Capless multiaxial screw and spinal fixation assembly and method

Abstract

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

1 . A capless multiaxial screw system comprising: 
 a receiver comprising a receiver end comprising a receiver bore for receiving a threaded portion of a screw having a screw head; and    a sleeve having a sleeve end for situating against at least a portion of said screw head after said threaded portion is received in said receiver bore, said sleeve having a sleeve bore associated with said sleeve end;    said receiver having a channel for receiving an elongated member;    said sleeve being adapted to permit said elongated member to engage said at least of portion of said screw head when said elongated member is received in said channel and said receiver is rotated to a locked position.    
   
   
       2 . The capless multiaxial screw system as recited in  claim 1  wherein said sleeve end comprises an outer end surface that is tapered or concave, said outer end surface engaging said at least a portion of said screw head.  
   
   
       3 . The capless multiaxial screw system as recited in  claim 1  wherein said sleeve end comprises an inner end surface, said at least a portion of said screw head extending through said sleeve bore beyond said inner end surface when said receiver is in said locked position.  
   
   
       4 . The capless multiaxial screw system as recited in  claim 1  wherein said receiver comprises a plurality of channels for receiving said elongated member.  
   
   
       5 . The capless multiaxial screw system as recited in  claim 4  wherein each of said plurality of channels defines an intermediate area for capturing said elongated member to facilitate adjusting a position of said elongated member before it is locked in said receiver.  
   
   
       6 . The capless multiaxial screw system as recited in  claim 5  wherein said plurality of channels are defined by a first surface and a second surface, each of said plurality of channels having an intermediate step for defining said intermediate area.  
   
   
       7 . The capless multiaxial screw system as recited in  claim 6  wherein at least one of said first or second surfaces is not planar.  
   
   
       8 . The capless multiaxial screw system as recited in  claim 1  wherein said channel is a helical channel defined by at least one surface of said receiver.  
   
   
       9 . The capless multiaxial screw system as recited in  claim 1  wherein said sleeve end comprises a generally concave or semispherical seat, at least a second portion of said screw head having a curvature that generally complements said generally concave or semispherical seat.  
   
   
       10 . The capless multiaxial screw system as recited in  claim 1  wherein said channel comprises a receiving area that is generally parallel to an axis of said receiver and comprises a locking area that spirals about said axis of said receiver when moving in an axial direction.  
   
   
       11 . The capless multiaxial screw system as recited in  claim 10  wherein said locking area extends in a direction that is generally not parallel to said axis of said receiver.  
   
   
       12 . The capless multiaxial screw system as recited in  claim 1  wherein said receiver comprises at least one camming surface that cooperates with an opposing surface for defining said channel, said at least one camming surface facilitates compressing said elongated member directly against said at least a portion of said screw head.  
   
   
       13 . The capless multiaxial screw system as recited in  claim 1  wherein said receiver comprises a plurality of camming surfaces that cooperate with a plurality of opposing surfaces, respectively, to define said channel, said plurality of camming surfaces for camming against said elongated member and forcing it into compression against said at least a portion of said screw head.  
   
   
       14 . The capless multiaxial screw system as recited in  claim 13  wherein said locking channel comprises a first locking channel area and a second locking channel area, said receiver comprises a first camming surface generally opposed to a first opposing surface to define said first locking channel area and a second camming surface generally opposed to a second opposing surface to define said second locking channel area, said first and second camming surfaces camming against said elongated member to cause said elongated member to apply a compressive force against said screw head when said receiver is rotated.  
   
   
       15 . The capless multiaxial screw system as recited in  claim 1  wherein said channel comprises a lock member associated therewith for facilitating retaining said receiver in a locked position.  
   
   
       16 . The capless multiaxial screw system as recited in  claim 15  wherein said lock member cooperates with an end wall of said channel to define a locking area at which said receiving member is locked when it is in said locked position.  
   
   
       17 . The capless multiaxial screw system as recited in  claim 1  wherein said channel lies in a first plane that is generally planar and said receiver further comprising a locking channel that lies in a second plane that is non-planar.  
   
