terventions for symptomatic lumbar spinal spondylolisthesis A randomized controlled multinational, multicenter trial protocol Kiok Kim, KMD, PhDs, Yousuk Youn, KMD, PhD', Sang Ho Lee, KMD, PhDa, Jung Chul Choi, MD', Jae Eun Jung, MD°, Jaehong Km, MBAa, Wenchun Qu, MD, PhD", Jason Eldrige, MDd, Tae-Hun Kim