Long-term Observation Of The Clinical Outcomes And Kinetics Of Lumbar Intervertebral Disc Herniation Treated By Non-fusion Technique(Dynesys)

Objective: To evaluate the long-term clinical outcomes and kinetics of Dynesys in the treatment of lumbar disc herniation.To observe the changes of lumbar kinetics after lumbar intervertebral disc herniation treated with Dynesys dynamic internal fixation and analyze the correlation between the changes of lumbar kinetics and the clinical effect.Meanwhile,the incidence of adjacent segment degeneration after Dynesys internal fixation was observed.Methods: Retrospective analysis of lumbar disc herniation patients underwent surgical treatment in PLA army general hospital from July 2008 to June 2012.Through the screening of inclusion criteria and exclusion criteria in this study,62 patients(Dynesys group)and 87 patients with posterior interbody fusion(PLIF group)were included.The preoperative and final clinical outcome was evaluated by visual analogue scale(VAS)and Oswestry disability index(ODI).Radiographic evaluations included the range of motion(ROM),disc height,lumbar lordosis and University of California at Los Angeles Grading Scale for adjacent segment degeneration.Pearson correlation analysis was used to analyze the correlation between lumbar kinetics and ODI score in the two groups.Results: All patients completed the follow-up.The follow-up time of Dynesys and fusion group was(79±16)and(75.1±11.4)months,respectively.The ODI and VAS score significantly improved at the final follow-up compared with the preoperative score(P<0.05).There was significant difference of ODI score between the Dynesys and PLIF groups.No disc herniation recurred in all Dynesys cases.The ROM of Dynesys and PLIF surgical segments decreased from(8.8±5.8)°,(10.6±5.7)° to (3.8±1.9)°,0° at the final follow-up,respectively(P<0.05).The ROM of proximal adjacent segments in both groups increased significantly at the final follow-up.The changes were significant between the two groups(P<0.05).The ROM of the all upper segment increased significantly at the final follow-up in PLIF groups(P<0.05),but there was no significantly difference in the Dynesys group(P>0.05).The ROM of the L1-S1 was significantly lower than preoperation in PLIF group(P<0.05),but there was no significant in Dynesys groups.The final follow-up of surgical segment disc height in the Dynesys group was significantly lower than before the operation(P<0.05),while the PLIF group was no significant than preoperation(P>0.05).There was significant difference of intervertebral height of adjacent segments between the preoperative and final follow-up in PLIF group(P>0.05).Surgical segmental lordosis in Dynesys group at the final follow-up were significantly decreased(P<0.05).Pearson correlation analysis showed that there was correlation between L1-S1 ROM,lumbar lordosis,the surgical segment ROM of Dynesys group and ODI(P<0.05).According to University of California at Los Angeles Grading Scale,there were 11 cases in the Dynesys group and 43 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.Conclusion: The results of clinical follow-up showed that Dynesys was effective for the treatment of lumbar disc herniation.The improvement of ODI score is better than that of the PLIF.Compared with PLIF,Dynesys could retain the motion of the surgical segment and reduce the adjacent segments degeneration.Dynesys is superior to PLIF in improving the range of motion of the lumbar spine after operation.However,PLIF is superior to Dynesys dynamic internal fixation in maintaining lumbar lordosis and intervertebral space height of surgical segmental.Keeping operative range of motion,improving the lumbar overall range of motion and maintaining the lumbar lordosis play a positive role in the improvement of clinical outcomes(ODI).