Apparatus for connecting a bone fastener to a longitudinal rod

Abstract

A device for connecting a bone fastener to a longitudinal rod has two bores spaced a distance apart and generally parallel axes. A holding member may be associated with one bore, the holding member configured to engage a bone fastener such as a bone screw or pedicle hook. A rod coupling member may be associated with the other bore, the coupling member configured to engage a longitudinal rod. The holding member and rod coupling member both are configured to articulate within their respective bores, thus allowing the rod and rod coupling, as well as the holding member and bone fastener, to rotate about both bore axes. The holding member and rod coupling member also separately lockable to allow independent locking of the bone fastener and the rod to the connector, thus preventing or enabling relative rotation as desired.

1 . A connector for connecting a bone fastener to a rod, the connector comprising: 
 a coupling portion having top and bottom surfaces and first and second bores, each bore having a longitudinal axis, the axes separated by a distance; and    a rod coupler associated with the second bore and comprising a rod receiving portion having an axis, a tab segment, and a bore engaging portion having a bottom end with an increased portion, the increased portion having a dimension greater than that of the second bore, wherein:    the increased portion prevents the rod coupler from passing through the coupling portion when the rod coupler is inserted into the second bore; and    the tab segment contacts the top surface of the coupling portion such that the rod coupler is axially fixed with respect to the coupling portion when the rod coupler is inserted into the second bore.    
   
   
       2 . The connector of  claim 1  wherein the rod coupler is rotatable about the second bore longitudinal axis.  
   
   
       3 . The connector of  claim 1  wherein the rod coupler is rotatable about the first bore longitudinal axis.  
   
   
       4 . The connector of  claim 1  wherein the increased portion comprises a conical flange and the second bore comprises a corresponding conical recess adjacent to the bottom surface of the coupling portion.  
   
   
       5 . The connector of  claim 4  wherein the conical flange and conical recess have corresponding engagement surfaces, and at least one of the engagement surfaces comprises serrations configured to prevent relative rotation between the flange and the bore.  
   
   
       6 . The connector of  claim 1  wherein the rod receiving portion has first and second vertical legs configured to receive a rod, the rod coupler further having locked and unlocked positions.  
   
   
       7 . The connector of  claim 1  wherein the rod receiving portion comprises a channel having a longitudinal axis, a top end distal from the bore engaging portion and a bottom end opposite the top end, the channel longitudinal axis coaxial with the rod receiving portion axis, the channel top end being open to allow a rod to be introduced into the rod receiving portion by pressing the rod through the channel top end in a direction substantially parallel to the second bore axis.  
   
   
       8 . The connector of  claim 1  wherein the first and second bore longitudinal axes are substantially parallel.  
   
   
       9 . The connector of  claim 1  further comprising a locking member having a rod coupler engaging portion.  
   
   
       10 . The connector of  claim 1  further comprising a holding member associated with the first bore and configured to engage the bone fastener and to connect the bone fastener to the coupling portion.  
   
   
       11 . The connector of  claim 10  wherein the holding member is rotatable about the second bore longitudinal axis.  
   
   
       12 . The connector of  claim 10  wherein the holding member comprises top and bottom surfaces and a wall, the wall having at least one vertical slot disposed therein and intersecting one of the top and bottom surfaces.  
   
   
       13 . The connector of  claim 10  wherein the rod coupler and the holding member each have locked and unlocked positions independent of each other.  
   
   
       14 . The connector of  claim 10  wherein the holding member comprises a head portion of the bone fastener.  
   
   
       15 . The connector of  claim 10  wherein the holding member has a bore configured to accept the bone fastener, the holding member further having locked and unlocked positions.  
   
   
       16 . The connector of  claim 15  wherein the rod coupler is rotatable 360 degrees within the second bore when the holding member is in the locked position with a bone fastener.  
   
   
       17 . The connector of  claim 15  further comprising a tensioner sized and configured to engage the holding member in the locked position wherein the holding member is immobilized with respect to the coupling portion and the bone fastener is immobilized within the holding member.  
   
   
       18 . The connector of  claim 17  wherein the tensioner comprises a head portion of the bone fastener.  
   
   
       19 . The connector of  claim 17  wherein the holding member bore has a conical profile and internal threads and the tensioner further comprises a conical outer profile and external threads corresponding to those of the holding member bore.  
   
   
       20 . The connector of  claim 17  wherein the holding member is configured to be resiliently displaceable such that the holding member having an outer spherical surface expands to engage the coupling first bore having an inner spherical surface to configure the holding member in the locked position when the tensioner engages the bore.  
   
   
       21 . The connector of  claim 10  wherein the coupling portion first bore comprises a substantially spherical inner surface and the holding member comprises a substantially spherical outer surface configured to slide within the spherical bore inner surface such that the holding member is rotatable within the first bore about multiple axes.  
   
   
       22 . The connector of  claim 21  wherein the holding member is slidable within the spherical bore inner surface about axes both parallel and perpendicular to the first bore axis.  
   
   
       23 . The connector of  claim 1  wherein the bone fastener comprises a bone screw or hook.  
   
   
       24 . A connector for connecting a bone fastener to a rod, the connector comprising: 
 a coupling portion having top and bottom surfaces and first and second bores, each bore having an axis, the axes separated by a distance; and    a rod coupler associated with the second bore and comprising a rod receiving portion and a bore engaging portion, the bore engaging portion having a bottom flange and an increased portion, the increased portion being between the bottom flange and the rod receiving portion, the flange and increased portion each having a dimension greater than that of the second bore such that the flange prevents the rod coupler from passing through the coupling portion when the rod coupler is inserted into the second bore and the increased portion contacts the top surface of the coupling portion such that the rod coupler is axially fixed with respect to the coupling portion when the rod coupler is inserted into the second bore.    
   
   
       25 . The connector of  claim 24  further comprising a bone fastener connected to the coupling portion via the first bore.  
   
   
       26 . The connector of  claim 25  wherein the bone fastener comprises a bone screw or hook.  
   
   
       27 . The connector of  claim 24  wherein the rod receiving portion comprises first and second vertical legs configured to receive a rod placed there between.  
   
   
       28 . The connector of  claim 27  further comprising a rod locking member configured to engage a top portion of each of the first and second vertical legs to hold the rod between the rod locking member and a top surface of the connector.  
   
   
       29 . The connector of  claim 28  wherein the rod locking member comprises threads configured to engage corresponding threads in the top portion of at least one of the first and second vertical legs.  
   
   
       30 . The connector of  claim 24  further comprising a holding member associated with the first bore and configured to engage a bone fastener.  
   
   
       31 . The connector of  claim 30  wherein the holding member has a bore configured to receive the bone fastener, the holding member further having an unlocked position in which it is free to rotate within the first bore, and a locked position in which it is immobilized within the first bore.  
   
   
       32 . The connector of  claim 30  wherein the connector further comprises a tensioner configured to engage the holding member and to lock the holding member in position such that the holding member is immobilized within the first bore.  
   
   
       33 . The connector of  claim 32  wherein when the holding member engages the bone fastener, the tensioner engages the holding member, and the rod coupler engages a rod, the rod and rod coupler are rotatable 360 degrees about both the first and second bore longitudinal axes.  
   
   
       34 . The connector of  claim 32  wherein the tensioner comprises external threads configured to engage corresponding internal threads in the holding member bore.