title: A new technique of bone cement augmentation via the disc space for percutaneous pedicle screw fixation.
abstract: OBJECTIVE
  In elderly patients with severe osteoporosis, instrumented lumbar interbody fusion may result in fixation failure or nonunion because of decreased pedicle screw pullout strength or increased interbody graft subsidence risk. Thus, given its many advantages, percutaneous pedicle screw fixation with cement augmentation can be an effective method to use in elderly patients. The authors report on an easy, safe, and economical technique for bone cement augmentation using a bone biopsy needle inserted into the disc space in 2 osteoporotic patients who were treated with posterior interbody fusion and percutaneous pedicle screw fixation.
  
  
  METHODS
  Two elderly patients who complained of back pain and intermittent neurological claudication underwent posterior interbody fusion with percutaneous pedicle screw fixation. After routinely assembling rods on the screws, a bone biopsy needle was inserted into the disc space via the operative field; the needle was then placed around the tips of the screws using fluoroscopic radiography for guidance. Bone cement was injected through the bone biopsy needle, also under fluoroscopic radiography guidance.
  
  
  RESULTS
  Both patients' symptoms improved after the operation, and there was no evidence of cage subsidence or screw loosening at the 4-month follow-up.
  
  
  CONCLUSIONS
  The indirect technique of bone cement augmentation via the disc space for percutaneous screw fixation could be an easy, safe, and economical method.
authors.affiliation: Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea.
authors.forename: Chang Kyu
authors.initials: CK
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea.
authors.forename: Choon Keun
authors.initials: CK
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea.
authors.forename: Dong Chan
authors.initials: DC
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea.
authors.forename: Dong Geun
authors.initials: DG
authors.lastname: Lee
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008422:Materials Testing; D010024:Osteoporosis / Q000601:surgery; D065289:Pedicle Screws; D019904:Polymethyl Methacrylate / Q000627:therapeutic use*; D013123:Spinal Fusion / Q000379:methods
chemical_list: D001843:Bone Cements; D019904:Polymethyl Methacrylate
keywords: DEXA = dual-energy x-ray absorptiometry; PMMA = polymethylmethacrylate; QCT = quantitative CT; bone cement augmentation; disc space; percutaneous pedicle screw fixation; posterior lumbar interbody fusion; technique