as such fig1 and 12 depict a differently shaped spinal fusion implant 32 than those found in fig7 10 fig1 16 depict the application of an alternate embodiment of the barrier 100 of the present invention like the previously described embodiment of the barrier 10 the barrier 100 includes a valve unit 12 tubing 14 and an inflatable seal 102 the valve unit 12 and tubing 14 are substantially identical to that described in relation to barrier 10 the barrier 100 is composed in such a way that the inflatable seal 102 assumes a curved or crescent shape upon inflation this curved shape may better approximate the shape of the vertebral bodies 105 being fused and thus may provide better sealing capabilities as shown in fig1 and 14 this embodiment may be created by varying the thickness of the material used to compose the seal 102 so that upon inflation the seal 102 expands to take a curved or crescent shape this can be accomplished by providing a seal with significantly thicker walls on the anterior and posterior sides 103 than on the corners 104 where expansion is to be the greatest as such when the inflation fluid enters the seal 102 the path of least resistance is through the corners 104 and thus the corners 104 expand to a greater degree than the thicker walls of the anterior.