and generally schematic view of a patient&#39;s spine similar to  FIG.  40   , showing cut-away portions of all four tool assemblies, illustrating an intermediate stage of implanting a rod. 
         FIG.  43    is a partial and generally schematic view of a patient&#39;s spine similar to  FIG.  42   , showing cut-away portions of three of the tool assemblies and one assembly without an end tool, illustrating the rod fully installed in all the bone screws. 
         FIG.  44    is an exploded front elevational view of an anti-torque tool assembly according to the present invention showing an antitorque tool and a closure top installation tool cooperating with a break-away bone screw closure member. 
         FIG.  45    is a bottom plan view of the anti-torque tool shown in  FIG.  44   . 
         FIG.  46    is a fragmentary and front elevational view of a bone screw with attached break-away closure member and installed rod, and further showing the closure top installation tool of  FIG.  44    with the anti-torque tool. 
         FIG.  47    is a fragmentary and front elevational view of a bone screw and anti-torque tool with portions broken away to show a torque driver advancing toward the break-away closure member in a process according to the invention. 
         FIG.  48    is a fragmentary and front elevational view of the bone screw and anti-torque tool similar to  FIG.  47   , with portions broken away to show a fully installed rod and closure member with the break-away head removed from the top by the torque driver. 
         FIG.  49    is an enlarged and fragmentary front elevational view showing an alternative snap- or twist-on and twist-off attachment structure according to the invention on a guide tool and on a cooperating polyaxial bone screw head. 
         FIG.  50    is an enlarged and fragmentary front elevational view of the attachment structure shown in  FIG.  49    showing the guide tool installed on the bone screw head. 
         FIG.  51    is an enlarged and fragmentary view of the attachment structure shown in  FIG.  49    with portions removed to show the detail thereof showing an early stage of the snap on installation of the guide tool on the bone screw head. 
         FIG.  52    is an enlarged and fragmentary view similar to  FIG.  51    showing a later stage of installation of the guide tool on the bone screw head. 
         FIG.  53    is an enlarged and fragmentary view similar to  FIGS.  51  and  52    showing the guide tool installed on the bone screw head. 
         FIG.  54    is an enlarged and fragmentary front elevational view of a polyaxial bone screw shank with a pivotally attached head or receiver and shown with a guide tool, with portions broken away to show the detail thereof, illustrating a second alternative snap-on and pry-off attachment structure according to the invention on a guide tool and on the polyaxial bone screw head, showing and early stage of snap-on installation. 
         FIG.  55    is an enlarged and fragmentary view, identical to  FIG.  54    with the exception that an intermediate stage of snap-on installation is shown. 
         FIG.  56    is an enlarged and fragmentary view, identical to  FIG.  54    with the exception that the guide tool is shown fully installed on the bone screw head. 
         FIG.  57    is an exploded perspective view of a bone screw having a shank and a head or receiver, the receiver having a third alternative snap-on or slide-on and slide-off or push-off attachment structure according to the invention. 
         FIG.  58    is an enlarged front elevational view of the receiver of  FIG.  57   . 
         FIG.  59    is an enlarged side elevational view of the receiver and shank of  FIG.  57    shown with a guide tool with cooperating attachment structure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     With reference to  FIG.  1   , and for example, also  FIGS.  37  and  40   , reference numeral  1  generally designates a tool assembly according to the present invention and reference numeral  2  generally designates a tool set according to the invention, made up of a number and variety of tool assemblies  1  for use in installing a set of bone screws  4  into a patient&#39;s spine  6 , followed by the installation of an orthopedic spinal rod or longitudinal member  8  into the bone screws  4  in a process according to the present invention. 
     The tool embodiment assembly  1  includes an end guide tool  9  or an intermediate guide tool  10  mated with a multi-purpose installation tool  12  configured to function as a guide tool stabilizer and supporter, a tang container and deployer and a rod pusher and reducer. The tool assembly  1  may further include a driver  14 . A set  2  of the illustrated embodiment includes a pair of end guide tools  9  and a plurality of intermediate guide tools  10 , which in the illustrated embodiment includes a pair of intermediate guide tools  10  on each side of a patient&#39;s spine  6 , but which can include none, one or many intermediate guide tools  10  depending upon the particular application, so that one intermediate guide tool  10  is used for each intermediate bone screw  4  to which the rod  8  is to be attached. 
     The driver  14  is used in conjunction with the guide tool  9  and the guide tool  10  to implant bone screws  4  in the patient&#39;s spine  6  and, in particular, in vertebrae  16  along the spine  6  as shown in  FIG.  37   . Each end guide tool  9  and intermediate guide tool  10  is configured to cooperate with the multi-purpose installation tool  12  to install the rod  8 . However, it may be sufficient according to a process of the invention to not utilize the multi-purpose installation tool  12  or to use only one multi-purpose installation tool  12  in a particular tool set  2 , as shown in  FIG.  40   . Rods  8  or other longitudinal members are often installed on both sides of the spine  6  during the same procedure. 
     It is 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 drawing figures, as well as the normal connotations applied to such devices, and is not intended to restrict positioning of the assembly  1  or the tool set  2  in actual use. 
     The end guide tool  9  is illustrated in  FIG.  1    and  FIGS.  5  through  8   . In particular, each end guide tool  9  has an elongate body  18  that is sized and shaped to be sufficiently long to extend from implanted bone screws  4  through an exterior of a patient&#39;s skin  20  so as to provide an outwardly extending and upper handle portion  22  that allows and provides for gripping by a surgeon during procedures utilizing the tool set  2 , with or without an attached multi-purpose installation tool  12  and/or driver  14 . 
     Each of the end guide tools  9  further includes an intermediate portion  24  and a lower implant engaging portion  26  which includes opposed implant engaging members for securing one the implants there between. Each end guide tool  9  has a substantially flat back wall  28  joining a pair of substantially cylindrically shaped side walls  32  and  33 . The back wall  28  provides a flexible holding structure that includes a pair of parallel slits  34  extending from near the lower handle portion  22  to an end  36  of the tool  9 . When pressed upon by a rod  8 , a flap or flexible tang  38  disposed between the slits  34  in the back wall portion is configured to flex or spring radially outwardly from the bottom and about the top thereof in a deployed position, as is shown in  FIG.  6   . The back wall portion flap or tang  38  provides a surgeon with some additional working space and flexibility when working with the rod  8  during surgery, so the rod  8  can extend beyond the bone screws  4  while remaining under resilient tension produced by outward biasing of the flexible back wall portion so that the rod  8  remains in a desired position and under control. Further, the tang or flap  38  also functions to urge the rod  8  toward the other tools in the tool set  2 , as shown in  FIG.  40    and as will be discussed more fully below. 
     The upper portion  22  of each end guide tool  9  includes a laterally or sideways opening channel  39 , forming a U-shaped cross-section, a C-shaped cross-section, a crescent shaped cross-section or the like having a generally elongate and axially extending opening  40  with a side-to-side width  42 . Preferably, the channel  39  mates with other channel structure described below so as to extend the entire length of the end guide tool  9 . The opening  40  communicates with and forms part of the channel  39  that opens at an upper end  43  of the guide tool  9  and also opens perpendicularly with respect to a central axis of the guide tool  9  or laterally to one side of the end guide tool  9 , thus defining the opening  40 . The opening  40  narrows near the upper end  43  providing a slot  44  having a side-to-side width  45  that is smaller than the side-to-side width  42 . The slot  44  is configured for sliding engagement with a rotational locking pin  46  disposed on the driver  14  and discussed more fully below. Disposed on either side of the slot  44  are co-planar surfaces  47  and  48  that are parallel with the back wall  28 . The surfaces  47  and  48 , as well as the back wall  28 , provide alignment surfaces when the multi-purpose tool  12  is inserted onto the guide tool  9  discussed more fully below. 
     The opening  40  is of substantially constant width through a mid-section  48  of the handle portion  22 , sufficiently wide to receive additional tools and/or a closure top for sideways loading into the channel  39 , as will be discussed below. 
     The upper portion  22  also includes an outer helically wound discontinuous guide and advancement structure  50  disposed on outer surfaces of both of the substantially cylindrically shaped side walls  32  and  33 , which may include conventional helically wound V type threads, buttress threads, helically wound square threads, or other guide and advancement structure to cooperate with equivalent or mateable structure within the multi-purpose installation tool  12  and the driver  14 , as described more fully below. The advancement structure  50  extends from near the intermediate portion  24  to the open end  43 . The back wall  28  extending between the threaded sides  32  and  33  has an outer substantially planar and smooth surface finish. 
     Extending from the upper portion  22  and into the intermediate portion  24  of each end guide tool  9  is an outward facing channel  51  that has an opening  52  with a side-to-side width  53  that is somewhat smaller than the width  42  of the upper handle portion  22 , such that the channel  51  and opening  52  are sized and shaped to receive and allow passage of certain tools and implants, as described below. 
     Furthermore, a remaining portion of the end guide tool intermediate portion  24  and the lower portion  26  includes a groove or channel  55 , with an elongate, axially extending and radially outward opening  57 , having a side-to-side width  58  that is slightly smaller than the width  42  of the opening  40 , but larger than the slot width  45  and the opening width  53 . The channel opening  57  is disposed opposite the flexible tang or flap  38 . All of the channels  39 ,  51  and  55  communicate with one another and are aligned with one another so as to provide a continuous elongate interior and sideways open passageway with an open side from near the top end  43  to near the bottom  36  thereof. This passageway provides a continuous open path of non-uniform cross-sectional radius throughout from the top  43  to the bottom  36  thereof that is parallel to an elongate axis A of each end guide tool  9 . As will be discussed more fully below, each end guide tool channel opening  57  is sized and shaped to slidingly receive a respective end  59  of the rod  8  therein. It is foreseen that one or all of the channel openings forming the open side that extends from near the top end  43  to near the bottom  36  of the guide tool  9  may be sized and shaped to receive the end  59  of the rod  8 . It is also foreseen that the rod  8  may be of uniform or non-uniform diameter, regular or uneven surface construction, or smooth or roughened surface finish, and that the channel openings may in turn be sized and shaped to receive such a rod end that may exhibit a greater or smaller width or diameter than at other locations along the rod. 
