Polyaxial bone anchor with non-pivotable retainer and pop-on shank, some with friction fit

Abstract

A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. The upper portion expands a retaining member in the receiver cavity to capture the shank upper portion in the receiver. In some embodiments either the retaining member or an insert provide for a friction fit of the shank upper portion in the receiver resulting in non-floppy placement of the shank with respect to the receiver.

1 .- 27 . (canceled) 
     
     
         28 . In a polyaxial bone anchor, the improvement comprising:
 a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber having an upper and lower portion;   b) a shank having an upper portion and the chamber upper portion being wider than the shank upper portion; and   c) an expandable retainer with a supra structure, and having a non-expanded configuration and an expanded configuration, the retainer being narrower than the chamber upper portion in the non-expanded configuration, the retainer being located in the chamber lower portion in the non-expanded configuration, the retainer being pushed to the chamber upper portion during assembly when the shank upper portion is uploaded into the receiver chamber, and thereafter the retainer expanding to the expanded configuration, so as to receive the shank upper portion therethrough and capture the shank upper portion in the chamber by returning to the non-expanded configuration.   
     
     
         29 . The improvement of  claim 28 , wherein the supra structure frictionally engages the shank when the retainer and the shank are in an unlocked engagement. 
     
     
         30 . The improvement of  claim 28 , wherein the shank upper portion is in spaced relation with the receiver when in the locked orientation with respect to the receiver. 
     
     
         31 . The improvement of  claim 28 , wherein the retainer is expanded outwardly against the receiver when in locking engagement with the shank upper portion. 
     
     
         32 . The improvement of  claim 28 , wherein the supra structure has a surface releasably wedged against a surface of the receiver. 
     
     
         33 . The improvement of  claim 28 , further comprising a compression insert in engagement with the shank upper portion and located between the shank upper portion and the portion of the longitudinal connecting member located in the receiver channel. 
     
     
         34 . The improvement of  claim 33 , wherein the insert has a locked configuration and an unlocked configuration with respect to the shank upper portion. 
     
     
         35 . The improvement of  claim 34 , wherein the insert has at a bottom surface frictionally engaging the shank in a non-floppy manner when the insert is in the unlocked configuration. 
     
     
         36 . The improvement of  claim 35 , wherein the shank upper portion directly engages the longitudinal connecting member portion. 
     
     
         37 . The improvement of  claim 28 , wherein the retainer is up-loadable into the receiver. 
     
     
         38 . The improvement of  claim 28 , wherein the retainer is down-loadable into the receiver. 
     
     
         39 . The improvement of  claim 38 , wherein the retainer is expandable only. 
     
     
         40 . The improvement of  claim 28 , wherein the retainer is both expandable and compressible. 
     
     
         41 . The improvement of  claim 28 , further comprising an up-loadable compression insert. 
     
     
         42 . The improvement of  claim 28 , further comprising a down-loadable compression insert. 
     
     
         43 . The improvement of  claim 42 , wherein the receiver channel has a first channel and the insert has a second channel, the insert is rotated into position above the retainer, the insert having a blocking feature and the receiver having a stop for abutment with the blocking feature when the second channel is aligned with the first channel. 
     
     
         44 . The improvement of  claim 28 , further comprising a compression insert, the receiver having tabs to capture the insert within the receiver. 
     
     
         45 . The improvement of  claim 44 , wherein the receiver channel has a first channel and the insert has a second channel, the one of the crimp tabs and spring tabs aligning the second channel with the first channel. 
     
     
         46 . The improvement of  claim 28 , wherein the retainer is an open ring. 
     
     
         47 . The improvement of  claim 46 , wherein the ring has at least one planar surface. 
     
     
         48 . The improvement of  claim 28 , wherein the retainer has an open, non-tapered body portion in engagement with the receiver supra structure, and the supra structure having panels for temporary frictional engagement with the shank upper portion when the retainer is not locked to the receiver. 
     
     
         49 . The anchor according to  claim 28 , wherein: the chamber lower portion is approximately the same diameter as the retainer in the non-expanded configuration so as to prevent the retainer from expanding when the retainer is in the chamber lower portion. 
     
     
         50 . In a polyaxial bone anchor, the improvement comprising:
 a) a receiver defining a chamber having an upper and lower portion commun , a channel sized and shaped for receiving a portion of a longitudinal connecting member;   b) a shank having an upper portion and the chamber upper portion being wider than the shank upper portion; and   c) an expandable open retainer with a supra structure and having a non-expanded configuration and an expanded configuration, the retainer being narrower than the chamber upper portion in the non-expanded configuration, and being located in the chamber lower portion in the non-expanded configuration, the retainer being pushed to the chamber upper portion during assembly when the shank upper portion is uploaded into the receiver chamber, and thereafter the retainer expanding to the expanded configuration, so as to receive the shank upper portion therethrough and capture the shank upper portion in the chamber by returning to the non-expanded configuration, and thereafter received between the shank upper portion and the receiver chamber lower portion, so as to prevent expansion of the retainer to the expanded configuration.   
     
     
         51 . The improvement of  claim 50 , wherein the supra structure frictionally engages the shank when the retainer and the shank are in an unlocked engagement. 
     
     
         52 . The improvement of  claim 50 , further comprising an insert located at least partially in the chamber, the insert having at least one surface frictionally engaging the shank when the retainer and the shank are in an unlocked engagement. 
     
     
         53 . The improvement of  claim 52 , wherein the insert has a lock and release feature in engagement with the receiver. 
     
     
         54 . The improvement of  claim 50 , wherein the retainer has a lock and release feature in engagement with the receiver. 
     
     
         55 . In a polyaxial bone anchor, the improvement comprising:
 a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber having an upper and lower portion;   b) a shank having an upper portion and the chamber upper portion being wider than the shank upper portion; and   c) an expandable retainer, and having a non-expanded configuration and an expanded configuration, the retainer being narrower than the chamber upper portion in the non-expanded configuration, the retainer being located in the chamber lower portion in the non-expanded configuration, the retainer being pushed to the chamber upper portion during assembly when the shank upper portion is uploaded into the receiver chamber, and thereafter the retainer expanding to the expanded configuration, so as to receive the shank upper portion therethrough and capture the shank upper portion in the chamber by returning to the non-expanded configuration; and   d) an insert having a locked configuration and a unlocked configuration engagement with the shank upper portion.   
     
     
         56 . The improvement of  claim 55 , wherein the shank upper portion directly engages the longitudinal connecting member portion. 
     
     
         57 . The improvement of  claim 55 , wherein the insert is up-loadable. 
     
     
         58 . The improvement of  claim 55 , wherein the retainer has an open, non-tapered body portion in engagement with the receiver and a supra structure having panels for temporary frictional engagement with the shank upper portion when the retainer is not locked to the receiver. 
     
     
         59 . The improvement of  claim 55 , wherein the retainer has a lock and release feature in engagement with the receiver. 
     
     
         60 . The improvement of  claim 55 , wherein the insert further comprises a pair of crown collet extensions, the collet extensions engaging and expanding about the shank upper portion at the same time as the retainer expands around the shank when the shank is uploaded into the receiver chamber. 
     
     
         61 . The improvement of  claim 55 , wherein the insert expands about the shank upper portion simultaneously with the retainer expanding about the shank upper portion.