Cortical Rim-Supporting Interbody Device

Abstract

A central inflatable distractor and a perimeter balloon are inserted into the disc space in uninflated configurations. The central inflatable distractor is then expanded, thereby distracting the vertebral endplates to the controlled height of the central inflatable distractor. The perimeter balloon is then inflated with a curable substance. The perimeter balloon expands as it is filled with the curable substance and conforms to the void remaining in the disc space around the central inflatable distractor, thereby creating a horseshoe shape. Once the flowable material in the perimeter balloon has cured, the central inflated distractor can be deflated and removed. The remaining void (or inner space) is then packed with graft for fusion.

We claim: 
     
         1 . An instrument for forming an intervertebral fusion device comprising:
 a) a distraction device comprising i) a first tube having a distal end portion and ii) an inflatable distractor attached to the distal end portion of the first tube, wherein the inflatable distractor is filled with a biological inert fluid,   b) a fusion assembly comprising i) a second tube having a distal end portion and ii) an inflatable balloon attached to the distal end portion of the second tube, wherein the inflatable balloon is filled with a curable material and has a height sized to span a disc space,   
       wherein the distal end portion of the first tube is substantially adjacent the distal end portion of the second tube. 
     
     
         2 . The instrument of  claim 1  further comprising:
 c) a delivery cannula having a proximal end portion and a distal end portion; 
 
       wherein each tube is substantially received in the delivery cannula so that the distal end of the first tube projects from the distal end of the delivery cannula, and the distal end of the second tube projects from the distal end of the delivery cannula. 
     
     
         3 . The instrument of  claim 1  wherein the balloon forms an annular shape defining an inner space and the inflatable distractor is disposed in the inner space. 
     
     
         4 . The instrument of  claim 1  wherein the balloon forms a substantially horseshoe-shape defining an inner space and the inflatable distractor is disposed in the inner space. 
     
     
         5 . The instrument of  claim 1  wherein the first and second tubes are portions of a dual lumen tube. 
     
     
         6 . The instrument of  claim 1  wherein the inflatable distractor is not integral with the inflatable balloon. 
     
     
         7 . The instrument of  claim 1  wherein the inflatable balloon has a track associated therewith. 
     
     
         8 . The instrument of  claim 1  wherein the balloon is elastic. 
     
     
         9 . The instrument of  claim 1  wherein the balloon is inelastic and forms a predetermined shape when inflated. 
     
     
         10 . The instrument of  claim 1  wherein the inflatable distractor has a track associated therewith. 
     
     
         11 . A method of forming an interbody fusion cage, comprising the steps of;
 a) introducing an inflatable distractor into a disc space in an uninflated form,   b) inflating the inflatable distractor with a biologically inert fluid to distract the disc space,   c) introducing an inflatable balloon into the disc space,   d) filling the inflatable balloon with a curable material;   
     
     
         12 . The method of  claim 11  further comprising the step of:
 e) deflating the inflated distractor after the curable material has cured. 
 
     
     
         13 . The method of  claim 12  further comprising the step of:
 f) removing the deflated distractor from the disc space. 
 
     
     
         14 . The method of  claim 13 , wherein the balloon has a substantially annular form defining an inner space, further comprising the step of:
 g) filling the inner space with an osteogenic material.   
     
     
         15 . The method of  claim 14  wherein the distractor occupies the inner space defined by the balloon. 
     
     
         16 . The method of  claim 15  wherein the balloon is elastic. 
     
     
         17 . The method of  claim 15  wherein the balloon is inelastic and forms a predetermined shape when inflated. 
     
     
         18 . The method of  claim 11  wherein the balloon forms an annular shape. 
     
     
         19 . The method of  claim 11  wherein the balloon forms a substantially horseshoe-shape. 
     
     
         20 . The method of  claim 11  wherein the balloon wraps around the distractor so that an inner surface of the fusion balloon contacts an outer perimeter of the inflated distractor. 
     