     The slits  34  are spaced in order to have a back wall or flap flex region having a size and shape to allow at least partial passage of a respective end  59  of the rod  8  between the side walls  32  and  33 . Also located near the end guide bottom  36  is a rod abutment recess  61  that is sized and shaped for the purpose of bridging the rod  8  when the end guide tool  9  is rotated for removal, as described below. However, it is foreseen that other removal means could be used. The end guide tool  9  also receives a closure top  62 , as will be described below. Still further, near the bottom  36  of each of the end guides  9  on inner surfaces of the side walls  32  and  33 , is a helical wound, discontinuous guide and advancement structure  64  which may include conventional helically wound V-shaped threads, buttress threads, reverse angle threads, helically wound square threads, or other guide and advancement structure to cooperate with equivalent or mateable structure within the bone screw heads  4  and on the closure top  62 , as also described below. 
     At the lower portion  26 , the substantially cylindrical side walls  32  and  33  include an outer radially extending bevel  66  and substantially cylindrical outer side walls  68  and  69 , respectively. The walls  68  and  69  uniformly increase the thickness of the respective side walls  32  and  33 , resulting in a substantially cylindrical cross-section of greater diameter than a diameter created by an outer surface of the side walls  32  and  33  at the intermediate portion  24 . 
     As will be discussed more fully below, in addition to increasing the diameter, the walls  68  and  69  are configured with co-planar front walls or facets  70  and co-planar back walls or facets  71  with the facets  70  being disposed parallel to the facets  71 , providing for alignment and mating with an interior of the multi-purpose installation tool  12  to ensure that the end guide tool  9  is retained in a selected, non-rotatable position with respect to the multi-purpose installation tool  12  when installed therein. Each of the walls  68  and  69  can include an abutment pin  67  located at an outer surface thereof and near the bottom or end  36 . The pin  67  may serve as a stop for the multi-purpose installation tool  12  as will be described more fully below; however, such a pin stop is not always needed. 
     Near the end or bottom  36  of each end guide tool  9 , disposed on an inner surface of each of the side walls  32  and  33 , is a radially inward facing attachment structure, generally  72 , that will be described below in conjunction with a similar structure on the intermediate guide tool  10  and the bone screw  4 . 
     Each of the intermediate guide tools  10 , specifically illustrated in  FIGS.  2  to  4   , have a somewhat similar overall shape when compared to the end guide tools  9  in that both are preferably of the same axial length and width and also have much structure in common; however with certain differences as noted. Each intermediate guide tool  10  has an overall elongate body  74  with an upper handle portion  76 , an intermediate portion  77  and a lower implant engaging portion  78  which includes opposed implant engaging members for securing one of the implants there between. In the upper portion  76 , the body  74  is generally C-shaped defining a radially outward opening  79  communicating with an elongate and axially extending channel  80  defined by a rear wall  81  having a lower web edge  96  and side walls  82  and  83 . With reference to  FIG.  2   , the channel  80  front opening  79  extends parallel to an axis B of the body  74  and has a side-to-side width  85  configured to receive tools and elements described below. 
     Similar to the end guide tool  9 , the opening  85  narrows near an upper end  87  providing an elongate slot  88  having a side-to-side width  89  that is smaller than the width  85 . The slot  88  is configured for sliding engagement with the pin  46  disposed on the driver  14  and discussed more fully below. Disposed on either side of the slot  88  are co-planar surfaces  91  and  92  that are parallel with the rear wall  81 . The surfaces  91  and  92 , as well as the rear wall  81 , provide alignment surfaces when the multi-purpose tool  12  is inserted onto the guide tool  10 , discussed more fully below. Below the slot  88 , the side-to-side opening width  85  is substantially constant through a mid-section  90  of the handle portion  76 , sufficient to receive additional tools and/or a closure top, as will be discussed below. 
     The upper or handle portion  76  also includes an outer helically wound discontinuous guide and advancement structure  93  disposed on outer sides of both of the substantially cylindrically shaped side walls  82  and  83 , which may include conventional helically wound V-threads, helically wound square threads, buttress threads or other guide and advancement structure to cooperate with equivalent or mateable structure within the multi-purpose installation tool  12  and the driver  14  as described more fully below. The advancement structure  93  extends from near the intermediate portion  77  to the open end  87 . An outer surface of the rear wall  81  extending between the threaded sides  32  and  33  is substantially planar and smooth. 
     The upper or handle portion  76  further includes an outward facing channel  94  communicating with the channel  80 . The channel  94  is defined in part by a rear wall or web  95  having a lower end with the web edge  96 , the wall  95  being integral with the wall  81 . Communicating with the channel  94  is an elongate and axially extending opening  98  having a side-to-side width  99  that is somewhat smaller than the width  85  of the opening  79 . The opening  98  is further defined by the walls  82  and  83 . The channel  94  and opening  98  are configured to receive, contain and allow translational movement therealong or rotational relative movement of certain tools, as described more fully below. Although not shown in the drawings, it is foreseen that the channel  94 , channel opening  98  and rear wall or web  95  may extend into the intermediate portion  77  to provide greater strength and stability to the lower portion  78  of the intermediate tool  10 , with the opening  98  also extending into the lower portion  78  providing greater retention of small tools or parts being inserted through the channel  94 . 
     The intermediate portion  77  of the intermediate tool  10  includes two spaced side walls or legs  102  and  103 , extending from and integral with the side walls  82  and  83 , respectively. The legs  102  and  103  have outer surfaces that are partially cylindrical. 
     Similar to the end tool  9 , at the juncture of the intermediate portion  77  and the lower portion  78 , each of the legs  102  and  103  include an outwardly facing radially extending bevel  106  integral with substantially cylindrical outer side walls  107  and  108 , respectively. The outer walls  107  and  108  extend along the length of the lower portion  78  and uniformly increase the thickness of the respective legs  102  and  103 , resulting in a substantially cylindrical cross-section of greater outer diameter at the lower portion  78  than an outer diameter created by the outer surfaces of the legs  102  and  103  along the intermediate portion  77 . As will be discussed more fully below, in addition to increasing the diameter, the walls  107  and  108  are configured with co-planar front facets or walls with flat surfaces  109  and co-planar rear facets or walls with flat surfaces  110 , the facets  109  disposed parallel to the facets  110 , providing for alignment with an interior of the multi-purpose installation tool  12  to ensure that the intermediate guide tool  10  is properly mated with and retained in a selected, non-rotatable position with respect to the multi-purpose installation tool  12  when installed therein. 
     Along both the intermediate and lower portions  77  and  78  of the intermediate tool  10 , the legs  102  and  103  define an elongate and axially extending passthrough slot  111  sized and shaped to slidingly receive the rod  8 . The slot or opening extends from the lower edge of the web end  96  of the rear wall  95  to an open end or bottom  112  of the tool  10  configured to secure an open ended spinal surgery implant there between. 
     Near the bottom  112  of each implant engaging leg member  102  and  103  of the intermediate guide tool  10  is a helically wound but discontinuous square thread  114  and it is foreseen that other type of guide and advancement structure may be utilized such as helically wound flange forms, reverse angle threads, buttress threads, etc. The thread form  114  cooperates with the closure top  62 , as described below. The lower end of each leg  102  and  103  of the intermediate guide tool  10  also includes a cutout or rod-abutment recess  116  similar to the recess  61  described with respect to the end tool  9 . Each of the walls  107  and  108  can include an abutment pin  118  located at an outer surface thereof and near the bottom or end  112 . The pin  118  may serve as a stop for the multi-purpose installation tool  12  as will be described more fully below. 
     Also near the end or bottom  112  of each leg  102  and  103  of the intermediate guide tool  10 , disposed on inner substantially cylindrical surfaces  120  and  121 , respectively, is a radially inward facing attachment structure, generally  124 , substantially similar to the structure  72  disposed on the end guide tool  9 . The structure  124  will be described herein in conjunction with the bone screw  4 . 
     With reference to  FIGS.  9 - 11   , the embodiment shown includes an attachment structure  124  having a first projection, stop or pin  126  in spaced relation with a second smaller projection, stop or pin  127 , both pins being disposed on the surface  120 . In the embodiment shown, the structure  123  further includes a cooperating third projection, stop or pin  130  in spaced relation with a fourth smaller projection, stop or pin  131 , the pins  130  and  131  being disposed on the surface  121 . 
     The larger pins  126  and  130  are substantially configured the same, both being substantially rounded, radially inward projecting nodules, each having a ridge or lip  132  and  133 , respectively, projecting upwardly toward the guide and advancement structure  114  and that preferably follows the curvature of the respective leg inner surface  120  and  121 . 
     The lips  132  and  133  with respective surfaces  120  and  121  define slots  134  and  135 , respectively, for receiving the bone screw  4  as will be discussed more fully below. The pin  126  is configured slightly larger than the pin  130 , requiring similar modification in the bone screw  4 , resulting in a method of operation wherein the bone screw  4  may only be mated with the guide  9  or  10  from a single direction, ensuring appropriate alignment between the bone screw  4  and guide tool advancement structure  114  with respect to the installment of the closure top  62 . 