   
       18 . The capless multiaxial screw system as recited in  claim 1  wherein said receiver comprises a locking channel that spirals about an axis of said retainer.  
   
   
       19 . The capless multiaxial screw system as recited in  claim 1  wherein said receiver comprises a seat, said screw head having a screw head end that is generally spherical or semispherical and said seat is adapted to receive and complement said screw head end.  
   
   
       20 . The capless multiaxial screw system as recited in  claim 1  wherein said screw head comprises a plurality of recessed areas in at least a portion of said screw head adapted to receive a tool for driving said screw.  
   
   
       21 . The capless multiaxial screw system as recited in  claim 1  wherein said screw head comprises a simple recessed area adapted to receive a tool for driving said screw.  
   
   
       22 . The capless multiaxial screw system as recited in  claim 1  wherein said at least a portion of said screw head comprises an outer surface that is arcuate, curved, semispherical or spherical.  
   
   
       23 . The capless multiaxial screw system as recited in  claim 22  wherein said outer surface is spherical.  
   
   
       24 . The capless multiaxial screw system as recited in  claim 1  wherein said sleeve end is adapted to permit direct engagement or compression of said elongated member against said at least a portion of said screw head.  
   
   
       25 . The capless multiaxial screw system as recited in  claim 1  wherein said screw head is adapted to permit point contact and compression of said elongated member against said at least a portion of said screw head when a screw axis of said screw is not coaxial with a receiver axis of said receiver.  
   
   
       26 . The capless multiaxial screw system as recited in  claim 3  wherein said sleeve bore is adapted to permit said at least a portion of said screw head to extend into said sleeve bore a predetermined distance such that it extends into said channel.  
   
   
       27 . The capless multiaxial screw system as recited in  claim 1  wherein said sleeve comprises two generally opposing walls that stabilize and align said elongated member in said receiver.  
   
   
       28 . The capless multiaxial screw system as recited in  claim 27  wherein said at least a portion of said screw head comprises an outer surface that is arcuate, curved, semispherical or spherical in cross section.  
   
   
       29 . A bone fixation assembly comprising: 
 a receiver having a receiver bore for receiving a screw having a screw head and a receiver channel in communication with said receiver bore for receiving an elongated member; and    a stabilizer adapted to be received in said receiver bore, said stabilizer having a stabilizer channel and a stabilizer bore through said stabilizer, said stabilizer adapted to permit direct contact between at least a portion of said screw head and said elongated member;    said receiver being capable of rotating relative to said elongated member after said elongated member is received in said receiver channel to force said elongated member into contact with said at least a portion of said screw head.    
   
   
       30 . The bone fixation assembly as recited in  claim 29  wherein said receiver comprises at least one engaging surface for engaging said elongated member and for locking said elongated member to said at least a portion of said screw head when said receiver is rotated to a locked position.  
   
   
       31 . The bone fixation assembly as recited in  claim 29  wherein said receiver is generally cylindrical and said receiver bore extends along an axis of said receiver, said receiver comprising a first locking aperture in communication with said receiver bore and a second locking aperture in communication with said receiver bore; said first and second locking apertures cooperating to define a locking channel.  
   
   
       32 . The bone fixation assembly as recited in  claim 31  wherein said locking channel is defined by a first channel in a wall of said receiver and a second channel in said wall of said receiver, said first and second channels being generally opposed.  
   
   
       33 . The bone fixation assembly as recited in  claim 32  wherein said first channel and said second channel extend away from said receiver channel about a receiver axis of said receiver such that rotation of the receiver will cause said elongated member to move to a locked position whereupon it engages said at least a portion of said screw head.  
   
   
       34 . The bone fixation assembly as recited in  claim 32  wherein said first channel and said second channel spiral in a common direction about a receiver axis of said receiver.  
   
   
       35 . The bone fixation assembly as recited in  claim 29  wherein said receiver comprises a wall that lies in a generally circular or arcuate plane about a receiver axis of said receiver and said receiver channel being by said wall.  
   