     
         21 . A balloon assembly for treating an intervertebral disc space, comprising:
 a) an inflated distractor having an outer perimeter and being sized to distract the intervertebral disc space, the inflated distractor filled with a biologically inert fluid,   b) an inflated fusion balloon forming a shape having an outer perimeter and an inner surface, the fusion balloon filled with a curable material,   
       wherein the balloon wraps around the distractor so that the inner surface of the fusion balloon contacts the outer perimeter of the inflated distractor. 
     
     
         22 . The assembly of  claim 21  wherein the balloon forms an annular shape defining an inner space and the inflated distractor is disposed in the inner space. 
     
     
         23 . The assembly of  claim 21  wherein the balloon forms a substantially horseshoe-shape defining an inner space and the inflatable distractor is disposed in the inner space. 
     
     
         24 . The assembly of  claim 21  wherein the balloon is elastic. 
     
     
         25 . The assembly of  claim 21  wherein the balloon is inelastic and forms a predetermined shape when inflated. 
     
     
         26 . The assembly of  claim 21  wherein the inner surface of the fusion balloon is not integral with the outer perimeter of the inflated distractor. 
     
     
         27 . The assembly of  claim 21  wherein the inflated distractor is fluidly coupled with a hydraulic pressurizier capable of pressurizing and de-pressurizing the distractor. 
     
     
         28 . A balloon assembly for treating an intervertebral disc space, comprising:
 a) a deflated distractor having an outer perimeter,   b) an inflated fusion balloon forming a shape having an outer perimeter and an inner surface defining an inner space, the fusion balloon filled with a cured material, the balloon being sized to distract the intervertebral disc space,   
       wherein the deflated distractor is disposed within the inner space of the balloon. 
     
     
         29 . A balloon assembly for treating an intervertebral disc space, comprising:
 a) an inflated distractor having an outer perimeter and filled with a biologically inert fluid,   b) an inflated fusion balloon forming a horsehoe-shape having an outer perimeter, an inner surface defining an inner space and an open end, the fusion balloon filled with a cured material, the balloon being sized to distract the intervertebral disc space,   
       wherein the inflated distractor is disposed within the inner space of the balloon. 
     
     
         30 . A method of preparing a disc space, comprising the steps of:
 a) removing disc tissue to create a disc space;   b) inserting the central inflatable distractor into the disc space;   c) expanding the central inflatable distractor;   d) inserting the perimeter balloon into the disc space;   e) introducing a curable material into the perimeter balloon, and   f) separating the perimeter balloon from its second delivery tube.   
     
     
         31 . The method of  claim 30  further comprising the step of:
 g) retracting the central inflatable distractor and removing it from the disc space to create an inner space. 
 
     
     
         32 . The method of  claim 31 , further comprising the step of:
 h) filling the inner space with a flowable support material.   
     
     
         33 . The method of  claim 31  further comprising the steps of:
 h) passing an instrument into the inner space, and 
 i) performing a task with the instrument. 
 
     
     
         34 . The method of  claim 30  further comprising the steps after step c) of:
 g) passing an instrument into the disc space, and 
 i) performing a task with the instrument. 
 
     
     
         35 . The method of  claim 30  further comprising the step of:
 g) injecting a support material into the central inflatable distractor. 
 
     
     
         36 . The method of  claim 35  further comprising the step of:
 h) separating the central inflatable distractor from a delivery tube. 
 
     
     
         37 . A device for preparing an intervertebral disc space, comprising:
 a) an inflatable device sized to fit in the disc space,   b) an instrument attached to the inflatable device   
     
     
         38 . The device of  claim 37  wherein the instrument is attached to the inflatable device by a track associated with the inflatable device. 
     
     
         39 . The device of  claim 38  further comprising:
 c) a magnetic wheel located on the track. 
 
     
     
         40 . The device of  claim 37  wherein the instrument is attached to the inflatable device by a docking port associated with the inflatable device. 
     
     
         41 . The device of  claim 37  wherein the instrument comprises a distal docking element that mates with the docking port.