     Each of the larger pins  126  and  130  is also disposed at substantially the same distance from respective bottom surfaces  138  and  139 , at the end  112  of the guide tool  10  and adjacent a rod-abutment recess  116 . Furthermore, each of the larger pins  126  and  130  is also disposed at substantially the same distance from respective parallel seating surfaces  140  and  141 , that form a base of the guide and advancement structure  114 . Additionally, in this embodiment the pins  126  and  130  are disposed in diametrically opposed relation when viewed in cross-section as shown in  FIG.  10   . 
     The smaller pins  127  and  131  are also substantially configured the same, the pin  131  being slightly larger than the pin  127 , but otherwise both pins  127  and  131  being substantially rounded, radially inwardly projecting nubs, each disposed at substantially the same distance from the respective bottom surfaces  138  and  139  and the respective seating surfaces  140  and  141 . Furthermore, the pins  127  and  131  are disposed in diametrically opposed relation when viewed in cross-section as shown in  FIG.  10   . Each of the pins  127  and  131  are disposed closer to the respective end surfaces  138  and  139  than are the larger pins  126  and  130 . It is noted that other orientations and pin sizes may be utilized according to the invention, with the pin sizes and locations cooperating with respective features on the bone screws  4 . Preferably, the pins are of different sizes to provide for mating of the guide tool  9  or  10  with the bone screw  4  from a single direction, resulting in a desired alignment between the bone screw  4  guide and advancement structure  114  and the closure top  62  guide and advancement structure. 
     The pins  126 ,  127 ,  130  and  131  cooperate and mate with the bone screw  4 , at a receiver portion, generally identified by the reference numeral  145 , of a head  146  thereof. With reference to  FIGS.  12 - 15   , each of the bone screws  4  further includes a threaded shank  148  attached to the head  146 , the shank  148  for screwing into and seating in a vertebra  16  that is part of the human spine  6 . The head  146  includes first and second arms  150  and  151  that define a rod receiving channel  153  passing therethrough. Each of the bone screw shanks  148  includes an upper portion  154  that extends into the head  146  and is operationally secured therein, so that the head  146  is rotatable on the shank  148  until locked in position through engagement with the rod  8  under pressure. 
     The receiver portion  145  is disposed on outer surfaces of the arms  150  and  151 . The receiver portion  145  of arm  150  includes a slot or groove  158  communicating with a recess  159  defined in part by a flange  160 . The groove  158  and recess  159  open at a front surface  162  of the arm  150  and extend across a facet  163  and into a side surface  164  thereof. With reference to  FIG.  21   , the groove  158  is configured to mate with the large pin  126  with the lip  132  extending into the recess  159  and the flange  160  disposed in the slot  134  when the guide tool  10  is attached to the bone screw head  146 . The width of the slot  134  is sized to prevent passage therethrough of the pin  126  except by twisting or rotational relative movement therebetween. The receiver portion  145  of the arm  150  further includes a rounded aperture  165  disposed substantially centrally on a face or facet  167  of the arm  150 , the facet  167  disposed adjacent to the side surface  163 . The aperture  165  is configured to mate with the small pin  127 . 
     Similar to the arm  150 , the receiver portion  145  of the arm  151  defines a groove  168  communicating with a recess  169  defined in part by a flange  170 . The groove  168  and recess  169  open at a back surface  172  of the arm  151  and extend across a facet  173  into a side surface  174  thereof. 
     Similar to what is shown in  FIG.  21    with respect to the arm  150 , the groove  168  is configured to mate with the large pin  130  with the lip  133  extending into the recess  169  and the flange  170  disposed in the slot  135  when the guide tool  10  is attached to the bone screw head  146 . The receiver portion  145  of the arm  151  further includes a rounded aperture  175  disposed substantially centrally on a face or facet  177  of the arm  151 , the facet  177  disposed adjacent to the side surface  173 . The aperture  175  is configured to mate with the small pin  131 . 
     In the embodiment shown, to attach the bone screw head  146  to the guide tool  10 , the guide tool  10  is rotated about its axis B such that the legs  102  and  103  are lowered into place as shown in  FIGS.  17  and  18   , with the facets  167  and  177  of the head  146  disposed between the guide tool legs  102  and  103 , with the facet  167  adjacent the leg  102  and the facet  177  adjacent the leg  103 , thereby aligning the groove  158  with the large pin  126  and the groove  168  with the large pin  130 . The head  146  may then be twisted into place as shown by the arrow T in  FIGS.  18 ,  19  and  20   . The legs  102  and  103  may splay slightly as the head is twisted into place, but come to rest in a generally non-splayed configuration and held in place by the structure of the attachment mechanism to resist splaying. 
     In order to disengage the guide tool  9  or the guide tool  10  from the bone screw  4 , the guide tool  9 ,  10  is rotated counterclockwise from an attaching configuration (opposite to the arrow T), when viewing from the top so as to disengage the lips  132  and  133  from the recesses  159  and  169 , respectively. In this manner, end guide tools  9  and intermediate guide tools  10  that have previously twisted on, now twist off of respective bone screws  4 . 
     While a preferred embodiment of the invention has the respective pins of the attachment structure on the guide tools and the grooves on the bone screw heads, it is foreseen that these elements could be reversed in total or part in accordance with the invention. Also, other suitable attachment structure could be used, such as sloped or tapered undercut surfaces on the screw heads that overlap, mate and interlock with radially or linearly projecting structure on or near the ends of the guide tools. Such projecting structure can be snapped on or clipped on and translated up to provide for anti-splay overlapping surfaces. In addition, a groove could be put in the outer surface of the screw head and a fin on the guide tool could snap or slide into the groove. 
     In the embodiment shown, the recesses  61  and  116  disposed on the respective guide tools  9  and  10  are sized, shaped and positioned so that when the rod  8  is located in the bone screws  4 , the guide tools  9  and  10  can rotate about respective axes A and B, with the recess  61  and  116  allowing the respective guide tool  9  and  10  to straddle over the rod  8 , thereby allowing the guide tool  9  and  10  to twist relative to the bone screw  4  and free the attachment structures  72  and  124  from the receiver portion  145  of the bone screw  4  and thereafter be removed after all procedures are complete, as described below. 
     The closure top  62  closes between the spaced bone screw arms  150  and  151  to secure the rod  8  in the channel  153 . The closure top  62  can be any of many different plug type closures. With reference to  FIGS.  46 - 48   , preferably the closure top  62  has a cylindrical body  180  that has a helically wound mating guide and advancement structure  181 . The guide and advancement structure  181  can be of any type, including V-type threads, buttress threads, reverse angle threads, or square threads. Preferably the guide and advancement structure  181  is a helically wound flange form that interlocks with a reciprocal flange form as part of a guide and advancement structure  183  on the interior of the bone screw arms  150  and  151 . 
     A suitable locking guide and advancement structure of this type is disclosed in U.S. Pat. No. 6,726,689 from Ser. No. 10/236,123 which is incorporated herein by reference. The helically wound guide and advancement structures  64  and  114  in the respective guide tools  9  and  10  are sized and shaped to receive the mating guide and advancement structure  181  of the closure top  62  and align with the guide and advancement structure  183  of the bone screw  4  to form a generally continuous helically wound pathway, but does not require locking between the closure top  62  and the tools  9  and  10 , even when an interlocking flange form is utilized on the closure top  62 . 
     The guides  64  and  114  allow the closure top  62  to be rotated and the surgeon to develop mechanical advantage to urge or drive the rod  8 , while still outside or partially outside the bone screw  4 , toward and into the bone screw head  146 . This is especially helpful where the rod  8  is bent relative to the location of the vertebra  16  (which is sometimes the case) to which the rod  8  is to attach and is not easily placed in the bone screw head  146  without force and the mechanical advantage provided by the guides  64  and  114 . In particular, the guide and advancement structures  64  and  114  on the respective tools  9  and  10  are located and positioned to align with the guide and advancement structure  183  on the insides of the bone screw arms  150  and  151 , as shown in  FIG.  42    and pass the closure top  62  therebetween while allowing the closure top  62  to continue to rotate and to continuously apply force to the rod  8 , so as to aid in seating the rod  8  in the bone screw head  146 . 
     Each closure top  62  also preferably includes a break-off head  186  that breaks from the cylindrical body  180  in a break-off region  187  upon the application of a preselected torque, such as 95 to 120 inch-pounds. The break-off head  186  preferably has a hexagonal cross section faceted exterior that is configured to mate with a similarly shaped socket of a final closure driving or torquing tool  190  described below. It is foreseen that different driving heads or other methods of driving the closure top  62  can be utilized with certain embodiments of the invention, such as non-break-off closure top designs. 
     The present invention is not intended to be restricted to a particular type of bone screw, bone screw closure mechanism, or bone screw and guide tool attachment mechanism. In the present embodiment, a polyaxial type bone screw  4  is utilized wherein the shank  148  is locked in position by direct contact with the rod  8 . It is foreseen that the tool set  2  of the present invention can be used with virtually any type of bone screw, including fixed monoaxial and polyaxial bone screws of many different types wherein the head is locked relative to the shank by structure other than in the manner described in the illustrated embodiment. It is also foreseen that the screws could be cannulated. 
     With reference to  FIGS.  22 - 25   , the multi-purpose installation tool  12  of the tool assembly  1  of the invention includes an upper translation nut  202  rotatably and free wheelingably attached to a lower guide tool stabilizer or support sleeve  204 . The sleeve  204  has an inner substantially cylindrical surface  205  defining a substantially hollow passageway  206  sized and shaped to slidingly receive an end tool  9  or an intermediate tool  10  therein. Alternatively, is foreseen that the sleeve could have an inner and outer planar surface. The sleeve  204  is elongate and includes a receiving end  207 , a substantially cylindrical outer body  208  and a translation nut attachment end portion  210  disposed opposite the receiving end  207 . The receiving end  207  not only functions to receive the guide tool  9  or  10  into the sleeve  204 , but also as a pressing block  218  for contacting the flexible flap or spring tang  38  and as a pressing end  207  for contacting the rod  8  and translating the rod  8  toward the bone screw head  146  when the multi-purpose installation tool  12  is installed on the guide tool  9  or  10 , as will be discussed more fully below. 