   
       36 . The bone fixation assembly as recited in  claim 29  wherein said screw head comprises a plurality of recessed areas.  
   
   
       37 . The capless multiaxial screw system as recited in  claim 29  wherein said screw head comprises a single recessed area adapted to receive a tool for driving the screw.  
   
   
       38 . The bone fixation assembly as recited in  claim 29  wherein an outer surface of said at least a portion of said screw head is arcuate, curved, spherical or semispherical in cross section.  
   
   
       39 . The bone fixation assembly as recited in  claim 29  wherein an outer surface of said at least a portion of said screw head is arcuate or spherical at said at least a portion of said screw head.  
   
   
       40 . The bone fixation assembly as recited in  claim 39  wherein said screw has a truncated area for permitting maximal polyaxial movement of said receiver relative to said screw head.  
   
   
       41 . The bone fixation assembly as recited in  claim 29  wherein said stabilizer bore of said stabilizer is adapted to permit point contact of said elongated member against said at least a portion of said screw head.  
   
   
       42 . The bone fixation assembly as recited in  claim 39  wherein said stabilizer bore of said stabilizer is adapted to permit point contact of said elongated member against said at least a portion of said screw head.  
   
   
       43 . The bone fixation assembly as recited in  claim 29  wherein said screw head and said stabilizer bore are adapted to permit point contact of said elongated member against said at least a portion of said screw head and when a screw axis of said screw is not coaxial with a receiver axis of said receiver.  
   
   
       44 . The bone fixation assembly as recited in  claim 29  wherein said stabilizer bore is adapted to permit said at least a portion of said screw head to extend into said receiver bore a predetermined distance.  
   
   
       45 . The bone fixation assembly as recited in  claim 29  wherein said stabilizer comprises an inner end surface, said at least a portion of said screw head extends beyond said inner end surface and into said stabilizer bore when said elongated member is in a locked position in said receiver.  
   
   
       46 . The bone fixation assembly as recited in  claim 29  wherein said stabilizer comprises a first wall and a generally opposed second wall for defining a stabilizer receiving area or channel for receiving said elongated rod.  
   
   
       47 . The bone fixation assembly as recited in  claim 46  wherein said stabilizer bore is in communication with said stabilizer receiving area, said stabilizer bore being adapted to permit said at least a portion of said screw head to be received in said stabilizing bore so that said elongated member directly engages or is engaged by said at least a portion of said screw head when said receiver is rotated to a locked position.  
   
   
       48 . The bone fixation assembly as recited in  claim 47  wherein said stabilizer comprises a generally cylindrical wall that defines said stabilizer bore.  
   
   
       49 . The bone fixation assembly as recited in  claim 48  wherein said generally cylindrical wall comprises an inner diameter that generally corresponds to a distance between said first and second walls.  
   
   
       50 . An intermediate member for use with a polyaxial screw having a head that is generally spherical comprising: 
 a body having a bore; and    a channel for receiving an elongated member;    said bone being adapted to permit at least a portion of a screw head of the polyaxial screw to enter into said bore.    
   
   
       51 . The intermediate member as recited in  claim 50  wherein a width of said channel is at least as large as a radius of said bore.  
   
   
       52 . The intermediate member as recited in  claim 50  wherein said intermediate member comprises an end having a frusto-conical, or spherical or semispherical surface for engaging said screw head.  
   
   
       53 . The intermediate member as recited in  claim 50  wherein said intermediate member comprises an end having an opening adapted to permit said elongated member to engage or be engaged by at least one portion of said screw head.  
   
   
       54 . A bone fixation assembly comprising: 
 a receiver having a bore for receiving a screw having a screw head; and    an intermediate member dimensioned to be received in said bore and having a first end and a second end;    said receiver comprising an integral rotary lock for forcing and locking an elongated member directly against said screw head when said receiver is rotated.    
   
