RT Journal Article SR Electronic T1 Meta-analysis JF International Journal of Spine Surgery JO Int J Spine Surg FD International Society for the Advancement of Spine Surgery SP 67 OP 67 DO 10.1016/j.esas.2010.07.001 VO 4 IS 3 A1 Paul A. Anderson YR 2010 UL http://ijssurgery.com//content/4/3/67.abstract AB