Interbody cage and method of insertion

Abstract

An interbody cage which comprises a cage body and a mobile rotational element which, when said mobile element is rotated around a longitudinal axis of the body of the cage, may engage one or both adjoining vertebrae and temporally distract the intervertebral space for easier insertion of the cage body. The rotational element may also be designed to durably engage the adjoining vertebrae after its rotation, so as to allow a durable increase of the distraction of the vertebrae. Methods of insertion of the interbody cage are provided wherein the vertebrae are first distracted by the insertion of the cage or of the mobile element, then further distracted by rotation of the mobile element, before the cage is fully inserted into the intervertebral space without the body's superior and inferior surfaces fully engaging the vertebrae in the process.

What is claimed is: 
     
         1 . A prism shaped intervertebral implantable device comprising:
 a first side, a second side, a third side and a fourth side;   an inner chamber bound by the first, second, third and fourth sides;   a stowable structure in the inner chamber rotatably attached to a shaft and extending longitudinally from the first side to the second side, and forming a diagonal structure thereof;   a prying element disposed at the second side of the implantable device to dislodge and separate an upper and lower vertebra, and to insert the implantable device in an interstitial space therebetween;   a removable insertion element disposed at the first side to orient and advance the implantable device to an implant site within the interstitial space generated by the prying element, and the insertion element further being coupled to the shaft to deploy the stowable structure;   wherein the implantable device being structured to engage the prying element and insertion element to one of slidably and rotatably move the implantable device to a first orientation within the interstitial space, and rotate to a second orientation to dynamically change a first form factor of the implantable device, and further move the device to a third orientation to deploy the stowable structure to effect a second form factor and transform a first cross section of the implantable device to a second cross section, and thereby secure the implantable device at the implant site.   
     
     
         2 . The implantable device of  claim 1  wherein the stowable structure includes flanges vertically extending outward from the shaft to rotatably span across one of a first and second diagonal of the implantable device wherein the first and second diagonals are unequal in length and form the cross section of the prism shaped implantable device. 
     
     
         3 . The implantable device of  claim 1  wherein the stowable structure rotatably transforms the form factor of the implantable device. 
     
     
         4 . The implantable device of  claim 1  wherein the stowable structure dynamically transforms the cross section of the implantable device to the second cross section by equalizing a length of a first diagonal to a length of a second diagonal. 
     
     
         5 . The implantable device of  claim 1  wherein the stowable structure includes flanges having proximal and distal edges being attached to the shaft at the proximal edges, and further includes crenellations at the distal edges of the flanges. 
     
     
         6 . The implantable device of  claim 1  wherein the prying element is structured to be one of retractable and fixed at the second side. 
     
     
         7 . The implantable device of  claim 1  wherein the prying element includes one of a fixed wedge tip, a rotating wedge tip, a flat panel, a rotating helix, a plurality of rods and a quadrant structure being fixed at the second side. 
     
     
         8 . The implantable device of  claim 1  wherein the insertion element includes structural connections to the shaft, to effect one of a separate and combined movement of the stowable structure and the implantable device through the first, second and third orientations. 
     
     
         9 . The implantable device of  claim 1  wherein the implantable device includes rounded corners to enable ease of mobility within the interstitial space and thereby reduce one of trauma and stress on the upper and lower vertebra. 
     
     
         10 . A method of implanting a prism shaped intervertebral implantable device comprising the steps of:
 separating an upper and lower vertebra to advance the device in an interstitial space between an upper and lower vertebra while positioning the device in a first orientation;   moving the device along an axis parallel to opposite corners of the device, rotatably positioning the device in a second orientation and deploying a stowed structure from a first position across a first diagonal to a second position across a second diagonal; and   securing the device at the implant site by positioning the device in a third orientation.   
     
     
         11 . The method of  claim 10  wherein the step of separating the upper and lower vertebra includes introducing a prying element in the interstitial space between the vertebrae to increase the space therebetween. 
     
     
         12 . The method of  claim 10  wherein the step of moving the device along an axis parallel to opposite corners of the device includes increasing the form factor of the implantable device. 
     
     
         13 . The method of  claim 10  wherein said step of deploying the stowed structure from the first diagonal to the second diagonal effects a change in a cross section of the device. 
     
     
         14 . The method of  claim 10  wherein said step of deploying the stowed structure from the first diagonal to the second diagonal position includes exposing crenellations disposed at the distal edges of the stowable structure, and further includes changing a form factor of the device. 
     
     
         15 . The method of  claim 10  wherein the step of moving the device along an axis parallel to opposite corners of the device includes rotatably changing a form factor of the device, and slidably advancing the device using a removable insertion element. 
     
     
         16 . The method of  claim 10  wherein the step of positioning the device in a first orientation includes rotating the device to align the first diagonal perpendicular to the upper and lower vertebrae, and slidably advancing the device in the interstitial space between the vertebrae. 
     
     
         17 . The method of  claim 10  wherein the step of positioning the device in a second orientation includes rotating the device to align the second diagonal perpendicular to the upper and lower vertebrae and deploying the stowed structure from a first position at the second diagonal to a second position at the first diagonal. 
     
     
         18 . The method of  claim 10  wherein the step of positioning the device in a third orientation includes changing the cross section and form factor of the device and further aligning crenellations, disposed at extremities of the stowed structure, in contact with the upper and lower vertebrae to secure the device at the implant site. 
     
     
         19 . A dynamically shape-shifting intervertebral implantable device comprising:
 a first side, a second side, a third side and a fourth side;   an inner chamber bound by the first, second, third and fourth sides and forming an irregular rhombic cross section having a first diagonal and second diagonal, with the first diagonal being longer than the second diagonal;   a stowable structure with flanges disposed in the inner chamber and rotatably attached to a shaft extending longitudinally from the first side to the second side, and forming a diagonal structure within the irregular rhombic cross section to span across the first diagonal;   a prying element disposed at the second side of the implantable device to dislodge and separate an upper and lower vertebra, and to insert the implantable device in an interstitial space therebetween;   a removable insertion element disposed at the first side to orient and advance the implantable device to an implant site within the interstitial space, generated by the prying element, and the insertion element further being coupled to the shaft to deploy the stowable structure;   wherein the implantable device being structured to engage the prying element and insertion element to one of slidably and rotatably move the implantable device to a first orientation within the interstitial space, and rotate to a second orientation to dynamically change a first form factor of the implantable device, and further move the device to a third orientation to deploy the stowable structure to effect a second form factor and transform the irregular rhombic cross section of the implantable device , and thereby secure the implantable device at the implant site.   
     
     
         20 . the implantable device of  claim 19 , wherein the irregular rhombic cross section is shape shiftable by deploying the stowed structure to span across the second diagonal. 
     
     
         21 . the implantable device of  claim 19  wherein the flanges of the stowed structure are equal to the length of the first diagonal within the inner chamber. 
     
     
         22 . the implantable device of  claim 19 , wherein the irregular rhombic cross section is shape shiftable by deploying the stowed structure to span across the second diagonal. 
     
     
         23 . the implantable device of  claim 19 , wherein the irregular rhombic cross section is dynamically shape shiftable by deploying the stowed structure to span across the second diagonal and thereby equalize the length of the second diagonal to the length of the first diagonal. 
     
     
         24 . the implantable device of  claim 19 , wherein the irregular rhombic cross section is shape shiftable and the device is longitudinally tapered.