   
       55 . The bone fixation assembly as recited in  claim 54  wherein said integral rotary lock comprises a continuous channel for receiving said elongated member and for urging said elongated member toward said screw head when said receiver is rotated.  
   
   
       56 . The bone fixation assembly as recited in  claim 54  wherein said integral rotary lock comprises a first channel that extends about a receiver axis in a first direction and a second channel that extends about said receiver axis in a second direction and a receiver channel coupling said first and second channels.  
   
   
       57 . The bone fixation assembly as recited in  claim 56  wherein said first and second directions extend away from said receiver channel about a receiver axis of said receiver such that rotation of said receiver will move said elongated member from an unlocked position to a locked position.  
   
   
       58 . The bone fixation assembly as recited in  claim 56  wherein said receiver channel lies in a plane that generally extends along an axis of said receiver.  
   
   
       59 . The bone fixation assembly as recited in  claim 56  wherein said first and second channels spiral about said receiver axis.  
   
   
       60 . The bone fixation assembly as recited in  claim 56  wherein said first and second channels lie in imaginary planes that intersect an axis of said receiver at acute angles.  
   
   
       61 . The bone fixation assembly as recited in  claim 56  wherein said receiver channel lies in a receiver plane, said first channel lies in a first plane and said second channel lies in a second plane, each of said first and second planes intersecting said receiver plane at an acute angle that extends toward a bone when said screw is screwed into the bone.  
   
   
       62 . The bone fixation assembly as recited in  claim 54  wherein said receiver comprises a removable intermediate member for stabilizing said elongated member.  
   
   
       63 . The bone fixation assembly as recited in  claim 62  wherein said removable intermediate member comprises an end having an opening, said screw head and said opening being adapted to enable said elongated member to contact at least one portion of said screw head.  
   
   
       64 . The bone fixation assembly as recited in  claim 54  wherein said screw head is generally spherical.  
   
   
       65 . The bone fixation assembly as recited in  claim 62  wherein said screw head is generally spherical.  
   
   
       66 . A bone fixation assembly comprising: 
 a receiver having an opening for receiving a screw having a screw head; and    an intermediate member dimensioned to be received in said opening and having an intermediate member receiving channel for receiving an elongated member and a screw head receiving opening adapted to receive at least a portion of said screw head;    said receiver comprising a receiver channel for receiving said elongated member, said receiver channel compressing said elongated member against said screw head when said receiver is rotated from an unlocked position to a locked position.    
   
   
       67 . The spiral fixation assembly as recited in  claim 66  wherein said receiver channel comprises a locking channel that spirals about an axis of said receiver.  
   
   
       68 . The spiral fixation assembly as recited in  claim 67  wherein said locking channel provides a bayonet connection between said elongated member and said screw.  
   
   
       69 . The bone fixation assembly as recited in  claim 66  wherein said receiving channel comprises at least a portion that lies in a first plane and said intermediate member receiving channel comprises at least a portion that lies in a second plane, said second plane and said first plane being generally parallel when said elongated member is in said unlocked position and generally perpendicular when said elongated member is in said locked position.  
   
   
       70 . The bone fixation assembly as recited in  claim 66  wherein when said receiver is rotated from said unlocked position to said locked position, said elongated member directly engages said at least a portion of said screw head and becomes situated closer to said screw compared to when said elongated member is in said unlocked position.  
   
   
       71 . The bone fixation assembly as recited in  claim 70  wherein said receiver channel is in communication with a locking channel so that when said receiver is in said unlocked position, said receiving channel becomes generally aligned with said intermediate member receiving channel in said intermediate member.  
   
   
       72 . The bone fixation assembly as recited in  claim 66  wherein said receiver channel is generally perpendicular to an elongated member axis of said elongated member when said receiving member is in said locked position.  
   
   
       73 . The bone fixation assembly as recited in  claim 66  wherein said receiver channel comprises a locking channel that spirals from a first end of said receiver toward a second end of said receiver.  
   
   
       74 . The bone fixation assembly as recited in  claim 73  wherein said locking channel defines a helix.  
   
