title: Injectable form of calcium sulphate as treatment of aneurysmal bone cysts.
abstract: BACKGROUND
  Aneurysmal bone cysts (ABC) are a rare condition in adolescents and teenagers but may result in pain, fracture and growth abnormalities. The gold standard of open curettage carries the risk of surgical complications and still a local recurrence rate of 20-30%. Percutaneous treatment of ABC have rarely been reported and a poor response the usual outcome. This study investigated a new technique of percutaneous aspiration and injection of ABC using an aqueous solution of calcium sulphate.
  
  
  METHODS
  A radiological diagnosis of a bone cyst was made in 15 consecutive patients and pathologically confirmed as ABC. Most had already sustained a fracture and/or had been previously unsuccessfully treated by minimally invasive techniques including embolization or methylprednisolone injection. The procedure of aspiration and injection with calcium sulphate was undertaken, and the patients were reviewed regularly both clinically and radiologically for a minimum of 2 years.
  
  
  RESULTS
  The calcium sulphate cement was reabsorbed completely within 8 weeks. The first osseous response was periosteal new bone formation circumferentially followed by gradual opacification of the cystic cavity. All except one patient that described pain before the procedure reported complete relief of symptoms by 4 weeks. Two patients developed a local recurrence of the cyst, and one subsequently developed a pathological fracture. Two patients sustained pathological fractures through healed cysts, 12 and 22 months after the procedure, respectively.
  
  
  CONCLUSIONS
  This new technique has shown good early clinical and radiological responses and a low complication rate in a consecutive group of patients with ABC.
authors.affiliation: South Australian Musculoskeletal Tumour Unit, Adelaide, South Australia, Australia. mclayer@mail.rah.sa.gov.au
authors.forename: Mark
authors.initials: M
authors.lastname: Clayer
mesh_terms: D000293:Adolescent; D000328:Adult; D001843:Bone Cements; D017824:Bone Cysts, Aneurysmal / Q000628:therapy*; D002133:Calcium Sulfate / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004322:Drainage; D005260:Female; D006801:Humans; D015552:Injections, Intralesional; D008297:Male
chemical_list: D001843:Bone Cements; D002133:Calcium Sulfate