Bilateral and unilateral pedicle screw assisted interbody fusion for degenerative lumbar spondylolisthesis in the elderly 
Zhou Gang, Yang Xiao-hui, Huang Wei-min, Wang Cheng-wei, Zhang Yu-kun
Chinese Journal of Tissue Engineering Research . 2015, (31): 4973 -4977 .  DOI: 10.3969/j.issn.2095-4344.2015.31.010