Interbody spine fusion cage

Abstract

An improved spine fusion cage is provided which is particularly useful with biological compounds which are utilized in place of or in combination with a patient's bone matter. In one embodiment there is provided a cage with preselected perforated and non-perforated zones to direct the growth of bone in desired directions. In another embodiment there is provided a cage having inner and outer perforated cage bodies separated by an annulus. An end closure with occluding surfaces suitable for introduction into the annulus serves to establish one or more desired zones or patterns of occluded apertures in the cage body. In still another embodiment an end closure having occluding surfaces is provided for use in connection with conventional perforated fusion cages so as to establish desired zones or patterns of occluded apertures.

What is claimed is:  
     
         1 . An interbody spine fusion cage for promoting fusion between adjacent bone structures, comprising: 
 a cage body having a posterior end and an anterior end and defining an internal cavity, the cage body further having an outer surface and a plurality of radial apertures extending through the outer surface in communication with the internal cavity, the outer surface comprising a preselected pattern of perforated and non-perforated zones; and    a non-perforated end closure at each end of said cage body, at least one of the end closures being movable so as to provide access to the internal cavity; and wherein    the preselected pattern comprises at least a first non-perforated zone extending from the posterior end of the cage body for a length of 5-10 mm toward the anterior end of the cage body and at least one perforated zone positioned upon the outer surface of the cage body so as to be juxtaposed one of the bone structures upon implantation.    
     
     
         2 . The cage according to  claim 1 , wherein the preselected pattern further includes at least a second non-perforated zone extending from the first zone further toward the anterior end of the cage body on a lateral side of the cage body.  
     
     
         3 . The cage according to  claim 1 , wherein the preselected pattern further includes: 
 second and third non-perforated zones on the lateral sides of the cage extending in opposing relation from the first zone further toward the anterior end; and    two opposed perforated zones oriented so that upon insertion the perforated zones adjacent the bone structures to be fused.    
     
     
         4 . An interbody spine fusion cage for promoting fusion between adjacent bone structures, comprising: 
 a cage body having a posterior end and an anterior end and defining an internal cavity, the cage body further having an outer surface and a plurality of radial apertures extending through the outer surface in communication with the internal cavity;    a non-perforated end closure at each end of said cage body, at least one of the end closures being movable so as to provide access to the internal cavity; and wherein    the movable end closure has at least one aperture occluding surface extending therefrom, the surface being suitable for introduction into the internal cavity to establish a desired pattern of occluded apertures.    
     
     
         5 . The cage according to  claim 4 , further comprising: 
 a second cage body having a posterior end and an anterior end and being disposed within the internal cavity of the other cage body and so positioned as to form an annulus therebetween, the outer surface of the second cage body having a plurality of radial apertures extending therethrough so as to establish communication with the annulus; and wherein    the occluding surface of the movable end closure being suitable for introduction into the annulus to establish a desired pattern of occluded apertures.    
     
     
         6 . End closure means for effecting the closure of the posterior end of a fusion cage while establishing a desired occlusion pattern of apertures in the wall of the fusion cage which comprises: 
 a first sealing member to effect the closure of the posterior end of the internal cavity of said fusion cage; and    at least one occluding surface extending from the sealing member and essentially parallel to the longitudinal axis of the fusion cage so as to establish a predetermined pattern of occlusion of the apertures in the wall of the fusion cage.    
     
     
         7 . The end closure means according to  claim 6 , further comprising a pair of opposed occluding surfaces so spaced as to occlude laterally positioned apertures along the wall of the fusion cage.