title: Outcome of pedicle subtraction osteotomies for fixed sagittal imbalance of multiple etiologies: a retrospective review of 140 patients.
abstract: METHODS
  A retrospective study.
  
  
  OBJECTIVE
  To evaluate the efficacy and safety of the pedicle subtraction osteotomy (PSO) as a technique for correction of fixed sagittal imbalance with multiple etiologies.
  
  
  BACKGROUND
  This report represents the largest and longest series of patients with fixed sagittal imbalance other than ankylosing spondylitis who were managed with PSO.
  
  
  METHODS
  A total of 140 consecutive patients who had undergone PSO for the management of sagittal imbalance with any etiology were reviewed. Etiologic diagnoses were ankylosing spondylitis in 86 patients, flatback syndrome in 20, post-traumatic kyphosis in 17, congenital kyphoscoliosis in 9, and post-tuberculotic kyphosis in 8 patients. The average duration of the follow-up period was 8 years (range, 5-12.5 yr). Radiological and clinical outcome analyses were performed.
  
  
  RESULTS
  All patients showed a solid union upon follow-up radiographs and no pseudarthrosis was noted. Correction with PSO averaged 36.2°. Blood loss averaged 1515.6 mL. The Oswestry Disability Index improved from 40.5 to 18.8 at the last follow-up, and 90.7% of the patients were very or somewhat satisfied. There were 15 cases (10.7%) of reversible complications including transient radiculopathy and 3 cases (2.1%) of irreversible complications.
  
  
  CONCLUSIONS
  Based on the results of this study, PSO is considered a reliable and relatively safe procedure for the correction of fixed sagittal imbalance with multiple etiologies.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Kyung Hee University, Seoul, Korea.
authors.forename: Ki-Tack
authors.initials: KT
authors.lastname: Kim
authors.forename: Sang-Hun
authors.initials: SH
authors.lastname: Lee
authors.forename: Kyung-Soo
authors.initials: KS
authors.lastname: Suk
authors.forename: Jung-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Bi-O
authors.initials: BO
authors.lastname: Jeong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016063:Blood Loss, Surgical; D001863:Bone Screws; D055111:Failed Back Surgery Syndrome / Q000601:surgery; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009989:Orthotic Devices; D010027:Osteotomy / Q000379:methods / Q000706:statistics & numerical data*; D011187:Posture; D012189:Retrospective Studies; D012600:Scoliosis / Q000601:surgery; D013122:Spinal Diseases / Q000601:surgery*; D013167:Spondylitis, Ankylosing / Q000601:surgery; D055815:Young Adult