Longitudinal connecting member with sleeved tensioned cords

Abstract

A dynamic fixation medical implant having at least two bone anchors includes a longitudinal connecting member assembly having rigid sleeves for attachment to the bone anchors, at least one spacer engaging the bone anchors and the sleeves, and in some embodiments, an end elastic bumper. A flexible cord is initially slidingly received within the rigid sleeves, the spacer and the bumper. The spacer may include an optional inelastic inner liner, with at least one of the sleeves having an extension slidingly receivable within the liner. Some sleeves include apertures for receiving a closure top portion for locking the cord against the sleeve, or alternatively receiving a closure top that does not extend into the aperture, the slip or grip option provided by the aperture in each sleeve resulting in an overall connector with variable segmental stiffness.

What is claimed and desired to be secured by Letters Patent is as follows: 
     
         1 . In a medical implant assembly having at least first and second bone anchors cooperating with a longitudinal connecting member having a tensioned cord, the bone anchors having opposed upstanding arms, the improvement comprising:
 a) a first non-elastic sleeve for attachment to the first bone anchor, the first sleeve having a first through bore sized and shaped for slidably receiving the tensioned cord, a first aperture formed in the sleeve substantially transverse to the through bore, the aperture sized and shaped for receiving a portion of a first optional cord gripping closure top and a first body portion sized and shaped for being closely received between the bone anchor arms;   b) a second non-elastic sleeve for attachment to the second bone anchor, the second sleeve having a second through bore sized and shaped for slidably receiving the tensioned cord, a second aperture formed in the sleeve substantially transverse to the second through bore, the second aperture sized and shaped for receiving a portion of a second optional cord gripping closure top and a second body portion sized and shaped for being closely received between the second bone anchor arms;   c) a spacer located between the first and second bone anchors, the spacer engaging each of the first and second sleeves, the cord extending through the spacer and held in tension at least first and second ends of the connecting member; and   d) wherein at least one of the first and second sleeves includes an outer flange abutting against an outer surface of the spacer.   
     
     
         2 . The improvement of  claim 1  wherein the outer flange is a first outer flange and further comprising a second outer flange disposed at an obtuse angle with respect to the first outer flange, each flange being disposed outside of the bone anchor. 
     
     
         3 . The improvement of  claim 2  further comprising at least one tubular structure extending outwardly from at least one of the flanges. 
     
     
         4 . The improvement of  claim 1  wherein at least one of the first and second sleeves has a first U-shaped lower surface sized and shaped to frictionally engage a second U-shaped surface of a pressure insert located within the bone anchor. 
     
     
         5 . In a surgical method for implanting a tensioned cord between at least first and second implanted bone anchors with a spacer disposed between the bone anchors, the bone anchors having opposed upstanding arms, the improvement comprising:
 a) providing a first non-elastic sleeve for attachment to the first bone anchor, the first sleeve having a first through bore sized and shaped for slidably receiving the cord, a first aperture formed in the sleeve substantially transverse to the through bore, the aperture sized and shaped for receiving a portion of a first optional cord gripping closure top and a first body portion sized and shaped for being closely received between the bone anchor arms;   b) providing a second non-elastic sleeve for attachment to the second bone anchor, the second sleeve having a second through bore sized and shaped for slidably receiving the cord, a second aperture formed in the sleeve substantially transverse to the second through bore, the second aperture sized and shaped for receiving a portion of a second optional cord gripping closure top and a second body portion sized and shaped for being closely received between the second bone anchor arms;   c) loading the first sleeve on the cord, followed by the spacer, followed by the second sleeve;   d) inserting the first sleeve in the first bone anchor and the second sleeve in the second bone anchor;   e) tensioning the cord and fixing the cord at each end of the connector;   f) optionally fixing the cord to one of the first and second bone anchors by inserting a closure top through one of the first and second sleeves into engagement with the cord; and   g) optionally allowing the cord to slip with respect to one of the first and second bone anchors by inserting a closure top into one of the first and second bone anchors, the closure top having an end surface that remains spaced from the sleeve aperture.   
     
     
         6 . In a medical implant assembly having first and second bone anchors cooperating with a longitudinal connecting member having a tensioned cord, the improvement comprising:
 a) a non-elastic sleeve for attachment to the first bone anchor, the sleeve having a body portion sized and shaped for being closely received between opposed arms of the first bone anchor;   b) a spacer located between the first and second bone anchors, the cord extending through the spacer and held in tension at at least first and second ends of the connecting member; and   c) a blocker, the first bone anchor being located between the blocker and the spacer, the blocker located near the sleeve, the blocker being fixed to the tensioned cord.   
     
     
         7 . The improvement of  claim 6  wherein the blocker is adjacent the first bone anchor. 
     