   
       75 . The bone fixation assembly as recited in  claim 66  wherein said receiver channel extends from an end of said receiver in a direction that is generally parallel to an axis of said receiver and further comprises a locking channel that extends at least partially about said axis of said receiver.  
   
   
       76 . The bone fixation assembly as recited in  claim 66  wherein said intermediate member receiving channel becomes generally aligned with said receiver channel when said elongated member is received in said receiver and said receiver channel and said intermediate member receiving channel become non-aligned when said receiver is rotated to said locked position.  
   
   
       77 . The bone fixation assembly as recited in  claim 66  wherein said receiver channel comprises a locking channel, said receiver comprising at least one camming surface that cooperates with an opposing surface that cooperates to define said receiver channel, said at least one camming surface camming against said elongated member to move said elongated member against said screw head when said receiver is rotated.  
   
   
       78 . The bone fixation assembly as recited in  claim 66  wherein said receiver comprises a plurality of camming surfaces that cooperate with a plurality of opposing surfaces, respectively, to define a locking channel, said plurality of camming surfaces camming against said elongated member to cause said elongated member to apply a compressive force against said screw head when said receiver is rotated.  
   
   
       79 . The bone fixation assembly as recited in  claim 66  wherein said receiver comprises a locking channel comprising a first locking channel area and a second locking channel area 
 said receiver comprises a first camming surface generally opposed to a first opposing surface to define said first locking channel area and a second camming surface generally opposed to a second opposing surface to define said second locking channel area, said first and second camming surfaces camming against said elongated member to force said elongated member to apply a compressive force against said screw head when said receiver is rotated.    
   
   
       80 . The bone fixation assembly as recited in  claim 79  wherein said receiver comprises a detent or protrusion or a plurality of detents or protrusions in communication with said locking channel.  
   
   
       81 . The bone fixation assembly as recited in  claim 79  wherein said receiver comprises a surface that defines an end wall of said locking channel to define a locking area at which said elongated member is locked when it is in said locked position.  
   
   
       82 . The bone fixation assembly as recited in  claim 66  wherein said receiver comprises a locking channel, said receiver channel lies in a first plane that is generally planar and said locking channel lies in a second plane that is non-planar.  
   
   
       83 . The bone fixation assembly as recited in  claim 82  wherein said second plane spirals about an axis of said receiver.  
   
   
       84 . The bone fixation assembly as recited in  claim 82  wherein said locking channel extends in a direction that is non-axial relative to an axis of said receiver.  
   
   
       85 . The bone fixation assembly as recited in  claim 66  wherein said screw head is generally arcuate, spherical, semispherical or curved and said intermediate member comprises an end having an outer end surface that is generally complementary in shape and adapted to receive said screw head.  
   
   
       86 . The bone fixation assembly as recited in  claim 66  wherein said screw head comprises a plurality of recessed areas surrounding said at least a portion of said screw head.  
   
   
       87 . The bone fixation assembly as recited in  claim 66  wherein said at least a portion of said screw head is spherical in cross section.  
   
   
       88 . The bone fixation assembly as recited in  claim 66  wherein said at least a portion of said screw head is spherical in cross section at an area where said elongated member directly engages said screw head.  
   
   
       89 . The bone fixation assembly as recited in  claim 66  wherein said outer surface of said screw head is adapted to permit point contact of said elongated member directly against said at least a portion of said screw head.  
   
   
       90 . The bone fixation assembly as recited in  claim 66  wherein said screw head is adapted to permit point contact of said elongated portion against said at least a portion of said screw head when a screw axis of said screw is not coaxial with a receiver axis of said receiver.  
   
   
       91 . The bone fixation assembly as recited in  claim 66  wherein said intermediate member comprising an end having an opening adjusted to permit an engaging portion of said screw head to extend into said receiver opening a predetermined distance.  
   
   
       92 . The bone fixation assembly as recited in  claim 66  wherein said intermediate member comprises a bottom surface, said at least a portion of said screw extending beyond said bottom surface and into said receiver channel when said elongated member is in said locked position.  
   
