Biomechanical change in adjacent segments after cervical fusion and non-fusion: a meta-analysis of second surgery rate   
Li Zhong-hai, Hou Shu-xun, Li Li, Tang Jia-guang, Ren Dong-feng, Zhao Yan-tao
Chinese Journal of Tissue Engineering Research . 2015, (4): 642 -647 .  DOI: 10.3969/j.issn.2095-4344.2015.04.026