Medium And Long Term Effect Of Posterolateral Fusion And Pedicle Screw Fixation For Lumbar Spondylolisthesis

【Objective】To evaluate the outcome of lumbar spondylolisthesis treated with pedicle screw system and posterolateral fusion retrospectively, and to analyse the influential factors of curative effect.【Methods】From 1995 to 2005, there were thirty-six grade I or II spondylolythsis cases with complete clinical data who underwent pedical screw fixation and posterolateral fusion.JOA, VAS,ODI and radiological evaluation system were used. We compared curative effect with the radiological change(rate of spondylolythsis,,segmental lordosis, lumbar lordosis), and analyse the relationship between intervertebral space height and improvement rate of JOA.The related factors(grade of spondylolythsis, classification of spondylolythsis, associated symptom, condition of nerve root, number of fixation segment, fixation segment, decompression, history of back muscle execise, fusion) of surgical curative effect and causes of surgical complication were also analysed.【Results】Thirty-six patients were followed up for an average of 47.6 months(36 months-120 months). According to the JOA evaluation systerm analysis the outcome of before and after operation in 36 cases the recoverty rate was 82.2%±14.4%. ODI score improved significantly from 65.1±19.7 preoperatively to 10.7±11.3 at follow-up. The relative height of intervertebral restored from 36.4%±9.1% to 45.9%±7.6% postoperatively and 38.2%±9.4% at last follow-up.Comparison of pre- and post operative slip showed a postoperative correction rate of 67.2%±36.1%, and 59.5%±34.9% at follow-up.the disc space height and lumbar lordosis increased.During the perived of follow-up,recumence of deformity was found. Solid fusion was obtained in 72.2% of patients,Screw broken rate was 2.8%.There were 3ecases of intraoperative nerve root injury and 7cases of degeneration of adjacent segments. Multivariate linear regression showed history of back muscle exercise and and fusion were relative factors of improvement of JOA.【Conclusion】The mid-long period outcome of fixation of pedical screw and posterolateral fusion is satisfactory, and related with the history of back muscle exercises and fusion condition.