Lumbar arthrodesis is a commonly performed operative procedure for the treatment of low-back pain; however, the indications, techniques, and results remain controversial and unclear. The frequency of spinal arthrodesis for the treatment of back pain is increasing in the United States, as are criticism of the procedure and the study of available information on its outcomes. The concept of spinal arthrodesis is based on experience with other regions of the body in which arthrodesis has been used to treat painful joints by eliminating motion. Initially, spinal arthrodesis was used for the treatment of infectious conditions, deformity, and trauma of the spine. On the basis of these successful experiences and because of technical advances in imaging, operative procedures, implants, and bone-grafting, the indications for spinal arthrodesis have been expanded in an attempt to control pain attributed to abnormal or unstable motion between one vertebra and an adjacent vertebra or pain due to mechanical degeneration of the intervertebral disc.