   
       93 . The bone fixation assembly as recited in  claim 66  wherein said intermediate member comprises an end having an outer end surface that is frusto-conical.  
   
   
       94 . The bone fixation assembly as recited in  claim 66  wherein said screw head comprises an outer surface and at least one tool aperture or area for receiving a tool.  
   
   
       95 . A capless multiaxial screw system comprising: 
 a screw having a threaded portion and a screw head;    a receiver having a receiver bore for receiving said threaded portion and a receiving channel for receiving an elongated member, said receiver further comprising a locking channel in communication with said receiving channel;    an intermediate member adapted to be situated in said receiver bore, said intermediate member comprising an intermediate member bore for receiving at least a portion of said screw head; and    said intermediate member bore and said screw head being adapted to permit said at least a portion of said screw head to extend into said locking channel so that said elongated member may engage and compress against said at least a portion of said screw head when said elongated member is received in said receiving channel and said receiver is rotated.    
   
   
       96 . The capless multiaxial screw system as recited in  claim 95  wherein said locking channel comprises a plurality of channels, each of said plurality of channels defining an intermediate area for capturing said elongated member to facilitate adjusting a position of said elongated member before it is locked in said receiver.  
   
   
       97 . The capless multiaxial screw system as recited in  claim 96  wherein each of said plurality of channels are defined by a first surface and a second surface, each of said plurality of channels having an intermediate step on at least one of said first surface or said second surface for defining said intermediate area.  
   
   
       98 . The capless multiaxial screw system as recited in  claim 97  wherein at least one of said first and second surfaces is not planar.  
   
   
       99 . The capless multiaxial screw system as recited in  claim 95  wherein said locking channel is a helical channel defined by at least one surface in a body of said receiver.  
   
   
       100 . The capless multiaxial screw system as recited in  claim 95  wherein said intermediate member comprises an end having a first side comprising a generally concave seat, at least a second portion of said screw head having a curvature that generally complements said generally concave seat.  
   
   
       101 . The capless multiaxial screw system as recited in  claim 95  wherein said receiving channel is generally parallel along an axis of said receiver and said locking channel spirals about said axis of said receiver when moving in an axial direction.  
   
   
       102 . The capless multiaxial screw system as recited in  claim 95  wherein said receiving channel extends from an end of said receiver in a direction that is generally parallel to said axis of said receiver and said locking channel extends in a direction that is generally not parallel to said axis of said receiver.  
   
   
       103 . The capless multiaxial screw system as recited in  claim 95  wherein said receiver comprises at least one camming surface that cooperates with an opposing surface to define said locking channel, said at least one camming surface forcing said elongated member against said at least a portion of said screw head.  
   
   
       104 . The capless multiaxial screw system as recited in  claim 95  wherein said receiver comprises a plurality of camming surfaces that cooperate with a plurality of opposing surfaces, respectively, to define said locking channel, said plurality of camming surfaces camming against said elongated member to lock said receiver to said at least a portion of said screw head.  
   
   
       105 . The capless multiaxial screw system as recited in  claim 95  wherein said locking channel comprises a first locking channel area and a second locking channel area, said receiver comprises a first camming surface generally opposed to a first opposing surface to define said first locking channel area and a second camming surface generally opposed to a second opposing surface to define said second locking channel area, said first and second camming surfaces camming against said elongated member to force said elongated member against said at least a portion of said screw head when said receiver is rotated.  
   
   
       106 . The capless multiaxial screw system as recited in  claim 95  wherein said receiving channel lies in a first plane that is generally planar and said locking channel lies in a second plane that is non-planar.  
   
   
       107 . The capless multiaxial screw system as recited in  claim 106  wherein said second plane spirals about an axis of said receiver.  
   
   
       108 . The capless multiaxial screw system as recited in  claim 95  wherein said locking channel spirals about an axis of said receiver.  
   