     The cylindrical body  208  further defines a slotted U-shaped or C-shaped channel  212  that opens radially at an opening  213  and also opens at the receiving end  207  and extends substantially along a length of the body  208  to a location  214  spaced from the nut attachment end portion  210 . The channel opening has a side-to-side width  216  sized to receive the back wall tang portion or flexible flap  38  of the end guide tool  9  therethrough, when aligned therewith. For example, with reference to  FIG.  38   , the multi-purpose installation tool  12  is shown partially removed from an end guide tool  9  and deploying the tang  38  after the bone screw has been inserted. Because of the substantial length of the channel  212  as defined by the location  214  and because of the channel width  216 , the multi-purpose installation tool  12  can be removed, turned 180 degree. and reattached to the end guide tool  9  thereby providing access through the channel opening  213  for protrusion of the back wall tang portion or flap  38  of the end guide tool  9 . The flap  38  is thus not encumbered or restricted by the tool  12  during the rod pushing application and the flap  38  can be flexed outwardly by a rod  8  (not shown) or other forces, when the devices are assembled in this configuration. 
     Disposed flush to the lower sleeve end  207  and rigidly attached to the inner cylindrical surface  205  is the solid guide tool alignment and tang/rod pressing block  218 . The block  218  has a substantially smooth, planar and rectangular surface  220  facing inwardly radially from the inner surface  205 . The block  218  also follows the curve of the cylindrical surface  220  at a surface  222  thereof. Thus, as shown in  FIG.  24   , the block  218  has a segment shape when observed from a bottom plan view. The term segment used herein is defined as the part of a circular area bounded by a chord and an arc of a circle cut off by the chord. This segment shape of the block  218  provides a mechanical advantage for compressing the flexible flap  38  flush with the end guide tool  9  and for advancing the rod  8  into the bone screw  4  with the multi-purpose installation tool  12  which will be discussed more fully below. 
     The flat, rectangular surface  220  provides structure for installing the guide tool  9  or  10  in a mating and desired alignment with respect to the multi-purpose installation tool  12 . For example, with respect to the guide tool  10 , a preferred alignment is that the rear wall  81  of the tool  10  be disposed adjacent to the surface  220  when inserting the tool  10  into the multi-purpose installation tool  12 . Then, the tool  10  is slid into the multi-purpose tool sleeve  204 , with the block  218  preventing axial rotation of the tool  10  with respect to the sleeve  204 , and resulting in the preferred alignment of the opening  79  and the pass-through slot  11  of the tool  10  and the U-shaped channel  212  of the multi-purpose tool in this application. 
     With respect to the end guide tool  9 , the block  218  with the planar surface  220  provides for the insertion of the tool  9  in a first, installation tang containing position or a second, rod pushing position. When utilizing the assembly  1  of the invention to install a bone screw  4 , it is advantageous for the flexible back wall portion or tang  38  of the tool  9  to be fully restrained by the multi-purpose installation tool  12  and for the walls  68  and  69  to be locked in a non-splayable or anti-splay position. Therefore, in the first, bone screw installation tang containing position, the multi-purpose installation tool  12  is inserted onto the tool  9  with the back wall  28  of the tool  9  disposed adjacent to the sleeve surface  220 . Then, the tool  9  and the sleeve  204  are attached with the block  218  preventing axial rotation of the tool  9  with respect to the multi-purpose installation tool  12 . This results in the preferred alignment wherein the flexible back wall portion or tang  38  is disposed adjacent to the multi-purpose tool sleeve  204  and contained and disposed opposite the U-shaped channel  212 . After the bone screw  4  is installed and it is desired to install the rod  8  in two or more bone screws  4 , the multi-purpose installation tool  12  is removed from the end guide tool  9  and replaced thereon with the slot  44  and channel openings  40  and  94  adjacent to and facing the alignment block  218 . 
     The translation nut  202  of the multi-purpose installation tool  12  is substantially cylindrical in shape and is shown with outer grooves  223  to aid a surgeon in handling the multi-purpose installation tool  12  and rotating the nut  202 . The nut  202  further includes an inner cylindrical surface  224  defining an inner substantially cylindrical passage  226  communicating with the passage  206  of the sleeve  204 . The inner surface  224  further includes a helical guide and advancement structure as shown by a V-shaped thread  228  that is configured to mate with the guide and advancement structure  50  of the end guide tool  9  or the guide and advancement structure  93  of the intermediate guide tool  10 . 
     With reference to  FIG.  25   , the inner cylindrical surface  224  extends from an upper open end  230  of the translation nut  202  to an annular seating surface  232  extending radially outwardly and perpendicular to the cylindrical surface  224 . As will be discussed more fully below, the surface  224  with associated thread  228  is of a length that provides an equivalent translation distance of the multi-purpose installation tool  12 , and in particular the tang/rod pressing block  218 , with respect to the guide tool  9  or  10  such that the pressing block  218  can be used to gradually push the rod  8  toward the bone screw  4  for the entire translation distance by rotating the nut  202  which can be continued until the rod is fully seated in the head of the bone screw. 
     Also with reference to  FIG.  25   , at the annular seating surface  232 , the sleeve  204  is in sliding contact with the nut  202 . A lower portion  234  of the nut  202  further defines a second inner cylindrical surface  236  of greater diameter than the surface  224 . The surface  236  has a diameter slightly greater than a diameter of the sleeve  204  and is configured to slidingly receive the sleeve  204  into the nut  202  along the surface  236 . The nut  202  further defines an annular recess or groove  238  configured to receive a pin  240  rigidly fixed to the sleeve  204 . The pin  240  may be accessed for attachment and removal from the sleeve  204  through an aperture  242  disposed in the translation nut  202 . The pin  240  slidingly mates with the nut  202  within the recess  238 , keeping the nut  202  and sleeve  204  in an attached but freely rotatable relation. 
     With reference to  FIGS.  26 - 28   , the driver  14  of an assembly  1  according to the invention includes a handle  250 , a guide tool fastener or nut  252 , and an elongate cylindrical stem or shaft  254  having a lower cylindrical portion  255  integral with a bone screw engager shown as a socket  256 . The socket  256  is configured to mate with the upper part of the bone screw shank  154 . The shaft  254  with attached socket  256  is receivable in and passes through the interior of the guides  9  and  10 , such as the channel  80  of the guide tool  10 . The lower portion  255  has a slightly smaller diameter than a diameter of the remainder of the shaft  254 , this smaller diameter provides for adequate clearance of the portion  254  from the guide and advancement structures  64  and  114  when the shaft  254  is installed within the interior of the respective guide tools  9  and  10 . The stem or shaft  254  is rigidly attached to the handle  250  and coaxial therewith. Both the handle  250  and the guide tool fastener  252  include outer grooves  258  and  259  respectively, about outer cylindrical surfaces thereof to aid in gripping and rotating the respective components. 
     The guide tool fastener  252  is a substantially hollow cylinder disposed in coaxial relationship with the handle  250  and the shaft  254 . The fastener has a threaded inner cylindrical surface  262  disposed at a lower portion  263  thereof, the threaded surface  262  configured to mate with the guide and advancement structure  50  of the end guide tool  9  or the guide and advancement structure  93  of the intermediate guide tool  10 . The fastener  252  is disposed on the driver  14  between an annular surface  264  of the handle  250  and the pin  46  that is fixed to the shaft  254  and extends laterally therefrom. 
     The driver  12  further includes a lateral pin  266  projecting radially outwardly from a cylindrical surface  268  adjacent the handle  250 . In the embodiment shown, the cylindrical surface  268  is integral with the handle  250  and fixedly attached to the shaft  254 . The pin  266  is disposed within an annular recess  270  defined by the cylindrical surface  268 , and surfaces of the fastener  252 , including an upper seating surface  272 , a lower seating surface  274  and an inner cylindrical surface  276 . The pin  266  disposed in the recess  270  allows for both rotational and axial or vertical translational movements of the fastener  252  with respect to the shaft  254 . Thus, as shown in  FIG.  26   , the fastener  252  is rotatable about an axis C. Furthermore, the fastener is slidable along the axis C between the annular surface  264  and the pin  46 , with  FIG.  26    showing a first or unattached position with the fastener  252  in contact with the annular surface  264  and  FIGS.  27  and  28    showing a second, engagement position, with the fastener  252  partially covering, but not contacting the pin  46 , with the pin  266  abutting the upper seating surface  272  prohibiting further downward or vertical (axial) translational movement of the fastener  252  with respect to the shaft  254 . 
     As stated previously herein, the pin  46  is configured for sliding engagement with both the slot  44  of the guide tool  9  and the slot  88  of the guide tool  10  when the driver shaft  254  is disposed in an interior of the guide tool  9  or  10 . When the pin  46  is received in the slot  44  or the slot  88 , any relative rotational movement between the guide tool  9  or  10  and the driver  14  is prevented, but the driver is free to slide axially with respect to the guide tool  9  or  10 . When the fastener or nut  252  is slid into the second position shown in  FIGS.  27  and  28    and the fastener is mated with the guide and advancement structure  50  of the end guide tool  9  or the guide and advancement structure  93  of the intermediate guide tool  10  by rotating the fastener  252  to a location adjacent to the pin  46 , with the pin  266  in contact with the upper seating surface  272 , relative axial movement between the driver  14  and the guide tool  9  or  10  is also prevented. 
