Patent ID: 8211177

Claim:
An interbody fusion device comprising: body means for spacing apart opposing vertebral surfaces when said body means is implanted therebetween; and bone graft load sharing means for sharing loads, placed on said body means by the opposing vertebral surfaces, between said body means and bone graft material contained by said body means, said bone graft load sharing means including height reducing means for decreasing a height of said body means over time and loading both said body means and the bone graft material over time, said height reducing means including a male portion of said body means in sliding and mating engagement with a female portion of said body means defining a chamber therebetween for containing a bioresorbable material therein, said height reducing means including a collapsible chamber within said body means, said collapsible chamber including an open condition for containing bioresorbable material therein and a collapsed condition in which said body means reduces height thereof, an insert of resorbable material being disposed in said chamber to initially support said chamber in said open condition.