   
       109 . The capless multiaxial screw system as recited in  claim 95  wherein said receiver comprises a seat defining a seat area said screw head being generally spherical, said seat being adapted to receive and complement said screw head.  
   
   
       110 . The capless multiaxial screw system as recited in  claim 95  wherein said screw head comprises a plurality of recessed areas for receiving a tool used to turn said screw.  
   
   
       111 . The capless multiaxial screw system as recited in  claim 95  wherein said at least a portion of said screw head is spherical or semispherical.  
   
   
       112 . The capless multiaxial screw system as recited in  claim 95  wherein said at least a portion of said screw head is arcuate or spherical in cross section.  
   
   
       113 . The capless multiaxial screw system as recited in  claim 95  wherein said intermediate member comprises a seat defining a seat area adapted to permit point contact between said elongated member and said at least a portion of said screw head.  
   
   
       114 . The capless multiaxial screw system as recited in  claim 95  wherein said screw head and said screw head receiving opening are adapted to permit point contact of said elongated member against said at least a portion of said screw head when a screw axis of said screw is not coaxial with a receiver axis of said receiver.  
   
   
       115 . The capless multiaxial screw system as recited in  claim 95  wherein said intermediate member comprises an end, said intermediate member bore being adapted to permit said at least a portion of said screw head to extend into said locking channel a predetermined distance.  
   
   
       116 . The capless multiaxial screw system as recited in  claim 95  wherein said intermediate member comprises a first wall and a generally opposed second wall for defining an intermediate member receiving area for receiving said elongated member.  
   
   
       117 . The capless multiaxial screw system as recited in  claim 95  wherein said intermediate member bore is in communication with said intermediate member receiving area, said intermediate member bore being dimensioned to permit said at least a portion of said screw head to be received in both said receiver bore and said intermediate member bore so that when said receiver is rotated, said elongated member engages and locks against said at least a portion of said screw head.  
   
   
       118 . The capless multiaxial screw system as recited in  claim 95  wherein said intermediate member is generally cylindrical and defined by a generally cylindrical wall, an inner diameter of said generally cylindrical wall being greater than a diameter of said elongated member.  
   
   
       119 . A capless multiaxial screw fixation assembly comprising: 
 a screw having a threaded portion and a screw head;    a receiver having an aperture for receiving said threaded portion and a receiving channel for receiving an elongated member, said receiving channel further comprising a locking channel in communication with said receiving channel; and    a guide for situating in said bore, said guide comprising: 
 a second receiving channel associated with a first end of said guide and a seat area associated with a second end of said guide;  
   said guide being adapted to permit at least a portion of said screw head to extend into said receiving channel and said second receiving channel so that said elongated member may engage said screw head to lock or compress said elongated member to said screw when said elongated member is received in said first and second receiving channels and said receiver is rotated from an unlocked position to a locked position.    
   
   
       120 . A bone fixation assembly comprising: 
 a receiver having a receiver bore for receiving a screw having a screw head, said receiver further comprising a locking channel and a receiving channel in communication with said locking channel; and    an intermediate member dimensioned to be received in said receiver bore, said intermediate member comprising a body having a first end having an intermediate member channel and a second end having an intermediate member opening;    said intermediate member opening being adapted to permit at least a portion of said screw head to engage an elongated member after said elongated member is received in said receiving channel, said locking channel and said intermediate member channel and said receiver is moved to a locked position.    
   
   
       121 . The bone fixation assembly as recited in  claim 120  wherein said intermediate member comprises a pair of generally opposed walls that cooperate with said second end to define stabilize and align the elongated member in said receiver channel.  
   
   
       122 . The bone fixation assembly as recited in  claim 121  wherein said intermediate member bore is generally cylindrical and comprises a diameter substantially the same as a distance between said pair of generally opposed walls.  
   
   
       123 . A method for stabilizing one or more bones, said method comprising the steps of: 
 placing an elongated member into a receiving channel of said receiver and channel of said intermediate member; and    rotating said receiver to cause said elongated member to directly engage at least a portion of said screw head.