Comparisons of Dynesys stabilization and posterior lumbar interbody fusion for lumbar degenerative disease

Objective To compare the clinical and radiographic outcomes of Dynesys stabilization and posterior lumbar interbody fusion( PLIF) in the treatment of lumbar degenerative disease. Methods A total of 46 patients( Dynesys group) treated by lumbar spine stabilization with Dynesys for lumbar degenerative disease were retrospectively analyzed from July 2008 to March 2011. The follow-up period was more than 24 months. Other 50 patients( PLIF group) treated by PLIF for lumbar degenerative disease at the same stage were retrospectively matched as control group. Clinical outcomes were evaluated using Oswestry disability index( ODI) and visual analogue scale( VAS). Radiographic evaluations included the disc height and range of motion( ROM) of stabilized segments and the upper adjacent segments by lumbar neutral,flexion,and extension X-ray. The occurrence of radiographic and symptoms of adjacent segment degeneration( ASD) was evaluated between the 2 groups. Results The ODI and VAS scores were both significantly improved in the 2 groups at 3 months and the final follow-up( P 0. 05),but the difference of the improvement between the 2 groups was statistically significant( P 0. 05). At the final follow-up,the dices height of stabilized segments in the Dynesys group increased slightly( P 0. 05),while the increase was significant in the PLIF group( P 0. 05),the difference between the 2 groups was significant( P 0. 05). The ROM of stabilized segments in Dynesys group decreased from 7. 1 ° to 4. 9 °( P 0. 05),while that of in the PLIF group decreased from 7. 3 ° to 0 °( P 0. 05) at the final follow-up. The height of upper segment in both groups did not decrease significantly( P 0. 05). The ROM of the upper segment increased significantly in both groups at the final follow-up( P 0. 05),the change was more significant in the PLIF group than that of in the Dynesys group( P 0. 05). There were 6 cases of radiographic ASD in the Dynesys group and 15 cases in the PLIF group,the difference was significant( P 0. 05). Only 1 case with ASD symptoms occurred in the PLIF group,and the patients received a second operation. Conclusion Both Dynesys and PLIF can improve the clinical outcomes for lumbar degenerative disease. Compared to PLIF,Dynesys stabilization partially can preserve the ROM of stabilized segments,and limit the hypermobility in the upper adjacent segment,and may prevent the occurrence of ASD.