title: Analysis of Sagittal Parameters in Patients Undergoing One- or Two-Level Closing Wedge Osteotomy for Correcting Thoracolumbar Kyphosis Secondary to Ankylosing Spondylitis.
abstract: METHODS
  Retrospective analysis of clinical records.
  
  
  OBJECTIVE
  To assess and compare the improvement in sagittal balance after one- or two-level closing wedge osteotomy for correcting thoracolumbar kyphosis secondary to ankylosing spondylitis (AS).
  
  
  BACKGROUND
  Closing wedge osteotomy represents a common approach to correct kyphosis in AS. Although several reports have described the outcomes of one- or two-level closing wedge osteotomy in terms of sagittal parameters, data comparing the outcomes of these procedures are scarce.
  
  
  METHODS
  Between January 2010 and December 2014, 22 patients with AS underwent closing wedge osteotomy (one-level, 12 patients; two-level, 10 patients) for correcting thoracolumbar kyphosis (mean follow-up, 24.8 months; range, 12-60 months). Preoperative and postoperative chin-brow vertical angle, and the sagittal parameters of the vertebral osteotomy segment were documented and compared. Perioperative and postoperative complications were also recorded.
  
  
  RESULTS
  The chin-brow vertical angle improved significantly, from 55.0° ± 27.3° to 4.7° ± 4.9° and from 38.2° ± 14.9° to 3.2° ± 5.4° in the one-level and two-level groups, respectively. The total correction (thoracic kyphosis and lumbar lordosis) was 32.8° ± 18.2° and 53.7° ± 9.4° in the one-level and two-level groups, respectively. No death, complete paralysis, or vascular complications occurred during the procedure, but cerebrospinal fluid leak was noted in one and two patients from the one-level and two-level groups, respectively. A distal pedicle screw adjacent to the osteotomy segment became loose during surgery in one patient (one-level group). Postoperatively, no transient neurological deficit, infection, delay union, or loosening or breaking of the internal fixation devices was observed. Osteotomy site fusion was achieved in all patients, and the Oswestry Disability Index scores improved significantly.
  
  
  CONCLUSIONS
  Closing wedge osteotomy is effective and safe for correcting thoracolumbar kyphosis in patients with AS. Significant correction and improvement in all sagittal parameters were noted in both groups, but two-level closing wedge osteotomy provided better correction.
  
  
  METHODS
  3.
authors.affiliation: Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Hua
authors.forename: Yu-Kun
authors.initials: YK
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Gao
authors.forename: Xian-Zhe
authors.initials: XZ
authors.lastname: Liu
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Yang
authors.forename: Xing-Huo
authors.initials: XH
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Cao
authors.initials: C
authors.lastname: Yang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D012189:Retrospective Studies; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D055815:Young Adult