     
         8 . The improvement of  claim 6  wherein the blocker engages the sleeve. 
     
     
         9 . The improvement of  claim 6  further comprising a bumper located between the blocker and the first bone anchor. 
     
     
         10 . The improvement of  claim 6  wherein the second bone anchor is a monoaxial bone screw fixed to the cord. 
     
     
         11 . The improvement of  claim 6  wherein the at least one sleeve is a first sleeve and further comprising a second sleeve, the second sleeve for attachment to the second bone anchor. 
     
     
         12 . In a medical implant assembly having first and second bone anchors cooperating with a longitudinal connecting member having a tensioned cord, each of the bone anchors having opposed upstanding arms, the assembly comprising:
 a) a non-elastic sleeve for attachment to the first bone anchor, the sleeve having a body positionable entirely between the inner surfaces of the bone anchor arms, a cylindrical longitudinally projecting central extension for engagement of a tube-like spacer, and a longitudinal through bore extending through the body and the central extension for receiving the cord therethrough;   b) the central extension being adapted to project outwardly beyond the bone anchor arms; and   c) a tube-like spacer disposed about the central extension and engaging both the sleeve body and the bone anchor arms.   
     
     
         13 . The assembly of  claim 12  wherein the sleeve has a first U-shaped lower surface sized and shaped to frictionally engage a second U-shaped surface of a pressure insert located within the first bone anchor. 
     
     
         14 . In a medical implant assembly having first and second bone anchors cooperating with a longitudinal connecting member having a tensioned cord, each of the bone anchors having opposed upstanding arms with inner surfaces, the assembly comprising:
 a) a non-elastic sleeve for attachment to the first bone anchor, the sleeve having a body positionable entirely between the inner surfaces of the bone anchor arms;   b) a spacer, the sleeve having a longitudinally projecting central extension cooperating with the spacer;   c) the sleeve having a longitudinal through bore extending through the sleeve body and the central extension for receiving the cord therethrough;   d) the central extension being adapted to project outwardly beyond the bone anchor arms and wherein   e) the spacer overlaps the sleeve central extension and the spacer disposed about the central extension and engaging both the sleeve body and the bone anchor arms.   
     
     
         15 . The assembly of  claim 14  wherein the sleeve has a first U-shaped lower surface sized and shaped to frictionally engage a second U-shaped surface of a pressure insert located within the bone anchor. 
     
     
         16 . In a medical implant assembly having first and second bone anchors cooperating with a longitudinal connecting member having a central core, each of the bone anchors having inner surfaces and opposed upstanding arms, the assembly comprising:
 a) a non-elastic sleeve for attachment to the first bone anchor having a first end and a second end, the sleeve having a body positionable between the inner surfaces of the bone anchor arms, a cylindrical longitudinally projecting central extension on the first end, an elongate solid rod portion on the second end, and a longitudinal bore extending through the body and the central extension for receiving the cord therethrough;   b) a tub-like spacer engaging the central extension; and   c) the central extension projecting outwardly beyond the bone anchor arms.   
     
     
         17 . The assembly of  claim 16 , wherein the sleeve body and the central extension are integral. 
     
     
         18 . The assembly of  claim 16 , wherein the tube-like spacer being disposed about the central extension and engages both the sleeve body and the first bone anchor arms. 
     
     
         19 . The assembly of  claim 18 , further comprising a hard liner disposed between the central extension and the spacer, the central extension being in slidable relation with the hard liner, the liner being in fixed relation with respect to the spacer. 
     
     
         20 . The assembly of  claim 16 , further comprising a closure top having an extended portion in gripping contact with the core and fixed to the sleeve body. 
     
     
         21 . The assembly of  claim 16 , wherein the sleeve includes an outer flange abutting against an outer surface of the spacer. 
     
     
         22 . The assembly of  claim 16 , wherein the sleeve has an outer surface flush with an outer surface of the first bone anchor. 
     
     
         23 . The assembly of  claim 16 , wherein the sleeve has a first U-shaped lower surface sized and shaped to frictionally engage a second U-shaped surface of a pressure insert located within the first bone anchor. 
     
     
         24 . The assembly of  claim 16 , wherein the sleeve has a first planar surface in frictional engagement with a second planar surface of a pressure insert located within the first bone anchor. 
     
     
         25 . The assembly of  claim 16 , wherein the first bone anchor is a polyaxial bone screw having a shank pivotable with respect to a receiver, the sleeve being held within the receiver and directly engaging the shank. 
     
     
         26 . The assembly of  claim 16 , comprising a pin having an extended portion in operational gripping contact with the core and fixed to the sleeve body. 
     
