A Comparative Study Between Dynamic Internal Fixation (Dynesys) And Posterior Lumbar Interbody Fusion In Treating Lumbar Spinal Stenosis

Objective: To compare the effectiveness and radiological changes aftermonosegmental posterior dynamic stabilization and lumbar fusion for lumbar spinalstenosis．Methods: Between August2008and March2011, a comparative study was carried outon patients with lumbar spinal stenosis at L4/5. In group A,12patients underwent posteriordecompression combined with Dynesys; there were5males and7females with an averageage of53.9years (range,30-68years); In group B,12patients underwent posteriordecompression combined with posterior lumbar interbody fusion treatment; there were7males and5females with an average age of55.7years (range,44-72years); There were nosignificant difference in gender and age. Observe two groups operative time, blood lossand incision length. Clinical outcomes were evaluated using Oswestry Disability Index(ODI), Visual Analogue Scale (VAS) score and Japanese Orthopaedic Association (JOA)before and after operation. Imaging examinations for the relative height of intervertebral,segmental movement and degeneration were obtained．Results: The average follow-up was18.9months in group A and16.9months in groupB. The sex and age of two groups were no difference on statistics (P﹥0.05). All casesobtained preferably clinical effect after the operation. The symptoms, signs beforeoperation were released, and clinical choiceness rate of two groups had no difference onstatistics(P﹥0.05). There were significant difference between two groups of blood loss andoperative time (P<0.05) and no significant difference between two groups of incisionlength (P﹥0.05). At the last follow-up, the VAS, JOA scores, and ODI of groups A and Bwere significantly improved when compared with the preoperative values (P<0.05). Therelative height of intervertebral of L4/5of group A was improved remarkably from33.25±5.19%preoperatively to43.17±5.34%postoperatively. While the group B was increased from32.67±5.31%to44.83±5.11%. There was significant difference in therelative height of intervertebral of L4/5of groups A and B between pre-and post-operation(P<0.05). There were no significant difference in the intervertebral height in each timebetween groups A and B (P﹥0.05). There was no significant difference in the ROM ofL3/4in group A between pre-and post-operation (P>0.05). In group B, the ROM of L3/4was significantly reduction (P<0.05) compared with the preoperative one. Compared withpreoperative the ROM of L4/5in group A was significantly reduction (P<0.05), and itachiecved bone fusion in the group B at last follow-up. There was no significant differencein the ROM of L5S1in group A between pre-and post-operation (P>0.05). There were nosignificant difference in the ROM of L3/4and L5S1in each time between groups A and B(P﹥0.05). There was no significant difference in the complications in groups A and B atpostoperation(P>0.05).Conclusion: Posterior decompression combined with Dynesys has the sameeffectiveness as posterior lumbar interbody fusion in treating lumbar spinal stenosis at L4/5.But the former has less invasive, shoter time and little hemorrhage, and it can provideenough stability, delay and prevent the adjacent segments degeneration.