Polyaxial bone screw

Abstract

The present invention generally provides a polyaxial fixation device having a shank with a spherical head formed on a proximal end thereof, and a receiver member having an axial passage formed therein that is adapted to polyaxially seat the spherical head of the shank. The polyaxial bone screw further includes an engagement member that is adapted to provide sufficient friction between the spherical head and the receiver member to enable the shank to be maintained in a desired angular orientation before locking the spherical head within the receiver member.

1 - 31 . (canceled) 
   
   
       32 . A method of producing an apparatus for retaining bone portion in a desired spatial relationship, comprising:
 providing a fastener having a longitudinal axis, a first threaded end portion engageable with a bone portion and a second end portion;   providing a housing having a first passage capable of receiving a longitudinal member and a second passage for receiving the fastener, the second passage having a longitudinal axis;   extending the fastener through an opening in the housing into the second passasge so that the fastener is pivotable relative to the housing and the longitudinal axis of the fastener is positionable in any one of a plurality of angular positions relative to the longitudinal axis of the second passage; and   limiting relative movement between the fastener and the housing by creating a frictional engagement that holds the position of the housing relative to the fastener when the longitudinal member is not recieved in the first passage of the housing.   
   
   
       33 . The method of  claim 32 , wherein the first passage is transverse to the second passage. 
   
   
       34 . The method of  claim 32 , wherein the first passage and the second passage intersect. 
   
   
       35 . The method of  claim 32 , wherein the frictional engagement is created between the second end portion of the fastener and an inner surface of the housing. 
   
   
       36 . The method of  claim 32 , further comprising inserting a spacer into the second passage of the housing, the spacer applying an axial force toward the fastener to create the frictional engagement between the second end portion of the fastener and the inner surface of the housing. 
   
   
       37 . The method of  claim 32 , further comprising inserting a spring member into the second passage of the housing, the spring member compressing to apply an axial force to the spacer and urging the spacer axially toward the fastener to create the frictional engagement that holds the position of the housing relative to the fastener when the longitudinal member is not received in the first passage of the housing. 
   
   
       38 . A method of producing an apparatus for retaining bone portions in a desired spatial relationship, comprising:
 providing a fastener having a longitudinal axis, a first threaded end portion engageable with a bone portion and a second end portion;   providing a housing having a first passage capable of receiving a longitudinal member and a second passage, the second passage having a longitudinal axis extending transverse to the first passage;   extending the fastener through an opening in the housing into the second passage so that the second end portion of the fastener engages an inner surface of the housing and the fastener is pivotable relative to the housing so that the longitudinal axis of the fastener is positionable in any one of a plurality of angular positions relative to the longitudinal axis of the second passage; and   inserting a spacer in the housing, the spacer configured to engage the longitudinal member, wherein the spacer applies an axial force toward the fastener to create a frictional engagement between the second end portion of the fastener and the inner surface of the housing;   wherein the frictional engagement holds the position of the housing relative to the fastener when the longitudinal member is disengaged from the spacer, and the fastener and the housing are manually moveable relative to each other when the longitudinal member is disengaged from the spacer and the spacer applies the axial force.   
   
   
       39 . The method of  claim 38 , wherein the second end portion of the fastener comprises a part spherical surface. 
   
   
       40 . The method of  claim 39 , wherein the part spherical surface of the fastener engages a concave part spherical surface of the housing. 
   
   
       41 . The method of  claim 38 , wherein the spacer engages the fastener. 
   
   
       42 . The method of  claim 41 , further comprising inserting a spring member in the housing and compressing the spring member to urge the spacer axially toward the fastener to prevent relative movement between the fastener and the housing when the longitudinal member is disengaged from the spacer and the spacer engages the fastener. 
   
   
       43 . The method of  claim 41 , wherein the spacer has a concave part spherical surface that engages a part spherical surface of the fastener. 
   
   
       44 . The method of  claim 38 , further comprising providing a cap screw, the cap screw configured to threadably engage the housing and apply a force to a longitudinal member positioned in the first passage of the housing to press the longitudinal member against the spacer. 
   
   
       45 . A method of producing an apparatus for retaining bone portions in a desired spatial relationship, comprising:
 providing a fastener having a longitudinal axis, a first threaded end portion engageable with a bone portion and a second end portion;   providing a housing having a first passage capable of receiving a longitudinal member and a second passage for receiving the fastener, the second passage having a longitudinal axis, wherein the fastener extends through an opening in the housing into the second passage so that the fastener is pivotable relative to the housing and the longitudinal axis of the fastener is positionable in any one of a plurality of angular positions relative to the longitudinal axis of the second passage;   connecting the fastener to a vertebra, wherein a frictional engagement holds the position of the housing relative to the fastener prior to the longitudinal member being received in the first passage of the housing;   positioning the longitudinal member in the first passage of the housing; and   threadably engaging a set screw in the housing, the set screw engaging and applying a force to the longitudinal member.   
   
   
       46 . The method of  claim 45 , wherein the frictional engagement is created between the second end portion of the fastener and an inner surface of the housing. 
   
