8Beutler W J, Fredrickson B E, Murtland A, et al. The natural history of spondylolysis and spondylolisthesis: 45 year follow up evaluation[J]. Spine(Phila Pa 1976) ,2003,28(10) : 1027- 1035.
9Sengupta D K, Herkowitz H N. Degenerative spondylolisthesis: review of current trends and controversies[J].Spine, 2005,30(6 Suppl) : S71-81.