[The value and limits of intervertebral cages in lumbar arthrodesis].

Cages are not disk prosthesis, they not preserve intervertebral mobility. In selected cases they are useful to improve immediate intervertebral stability when lumbar interbody fusion is performed, they also avoid the risk of bone graft crushing before fusion is obtained thanks to their rigidity. In most cases, additional instrumentation is mandatory. A perfect surgical procedure is required to avoid specific complication and failure. The use of cages does not preclude the use of more classical spinal fusion procedures, they have specific indications and do not replace former techniques.