     With reference to  FIGS.  1  and  29 - 35   , a three-component assembly  1  according to the invention including the guide tool  9 , the multi-purpose installation tool  12  and the driver  14  may be assembled as follows: The guide tool  9  shown with attached bone screw  4  is inserted into the multi-purpose installation tool  12  with the upper end  43  being inserted into the receiving end  207  of the multi-purpose installation tool  12 . With respect to the assembly shown in  FIGS.  29 - 31   , illustrated is a particular assembly wherein the multi-purpose installation tool  12  is being utilized as a support or stabilizer for the end guide tool  9  during installation of the bone screw  4  into the vertebra  16 , specifically, to contain and compress the tang  38  and to provide extra support to the walls, such as walls  68  and  69  of tool  9 . Thus, the guide tool  9  is received into the multi-purpose installation tool  12  with the rear wall  28  facing the alignment block  218  as shown in  FIG.  29   . 
     As the guide tool  9  is received into the multi-purpose installation tool  12 , rotational movement is prevented by the alignment block  218  in sliding contact with the flat surfaces  28  of the guide tool  9 . The translation nut  202  is then rotated clock-wise as viewed from the top end  230  and shown by the arrow X, with the thread  50  of the guide tool  9  mating with the thread  228  disposed on the inner surface  224  of the translation nut  202 . The translation nut  202  is preferably rotated until the upper end  43  of the guide tool  9  is positioned outside of the body of the nut  202  with a few of the threads  50  exposed as shown in  FIGS.  30  and  31   . Furthermore, the sleeve  204  cannot be translated beyond the pin  67  that stops the sleeve near the rod abutment recess  61  disposed near the end of the guide tool  9 . During rotation of the translation nut  202 , the guide tool  9  is held in a preferred bone screw installation position and any rotational movement of the tool  9  is prevented by the alignment block  218  in contact with the co-planar back walls or facets  71  of the guide tool  9  as well as the planar back surface of the tang  38 . As illustrated in  FIGS.  30  and  31   , when the guide tool  9  is fully installed in the multi-purpose installation tool  12  in this first or bone screw installation position, the flexible back wall portion or flap  38  is compressed and retained in place between the side walls  32  and  33  by the alignment block  218 . 
     When the multi-purpose installation tool  12  is used as a rod pusher with the guide tool  9  as shown in  FIGS.  38  and  41   , the multi-purpose installation tool  12  is preferably used first as an end guide tool stabilizer and tang  38  container, as already described herein, and thus must first be removed by rotating the translation nut  202  counter-clockwise until the multi-purpose installation tool  12  is disengaged from the end tool guide  9  thereby deploying the tang  38 . Thereafter, the multi-purpose installation tool  12  is removed and replaced on the guide tool  9  with the slot  44  and channel openings  40  and  94  adjacent to and facing the alignment block  218 . As the multi-purpose installation tool  12  reinserted onto the guide tool  9 , rotational movement is prevented by the alignment block  218  in sliding contact with the flat surfaces  47  and  48  of the guide tool  9 . The translation nut  202  is then rotated clock-wise as shown by the arrow X (FIG.  29 ), with the thread  50  of the guide tool  9  mating with the thread  228  disposed on the inner surface  224  of the translation nut  202 . Similar to what is shown in  FIGS.  30  and  31   , the translation nut  202  is rotated clockwise as shown by the arrow X, until the upper end  43  of the guide tool  9  is positioned outside of the body of the nut  202  with some of the threads  50  exposed. During rotation of the translation nut  202 , the guide tool  9  is held in position and any rotational movement of the tool  9  is prevented by the alignment block  218  in contact with the co-planar front walls or facets  70  of the guide tool  9 . When the multi-purpose installation tool  12  is used in this second or rod pushing position, the flexible back wall tang portion or flap  38  is not obstructed by the sleeve  204  of the multi-purpose installation tool  12  and may spring out or be further pushed out through the opening  213  of the U-shaped channel  212 . 
     An assembly  1  according to the invention may also include the intermediate guide tool  10  in the place of the guide tool  9  as shown in  FIGS.  40 - 42   . Because the intermediate guide tool  10  includes a pass-through slot  111  rather than a flexible back wall tang portion  38 , the alignment between the multi-purpose installation tool  12  and the guide tool  10  may be the same during bone screw installation as for the pushing of the rod  8 . Therefore, the tool guide  10  may be inserted into the multi-purpose installation tool  12  with either the rear wall  81  or the slot  88  adjacent to and facing the alignment block  218 . 
     Similar to the discussion herein with respect to the guide tool  9 , as the guide tool  10  is inserted into the multi-purpose installation tool  12 , rotational movement is prohibited by the alignment block  218  in sliding contact with either the rear wall  81  or the coplanar surfaces  91  and  92  of the guide tool  10 . The translation nut  202  is then rotated clock-wise as viewed looking toward the top  87  of the tool  10 , with the thread  93  of the guide tool  10  mating with the thread  228  disposed on the inner surface  224  of the translation nut. Similar to what is shown in  FIGS.  30  and  31   , the translation nut  202  is rotated until the upper end  87  of the guide tool  10  is positioned outside of the body of the nut  202  with some of the threads  93  exposed. During rotation of the translation nut  202 , the guide tool  10  is held in position, with rotational movement of the tool  10  being prevented by the alignment block  218  in contact with the co-planar front walls or facets  109  or the co-planar rear walls or facets  110  of the guide tool  10 . 
     Further discussion of the assembly  1  in this application will be directed toward the end guide tool  9  shown in the drawings. Unless specifically stated otherwise, the intermediate guide tool  10  can be utilized in similar fashion to what is being described herein with respect to the end guide tool  9 . 
     With reference to  FIGS.  1  and  32 - 35   , after installation of the multi-purpose installation tool  12  to the guide tool  9 , the driver  14  is inserted into the guide tool  9 /multi-purpose installation tool  12  combination by inserting the socket end  256  into the end  43  of the guide tool  9  and sliding the shaft  254  into the interior of the guide tool  9  until the socket end  256  contacts and surrounds the upper part of the shank  154  of the bone screw  4  as shown in  FIG.  35   . As the shaft  254  is being inserted into the guide tool  9 , the pin  46  on the shaft  254  of the driver  14  is aligned with and slid into the slot  44  of the guide tool  9 . In order to more easily view the pin alignment process, the guide tool fastener  252  is placed in the first or unattached position with the fastener  252  in contact with the annular surface  264  as shown in  FIG.  32   . Also as shown in  FIG.  32   , preferably, the pin  46  is slid to a position disposed substantially within the slot  44  when the socket end  256  engages the shank  154  of the bone screw  4 . The guide tool fastener or nut  252  is then rotated clockwise as viewed from the handle and illustrated by the arrow Y in  FIG.  33   , from the first unattached position toward the second engaged position, mating the thread  50  located near the end  43  of the guide tool  9  with the inner threaded surface  262  of the nut  252  of the driver  14 . If, after the fastener  252  is rotated to a hand-tightened position, and a gap or space remains between the fastener  252  and the translation nut  202 , as shown in  FIG.  33   , the translation nut  202  may then be rotated counter-clockwise as shown by an arrow Z in  FIG.  33   , and hand-tightened until the translation nut  202  abuts against the fastener  252 , as shown in  FIG.  34   . The assembly  1  is then fully assembled and may be used to install the bone screw  4  into the vertebra  16  as will be described more fully below. Thereafter, the driver  14  may be removed by rotating the fastener  252  in a counter-clockwise direction (arrow Z) and sliding the shaft  254  out of the multi-purpose installation tool  12  through the open end  230 . 
     Another tool used in implanting a spinal rod  8  is an antitorque tool  300  illustrated in  FIGS.  44  and  45    and further shown in  FIG.  44    with a closure top installation tool  302  engaging the break-away portion  186  of the closure top  62 . The closure top installation tool  302  includes an upper handle portion  303  and a lower, closure top engagement portion  304  configured to mate with and rotate the closure top  62 . 
     The antitorque tool  300  is also preferably used with a closure top torquing tool  305 , shown in  FIGS.  47  and  48   . The tool  305  is used to torque and set the closure top  62 , so it is snug against the rod  8 , and thereafter break away the break-off head  186  in the manner shown in  FIG.  48   . The torquing tool  305  is preferably in the form of a socket as shown in the drawings to allow for adequate tightening of the closure top  62  and also ease in removal of the break-off head  186  as shown in  FIG.  48   . 
     The antitorque tool  300  includes a tubular hollow shaft  306  that is sized and shaped to be slidably received over the installation tool  302  and also the torquing tool  305 . The shaft  306  has a lower end portion  308  that has a pair of diametrically spaced, curved bridges  310 . Each of the bridges  310  is sized and shaped to fit over the rod  8 , shown in  FIGS.  47  and  48   . When in place, as illustrated in  FIG.  47   , the antitorque tool  300  allows a surgeon to counter torque applied by the torquing tool  305 , when applying torque to and breaking away the break-off head  186 . The antitorque tool  300  also has an upper handle  316  disposed perpendicular to the shaft  306  and having an opening  318  through which the installation tool  302  and the torquing tool  305  passes in the manner suggested by  FIGS.  46 - 48   . 
     In use, the previously described tools are utilized to attach one or more rods  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&#39;s vertebra  16  and the requirements of the spinal support needed. Bone screws  4  having a rotatable or polyaxial head  146  are preferred but not required for the procedure, as such allow relatively easy adjustment of the rod  8  in the tools  9  and  10  during placement and for movement of the tools  9  and  10 , as described below. The bone screw  4  is also preferably cannulated so as to be receivable over and guided by a guide pin  355  as discussed more fully below. 
