摘要 |
When an intervertebral fusion is required, and the disc space is unusualy large, that disc space can be preserved by surgically implanting a pair of relatively large male-thread fusion cages 20, 20A with their threads 13 overlapping. Because of their large size, such fusion cages 20, 20A should be implanted by an anterior approach to the lower back. When each of the cages is made of a shape-retaining helix 22 of wire that is hollow within the helix 22 and has openings 23 between adjacent turns, the cages 20, 20A can be removed after the adjacent vertebrae have become fused together and without disrupting that fusion, thus guarding against possible rejection of the cages 20, 20A by the patient's body. The anterior approach and scaled-down fusion cages 20, 20A may be used in cervical spine fusions. |