title: Effect of cervical artificial disc replacement on adjacent inferior intervertebral space stress.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of C5/6 cervical artificial disc replacement (CADR), discectomy and intervertebral fusion on adjacent inferior (C6/7) intervertebral space stress, and provide a basis for application of CADR.
  
  
  METHODS
  Eleven fresh-frozen multisegmental (C3-T1) cervical spine specimens from healthy adults were studied. For analysis of stress on the adjacent inferior (C5/6) segment, they were divided into intact group, discectomy group, CADR group and interbody fusion group. The axial load (25-150 N) was exerted on each group. The changes of the adjacent inferior (C6/7) intervertebral space stress were observed.
  
  
  RESULTS
  The adjacent inferior intervertebral space stress in the CADR group was near to that of the intact group, without significant difference (p > 0.05). The stress in the discectomy group was significantly higher than in the intact group, and lower than in the interbody fusion group (p < 0.05 and p < 0.01, respectively). The stress in the interbody fusion group was significantly higher than in the intact and CADR groups, respectively (p < 0.01).
authors.affiliation: Department of Orthopaedics, Second People's Hospital of Hunan Province, Changsha 410007, China.
authors.forename: L K
authors.initials: LK
authors.lastname: Chen
authors.affiliation: Department of Orthopaedics, Xiangya Hospital of Central South University, Changsha 410008, China. lkkhcn@yeah.net.
authors.forename: K H
authors.initials: KH
authors.lastname: Li