Application Of Expandable Pedicle Screws In Osteoporotic Lumbar Spinal Fixation

Objective:To evaluate the reliability and clinical efficacy of expandable pedicle screw (EPS) affixation for thoracolumbar patients afflicted with osteoporosis.Method:A retrospective analysis was adopted. For at least twelve months from January 2008 to May 2010,56 thoracolumbar patients with osteoporosis were treated and regularly monitored; of them,25 were male,31 female, and aged 45 to 72 years, with an average age of 61.3 years. For these patients, the course of the disease was between 2 months and 5 years, with an average course of 13.5months; Among the 56 patients, lumbar disc herniation 9 cases, lumbar spine canal stenosis 14 cases, lumbar spondylolisthesis 16 cases, lumbar tuberculosis 6 cases, lumbar compression fractures 7 cases, and revision surgery 4 cases. Among the patients with spondylothisthesis,7 were in the 1st degree,6 were in the 2nd degree, and 3 were in the 3rd degree. All patients underwent bone mineral density testing before surgery, which indicated bone mass density averaging 2.7 standard deviations below the norm. The patients were divided into two groups,28 patients with EPS posterior spinal fixation,28 patients with conventional posterior spinal fixation, Efficacy of the surgery was evaluated using a pain visual analogue scale (visual analogue scale, VAS), modified Prolo functional scores and X rays, and CT and other imaging assessments of screw stability and integration.Result:All patients were observed for 15 to 24 months post operation, for an average of 18 months. Both VAS and modified Prolo functional scores showed a significant improvement 3 months after operation,6 months after operation, and 12 months after operation. One year after operation in EPS,85.7% of the screw placements were stable, and the spinal fusion rate was 85.7%. One year after operation in CPS,60.0% of the screw placements were stable, and the spinal fusion rate was 85.0%. Eight patients (33.3%) developed complications (including systemic complications and spine-specific complications),22 cases (45.8%) required blood transfusions, and 1 patient's EPS broke during the process of removal.Conclusion:For thoracolumbar patients suffering from severe osteoporosis, EPS may be simpler and more effective than other forms of screw fixation. EPS fixation is on average stronger and can solve several postoperative problems such as screw loosening and screw loss.Decreased rate of postoperative complications is especially important due to the fact that osteoporosis patients with spinal disease are typically older and more susceptible to complications. Age of the patient should be paid close attention.