A Comparative Study On The Different Of Strengthen Pedicle Screw Fixation In The Lumbar Degenerative Disease Of Osteoporosis

ObjectiveTo compare the clinical effects of three types of surgical technique:pedicle screws with no combined materials, traditional polymethylmethacrylate (PMMA) bone cement combined pedicle screws and injectable calcium sulfate cement (CSC) combined pedicle screws on osteoporosis lumbar.MethodsIt was a retrospective study about36patients diagnosed with osteoporosis BMD between-2.5SD to-4.4SD (the average was-2.9±0.4SD), which with lumbar spinal instability, lumbar spinal stenosis and lumbar spondylolisthesis from May2008to May2010. All patients were divided into three groups:traditional PMMA bone cement group, calcium sulfate bone cement group, and pure pedicle screws internal fixation group according to their operation methods. Each group contained12patients. We used PMMA bone cement and injectable calcium sulfate cement to strengthen the pedicle screws in the1st and the2nd group. In the3rd group, we simply used pedicle screws to fix vertebrae. We observed pedicle screws’ implant torsion changing, evaluated the VAS score, JOA score and JOA improvement rate and reviewed X-ray, CT results of the patients at1week,2months,12months after the operations to observe the presence of screw displacement, loose, or fall off.ResultWe observed sulfate bone cement group pedicle screws’ implant torsion changing, evaluated the VAS score, JOA score and JOA improvement rate. There was no statistically significant difference between these two groups (P＞0.05). But the result of these two groups was obviously better than the pure osteoporosis group, which had statistically significant difference (P＜0.05). There was one patient in the simple pedicle screw internal fixation group had screw location change, a pedicle screw loosening, pulling out. The other patients’ pedicle screw position was good. Most of the calcium sulfate bone cement had been absorbed, and the degradation surrounding bone growth was good after12months postoperatively. The PMMA group and CSC group had the similar clinical effect. But PMMA had no degradation and osteoinductive activity, biological tissue compatibility was also poor. The bone cement existed in vivo lasting long time. It could cause nerve damage and pulmonary embolism possibility during operation due to bone cement leakage. Due to its vertebral strengthening after vertebral strength increase, it could cause vertebral bodies in adjacent segment fractures. At the same time for pedicle screw loosening and fracture patients, taking out nail in surgery repair is difficult. It would cause osteoporosis vertebral body damage easily, even broken fracture.ConclusionsThe application of injectable calcium sulfate combined pedicle screw for lumbar vertebra internal fixation is easy and convenient to operation. It can obtain the strengthen of holding power instantly during the operation. It can complete reset and fixation successfully, and maintain a stable internal fixation after a long time.It has good biological histocompatibility, no thermal polymerization. Its advantages include biodegradable postoperatively, inducing new bone formation, etc. So its clinical effect is good.