title: Polyaxial screws for lumbo-iliac fixation after sacral tumor resection: experience with a new technique for an old surgical problem.
abstract: BACKGROUND
  Although numerous reports have been published about various methods for reconstruction after sacrectomies, there are still biomechanical and technical dilemmas that are unaddressed. This report describes the experience at authors' institution of five cases in which polyaxial pedicle screws construct has been successfully used for lumbo-iliac fixation after sacral tumor resection.
  
  
  METHODS
  Five cases of sacral tumors, two of Ewing's sarcoma and three of giant cell tumor (GCT) underwent surgical resection and then reconstruction was done with hardware using vertical rods placed alongside the spine bilaterally, transfixing monoaxial and polyaxial pedicle screws in lower lumbar levels and polyaxial screws into the ilium bilaterally. Cross links were also used to connect the two vertical members, thus enhancing biomechanical stability of the construct. Use of autologous bone grafts was relied upon to fill the gap created by sacral resection.
  
  
  RESULTS
  No instrumentation failure was noted and the continuity of the spine and pelvis was well established with the instrumentation and auto grafts. In follow up of these patients (1-3 years), no complications were seen.
  
  
  CONCLUSIONS
  Polyaxial pedicle screws fixation is an effective technique to transmit axial load from spine to the appendicular bone and can be used safely in patients in whom sacral integrity is compromised after surgical resection. However, the long term benefits of this technique need to be evaluated.
authors.affiliation: Department of Surgery, Aga Khan University Hospital, Karachi, Pakistan.
authors.forename: Syed Faraz
authors.initials: SF
authors.lastname: Kazim
authors.forename: Syed Ather
authors.initials: SA
authors.lastname: Enam
authors.forename: Imtiaz
authors.initials: I
authors.lastname: Hashmi
authors.forename: Riaz Hussain
authors.initials: RH
authors.lastname: Lakdawala
mesh_terms: D000293:Adolescent; D000328:Adult; D001863:Bone Screws; D018286:Carcinoma, Giant Cell / Q000473:pathology / Q000601:surgery; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007085:Ilium / Q000601:surgery; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D009367:Neoplasm Staging; D019651:Plastic Surgery Procedures / Q000295:instrumentation* / Q000379:methods; D018570:Risk Assessment; D012447:Sacrum / Q000473:pathology / Q000601:surgery*; D012494:Sampling Studies; D012512:Sarcoma, Ewing / Q000473:pathology / Q000601:surgery; D013125:Spinal Neoplasms / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome