Purpose: 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 nearto that of the intact group, without significant difference (p > 0.05). The stress in the discectomy group was significantly higher than 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).
Conclusion: The intervertebral fusion and intervertebral disc discectomy can significantly affect the adjacent inferior intervertebral space stress. There is no obvious effect of CADR on adjacent inferior intervertebral space stress.