Comparisons of Dynesys stabilization and posterior lumbar interbody fusion for L4/5 single-segment lumbar degenerative disease

English Keywords:Lumbar spine  Dynesys system  Dynamic fixation  Posterior lumbar interbody fusion  Pedicle screw  Adjacent segment degeneration

English Abstract:

  【Abstract】 Objectives: To evaluate the clinical and radiographic results between Dynesys and posterior lumbar interbody fusion(PLIF) in the treatment of lumbar degenerative disease. Methods: 76 cases of lumbar degenerative disease were treated with either Dynesys or PLIF between July 2008 and July 2012, 35 patients underwent Dynesys procedure and 41 underwent PLIF. The follow-up period was more than 24 months. The clinical outcome was evaluated by visual analogue scale(VAS) and Oswestry disability index (ODI). Range of motion(ROM) and the intervertebral height of lumbar segments were measured by X-rays. The change of intervertebral disc signal was defined by MRI, and disc degeneration was classified according to the Pfirrmann grade classification. Results: The ODI and VAS score significantly improved in both groups at the final follow-up(P<0.05), but the difference between two groups was not significant(P>0.05). The ROM of proximal adjacent segments in both groups(Dynesys group, 8.3°±2.1°; PLIF group, 8.4°±1.5°) increased significantly(P<0.05) at the final follow-up(Dynesys group, 10.2°±2.2°; PLIF group, 12.9°±2.1°). The changes were significant between two groups(P<0.05). The ROM of distal adjacent segments in both groups increased significantly(P<0.05) at the final follow-up, but there was no significant between two groups(P＞0.05). There were significant changes of Pfirrmann grade between the preoperation and final follow-up in both groups(P<0.05). According to University of California at Los Angeles Grading Scale, there were 8 cases in the Dynesys group and 22 in the PLIF group with radiological adjacent segment degeneration, the difference was significant between two groups(P<0.05). Only 1 case in PLIF group had symptomatic adjacent segment degeneration, and received a second operation. Conclusions: Both Dynesys and PLIF are reliable for lumbar degenerative disease. Dynesys stabilization has less influence on the ROM of cranial adjacent segments, and therefore less risks in developing ASD.