     
         27 . The assembly of  claim 21 , wherein the outer flange is disposed at an obtuse angle with respect to the elongate rod. 
     
     
         28 . In a medical implant assembly having first and second bone anchors cooperating with a longitudinal connecting member having a central core, each of the bone anchors having opposed upstanding arms with inner surfaces, the assembly comprising:
 a) a non-elastic sleeve for attachment to the first bone anchor having a first end and a second end, the sleeve having a body positionable between the inner surfaces of the first bone anchor arms, a cylindrical longitudinally projecting central extension on the first end, an elongate solid rod portion on the second end, and a longitudinal bore extending through the body and the central extension for receiving the cord therethrough;   b) a tube-like spacer engaging the central extension;   c) the central extension projecting outwardly beyond the first bone anchor arms;   d) the spacer engaging the first end, and the core extending through the spacer.   
     
     
         29 . The assembly of  claim 28 , wherein the sleeve body and the central extension are integral. 
     
     
         30 . The assembly of  claim 29 , further comprising a hard liner disposed between the central extension and the spacer, the central extension being in slidable relation with the hard liner, the liner being in fixed relation with respect to the spacer. 
     
     
         31 . The assembly of  claim 28 , further comprising a closure top having an extended portion in gripping contact with the core and fixed to the sleeve body. 
     
     
         32 . The assembly of  claim 28 , wherein the sleeve includes an outer flange abutting against an outer surface of the spacer. 
     
     
         33 . The assembly of  claim 28 , wherein the sleeve has an outer surface flush with an outer surface of the first bone anchor. 
     
     
         34 . The assembly of  claim 28 , wherein the sleeve has a first U-shaped lower surface sized and shaped to frictionally engage a second U-shaped surface of a pressure insert located within the first bone anchor. 
     
     
         35 . The assembly of  claim 28 , wherein the sleeve has a first planar surface in frictional engagement with a second planar surface of a pressure insert located within the first bone anchor. 
     
     
         36 . The assembly of  claim 28 , wherein the first bone anchor is a polyaxial bone screw having a shank pivotable with respect to a receiver, the sleeve being held within the receiver and directly engaging the shank. 
     
     
         37 . The assembly of  claim 28 , comprising a pin having an extended portion in operational gripping contact with the core and fixed to the sleeve body. 
     
     
         38 . The assembly of  claim 22 , wherein the outer flange is disposed at an obtuse angle with respect to the elongate rod. 
     
     
         39 . In a medical implant assembly having first and second bone anchors cooperating with a longitudinal connecting member having a tensioned cord, each of the bone anchors having opposed upstanding arms with inner surfaces, the improvement comprising:
 a) a non-elastic sleeve for attachment to one of the first bone anchor, the sleeve having a body positionable between the inner surfaces of the first bone anchor arms having a first end and a second end, a longitudinally projecting central extension on the first end, an elongate solid rod portion on the second end, and a longitudinal through bore extending through the sleeve body and the central extension for receiving the cord therethrough;   b) a spacer cooperating with the central extension;   b) the central extension being adapted to project outwardly beyond the first bone anchor arms, and wherein   c) the spacer overlaps the sleeve central extension.   
     
     
         40 . The improvement of  claim 39 , wherein the sleeve body and the central extension are integral. 
     
     
         41 . The improvement of  claim 40 , further comprising a hard liner disposed between the central extension and the spacer, the central extension being in slidable relation with the hard liner, the liner being in fixed relation with the spacer. 
     
     
         42 . The improvement of  claim 39 , comprising a closure top having an extended portion in gripping contact with the cord and fixed to the sleeve body. 
     
     
         43 . The improvement of  claim 39 , wherein the sleeve includes an outer flange abutting against an outer surface of the spacer. 
     
     
         44 . The improvement of  claim 39 , wherein the sleeve has an outer surface flush with an outer surface of the bone anchor. 
     
     
         45 . The improvement of  claim 39 , wherein the sleeve has a first U-shaped lower surface sized and shaped to frictionally engage a second U-shaped surface of a pressure insert located within the first bone anchor. 
     
     
         46 . The improvement of  claim 39 , wherein the sleeve has a first planar surface in frictional engagement with a second planar surface of a pressure insert located within the first bone anchor. 
     
     
         47 . The improvement of  claim 39 , wherein the first bone anchor is a polyaxial bone screw having a shank pivotable with respect to a receiver, the sleeve being held within the receiver and directly engaging the shank. 
     
     
         48 . The improvement of  claim 39 , further comprising a pin having an extended portion in operational gripping contact with the cord and fixed to the sleeve body. 
     
     
         49 . The improvement of  claim 43 , wherein the outer flange is disposed at an obtuse angle with respect to the elongate rod.