     A relatively small incision, such as an incision  350  in the skin  20  is then made for each bone screw  4  to be used. Preferably, the incisions are sized so as to snugly receive the tools of the invention. The incisions  350  are stretched into a round shape with a circumference equal to or just slightly larger than the multi-purpose installation tool  12 . The skin  20  is relatively flexible and allows the surgeon to move the incision  350  around relative to the spine  6  to manipulate the various tools and implants, as required. In some cases, two screws can be inserted through one or the same incision. 
     With reference to  FIG.  36   , a drill (not shown) is utilized to form a first guide bore  366  in a vertebra  16  under guidance of non-invasive imaging techniques, which procedure is well known and established. The thin pin or guide wire  355  is then inserted in the first guide bore  366 . This first guide bore  366  and associated thin pin  355  function to minimize stressing the vertebra  16  and provide an eventual guide for the placement and angle of the bone screw shank  148  with respect to the vertebra  16 . 
     The guide bore  366  is enlarged utilizing a cannulated drilling tool or tap  360  having an integral or otherwise attached cannulated and threaded bit  362  with an outer surface sized and shaped to correspond to the size and shape of the chosen threaded bone screw  4 . The drilling tool  360  cooperates with a cylindrical holder or sleeve  368  having an inner surface in slidable mating arrangement with the tool  360  and being held in a position substantially co-axial therewith. The holder  368  is sized and shaped to fit within the incision  350  and prevents soft tissues from being rolled up in the threaded bit  362  as it is rotated. The tool  360  further includes a handle  370  fixedly attached to the tool  360  located at an end portion  372  thereof and of a size and shape for rotating the bit  362  along the pin  355  and into the first bore  366 . 
     With the pin  355  still in place, the enlargement of the guide bore  366  begins by threading the thin pin  355  through the end of the tap and inserting the holder  368  into the incision until the holder comes into contact with the vertebra  16 . The drill bit  362  is advanced downward along the pin  355  until the drill bit  362  comes into contact with the vertebra  16 . The tool  360  is then rotated within the holder  368  using the handle  370 , driving the bit  362  along the pin  355  until a full sized bore  380  is drilled to a depth desired by the surgeon. During drilling, the holder  368  remains stationary, shielding the surrounding tissue from the rotational movement of the bit  362  and tool  360 . 
     The tool  360  is then removed by rotating the bit  362  in reverse until the bit  362  is outside the bore  380 . The tool  360  is then removed from the holder  368 , followed by the removal of the holder  368  through the incision  350 . 
     Before placing the bone screw  4  in the vertebra  16 , the bone screw  4  is preferably joined to an associated guide tool  9  or  10 , with or without an associated multi-purpose installation tool  12 , and an associated driver  14 . It is foreseen that the driver can also be cannulated. It is possible, but typically not desirable, to join a guide tool  9  or  10  to the bone screw  4  after the installation of the bone screw  4  to the vertebra  16 . There also may be instances wherein it is desirable to join the bone screw  4  to an associated guide tool  9  or  10 , but not to the multi-purpose installation tool support  12  or the driver  14  until after the bone screw  4  is installed in the vertebra  16 , if at all. Furthermore, it is understood that the driver  14 , cannulated or not, may be used with a guide tool  9  or  10  without the multi-purpose installation tool  12 . However, it may be preferable to utilize the multi-purpose installation tool  12  during installation of a bone screw  4  into the vertebra  16  as the tool  12  provides some mechanical advantage and aids in preventing inadvertent splaying of side walls  32  and  33  of the end guide tool  9  and legs  102  and  103  of the intermediate guide tool  10 . 
     The attachment structure  124  of the intermediate guide tool  10  is joined to a bone screw  4  by first rotating the tool  10  relative to the bone screw  4  so that the legs  102  and  103  are positioned as shown in  FIGS.  17  and  18   , with the facets  167  and  177  of the head  146  disposed between the guide tool legs  102  and  103 , and with the facet  167  adjacent the leg  102  and the facet  177  adjacent the leg  103 , thereby aligning the groove  158  with the large pin  126  and the groove  168  with the large pin  130 . A slight splaying of the legs  102  and  103  is possible during alignment with the head arms  150  and  151 . 
     The head  146  is then twisted into place by rotating the tool  10  axially in a clockwise direction as shown by the arrow T in  FIGS.  18  and  19   . 
     The twist-on procedure described herein with respect to the attachment structure  124  of the intermediate tool  10  is also followed with respect to the end guide tool  9  attachment structure  72 . As previously stated herein, the attachment structure  72  is substantially similar to the attachment structure  124  of the intermediate tool  10 , with the only difference being that the end guide tool  9  includes a flexible back wall tang portion  38  rather than the pass-through slot  111  of the intermediate guide tool  10 . 
     After the bone screws  4  have been attached to the guide tools  9  and  10 , a multi-purpose installation tool  12  can be attached to each of the guide tools  9  and  10 . With respect to each of the intermediate guide tools  10 , the multi-purpose installation tool  12  is preferably installed as follows: The rear wall  81  of the tool  10  is positioned adjacent to the surface  220  and the tool  10  is inserted into the hollow passage  206  and slid into the rod pusher sleeve  204  until the end  87  contacts the translation nut  210 , with the block  218  preventing axial rotation of the guide tool  10  with respect to the multi-purpose installation tool  12 , and resulting in the preferred alignment of the sleeve slot  11  and the opening  79  of the tool  10  with the U-shaped channel  212  of the multi-purpose installation tool  12 . However, because the slot  11  is a pass-through slot, the alignment of the guide tool  10  with respect to the multi-purpose installation tool  12  is not critical to processes according to the invention. Therefore, in most instances the rear wall  81  of the tool  10  may also be positioned opposite the surface  220  upon entry into the multi-purpose installation tool  12 . 
     The translation nut  202  is then rotated with the thread  228  of the nut  202  mating with the thread  93  of the tool  10 . The nut  202  is rotated in a clockwise direction as illustrated by the arrow X in  FIG.  29    until the end  87  is disposed outside of the nut  202  and positioned similar to what is shown with respect to the multi-purpose installation tool  12  and end guide tool  9  assembly shown in  FIGS.  30  and  31   . The abutment pin  118  prevents further rotation of the nut  202  and advancement of the sleeve  204  beyond the pin  118 . 
     As shown in  FIGS.  29 - 31   , the end guide tools  9  are similarly equipped with multi-purpose installation tools  12 . In order to compress the tang  38  during installation of a bone screw  4  into a vertebra  16 , the tool  9  is received into the multi-purpose installation tool  12  with the back wall  28  of the tool  9  disposed adjacent to the surface  220 . Then the multi-purpose installation tool  12  is slid onto the tool  9  until the end  43  contacts the translation nut  202 , with the block  218  preventing axial rotation of the tool  9  with respect to the multi-purpose installation tool  12 , and resulting in the preferred alignment wherein the flexible back wall tang portion or flap  38  is disposed adjacent to the guide tool sleeve  204  disposed opposite the U-shaped channel  212 . The translation nut  202  is then rotated with the thread  228  of the nut  202  mating with the thread  50  of the end guide tool  9 . The nut  202  is rotated in a clockwise direction as illustrated by the arrow X in  FIG.  29    until the end  43  is disposed outside of the nut  202  and positioned as shown in  FIGS.  30  and  31   , but not beyond the pin  67 . 
     The driver  14  is then installed into the guide tool  9  as shown in  FIGS.  32 - 35    and as follows: The driver  14  is first prepared for ease of insertion by placing the guide tool fastener  252  in the first or unattached position with the fastener  252  in contact with the annular surface  264  of the driver  14  as shown in  FIG.  32   . Then, the driver end  256  is inserted into the guide tool  9  at the end  43  with the stem  254  being slid into the guide tool  9  with the pin  46  aligned with the channel  39  until coming to a stop with the pin  46  disposed in the slot  44  and the bone screw engager  256  in contact with the bone screw upper shank  154 . A slight rotation or jiggling of the bone screw shank  148  may be required for the hex socket of the bone screw engager  256  to become positioned in operational engagement with the hex shaped upper shank  154 . The guide tool fastener or nut  252  is then moved downward and toward the end  43  and then rotated clockwise as viewed from the handle  250  and illustrated by the arrow Y in  FIG.  33   , mating the thread  50  disposed near the end  43  of the guide tool  9  with the inner threaded surface  262  of the nut  252  of the driver  14 . The nut  252  is rotated in this clock-wise fashion and hand-tightened until further translation of the nut  252  along the guide tool  9  is prevented by the pin  266  abutting the upper seating surface  272 . 
     If, after the fastener  252  is rotated to a hand-tightened position, and a gap or space remains between the fastener  252  and the translation nut  202  as shown in  FIG.  33   , the translation nut  202  is rotated counter-clockwise as shown by the arrow Z in  FIG.  33   , and hand-tightened until the translation nut  202  abuts against the fastener  252  as shown in  FIG.  34   . The assembly  1  is now ready for bone screw installation into the vertebra  16 . 
     The driver  14  is installed into the intermediate guide tool  10  and multi-purpose installation tool  12  assembly in steps similar to that described above with respect to the end guide tool  9 . 
     A series of bone screws  4  are installed in each vertebra  16  to be attached to the rod  8  by inserting each of the assemblies  1  through the skin incision  350  as shown in  FIG.  37   . The screw  4  is then rotated and driven into the tapped bore  380  with the surgeon holding and rotating the assembly  1  with the driver handle  250 , thereby rotating the entire assembly  1  as one unit until the shank  148  is disposed at a desired depth in the tapped bore  380  of the respective vertebra  16 . Preferably, the shank  148 , along with the screw driver  14  are also cannulated to receive the pin  355 , providing additional guidance for installation of the bone screw  4  into the vertebra  16 . 