   
       47 . The method of  claim 46 , wherein the housing is provided with a spacer positioned within the second passage, and the longitudinal member engages the spacer. 
   
   
       48 . The method of  claim 47 , wherein the housing is provided with a spring member that urges the spacer axially toward the fastener and the inner surface of the housing against the second end portion of the fastener. 
   
   
       49 . The method of  claim 45 , further comprising, prior to positioning the longitudinal member in the first passage of the housing, moving the fastener relative to the housing to overcome the frictional engagement. 
   
   
       50 . The method of  claim 45 , wherein the first passage is transverse to and intersects the second passage. 
   
   
       51 . The method of  claim 45 , wherein the second end portion of the fastener is part spherical, and the part spherical end portion of the fastener engages a concave inner surface of the housing. 
   
   
       52 . An apparatus comprising:
 a housing having a top end, a bottom end, and first and second side walls;   the first and second walls defining an opening in the top end of the housing and a channel extending through the housing having a longitudinal axis defining a passageway for receiving a spinal rod; and   a fastener configured to engage to bone, the fastener having a longitudinal axis, the fastener extending from the bottom end of the housing;   wherein each of the first and second side walls includes a downwardly facing horizontal surface and at least a partially cylindrical inwardly extending recess on an exterior surface thereof.   
   
   
       53 . The apparatus of  claim 52 , wherein the first and second side walls have an exterior side surface that is substantially arcuate. 
   
   
       54 . The apparatus of  claim 52 , wherein each of the first and second side walls define an interior side surface and an exterior side surface, the interior side surface further defining the channel and the exterior side surface located opposite the internal surface. 
   
   
       55 . The apparatus of  claim 52 , further comprising a rod positioned in the channel. 
   
   
       56 . The apparatus of  claim 55 , further comprising a clamping mechanism that clamps said rod and housing to said fastener to prevent movement of said fastener relative to said housing. 
   
   
       57 . The apparatus of  claim 56 , wherein the housing is internally threaded, and the clamping mechanism is a set screw. 
   
   
       58 . The apparatus of  claim 52 , wherein said fastener extends through an opening in the bottom end of the housing and is movable in any one of a plurality of angular positions relative to said housing. 
   
   
       59 . The apparatus of  claim 52 , wherein the recess extends partially through the housing. 
   
   
       60 . An apparatus comprising:
 a housing having a top end, a bottom end, and first and second side walls;   the first and second walls defining an opening in the top end of the housing and a channel extending through the housing having a longitudinal axis defining a passageway for receiving a spinal rod; and   a fastener configured to engage to bone, the fastener having a longitudinal axis, the fastener extending from the bottom end of the housing;   wherein each of the first and second side walls includes a downwardly facing horizontal surface extending along substantially the entirety of an exterior surface of each of the first and second side walls.   
   
   
       61 . An apparatus comprising: a fastener having a longitudinal axis and engageable with a bone portion;
 a housing having a passage with a first transverse dimension, said fastener extending through an opening in said housing into said passage and being movable relative to said housing, said longitudinal axis of said fastener being positionable in any one of a plurality of angular positions relative to said longitudinal axis of said passage;   a spacer received in said passage of said housing and engageable with said fastener, said spacer having an upper end and a lower end; and   a retaining structure having a second transverse dimension greater than the first transverse dimension;   wherein the retaining structure is configured to be press-fit into the passage, the distance between the retaining structure and the spacer determining an adjustable force applied by the spacer to the fastener to prevent relative movement between said fastener and said housing when the spacer engages the fastener; and   wherein an inner surface of the housing is substantially continuous at least from a location engaging the retaining structure to a location adjacent the lower end of the spacer.   
   
   
       62 . An apparatus as defined in  claim 61 , wherein the retaining structure and the spacer are separate members. 
   
   
       63 . An apparatus as defined in  claim 61 , wherein the retaining structure and the spacer are integral. 
   
   
       64 . An apparatus as defined in  claim 61 , wherein the inner surface of the housing is substantially continuous at least from a location engaging the retaining structure to a location within a plane transverse to the longitudinal axis of the housing, said transverse plane containing the lower end of the spacer. 
   
   
       65 . An apparatus comprising: a fastener having a longitudinal axis and engageable with a bone portion;
 a housing having a passage and being configured to receive a longitudinal member, said fastener extending through an opening in said housing into said passage and being movable relative to said housing, said longitudinal axis of said fastener being positionable relative to said longitudinal axis of said passage;   a spacer having a lower end engaged with said fastener; and   means for preventing relative movement between said fastener and said housing before a longitudinal member is received in the housing.   
   
   
       66 . An apparatus comprising: a fastener having a longitudinal axis and engageable with a bone portion;
 a housing having a passage and being configured to receive a longitudinal member, said fastener extending through an opening in said housing into said passage and being movable relative to said housing, said longitudinal axis of said fastener being positionable relative to said longitudinal axis of said passage; and   means for preventing relative movement between said fastener and said housing before a longitudinal member is received in the housing.