Bone Fixation System

Abstract

In a fixation system for controlling the alignment of adjacent vertebra after spinal surgery, aligned fixation rods are held in a mount on each of such vertebra, with their juxtaposed ends received in a sleeve between the mounts. At least one of the rods is movable in the sleeve relative to the other to allow controlled movement of adjacent vertebra. In some embodiments, the sleeve can itself be held in a mount installed on one of such vertebra with the aligned fixation rods being capable of relative movement therein. The system allows the spine to grow without the need for further surgery.

1 . A fixation system for controlling the alignment of adjacent vertebra after spinal surgery, which system comprises aligned fixation rods; a mount for installation on each of said vertebra and for holding a fixation rod; and a sleeve for receiving the juxtaposed ends of the rods in alignment between the mounts, at least one of the rods being movable in the sleeve relative to the other to allow controlled movement of adjacent vertebra. 
     
     
         2 . A fixation system for controlling the alignment of adjacent vertebra after spinal surgery, which system comprises aligned fixation rods; a mount for installation on each of said vertebra and for holding a fixation rod; and a sleeve for receiving the juxtaposed ends of the rods in alignment, the sleeve being secured in a said mount at least one of the rods being movable in the sleeve relative to the other to allow controlled movement of adjacent vertebra. 
     
     
         3 . A fixation system according to  claim 1  wherein the sleeve includes a stop whereby said movement of at least one of the rods is restricted to retain a minimum end length thereof in the sleeve. 
     
     
         4 . A fixation system according to  claim 3  wherein an internal spigot in the sleeve is received in a longitudinal groove extending axially on the respective rod surface, the groove terminating short of the rod end. 
     
     
         5 . A fixation system according to  claim 1  wherein at least one of the fixation rods is curved. 
     
     
         6 . A fixation system according to  claim 5  wherein the rod movable in the sleeve has a curved section extending into the sleeve, and wherein the sleeve is correspondingly curved. 
     
     
         7 . A fixation system according to  claim 1  wherein the movable rod and the section of the sleeve in which it is received have complementary non-circular cross-sections preventing rotation of the rod in the sleeve. 
     
     
         8 . A fixation system according to  claim 1  including a pair of said mounts for holding fixation rods on each said vertebra; and two said sleeves for receiving juxtaposed ends of the respective rods, the rods and sleeves defining a plane of permitted movement. 
     
     
         9 . A fixation system according to  claim 8  wherein the two sleeves are coupled together. 
     
     
         10 . A fixation system according to  claim 8  wherein each pair of mounts is part of the same device secured to a said vertebra. 
     
     
         11 . A fixation system according to  claim 1  wherein at least one rod is fixed relative to its respective sleeve in an integral unit. 
     
     
         12 . A method of controlling the alignment of adjacent vertebra after spinal surgery, which method comprises fitting a mount for fixation rods on each of a plurality of vertebra in the spine under surgery; securing a plurality of aligned fixation rods in the mounts with juxtaposed ends of aligned rods in a sleeve in which at least one of the rods is slideable, movement of said at least one rod in the sleeve allowing the spine to grow without further intervention. 
     
     
         13 . A method according to  claim 12  wherein the sleeve is secured in a mount. 
     
     
         14 . A method according to  claim 12  wherein at least one of the fixation rods is curved. 
     
     
         15 . A method according to  claim 14  wherein the rod movable in the sleeve has a curved section extending into the sleeve, and wherein the sleeve is correspondingly curved. 
     
     
         16 . A method according to  claim 12  wherein two pluralities of aligned fixation rods are secured in mounts on vertebra with juxtaposed rod ends in respective sleeves, the rods and sleeves thereby defining a plane of permitted movement. 
     
     
         17 . A fixation system according to  claim 2  wherein the sleeve includes a stop whereby said movement of at least one of the rods is restricted to retain a minimum end length thereof in the sleeve. 
     
     
         18 . A fixation system according to  claim 2  wherein at least one of the fixation rods is curved. 
     
     
         19 . A fixation system according to  claim 2  wherein the movable rod and the section of the sleeve in which it is received have complementary non-circular cross-sections preventing rotation of the rod in the sleeve. 
     
     
         20 . A fixation system according to  claim 2  including a pair of said mounts for holding fixation rods on each said vertebra; and two said sleeves for receiving juxtaposed ends of the respective rods, the rods and sleeves defining a plane of permitted movement. 
     
     
         21 . A fixation system according to  claim 2  wherein at least one rod is fixed relative to its respective sleeve in an integral unit.