     After a specific bone screw  4  is installed, the driver  14  is removed from either the guide tool  9  or  10  by rotating the fastener  252  in a counter-clockwise direction (illustrated by the arrow Z in  FIG.  33   ) and sliding the shaft  254  towards the open end  230  of the multi-purpose installation tool  12 , if used, and pulling the driver  14  out of the assembly  1  by the handle  250 . 
     With respect to the end guide tools  9 , the multi-purpose installation tool  12 , if used, is then removed by rotating the translation nut  202  counter-clockwise until the thread  228  disposed on the inner surface  224  of the translation nut  202  is disengaged from the thread  50  of the tool  9 . The multi-purpose installation tool  12  is then slid off of the tool  9  deploying the flexible flap  38 , as shown in  FIG.  38   . If desired at this junction of a process according to the invention, the multi-purpose installation tool  12  many then be rotated 180 degrees and replaced on the tool  9  with the slot  44  and the channel openings  40  and  94  aligned adjacent to and facing the alignment block  218  of the multi-purpose installation tool  12  for a rod pushing application. The translation nut  202  is then rotated clockwise as illustrated by the arrow X in  FIG.  29   . In this rod pushing position, the flexible tang  38  is extendible into the U-shaped channel  212  of the multi-purpose installation tool  12 . 
     For each bone screw  4 , an associated guide tool  9  or  10  extends through the skin  14 , as illustrated in  FIG.  39   . An end guide tool  9  is located at each end of the series of bone screws  4  and an intermediate guide tool  10  is located on each intermediate bone screw  4 . 
     In order to install a rod  8  in two or more bone screws  4 , it may not be necessary to equip each guide tool  9  or  10  with a multi-purpose installation tool  12 . For example, with reference to  FIG.  40   , for a particular procedure, it may be desirable to utilize only one multi-purpose installation tool  12  with a tool set  2  according to the invention. In the process illustrated by the  FIG.  40   , the multi-purpose installation tools  12  have been removed from both of the end guide tools  9  and both of the intermediate guide tools  10  after which a rod  8  has been inserted and a multi-purpose tool  12  reattached to one tool  10 . Some pushing of the rod may be accomplished by just extending a rod or tool down the central channel of the guide tools  9  and  10  when mechanical advantage is not required to move the rod  8 . As required by the surgeon, one or more multi-purpose installation tools  12  may be added or removed at any time during the course of the rod pushing or reducing procedure. 
     With reference to  FIG.  39   , prior to installation of the rod  8 , the end guide tools  9  are turned or rotated so the channels  55  therein face one another and the intermediate guide tools  10  are aligned so the pass-through slots  111  align with the channels  55 . 
     With reference to  FIG.  40   , the rod  8  has been inserted diagonally through one of the end skin incisions  350  with the adjacent end guide  9  pushed to the side, so that one of the rod ends  59  first passes through the slots  111  in the intermediate guide tools  10  and then into the channel  55  of one of the guide tools  9 . Back muscle tissue separates easily here to allow the upper insertion of the rod  8  and can be further separated by finger separation or cutting through one of the incisions  350 , if required. 
     After initial insertion, the remaining opposed end  59  of the rod  8  is positioned in the channel  55  of the end guide tool  9  that is located next to the insertion point of the rod  8 . Manipulation of the rod  8  in the channels  55  is aided by the back wall tang portions or flexible flaps  38  of the guide tools  9  which may also be moved like a joy-stick toward or away from each other by the surgeon. Furthermore, once the rod  8  is disposed within the channels  111  and  55 , the back wall portions or flaps  38  resiliently bias against the rod ends  59 , substantially holding and containing the rod  8  in place between the end guide tools  9  of the tool set  2 . The reason that the tangs  38  are needed is that the rod  8  extends beyond the end bone screws  4  and the end guide tool  9  are located on the end bone screws  4 . Also, the rod may tend to slip out of one end screw head. When the rod is spaced above the bone screws  4 , the guide tools  9  can be manipulated to be spaced farther apart to receive the rod  8  therebetween, but as the rod  8  nears the bone screws  4 , the guide tools  9  cannot be manipulated enough to compensate so the rod  8  must extend beyond the bodies of the guide tool  9 . Therefore, the tangs  38  allow the rod  8  to be controlled and positioned outwardly of the end bone screws  8 . Moreover, the position of the rod  8  is controlled by equal pressure applied by the tangs  38  so that the rod  8  extends past the bone screws  4  approximately an equal amount on each side. 
     Also with reference to  FIGS.  40  and  41   , once the rod  8  is positioned in the guide tools  9  and  10 , the multi-purpose installation tool  12  may be utilized to push the rod  8  toward the bone screw  4 , normally when mechanical advantage is needed to seat the rod  8  in the bone screws  4 . This is accomplished by rotating the translation nut  202  in a clockwise direction (as viewed from above the skin  20 ), thereby translating the sleeve  204  in a downward direction toward the bone screw  4 , with the guide tool alignment block  218  abutting and pushing against the rod  8 . It is also possible to reduce or realign vertebral bodies by this maneuver. 
     As shown in  FIG.  40   , it may also be desirable to simultaneously or thereafter push the rod  8  toward the screw  4  of one or more guide tools  9  and  10  utilizing the closure top installation tool  302  pushing against a closure top  62  that in turn pushes against the rod  8 . In particular, a closure top  62  is placed in the elongate top to bottom channel associated with the guide tools  9  and  10 , preferably by entry from the side such as into the channel opening  40  of the guide tool  9  or alternatively into the channel  39  through the top end  43  of the guide tool  9 . If the guide tool  9  or  10  has the multi-purpose installation tool  12  attached, the closure top  62  can be placed into the guide tool by side insertion into the U-shaped channel  212 . The closure top installation tool  302  is then inserted into the top end  43  and through the channels disposed within the guide tool  9 , until the engagement portion  304  mates with a cooperating aperture disposed in the break-off head  186 . The closure top  62  is then driven or pushed under manual control of the surgeon by use of the installation tool  145  toward the rod  4 . 
     With reference to  FIG.  42   , near the bottom of the guide tools  9  and  10 , such as near the end  112  of the intermediate tool  10  and the bottom  36  of the back wall  28  of end guide tool  9 , the closure top  62  engages the helically wound guide and advancement structures  64  and  114  of respective guide tools  9  and  10 . The tools  302  and mated closure tops  62  are then rotated, mating the closure tops  62  with associated guide tools  9  and  10  so as to drive the closure top  62  downward against the rod  8  and to urge the rod  8  downward into the bone screw channel  153 . Preferably, the translation nut  202  of the multi-purpose installation tool  12  is rotated in a clockwise direction, translating the sleeve  204  and block  218  downwardly slightly in advance or substantially concurrent with the advancement of the closure tops  62 , providing additional mechanical advantage for the block flat surface  222  against the rod  8 . 
     With reference to  FIG.  43   , at the bottom of the guide tool  9  or  10 , the closure top mating structure  181  engages and begins to mate with the guide and advancement structure  183  on the respective bone screw  4  and continued rotation of the tool  302  drives the rod  8  downward and into engagement with the upper part of the bone screw shank  154 , so as to snug against and frictionally lock the shank  148  in position relative to the bone screw head  146 . 
     Once all of the closure tops  62  are in final seated position in respective bone screws  4  and the surgeon is satisfied with the position of all of the elements, such as is illustrated in  FIG.  43   , any and all multi-purpose installation tools  12  are removed by rotating the nut  202  counter-clockwise followed by sliding the sleeve  204  off of the guide tool  9  and  10  and out of the incision  350 . Thereafter, each of the guide tools  9  and  10  are now removed by rotating each guide tools  9  and  10  ninety degrees so that the recesses  116  straddle the rod  8  to allow the attachment structure  72  or  124  to disengage from the receiver portion  145  on the bone screw  4 . The guide tool  9  or  10  is then pulled axially upward away from the bone screw  4 , along the tool  302  and then out of the incision  350 . 
     The antitorque tool  300  is mounted over each closure top installation tool  302 , utilizing the tool  302  as a guide for re-entry through the incision  350 . The antitorque tool  300  is slid along the tool  302  until the bridges  310  straddle the rod  8 , preventing axial rotation of the tool  300 . As shown in  FIG.  46   , the closure top installation tool  302  is then pulled axially upward away from the bone screw  4  and out of the incision  350 . 
     With reference to  FIG.  47   , the closure top torquing tool  305  is then inserted into the antitorque tool  300  and engaged with the break-off head  186 . By cooperative use of the tools  300  and  305  a preselected torque is manually applied to the break-off head  186  which breaks from the closure top  62  as illustrated in  FIG.  48    and is thereafter removed, followed by removal of the antitorque tool  300 , after which the incision  165  is closed. 
     With reference to  FIGS.  49 - 53   , an alternative attachment structure, generally  401 , is illustrated. A portion of the structure  401  is located on a polyaxial bone screw head or receiver  406  that is pivotally attached to a shank  407 . Shown in phantom in the illustrated embodiment, the threaded shank  407  is cannulated, having a small central bore  408  extending an entire length of the shank body. The bore  408  provides a passage through the shank interior for a length of wire or pin inserted into a vertebra prior to the insertion of the threaded shank body  407 , the wire or pin providing a guide for insertion of the shank  407  into the vertebra. 
