Department of Orthopaedic Surgery，The 3rd Affiliated Hospital of Southern Medical University，510063，Guangzhou，China

English Keywords:Polymethylmethacrylate  Pedicle screw  Osteoporosis  Lumbar instability  Augmentation

English Abstract:

  【Abstract】 Objective：To determine the clinic efficacy of PMMA augmented pedicle screw instrumentation for degenerative lumbar instability.Method：From March 2002 to June 2007，23 cases with degenerative lumbar instability undergoing PMMA augmented pedicle screw instrumentation were included in this study.There were 6 males and 17 females，with the average age of 71 years（range，62-77 years）.Preoperative bone density and maximum screw insertion torque was measured.Pedicle screw were augmented with PMMA and 10 minute later the insertion torque was measured again，which was followed by decompression and bone graft．Result：All patients were followed up for 7-24 months and no peripheral complications were noted．The improving rate of lower back pain and neurological deficits was 87%．The screw insertion torque enhanced from 0.591±0.213N·m to 1.332±0.377N·m after augmentation，which showed significant difference（P<0.01）．PMMA distribution around screw was noted with no leakage．Conclusion：PMMA augmented pedicle screw instrumentation　enhance the screw strength significantly，and the appropriate surgical maneuver is critical to ensure a good prognosis.