Expandable vertebral implant and methods of use

Abstract

An implant for insertion between vertebral body endplates includes first and second end members, each with a respective endplate contact surface. The implant further includes a collapsible intermediate section disposed between the first and second end members and an inflatable member contained within the intermediate section. The intermediate section may be expandable upon the introduction of a substance into the inflatable member between a first size to space the first and second end members a first distance apart and a second enlarged size to space the first and second end members a second greater distance apart. The inflatable member may increase in size from a compressed size in which the inflatable member will pass through an opening in the intermediate section and an expanded size in which the inflatable member will not pass through the opening and is thereby captively retained within the intermediate section.

1 . An implant for insertion between vertebral body endplates in a patient, the implant comprising:
 a first end member including a first endplate contact surface;   a second end member including a second endplate contact surface;   a collapsible intermediate section disposed between the first and second end members; and   an inflatable member contained within the intermediate section,   the intermediate section being expandable upon the introduction of a substance into the inflatable member, the intermediate section being expandable between a first size to space the first and second end members a first distance apart and a second enlarged size to space the first and second end members a second greater distance apart.   
     
     
         2 . The implant of  claim 1  wherein the collapsible intermediate section is flexible. 
     
     
         3 . The implant of  claim 1  wherein the collapsible intermediate section comprises a plurality of tethers secured about a perimeter of the first and second end members. 
     
     
         4 . The implant of  claim 1  wherein the collapsible intermediate section comprises a single tether coupled between a perimeter of the first and second end members. 
     
     
         5 . The implant of  claim 4  wherein the single tether is coupled to the first and second end members with the tether disposed beneath the first and second endplate contact surfaces. 
     
     
         6 . The implant of  claim 1  wherein the collapsible intermediate section comprises a mesh member secured about a perimeter of the first and second end members. 
     
     
         7 . The implant of  claim 1  wherein the collapsible intermediate section maintains the first size to space the first and second end members the first distance apart when the inflatable member is not expanded through the introduction of the substance. 
     
     
         8 . The implant of  claim 1  wherein the collapsible intermediate section comprises attachment members slidably engaged to permit movement of the end members in an expansion direction, the attachment members including position locks at predetermined heights to stabilize the implant. 
     
     
         9 . An implant for insertion between vertebral body endplates in a patient, the implant comprising:
 a first end member including a first endplate contact surface;   a second end member including a second endplate contact surface;   a collapsible intermediate section disposed between the first and second end members, the intermediate section including an opening; and   an interior member positionable within the intermediate section, the interior member inflatable between a compressed size in which the interior member will pass through the opening and an expanded size in which the interior member will not pass through the opening.   
     
     
         10 . The implant of  claim 9  wherein the collapsible intermediate section is flexible. 
     
     
         11 . The implant of  claim 9  wherein the collapsible intermediate section comprises a plurality of tethers secured about a perimeter of the first and second end members, the distance between adjacent tethers forming the opening. 
     
     
         12 . The implant of  claim 9  wherein the collapsible intermediate section comprises a single tether coupled between a perimeter of the first and second end members in a plurality of runs, the distance between adjacent runs forming the opening. 
     
     
         13 . The implant of  claim 12  wherein the single tether is coupled to the first and second end members with the tether disposed beneath the first and second endplate contact surfaces. 
     
     
         14 . The implant of  claim 9  wherein the collapsible intermediate section comprises a mesh member secured about a perimeter of the first and second end members. 
     
     
         15 . The implant of  claim 9  wherein when the interior member is at the compressed size, the first and second end members are a first distance apart and when the interior member is at the expanded size, the first and second end members are a second greater distance apart. 
     
     
         16 . The implant of  claim 15  wherein the collapsible intermediate section maintains the first and second end members the first distance apart when the interior member is at the compressed size. 
     
     
         17 . The implant of  claim 9  wherein the collapsible intermediate section comprises attachment members slidably engaged to permit movement of the end members in an expansion direction, the attachment members including position locks at predetermined heights to stabilize the implant. 
     
     
         18 . A method of supporting vertebral bodies, the method comprising the steps of:
 positioning an implant between endplates of the vertebral members while the implant is in a first orientation having a first height;   inserting an inflatable member through an opening in the implant;   introducing a substance into the inflatable member;   inflating the inflatable member to an expanded size in which the inflatable member is captively retained within the implant; and   separating first and second end members and increasing a height of the implant.   
     
     
         19 . The method of  claim 18  wherein the substance includes a bone growth promoting substance. 
     
     
         20 . The method of  claim 18  wherein the step of separating first and second end members and increasing a height of the implant comprises forcing a bone-contact surface of the first and second end members into contact with the endplates of the vertebral members. 
     
     
         21 . The method of  claim 18  wherein the step of separating first and second end members and increasing a height of the implant comprises extending a collapsible intermediate section that is coupled between the end members. 
     
     
         22 . The method of  claim 18  wherein the step of separating first and second end members and increasing a height of the implant comprises extending a tether that is coupled between the end members. 
     
     
         23 . A method of supporting vertebral members, the method comprising the steps of:
 coupling first and second end members with a collapsible intermediate section;   positioning an inflatable member within the collapsible intermediate section;   inserting an amount of a substance into the inflatable member;   filling the inflatable member with the substance and causing the inflatable member to contact faces of the first and second end members;   exerting an expansion force at the faces and expanding the collapsible intermediate section and separating the first and second end members to an increased height; and   further expanding the first and second members into contact with the vertebral members.   
     
     
         24 . The method of  claim 23  wherein the substance includes a bone growth promoting substance. 
     
     
         25 . The method of  claim 23  wherein prior to filling the inflatable member with the substance and causing the inflatable member to contact faces of the first and second end members, the inflatable member is sized to pass through an opening in the collapsible intermediate section. 
     
     
         26 . The method of  claim 23  wherein the step of exerting an expansion force at the faces and expanding the collapsible intermediate section comprises extending a tether that is coupled between the first and second end members.