title: Timing of osteotomy for thoracolumabar or lumbar kyphosis secondary to ankylosing spondylitis.
abstract: OBJECTIVE
  Ankylosing spondylitis may lead to a rigid thoracolumbar kyphotic deformity. Several authors have reported the results of patients treated by a lumbar osteotomy, but there is no consensus on the level of the osteotomy and on timing of osteotomy. The purpose of this study is to explore timing of osteotomy for thoracolumabar or lumbar kyphosis secondary to ankylosing spondylitis by analyzing the natural history of 78 AS patients.
  
  
  METHODS
  To analyze the factors related to influence the timing of osteotomy for thoracolumabar or lumbar kyphosis secondary to ankylosing spondylitis. Patient Sample There were 78 patients including 69 male and 9 female; the mean age at the time of surgery was 38 years (range, 22-56 years). The characteristic of natural history of these 78 patients is lumbar pain stage, slowly progressive kyphosis stage, accerlated progressive kyphosis stage, stabilized kyphosis stage. The average preoperative deformity was 61 degrees (range, 40 degrees to 87 degrees). Twenty-eight patients underwent V shape osteotomy, and 50 patients underwent transpedicular osteotomy.
  
  
  RESULTS
  The average age of occurrence of lumbar pain symptom is 21 years,the average duration of slowly progressive kyphosis stage is 3 years (range, 1 to 8 year), and the average duration of accerlated progressive kyphosis stage is 4 (range, 2 to 10 year). The patients were followed up for a period of 4-60 months (mean 49 months). The total correction postoperatively was 40 degrees +/-11 degrees, the average loss of correction was 5 degrees at the final follow-up. Excellent results were obtained in 74 patients (95%), and good results were obtained in 4 patients (5%), there were no fair or poor results.
  
  
  CONCLUSIONS
  Lumbar pain arrests for more than 6 months (exclusive of mechanical pain of lumbar), normal blood sedimentation rate continues for two times, and reactive protein is negative. These factors must be considered in timing of osteotomy for thoracolumabar or lumbar kyphosis secondary to ankylosing spondylitis.
authors.affiliation: Spine Surgery, Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, China.
authors.forename: Bang-ping
authors.initials: BP
authors.lastname: Qian
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
mesh_terms: D000328:Adult; D002681:China; D005260:Female; D006801:Humans; D007738:Kyphosis; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D012600:Scoliosis; D013167:Spondylitis, Ankylosing / Q000601:surgery*; D013997:Time Factors