     The attachment structure  401  for holding cooperation between the polyaxial bone screw head or receiver  406  and a guide tool  410  is also located at a lower end portion  411  of the guide tool  410 . The lower end portion  411  has a cutout  412  and an inner attachment ledge  413 . The attachment ledge  413  has a body  414  with an upperwardly extending, projection, flange or hook member  415  that follows an inner curvature of the guide tool  410 . The body  414  extends radially inwardly and is sized and shaped to mate with and set within a tool receiving recess or groove  418  formed on the bone screw head  406 . The recess  418  is sufficiently wide to simultaneously receive both the body  414  and the hook member  415  in a radially inward direction, as is shown in  FIG.  52   . The attachment  413  is then set by axially raising the guide tool  410  relative to the bone screw  406  so at least part of the hook member  415  is located in an upper hidden recess  420 , thereby securing the guide tool  410  to a respective bone screw  406 , as shown in  FIG.  53   . This locks the guide tool  410  to a respective bone screw  406  and prevents outward splaying of the guide tool  410 . This is a snap-on type installation or assembly as seen in  FIG.  49    where the leg  411  splays outward during initial placement of the guide tool  410  over the bone screw  406  and then returns to an unsplayed position when the inner attachment structure  413  seats in the receiving recess  418 , as shown in  FIG.  52   . 
     Alternatively, the guide tool  410  can be rotated approximately 90 degree. about a rotational axis thereof prior to joining with a respective bone screw  406 , the attachment structure  413  lowered through the opening between bone screw arms  424  and  425  and aligned with the tool receiving recess  418 , after which the guide tool  410  is rotated back to the first position shown in  FIG.  53    in a twist on type assembly. In some instances the guide tool  410  is rotated somewhat more or less than ninety degrees to make the necessary alignment for removal which depends on the specific construction of the parts. 
     To remove the guide tool  410  from the bone screw receiver  406 , the guide tool  410  is rotated ninety degrees to align the inner attachment ledge  413  with the opening between bone screw arms  424  and  425 , to allow the attachment structure  413  to disengage from the recess  418 . The guide tool  410  is then pulled axially upward away from the bone screw  406 . 
     With reference to  FIGS.  54 - 56   , a second alternative attachment structure, generally  430 , for holding attachment of a bone attachment structure and a guide tool is illustrated. A polyaxial bone screw head or receiver  434  with a pivotally attached bone screw shank  435  is shown cooperating with a guide tool  436  having a lower end portion  438  thereof. On the bone screw receiver  434 , the attachment structure  430  includes tool engaging apertures  440  formed on outer surfaces of arms  444  and  445  for holding the receiver  434  during procedures such as bone screw assembly, implantation of the shank  435  into a vertebra, and subsequent procedures, such as rod reduction and closure top installation. The illustrated apertures  440  are substantially circular in cross-section and are disposed opposite one another, each including an upwardly projecting, hidden inner recess  448  for cooperating with complimentary bone screw holding components of the guide tool  436 , discussed more fully below. It is noted that the apertures  440  and the cooperating guide tool holding components may be configured to be of a variety of sizes and locations for attachment to the guide tool along any of the surfaces of the arms  444  and  445 . 
     On the guide tool  436 , the attachment structure  430  is disposed at the lower portion  438  and on inner slightly recessed surfaces  452  and  453  of respective legs or surfaces  456  and  457 . The attachment structure  430  includes diametrically opposed projections or pins  460  and  462 , extending radially inwardly from the surfaces  452  and  453 , respectively. The pins  460  and  462  are substantially configured the same, both being substantially rounded, radially inward projecting nodules, each having a lip  464  projecting upwardly and away from a bottom surface  468  and  469 , respectively. Each lip  464  partially defines a groove  470  for receiving the bone screw receiver  434 . The groove  470  is further defined by a base surface  472  and a wall  474  that faces the inner surface  452  or  453 . An upper wall  476  is substantially parallel to the base or bottom surface  468  or  469 . 
     The pins  460  and  462  are configured to mate with the opposed apertures  440  of the bone screw head or receiver  434  with the lip  464  extending into the inner recess  448 , when the guide tool  436  is fully installed on the bone screw head  434  as shown in  FIG.  56    and described more fully below. While a preferred embodiment of the invention has pins  460  and  462  of the implant engaging structure  430  on the guide tool  436 , and apertures  440  on the bone screw head  434 , it is foreseen that these elements could be reversed in total or part in accordance with the invention. 
     In use, before implanting the bone screw shank  435  in a vertebra, the bone screw head or receiver  434  is preferably joined to the guide tool  436 . It is also possible to join the guide tool  436  to the bone screw receiver  434  after the installation of the bone screw to the vertebra. The cooperating implant engaging structure  430  disposed on the guide tool  436  and the head or receiver  434  is joined by first manually spreading the legs  456  and  457  apart and inserting the guide tool  436  onto the bone screw head  434  as illustrated in  FIG.  54   . The inwardly projecting pins  460  and  462  are generally aligned with the apertures  440  and the tool is slid downwardly along the head  434  surface until the pins  460  and  462  snap into the apertures  440  as shown in  FIG.  55   . With reference to  FIG.  56   , the guide tool  435  is then pulled upwardly and away from the bone screw head  434 , causing the lips  464  to enter the recesses  448 . Engagement between the lips  464  and the structure defining the recesses  448  result in a firm attachment that also resists any attempt to spread or splay the legs  456  and  457 . 
     To remove the guide tool  436  from the bone screw head  434 , downward force is first placed on the guide tool  436  by the surgeon to move the lips  464  of the guide tool implant engaging structure  430  out of the inner recesses  448  of the bone screw head  434 . Then a prying tool may be inserted between the legs  456  and  457  to spread the lower portions of the legs  456  and  457  away from one another, while pulling up on the guide tool  436  to allow the guide tool to slide upwardly along the bone screw head  434  (as illustrated in reverse by  FIGS.  56 ,  55  and  54   ). The guide tool  436  is then pulled axially upwardly away from the bone screw head  434 . 
     With reference to  FIGS.  57 - 59   , a third alternative attachment structure, generally  480 , for holding a bone attachment, such as the bone screw, generally  482 , to a guide or holding tool  484  is illustrated. The illustrated bone screw  482  includes a head or receiver  486  hingedly attached to a bone screw shank  487 . With reference to  FIG.  57   , the shank  487  is bottom loaded into the receiver  486  and then rotated ninety degrees to seat an upper portion  489  of the shank  487  within the receiver  486  as shown in  FIG.  59   . First and second arms  490  and  492  of the receiver  486  each include outer substantially planar surfaces  494 . Each outer surface  494  of each arm  490  and  492  also includes a substantially V-shaped undercut  496  disposed near and running parallel to a top surface  498 , the undercut  496  extending along and through end surfaces  497  of the receiver  486  and sized and shaped for cooperating with complimentary bone screw holding components of the guide tool  484 . The undercut  496  includes a planar surface  500  disposed at an acute angle with respect to a second surface  501 , the surface  501  being perpendicular to the top surface  498 . 
     On the guide tool  484 , the attachment structure  480  includes diametrically opposed projections in the form of straight, hook-like ledges  502  extending along inner surfaces of the tool  484  and projecting inwardly and upwardly (operably in a direction away from the bone screw  482  and toward a remainder of the tool  484 ). The hook-like ledges  502  are sized and shaped to be received in the undercut  496  and be in frictional engagement with the angled surfaces  500 . First and second set screws  504  rotatably attached to the guide tool  484  are sized and shaped for frictional engagement with the top surface  498  of the receiver arms  490  and  492 , respectively, thereby frictionally fixing the projecting ledges  502  within the undercut  496 . 
     In use, before implanting the bone screw shank  487  in a vertebra, the bone screw head or receiver  486  is preferably joined to the guide tool  484 . It is also possible to join the guide tool  484  to the bone screw receiver  486  after the installation of the bone screw to the vertebra. The cooperating implant engaging structure  480  disposed on the guide tool  484  and the head or receiver  486  may be joined in more than one way. One option is to manually spread opposed legs or portions  506  and insert the guide tool  484  onto the bone screw receiver  486  outer arm surface  494  at a location spaced from the top surfaces  498 , thereby snapping the guide tool  484  onto the receiver  486  and thereafter pulling the guide tool  484  upwardly and away from the receiver  486 , the guide tool  484  sliding upwardly along an inwardly sloping surface  507  leading up to the undercut  496  until the ledges  502  are received in the undercut  496 . Engagement between the ledges  502  and the sloped surfaces  500  result in a firm attachment that also resists any attempt to spread or splay the legs  506 . The set screws  504  may then be rotated and thereby moved into frictional engagement with the top surfaces  498 . 
     Alternatively, the implant engaging structure  480  on the guide tool  484  may be aligned with the undercut  496  on the receiver  486 , the tool  484  disposed laterally of the bone screw receiver  486 . Then the tool  484  may be slid onto the bone screw receiver  486  with the ledges  502  in sliding engagement in the surfaces  500  of the undercuts  496  until the ledges  502  are fully received in the undercuts  496 . To fully engage the ledges  502  with the surfaces  500 , the guide tool  484  is pulled upwardly and away from the receiver  486 . The set screws  504  may then be rotated and placed in frictional engagement with the top surfaces  498 . 
     To remove the guide tool  484  from the bone screw head  434 , the set screws  504  are first rotated until the screws  504  are spaced from the top surfaces  498 . Downward force is then placed on the guide tool  484  by the surgeon to move the ledges  502  of the guide tool implant engaging structure  480  slightly out of the undercut  496 . Then the guide tool  484  is slid in a lateral direction, out of the undercut  496 . 
     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. For example, it is foreseen that more than one tool could be used to provide the described functions for the multi-purpose installation tool  12 . It is also possible to use the invention in an open surgical wound. Different types of screw drivers, both cannulated and non-cannulated, can be used with the invention.