title: Sagittal translation in opening wedge osteotomy for the correction of thoracolumbar kyphotic deformity in ankylosing spondylitis.
abstract: METHODS
  Retrospective.
  
  
  OBJECTIVE
  To document sagittal translation (ST) of the vertebral column in opening wedge osteotomy (OWO) for ankylosing spondylitis (AS) kyphosis.
  
  
  BACKGROUND
  Surgeons recognize displacement at the hinge of correction in OWO as an accidental event between the vertebrae on the side of OWO rather than ST of the cranial or caudal vertebral column. No report documents ST in this context.
  
  
  METHODS
  We evaluated radiographic and clinical results in 127 patients (aged 17-49 years) for ST, or displacement of more than 2 mm between the cranial and caudal vertebral columns at the OWO level, over 5 years.
  
  
  RESULTS
  Thirty-four (27%) patients had ST. In 31 (94%), the kyphotic apex was at T11 to L4. ST was positively correlated with the correction of lumbar lordosis and preoperative lumbar kyphosis. Five (15%) of 34 patients with ST had neurologic complications compared with 2 (2%) of 93 who did not.
  
  
  CONCLUSIONS
  ST is a basic mechanism for correcting sagittal imbalance and is likely to occur when the level of OWO is near the apex of deformity. Patients needing more correction of lumbar lordosis than others for best correction of sagittal imbalance need ST more to join the mechanism of correction.
authors.affiliation: Taiwan Spine Center and Department of Orthopaedic Surgery, Armed Forces Taichung General Hospital, Taiwan, Republic of China. iscspine@ms45.url.com.tw
authors.forename: Kao-Wha
authors.initials: KW
authors.lastname: Chang
authors.forename: Hung-Chang
authors.initials: HC
authors.lastname: Chen
authors.forename: Ying-Yu
authors.initials: YY
authors.lastname: Chen
authors.forename: Chien-Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Hsiang-Lan
authors.initials: HL
authors.lastname: Hsu
authors.forename: You-Hong
authors.initials: YH
authors.lastname: Cai
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D007796:Laminectomy; D008141:Lordosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010027:Osteotomy / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications; D011843:Radiculopathy / Q000209:etiology / Q000503:physiopathology; D011859:Radiography; D012189:Retrospective Studies; D013119:Spinal Cord Injuries / Q000209:etiology / Q000503:physiopathology; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*